Van der Waals potential and vibrational energy levels of the ground state radon dimer
Sheng, Xiaowei; Qian, Shifeng; Hu, Fengfei
2017-08-01
In the present paper, the ground state van der Waals potential of the Radon dimer is described by the Tang-Toennies potential model, which requires five essential parameters. Among them, the two dispersion coefficients C6 and C8 are estimated from the well determined dispersion coefficients C6 and C8 of Xe2. C10 is estimated by using the approximation equation that C6C10/C82 has an average value of 1.221 for all the rare gas dimers. With these estimated dispersion coefficients and the well determined well depth De and Re the Born-Mayer parameters A and b are derived. Then the vibrational energy levels of the ground state radon dimer are calculated. 40 vibrational energy levels are observed in the ground state of Rn2 dimer. The last vibrational energy level is bound by only 0.0012 cm-1.
Effendi Tri Bahtiar; Naresworo Nugroho; Dede Hermawan; Wilis Wirawan; Khuschandra
2018-01-01
Periodical control and measurement revealed that vibration level of motor and gearbox which was supported by Cooling Tower Unit 1 at PT Star Energy Geothermal (Wayang Windu) Ltd was significantly increasing since 2013. The vibration was not caused by machinery component failure, but induced by resonance of process flow. Decreasing stiffness of cooling tower structure was suspected causing the increasing vibration level. The physical, chemical, and mechanical properties of wood was deteriorate...
Yu, Hua-Gen; Han, Huixian; Guo, Hua
2016-04-14
Vibrational energy levels of the ammonium cation (NH4(+)) and its deuterated isotopomers are calculated using a numerically exact kinetic energy operator on a recently developed nine-dimensional permutation invariant semiglobal potential energy surface fitted to a large number of high-level ab initio points. Like CH4, the vibrational levels of NH4(+) and ND4(+) exhibit a polyad structure, characterized by a collective quantum number P = 2(v1 + v3) + v2 + v4. The low-lying vibrational levels of all isotopomers are assigned and the agreement with available experimental data is better than 1 cm(-1).
International Nuclear Information System (INIS)
Wang Guang-Qing; Liao Wei-Hsin
2015-01-01
This work focuses on how to maintain a high-energy orbit motion of a bistable oscillator when subjected to a low level excitation. An elastic magnifier (EM) positioned between the base and the bistable oscillator is used to magnify the base vibration displacement to significantly enhance the output characteristics of the bistable oscillator. The dimensionless electromechanical equations of the bistable oscillator with an EM are derived, and the effects of the mass and stiffness ratios between the EM and the bistable oscillator on the output displacement are studied. It is shown that the jump phenomenon occurs at a lower excitation level with increasing the mass and stiffness ratios. With the comparison of the displacement trajectories and the phase portraits obtained from experiments, it is validated that the bistable oscillator with an EM can effectively oscillate in a high-energy orbit and can generate a superior output vibration at a low excitation level as compared with the bistable oscillator without an EM. (paper)
Directory of Open Access Journals (Sweden)
Effendi Tri Bahtiar
2018-06-01
Full Text Available Periodical control and measurement revealed that vibration level of motor and gearbox which was supported by Cooling Tower Unit 1 at PT Star Energy Geothermal (Wayang Windu Ltd was significantly increasing since 2013. The vibration was not caused by machinery component failure, but induced by resonance of process flow. Decreasing stiffness of cooling tower structure was suspected causing the increasing vibration level. The physical, chemical, and mechanical properties of wood was deteriorated. The residual strength of the wood had been measured and the data was used to perform dynamic structural analysis on the cooling tower. Several scenarios of structure modification were modelled and drawn, and the best one which the most effectively reducing the vibration level among others was constructed in the field. Triangle inner structure was chosen and applied to modify the cooling tower structure to achieve stiffer and more rigid structure. The vibration level before and after structure modification were measured, and it was proved that the vibration level was significantly reduced after structure modification. Furthermore the cooling tower was not in zone D (danger anymore and the vibration level was accepted according to ISO 10816-3. Keywords: Cooling tower, Dynamic structural analysis, Geothermal power plant, Structural failure, Vibration level
Review of Energy Harvesters Utilizing Bridge Vibrations
Directory of Open Access Journals (Sweden)
Farid Ullah Khan
2016-01-01
Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.
Dral, Pavlo O.; Owens, Alec; Yurchenko, Sergei N.; Thiel, Walter
2017-06-01
We present an efficient approach for generating highly accurate molecular potential energy surfaces (PESs) using self-correcting, kernel ridge regression (KRR) based machine learning (ML). We introduce structure-based sampling to automatically assign nuclear configurations from a pre-defined grid to the training and prediction sets, respectively. Accurate high-level ab initio energies are required only for the points in the training set, while the energies for the remaining points are provided by the ML model with negligible computational cost. The proposed sampling procedure is shown to be superior to random sampling and also eliminates the need for training several ML models. Self-correcting machine learning has been implemented such that each additional layer corrects errors from the previous layer. The performance of our approach is demonstrated in a case study on a published high-level ab initio PES of methyl chloride with 44 819 points. The ML model is trained on sets of different sizes and then used to predict the energies for tens of thousands of nuclear configurations within seconds. The resulting datasets are utilized in variational calculations of the vibrational energy levels of CH3Cl. By using both structure-based sampling and self-correction, the size of the training set can be kept small (e.g., 10% of the points) without any significant loss of accuracy. In ab initio rovibrational spectroscopy, it is thus possible to reduce the number of computationally costly electronic structure calculations through structure-based sampling and self-correcting KRR-based machine learning by up to 90%.
Directory of Open Access Journals (Sweden)
Congcong Cheng
2016-01-01
Full Text Available A practical piezoelectric vibration energy harvesting (PVEH system is usually composed of two coupled parts: a harvesting structure and an interface circuit. Thus, it is much necessary to build system-level coupled models for analyzing PVEH systems, so that the whole PVEH system can be optimized to obtain a high overall efficiency. In this paper, two classes of coupled models are proposed by joint finite element and circuit analysis. The first one is to integrate the equivalent circuit model of the harvesting structure with the interface circuit and the second one is to integrate the equivalent electrical impedance of the interface circuit into the finite element model of the harvesting structure. Then equivalent circuit model parameters of the harvesting structure are estimated by finite element analysis and the equivalent electrical impedance of the interface circuit is derived by circuit analysis. In the end, simulations are done to validate and compare the proposed two classes of system-level coupled models. The results demonstrate that harvested powers from the two classes of coupled models approximate to theoretic values. Thus, the proposed coupled models can be used for system-level optimizations in engineering applications.
Adaptive learning algorithms for vibration energy harvesting
International Nuclear Information System (INIS)
Ward, John K; Behrens, Sam
2008-01-01
By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as human movement, wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilize a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaptation to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using an off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27–34%
International Nuclear Information System (INIS)
Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Carleer, Michel R.; Csaszar, Attila G.; Gamache, Robert R.; Hodges, Joseph T.; Jenouvrier, Alain; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Toth, Robert A.; Vandaele, Ann Carine; Zobov, Nikolai F.; Daumont, Ludovic; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Mikhailenko, Semen N.
2009-01-01
This is the first part of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, pressure dependence and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. The present article contains energy levels and data for line positions of the singly substituted isotopologues H 2 17 O and H 2 18 O. The procedure and code MARVEL, standing for measured active rotational-vibrational energy levels, is used extensively in all stages of determining the validated levels and lines and their self-consistent uncertainties. The spectral regions covered for both isotopologues H 2 17 O and H 2 18 O are 0-17125cm -1 . The energy levels are checked against ones determined from accurate variational calculations. The number of critically evaluated and recommended levels and lines are, respectively, 2687 and 8614 for H 2 17 O, and 4839 and 29 364 for H 2 18 O. The extensive lists of MARVEL lines and levels obtained are deposited in the Supplementary Material, as well as in a distributed information system applied to water, W-DIS, where they can easily be retrieved. A distinguishing feature of the present evaluation of water spectroscopic data is the systematic use of all available experimental data and validation by first-principles theoretical calculations.
International Nuclear Information System (INIS)
Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Al Derzi, Afaf R.; Fábri, Csaba; Fazliev, Alexander Z.; Furtenbacher, Tibor
2013-01-01
This is the third of a series of articles reporting critically evaluated rotational–vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational–vibrational transitions of the most abundant isotopologue of water, H 2 16 O. The latest version of the MARVEL (Measured Active Rotational–Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H 2 16 O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H 2 16 O containstwo components, an ortho (o) and a para (p) one. For o-H 2 16 O and p-H 2 16 O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000 K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184 667 of which 182 156 are validated: 68 027 between para states and 114 129 ortho ones. These transitions give rise to 18 486 validated energy levels, of which 10 446 and 8040 belong to o-H 2 16 O and p-H 2 16 O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a
Wideband Piezomagnetoelastic Vibration Energy Harvesting
DEFF Research Database (Denmark)
Lei, Anders; Thomsen, Erik Vilain
2014-01-01
This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation...... is achieved by placing the cantilever in a magnetic field induced by either one or two magnets located oppositely of the cantilever. The attraction force created by the magnetic field and iron foils introduces a mechanical force in opposite direction of the cantilevers restoring force causing a spring...
Calculations on the vibrational level density in highly excited formaldehyde
International Nuclear Information System (INIS)
Rashev, Svetoslav; Moule, David C.
2003-01-01
The object of the present work is to develop a model that provides realistic estimates of the vibrational level density in polyatomic molecules in a given electronic state, at very high (chemically relevant) vibrational excitation energies. For S 0 formaldehyde (D 2 CO), acetylene, and a number of triatomics, the estimates using conventional spectroscopic formulas have yielded densities at the dissociation threshold, very much lower than the experimentally measured values. In the present work we have derived a general formula for the vibrational energy levels of a polyatomic molecule, which is a generalization of the conventional Dunham spectroscopic expansion. Calculations were performed on the vibrational level density in S 0 D 2 CO, H 2 C 2 , and NO 2 at excitation energies in the vicinity of the dissociation limit, using the newly derived formula. The results from the calculations are in reasonable agreement with the experimentally measured data
Issues in vibration energy harvesting
Zhang, Hui; Corr, Lawrence R.; Ma, Tianwei
2018-05-01
In this study, fundamental issues related to bandwidth and nonlinear resonance in vibrational energy harvesting devices are investigated. The results show that using bandwidth as a criterion to measure device performance can be misleading. For a linear device, an enlarged bandwidth is achieved at the cost of sacrificing device performance near resonance, and thus widening the bandwidth may offer benefits only when the natural frequency of the linear device cannot match the dominant excitation frequency. For a nonlinear device, since the principle of superposition does not apply, the ''broadband" performance improvements achieved for single-frequency excitations may not be achievable for multi-frequency excitations. It is also shown that a large-amplitude response based on the traditional ''nonlinear resonance" does not always result in the optimal performance for a nonlinear device because of the negative work done by the excitation, which indicates energy is returned back to the excitation. Such undesired negative work is eliminated at global resonance, a generalized resonant condition for both linear and nonlinear systems. While the linear resonance is a special case of global resonance for a single-frequency excitation, the maximum potential of nonlinear energy harvesting can be reached for multi-frequency excitations by using global resonance to simultaneously harvest energy distributed over multiple frequencies.
Energy scavenging from environmental vibration.
Energy Technology Data Exchange (ETDEWEB)
Galchev, Tzeno (University of Michigan); Apblett, Christopher Alan; Najafi, Khalil (University of Michigan)
2009-10-01
The goal of this project is to develop an efficient energy scavenger for converting ambient low-frequency vibrations into electrical power. In order to achieve this a novel inertial micro power generator architecture has been developed that utilizes the bi-stable motion of a mechanical mass to convert a broad range of low-frequency (< 30Hz), and large-deflection (>250 {micro}m) ambient vibrations into high-frequency electrical output energy. The generator incorporates a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromagnetic scavenger. This frequency up-conversion technique enhances the electromechanical coupling and increases the generated power. This architecture is called the Parametric Frequency Increased Generator (PFIG). Three generations of the device have been fabricated. It was first demonstrated using a larger bench-top prototype that had a functional volume of 3.7cm3. It generated a peak power of 558{micro}W and an average power of 39.5{micro}W at an input acceleration of 1g applied at 10 Hz. The performance of this device has still not been matched by any other reported work. It yielded the best power density and efficiency for any scavenger operating from low-frequency (<10Hz) vibrations. A second-generation device was then fabricated. It generated a peak power of 288{micro}W and an average power of 5.8{micro}W from an input acceleration of 9.8m/s{sup 2} at 10Hz. The device operates over a frequency range of 20Hz. The internal volume of the generator is 2.1cm{sup 3} (3.7cm{sup 3} including casing), half of a standard AA battery. Lastly, a piezoelectric version of the PFIG is currently being developed. This device clearly demonstrates one of the key features of the PFIG architecture, namely that it is suitable for MEMS integration, more so than resonant generators, by incorporating a brittle bulk piezoelectric ceramic. This is the first micro-scale piezoelectric generator capable of <10Hz operation. The
Benefits of Spacecraft Level Vibration Testing
Gordon, Scott; Kern, Dennis L.
2015-01-01
NASA-HDBK-7008 Spacecraft Level Dynamic Environments Testing discusses the approaches, benefits, dangers, and recommended practices for spacecraft level dynamic environments testing, including vibration testing. This paper discusses in additional detail the benefits and actual experiences of vibration testing spacecraft for NASA Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL) flight projects. JPL and GSFC have both similarities and differences in their spacecraft level vibration test approach: JPL uses a random vibration input and a frequency range usually starting at 5 Hz and extending to as high as 250 Hz. GSFC uses a sine sweep vibration input and a frequency range usually starting at 5 Hz and extending only to the limits of the coupled loads analysis (typically 50 to 60 Hz). However, both JPL and GSFC use force limiting to realistically notch spacecraft resonances and response (acceleration) limiting as necessary to protect spacecraft structure and hardware from exceeding design strength capabilities. Despite GSFC and JPL differences in spacecraft level vibration test approaches, both have uncovered a significant number of spacecraft design and workmanship anomalies in vibration tests. This paper will give an overview of JPL and GSFC spacecraft vibration testing approaches and provide a detailed description of spacecraft anomalies revealed.
Review of magnetostrictive vibration energy harvesters
Deng, Zhangxian; Dapino, Marcelo J.
2017-10-01
The field of energy harvesting has grown concurrently with the rapid development of portable and wireless electronics in which reliable and long-lasting power sources are required. Electrochemical batteries have a limited lifespan and require periodic recharging. In contrast, vibration energy harvesters can supply uninterrupted power by scavenging useful electrical energy from ambient structural vibrations. This article reviews the current state of vibration energy harvesters based on magnetostrictive materials, especially Terfenol-D and Galfenol. Existing magnetostrictive harvester designs are compared in terms of various performance metrics. Advanced techniques that can reduce device size and improve performance are presented. Models for magnetostrictive devices are summarized to guide future harvester designs.
Electromagnetic Vibration Energy Harvesting for Railway Applications
Directory of Open Access Journals (Sweden)
Bradai S.
2018-01-01
Full Text Available Safe localization of trains via GPS and wireless sensors is essential for railway traffic supervision. Especially for freight trains and because normally no power source is available on the wagons, special solutions for energy supply have to be developed based on energy harvesting techniques. Since vibration is available in this case, it provides an interesting source of energy. Nevertheless, in order to have an efficient design of the harvesting system, the existing vibration needs to be investigated. In this paper, we focus on the characterization of vibration parameters in railway application. We propose an electromagnetic vibration converter especially developed to this application. Vibration profiles from a train traveling between two German cities were measured using a data acquisition system installed on the train’s wagon. Results show that the measured profiles present multiple frequency signals in the range of 10 to 50 Hz and an acceleration of up to 2 g. A prototype for a vibration converter is designed taking into account the real vibration parameters, robustness and integrability requirements. It is based on a moving coil attached to a mechanical spring. For the experimental emulation of the train vibrations, a shaker is used as an external artificial vibration source controlled by a laser sensor in feedback. A maximum voltage of 1.7 V peak to peak which corresponds to a maximum of 10 mW output power where the applied excitation frequency is close to the resonant frequency of the converter which corresponds to 27 Hz.
Vibrational and Rotational Energy Relaxation in Liquids
DEFF Research Database (Denmark)
Petersen, Jakob
Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...
Direct observation of vibrational energy dispersal via methyl torsions.
Gardner, Adrian M; Tuttle, William D; Whalley, Laura E; Wright, Timothy G
2018-02-28
Explicit evidence for the role of methyl rotor levels in promoting energy dispersal is reported. A set of coupled zero-order vibration/vibration-torsion (vibtor) levels in the S 1 state of para -fluorotoluene ( p FT) are investigated. Two-dimensional laser-induced fluorescence (2D-LIF) and two-dimensional zero-kinetic-energy (2D-ZEKE) spectra are reported, and the assignment of the main features in both sets of spectra reveals that the methyl torsion is instrumental in providing a route for coupling between vibrational levels of different symmetry classes. We find that there is very localized, and selective, dissipation of energy via doorway states, and that, in addition to an increase in the density of states, a critical role of the methyl group is a relaxation of symmetry constraints compared to direct vibrational coupling.
A Miniature Coupled Bistable Vibration Energy Harvester
International Nuclear Information System (INIS)
Zhu, D; Arthur, D C; Beeby, S P
2014-01-01
This paper reports the design and test of a miniature coupled bistable vibration energy harvester. Operation of a bistable structure largely depends on vibration amplitude rather than frequency, which makes it very promising for wideband vibration energy harvesting applications. A coupled bistable structure consists of a pair of mobile magnets that create two potential wells and thus the bistable phenomenon. It requires lower excitation to trigger bistable operation compared to conventional bistable structures. Based on previous research, this work focused on miniaturisation of the coupled bistable structure for energy harvesting application. The proposed bistable energy harvester is a combination of a Duffing's nonlinear structure and a linear assisting resonator. Experimental results show that the output spectrum of the miniature coupled bistable vibration energy harvester was the superposition of several spectra. It had a higher maximum output power and a much greater bandwidth compared to simply the Duffing's structure without the assisting resonator
High Energy Vibration for Gas Piping
Lee, Gary Y. H.; Chan, K. B.; Lee, Aylwin Y. S.; Jia, ShengXiang
2017-07-01
In September 2016, a gas compressor in offshore Sarawak has its rotor changed out. Prior to this change-out, pipe vibration study was carried-out by the project team to evaluate any potential high energy pipe vibration problems at the compressor’s existing relief valve downstream pipes due to process condition changes after rotor change out. This paper covers high frequency acoustic excitation (HFAE) vibration also known as acoustic induced vibration (AIV) study and discusses detailed methodologies as a companion to the Energy Institute Guidelines for the avoidance of vibration induced fatigue failure, which is a common industry practice to assess and mitigate for AIV induced fatigue failure. Such detailed theoretical studies can help to minimize or totally avoid physical pipe modification, leading to reduce offshore plant shutdown days to plant shutdowns only being required to accommodate gas compressor upgrades, reducing cost without compromising process safety.
Piezoelectric energy harvesting from broadband random vibrations
International Nuclear Information System (INIS)
Adhikari, S; Friswell, M I; Inman, D J
2009-01-01
Energy harvesting for the purpose of powering low power electronic sensor systems has received explosive attention in the last few years. Most works using deterministic approaches focusing on using the piezoelectric effect to harvest ambient vibration energy have concentrated on cantilever beams at resonance using harmonic excitation. Here, using a stochastic approach, we focus on using a stack configuration and harvesting broadband vibration energy, a more practically available ambient source. It is assumed that the ambient base excitation is stationary Gaussian white noise, which has a constant power-spectral density across the frequency range considered. The mean power acquired from a piezoelectric vibration-based energy harvester subjected to random base excitation is derived using the theory of random vibrations. Two cases, namely the harvesting circuit with and without an inductor, have been considered. Exact closed-form expressions involving non-dimensional parameters of the electromechanical system have been given and illustrated using numerical examples
Piezoelectric energy harvesting from broadband random vibrations
Adhikari, S.; Friswell, M. I.; Inman, D. J.
2009-11-01
Energy harvesting for the purpose of powering low power electronic sensor systems has received explosive attention in the last few years. Most works using deterministic approaches focusing on using the piezoelectric effect to harvest ambient vibration energy have concentrated on cantilever beams at resonance using harmonic excitation. Here, using a stochastic approach, we focus on using a stack configuration and harvesting broadband vibration energy, a more practically available ambient source. It is assumed that the ambient base excitation is stationary Gaussian white noise, which has a constant power-spectral density across the frequency range considered. The mean power acquired from a piezoelectric vibration-based energy harvester subjected to random base excitation is derived using the theory of random vibrations. Two cases, namely the harvesting circuit with and without an inductor, have been considered. Exact closed-form expressions involving non-dimensional parameters of the electromechanical system have been given and illustrated using numerical examples.
Collisional energy transfer between highly excited vibrational levels of K2 (11Σu+, V=46∼61) and H2
International Nuclear Information System (INIS)
Zhang Liping; Cai Qin; Luan Nannan; Dai Kang; Shen Yifan
2011-01-01
Using the CARS (Coherent Anti-stokes Raman Spectroscopy) detection technique, the electronic-to-rovibrational levels energy transfer between electronically excited K 2 (which is in the state of 1 1 ∑ u + , V=46∼61) and H 2 has been investigated. The scanned CARS spectra reveals that H 2 molecules are produced only at the V=1, J=2 and V=2, J=0, 1, 2 rovibrational levels during energy transfer processes. From scanned CARS spectral peaks the population ratios are obtained. The n 1 /n 4 9 n 2 /n 4 , and n 3 /n 4 are 3.3±0.5, 2.2±0.3 and 2.0±0.3, respectively, where n 1 , n 2 , n 3 and n 4 represent the number densities of H 2 at rovibrational levels (2, 0), (2, 1), (2, 2) and (1, 2), respectively. The population ratios indicate that the H 2 molecules produced by the energy transfer process are 88% populated at the V=2 level and 12% at V=1. The relative fractions (
Energy Technology Data Exchange (ETDEWEB)
Funaki, T.; Hayashi, S. [Osaka University, Osaka (Japan). Faculty of engineering
1996-12-31
It is known in estimating vibration characteristics of a ship that fluid range affects largely a structure. In order to analyze the compound vibration therein, a method was proposed, which estimates vibration levels without using the finite element method. However, the problem of mode decay ratio has not been solved. Therefore, this paper first describes a method to introduce an equivalent linear decay matrix. The paper then mentions difference in the decay effects due to fluid viscosity in a shallow and deep water regions. Furthermore, vibration levels in the deep water region were estimated in a model experiment to verify the estimation result. Under a hypothesis that two-node vibration in a rotating ellipse has displacement distributions in the deep and shallow water regions equivalent, and when a case of vibration in a layer flow condition is calculated, dissipation energy in the shallow region is larger than that in the deep region by about 26%. About 5% of the total dissipation energy is consumed at bottom of the sea. According to a frequency response calculation, estimated values for the response levels still differ from experimental values, although the trend that the vibration levels change can be reproduced. 6 refs., 15 figs., 2 tabs.
Energy Technology Data Exchange (ETDEWEB)
Funaki, T; Hayashi, S [Osaka University, Osaka (Japan). Faculty of engineering
1997-12-31
It is known in estimating vibration characteristics of a ship that fluid range affects largely a structure. In order to analyze the compound vibration therein, a method was proposed, which estimates vibration levels without using the finite element method. However, the problem of mode decay ratio has not been solved. Therefore, this paper first describes a method to introduce an equivalent linear decay matrix. The paper then mentions difference in the decay effects due to fluid viscosity in a shallow and deep water regions. Furthermore, vibration levels in the deep water region were estimated in a model experiment to verify the estimation result. Under a hypothesis that two-node vibration in a rotating ellipse has displacement distributions in the deep and shallow water regions equivalent, and when a case of vibration in a layer flow condition is calculated, dissipation energy in the shallow region is larger than that in the deep region by about 26%. About 5% of the total dissipation energy is consumed at bottom of the sea. According to a frequency response calculation, estimated values for the response levels still differ from experimental values, although the trend that the vibration levels change can be reproduced. 6 refs., 15 figs., 2 tabs.
Frequency adjustable MEMS vibration energy harvester
Podder, P.; Constantinou, P.; Amann, A.; Roy, S.
2016-10-01
Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.
Frequency adjustable MEMS vibration energy harvester
International Nuclear Information System (INIS)
Podder, P; Constantinou, P; Roy, S; Amann, A
2016-01-01
Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)
Vibration Energy Harvesting Potential for Turbomachinery Applications
Directory of Open Access Journals (Sweden)
Adrian STOICESCU
2018-03-01
Full Text Available The vibration energy harvesting process represents one of the research directions for increasing power efficiency of electric systems, increasing instrumentation nodes autonomy in hard to reach locations and decreasing total system mass by eliminating cables and higher-power adapters. Research based on the possibility of converting vibration energy into useful electric energy is used to evaluate the potential of its use on turbomachinery applications. Aspects such as the structure and characteristics of piezoelectric generators, harvesting networks, their setup and optimization, are considered. Finally, performance test results are shown using piezoelectric systems on a turbine engine.
Nanoscale piezoelectric vibration energy harvester design
Foruzande, Hamid Reza; Hajnayeb, Ali; Yaghootian, Amin
2017-09-01
Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs) can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton's principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.
A new vibrational level of the H2+ molecular ion
International Nuclear Information System (INIS)
Carbonell, J.; Lazauskas, R.; Delande, D.; Hilico, L.; Kilic, S.; Hilico, L.; Kilic, S.
2003-01-01
A new vibrational level of the molecular ion H 2 + with binding energy of 1.09 x 10 -9 a.u. ∼ 30 neV below the first dissociation limit is predicted, using highly accurate numerical non-relativistic quantum calculations, which go beyond the Born-Oppenheimer approximation. It is the first-excited vibrational level v=1 of the 2pσ u electronic state, antisymmetric with respect to the exchange of the two protons, with orbital angular momentum L=0. It manifests itself as a huge p - H scattering length of a = 750 ± 5 Bohr radii. (authors)
Magnetically levitated autoparametric broadband vibration energy harvesting
International Nuclear Information System (INIS)
Kurmann, L.; Jia, Y.; Manoli, Y.; Woias, P.
2016-01-01
Some of the lingering challenges within the current paradigm of vibration energy harvesting (VEH) involve narrow operational frequency range and the inevitable non-resonant response from broadband noise excitations. Such VEHs are only suitable for limited applications with fixed sinusoidal vibration, and fail to capture a large spectrum of the real world vibration. Various arraying designs, frequency tuning schemes and nonlinear vibratory approaches have only yielded modest enhancements. To fundamentally address this, the paper proposes and explores the potentials in using highly nonlinear magnetic spring force to activate an autoparametric oscillator, in order to realize an inherently broadband resonant system. Analytical and numerical modelling illustrate that high spring nonlinearity derived from magnetic levitation helps to promote the 2:1 internal frequency matching required to activate parametric resonance. At the right internal parameters, the resulting system can intrinsically exhibit semi-resonant response regardless of the bandwidth of the input vibration, including broadband white noise excitation. (paper)
Mechanical vibration to electrical energy converter
Kellogg, Rick Allen [Tijeras, NM; Brotz, Jay Kristoffer [Albuquerque, NM
2009-03-03
Electromechanical devices that generate an electrical signal in response to an external source of mechanical vibrations can operate as a sensor of vibrations and as an energy harvester for converting mechanical vibration to electrical energy. The devices incorporate a magnet that is movable through a gap in a ferromagnetic circuit, wherein a coil is wound around a portion of the ferromagnetic circuit. A flexible coupling is used to attach the magnet to a frame for providing alignment of the magnet as it moves or oscillates through the gap in the ferromagnetic circuit. The motion of the magnet can be constrained to occur within a substantially linear range of magnetostatic force that develops due to the motion of the magnet. The devices can have ferromagnetic circuits with multiple arms, an array of magnets having alternating polarity and, encompass micro-electromechanical (MEM) devices.
The high level vibration test program
International Nuclear Information System (INIS)
Hofmayer, C.H.; Curreri, J.R.; Park, Y.J.; Kato, W.Y.; Kawakami, S.
1989-01-01
As part of cooperative agreements between the US and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The objective of the test program was to use the NUPEC vibration table to drive large diameter nuclear power piping to substantial plastic strain with an earthquake excitation and to compare the results with state-of-the-art analysis of the problem. The test model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. A modified earthquake excitation was applied and the excitation level was increased carefully to minimize the cumulative fatigue damage due to the intermediate level excitations. Since the piping was pressurized, and the high level earthquake excitation was repeated several times, it was possible to investigate the effects of ratchetting and fatigue as well. Elastic and inelastic seismic response behavior of the test model was measured in a number of test runs with an increasing excitation input level up to the limit of the vibration table. In the maximum input condition, large dynamic plastic strains were obtained in the piping. Crack initiation was detected following the second maximum excitation run. Crack growth was carefully monitored during the next two additional maximum excitation runs. The final test resulted in a maximum crack depth of approximately 94% of the wall thickness. The HLVT (high level vibration test) program has enhanced understanding of the behavior of piping systems under severe earthquake loading. As in other tests to failure of piping components, it has demonstrated significant seismic margin in nuclear power plant piping
Collisional flow of vibrational energy into surrounding vibrational fields within S1 benzene
International Nuclear Information System (INIS)
Tang, K.Y.; Parmenter, C.S.
1983-01-01
Vapor phase fluorescence spectra are used to determine the absolute rate constants for the collisional transfer of vibrational energy from initial single vibronic levels of S 1 benzene into the surrounding S 1 vibronic field. 11 initial levels are probed with vibrational energies ranging to 2368 cm -1 where the level density is about 10 per cm -1 . CO, isopentane, and S 0 benzene are the collision partners. Benzene rate constants are three to four times gas kinetic for all levels, and electronic energy switching between the initial S 1 molecule and the S 0 collision partner probably makes important contributions. Isopentane efficiencies range from one to two times gas kinetic. Most of the transfer from low S 1 levels occurs with excitation of vibrational energy within isopentane. These V--V contributions decline to only about 10% for the high transfer. CO-induced transfer is by V-T,R processes for all levels. The CO efficiency rises from about 0.1 for low regions to about unity for levels above 1500 cm -1 . The CO efficiencies retain significant sensitivity to initial level identity even in the higher regions. Propensity rules derived from collisional mode-to-mode transfer among lower levels of S 1 benzene are used to calculate the relative CO efficiencies. The calculated efficiencies agree well enough with the data to suggest that it may be meaningful to model vibrational equilibration with the use of propensity rules. The rules suggest that only a small number of levels among the thousands surrounding a high initial level contribute significantly to the total relaxation cross section and that this number is rather independent of the level density
Adjustable Nonlinear Springs to Improve Efficiency of Vibration Energy Harvesters
Boisseau, S.; Despesse, G.; Seddik, B. Ahmed
2012-01-01
Vibration Energy Harvesting is an emerging technology aimed at turning mechanical energy from vibrations into electricity to power microsystems of the future. Most of present vibration energy harvesters are based on a mass spring structure introducing a resonance phenomenon that allows to increase the output power compared to non-resonant systems, but limits the working frequency bandwidth. Therefore, they are not able to harvest energy when ambient vibrations' frequencies shift. To follow sh...
The High Level Vibration Test Program
International Nuclear Information System (INIS)
Hofmayer, C.H.; Curreri, J.R.; Park, Y.J.; Kato, W.Y.; Kawakami, S.
1989-01-01
As part of cooperative agreements between the United States and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The objective of the test program was to use the NUPEC vibration table to drive large diameter nuclear power piping to substantial plastic strain with an earthquake excitation and to compare the results with state-of-the-art analysis of the problem. The test model was designed by modifying the 1/2.5 scale model of the PWR primary coolant loop. Elastic and inelastic seismic response behavior of the test model was measured in a number of test runs with an increasing excitation input level up to the limit of the vibration table. In the maximum input condition, large dynamic plastic strains were obtained in the piping. Crack initiation was detected following the second maximum excitation run. The test model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. This paper describes the overall plan, input motion development, test procedure, test results and comparisons with pre-test analysis. 4 refs., 16 figs., 2 tabs
The High Level Vibration Test program
International Nuclear Information System (INIS)
Hofmayer, C.H.; Curreri, J.R.; Park, Y.J.; Kato, W.Y.; Kawakami, S.
1990-01-01
As part of cooperative agreements between the United States and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The objective of the test program was to use the NUPEC vibration table to drive large diameter nuclear power piping to substantial plastic strain with an earthquake excitation and to compare the results with state-of-the-art analysis of the problem. The test model was designed by modifying the 1/2.5 scale model of the pressurized water reactor primary coolant loop. Elastic and inelastic seismic response behavior of the test model was measured in a number of test runs with an increasing excitation input level up to the limit of the vibration table. In the maximum input condition, large dynamic plastic strains were obtained in the piping. Crack initiation was detected following the second maximum excitation run. The test model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. This paper describes the overall plan, input motion development, test procedure, test results and comparisons with pre-test analysis
Combined Euler column vibration isolation and energy harvesting
Davis, R. B.; McDowell, M. D.
2017-05-01
A new device that combines vibration isolation and energy harvesting is modeled, simulated, and tested. The vibration isolating portion of the device uses post-buckled beams as its spring elements. Piezoelectric film is applied to the beams to harvest energy from their dynamic flexure. The entire device operates passively on applied base excitation and requires no external power or control system. The structural system is modeled using the elastica, and the structural response is applied as forcing on the electric circuit equation to predict the output voltage and the corresponding harvested power. The vibration isolation and energy harvesting performance is simulated across a large parameter space and the modeling approach is validated with experimental results. Experimental transmissibilities of 2% and harvested power levels of 0.36 μW are simultaneously demonstrated. Both theoretical and experimental data suggest that there is not necessarily a trade-off between vibration isolation and harvested power. That is, within the practical operational range of the device, improved vibration isolation will be accompanied by an increase in the harvested power as the forcing frequency is increased.
Design, simulation, fabrication, and characterization of MEMS vibration energy harvesters
Oxaal, John
Energy harvesting from ambient sources has been a longtime goal for microsystem engineers. The energy available from ambient sources is substantial and could be used to power wireless micro devices, making them fully autonomous. Self-powered wireless sensors could have many applications in for autonomous monitoring of residential, commercial, industrial, geological, or biological environments. Ambient vibrations are of particular interest for energy harvesting as they are ubiquitous and have ample kinetic energy. In this work a MEMS device for vibration energy harvesting using a variable capacitor structure is presented. The nonlinear electromechanical dynamics of a gap-closing type structure is experimentally studied. Important experimental considerations such as the importance of reducing off-axis vibration during testing, characterization methods, dust contamination, and the effect of grounding on parasitic capacitance are discussed. A comprehensive physics based model is developed and validated with two different microfabricated devices. To achieve maximal power, devices with high aspect ratio electrodes and a novel two-level stopper system are designed and fabricated. The maximum achieved power from the MEMS device when driven by sinusoidal vibrations was 3.38 muW. Vibrations from HVAC air ducts, which have a primary frequency of 65 Hz and amplitude of 155 mgrms, are targeted as the vibration source and devices are designed for maximal power harvesting potential at those conditions. Harvesting from the air ducts, the devices reached 118 nW of power. When normalized to the operating conditions, the best figure of merit of the devices tested was an order of magnitude above state-of-the-art of the devices (1.24E-6).
Vibration energy harvesting using the Halbach array
International Nuclear Information System (INIS)
Zhu, Dibin; Beeby, Steve; Tudor, John; Harris, Nick
2012-01-01
This paper studies the feasibility of vibration energy harvesting using a Halbach array. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field to almost zero on the other side. This arrangement can improve electromagnetic coupling in a limited space. The Halbach array offers an advantage over conventional layouts of magnets in terms of its concentrated magnetic field and low-profile structure, which helps improve the output power of electromagnetic energy harvesters while minimizing their size. Another benefit of the Halbach array is that due to the existence of an almost-zero magnetic field zone, electronic components can be placed close to the energy harvester without any chance of interference, which can potentially reduce the overall size of a self-powered device. The first reported example of a low-profile, planar electromagnetic vibration energy harvester utilizing a Halbach array was built and tested. Results were compared to ones for energy harvesters with conventional magnet layouts. By comparison, it is concluded that although energy harvesters with a Halbach array can have higher magnetic field density, a higher output power requires careful design in order to achieve the maximum magnetic flux gradient. (paper)
Broadband piezoelectric vibration energy harvesting using a nonlinear energy sink
Xiong, Liuyang; Tang, Lihua; Liu, Kefu; Mace, Brian R.
2018-05-01
A piezoelectric vibration energy harvester (PVEH) is capable of converting waste or undesirable ambient vibration energy into useful electric energy. However, conventional PVEHs typically work in a narrow frequency range, leading to low efficiency in practical application. This work proposes a PVEH based on the principle of the nonlinear energy sink (NES) to achieve broadband energy harvesting. An alternating current circuit with a resistive load is first considered in the analysis of the dynamic properties and electric performance of the NES-based PEVH. Then, a standard rectifying direct current (DC) interface circuit is developed to evaluate the DC power from the PVEH. To gain insight into the NES mechanism involved, approximate analysis of the proposed PVEH systems under harmonic excitation is sought using the mixed multi-scale and harmonic balance method and the Newton–Raphson harmonic balance method. In addition, an equivalent circuit model (ECM) of the electromechanical system is derived and circuit simulations are conducted to explore and validate the energy harvesting and vibration absorption performance of the proposed NES-based PVEH. The response is also compared with that obtained by direct numerical integration of the equations of motion. Finally, the optimal resistance to obtain the maximum DC power is determined based on the Newton–Raphson harmonic balance method and validated by the ECM. In general, the NES-based PVEH can absorb the vibration from the primary structure and collect electric energy within a broad frequency range effectively.
Resonant vibrational energy transfer in ice Ih
Energy Technology Data Exchange (ETDEWEB)
Shi, L.; Li, F.; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)
2014-06-28
Fascinating anisotropy decay experiments have recently been performed on H{sub 2}O ice Ih by Timmer and Bakker [R. L. A. Timmer, and H. J. Bakker, J. Phys. Chem. A 114, 4148 (2010)]. The very fast decay (on the order of 100 fs) is indicative of resonant energy transfer between OH stretches on different molecules. Isotope dilution experiments with deuterium show a dramatic dependence on the hydrogen mole fraction, which confirms the energy transfer picture. Timmer and Bakker have interpreted the experiments with a Förster incoherent hopping model, finding that energy transfer within the first solvation shell dominates the relaxation process. We have developed a microscopic theory of vibrational spectroscopy of water and ice, and herein we use this theory to calculate the anisotropy decay in ice as a function of hydrogen mole fraction. We obtain very good agreement with experiment. Interpretation of our results shows that four nearest-neighbor acceptors dominate the energy transfer, and that while the incoherent hopping picture is qualitatively correct, vibrational energy transport is partially coherent on the relevant timescale.
Improving Vibration Energy Harvesting Using Dynamic Magnifier
Directory of Open Access Journals (Sweden)
Almuatasim Alomari
2016-01-01
Full Text Available This paper reports on the design and evaluation of vibration-based piezoelectric energy-harvesting devices based on a polyvinylidene fluoride unimorph cantilever beam attached to the front of a dynamic magnifier. Experimental studies of the electromechanical frequency response functions are studied for the first three resonance frequencies. An analytical analysis is undertaken by applying the chain matrix in order to predict output voltage and output power with respect to the vibration frequency. The proposed harvester was modeled using MATLAB software and COMSOL multi- physics to study the mode shapes and electrical output parameters. The voltage and power output of the energy harvester with a dynamic magnifier was 2.62 V and 13.68 mW, respectively at the resonance frequency of the second mode. The modeling approach provides a basis to design energy harvesters exploiting dynamic magnification for improved performance and bandwidth. The potential application of such energy harvesting devices in the transport sector include autonomous structural health monitoring systems that often include embedded sensors, data acquisition, wireless communication, and energy harvesting systems.
Accurate ab initio vibrational energies of methyl chloride
International Nuclear Information System (INIS)
Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter
2015-01-01
Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH 3 35 Cl and CH 3 37 Cl. The respective PESs, CBS-35 HL , and CBS-37 HL , are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY 3 Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35 HL and CBS-37 HL PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm −1 , respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH 3 Cl without empirical refinement of the respective PESs
Accurate ab initio vibrational energies of methyl chloride
Energy Technology Data Exchange (ETDEWEB)
Owens, Alec, E-mail: owens@mpi-muelheim.mpg.de [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany); Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London (United Kingdom); Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London (United Kingdom); Thiel, Walter [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
2015-06-28
Two new nine-dimensional potential energy surfaces (PESs) have been generated using high-level ab initio theory for the two main isotopologues of methyl chloride, CH{sub 3}{sup 35}Cl and CH{sub 3}{sup 37}Cl. The respective PESs, CBS-35{sup HL}, and CBS-37{sup HL}, are based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set (CBS) limit, and incorporate a range of higher-level (HL) additive energy corrections to account for core-valence electron correlation, higher-order coupled cluster terms, scalar relativistic effects, and diagonal Born-Oppenheimer corrections. Variational calculations of the vibrational energy levels were performed using the computer program TROVE, whose functionality has been extended to handle molecules of the form XY {sub 3}Z. Fully converged energies were obtained by means of a complete vibrational basis set extrapolation. The CBS-35{sup HL} and CBS-37{sup HL} PESs reproduce the fundamental term values with root-mean-square errors of 0.75 and 1.00 cm{sup −1}, respectively. An analysis of the combined effect of the HL corrections and CBS extrapolation on the vibrational wavenumbers indicates that both are needed to compute accurate theoretical results for methyl chloride. We believe that it would be extremely challenging to go beyond the accuracy currently achieved for CH{sub 3}Cl without empirical refinement of the respective PESs.
International Nuclear Information System (INIS)
Machado, F.B.C.; Ornellas, F.R.
1988-10-01
An accurate potential energy curve for the BeF molecule in the X 2 Σ + state is calculated within the MRSDCI approach. Vibrational level spacings and the dissociation energy are reported. Agreement with the available experimental spacings is 15 cm -1 on the average. The theoretically computed D o , 5.92 eV, favors the experimental value of 5.85 eV over the higher value of 6.26 eV. Arguments are also presented that show why the value obtained by the Birge-Sponer linear extrapolation is accidentally a good one. (author) [pt
Methods of performing downhole operations using orbital vibrator energy sources
Cole, Jack H.; Weinberg, David M.; Wilson, Dennis R.
2004-02-17
Methods of performing down hole operations in a wellbore. A vibrational source is positioned within a tubular member such that an annulus is formed between the vibrational source and an interior surface of the tubular member. A fluid medium, such as high bulk modulus drilling mud, is disposed within the annulus. The vibrational source forms a fluid coupling with the tubular member through the fluid medium to transfer vibrational energy to the tubular member. The vibrational energy may be used, for example, to free a stuck tubular, consolidate a cement slurry and/or detect voids within a cement slurry prior to the curing thereof.
International Nuclear Information System (INIS)
Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Dénes, Nóra; Fazliev, Alexander Z.
2014-01-01
This paper is the fourth of a series of papers reporting critically evaluated rotational–vibrational line positions, transition intensities, pressure dependences, and energy levels, with associated critically reviewed assignments and uncertainties, for all the main isotopologues of water. This paper presents energy level and transition data for the following doubly and triply substituted isotopologues of water: D 2 16 O, D 2 17 O, and D 2 18 O. The MARVEL (Measured Active Rotational–Vibrational Energy Levels) procedure is used to determine the levels, the lines, and their self-consistent uncertainties for the spectral regions 0–14 016, 0–7969, and 0–9108 cm −1 for D 2 16 O, D 2 17 O, and D 2 18 O, respectively. For D 2 16 O, D 2 17 O, and D 2 18 O, 53 534, 600, and 12 167 lines are considered, respectively, from spectra recorded in absorption at room temperature and in emission at elevated temperatures. The number of validated energy levels is 12 269, 338, and 3351 for D 2 16 O, D 2 17 O, and D 2 18 O, respectively. The energy levels have been checked against the ones determined, with an average accuracy of about 0.03 cm −1 , from variational rovibrational computations employing exact kinetic energy operators and an accurate potential energy surface. Furthermore, the rovibrational labels of the energy levels have been validated by an analysis of the computed wavefunctions using the rigid-rotor decomposition (RRD) scheme. The extensive list of MARVEL lines and levels obtained is deposited in the Supplementary Material of this paper, in a distributed information system applied to water, W@DIS, and on the official MARVEL website, where they can easily be retrieved. - Highlights: • All published transitions are collected and analyzed. • A set of validated rovibrational transitions are presented. • Experimental energy levels for all three D 2 O isotopologues are determined. • Synthetic spectra are presented using these validated energy levels
Effect of vibrational states on nuclear level density
International Nuclear Information System (INIS)
Plujko, V. A.; Gorbachenko, O. M.
2007-01-01
Simple methods to calculate a vibrational enhancement factor of a nuclear level density with allowance for damping of collective state are considered. The results of the phenomenological approach and the microscopic quasiparticle-phonon model are compared. The practical method of calculation of a vibrational enhancement factor and level density parameters is recommended
Experimental vibration level analysis of a Francis turbine
International Nuclear Information System (INIS)
Bucur, D M; Dunca, G; Calinoiu, C
2012-01-01
In this study the vibration level of a Francis turbine is investigated by experimental work in site. Measurements are carried out for different power output values, in order to highlight the influence of the operation regimes on the turbine behavior. The study focuses on the turbine shaft to identify the mechanical vibration sources and on the draft tube in order to identify the hydraulic vibration sources. Analyzing the vibration results, recommendations regarding the operation of the turbine, at partial load close to minimum values, in the middle of the operating domain or close to maximum values of electric power, can be made in order to keep relatively low levels of vibration. Finally, conclusions are drawn in order to present the real sources of the vibrations.
Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester
Directory of Open Access Journals (Sweden)
Ali E. Kubba
2013-12-01
Full Text Available Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA was used as an initial tool to compare the three geometries’ stiffness (K, output open-circuit voltage (Vave, and average normal strain in the piezoelectric transducer (εave that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3, has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle.
Influence of Drive Level on the Fundamental Vibrator Signal
Noorlandt, R.P.; Drijkoningen, G.G.; Faber, C.A.M.
2013-01-01
In this abstract we show the influence of vibrator drive level on the signal it produces. For that purpose a field survey was carried out using an INOVA's AHV-IV vehicle with a modified 266kN (60.000 lbf) vibrator. A single linear sweep was repeated at 10 different drive levels ranging from 5 to 90% at two locations. Each drive level was repeated 10 times and each run was repeated twice per location. In total 400 sweeps were carried out. From this data set we conclude that; the vibrator signa...
Directory of Open Access Journals (Sweden)
Paul Cahill
2018-04-01
Full Text Available The data presented in this article is in relation to the research article “Vibration energy harvesting based monitoring of an operational bridge undergoing forced vibration and train passage” Cahill et al. (2018 [1]. The article provides data on the full-scale bridge testing using piezoelectric vibration energy harvesters on Pershagen Bridge, Sweden. The bridge is actively excited via a swept sinusoidal input. During the testing, the bridge remains operational and train passages continue. The test recordings include the voltage responses obtained from the vibration energy harvesters during these tests and train passages. The original dataset is made available to encourage the use of energy harvesting for Structural Health Monitoring.
Juhász, Imre Benedek; Csurgay, Árpád I.
2018-04-01
In recent years, the role of molecular vibrations in exciton energy transfer taking place during the first stage of photosynthesis attracted increasing interest. Here, we present a model formulated as a Lindblad-type master equation that enables us to investigate the impact of undamped and especially damped intramolecular vibrational modes on the exciton energy transfer, particularly its efficiency. Our simulations confirm the already reported effects that the presence of an intramolecular vibrational mode can compensate the energy detuning of electronic states, thus promoting the energy transfer; and, moreover, that the damping of such a vibrational mode (in other words, vibrational relaxation) can further enhance the efficiency of the process by generating directionality in the energy flow. As a novel result, we show that this enhancement surpasses the one caused by pure dephasing, and we present its dependence on various system parameters (time constants of the environment-induced relaxation and excitation processes, detuning of the electronic energy levels, frequency of the intramolecular vibrational modes, Huang-Rhys factors, temperature) in dimer model systems. We demonstrate that vibrational-relaxation-enhanced exciton energy transfer (VREEET) is robust against the change of these characteristics of the system and occurs in wide ranges of the investigated parameters. With simulations performed on a heptamer model inspired by the Fenna-Matthews-Olson (FMO) complex, we show that this mechanism can be even more significant in larger systems at T = 300 K. Our results suggests that VREEET might be prevalent in light-harvesting complexes.
Characterization of Direct Piezoelectric Properties for Vibration Energy Harvesting
Energy Technology Data Exchange (ETDEWEB)
Yoshimura, Takeshi; Miyabuchi, Hiroki; Ashida, Atsushi; Fujimura, Norifumi [Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 (Japan); Murakami, Syuichi, E-mail: tyoshi@pe.osakafu-u.ac.jp [Technology Research Institute of Osaka Prefecture, 2-7-1 Ayumino, Izumi, Osaka, 594-1157 (Japan)
2011-10-29
Direct piezoelectric effect of Pb(Zr,Ti)O{sub 3} (PZT) thin films was investigated to discuss the application of ferroelectric films to vibration energy harvesting. From the model of the piezoelectric vibration energy harvester, it was found that the figure of merit (FOM) is proportional of the square of the effective transverse piezoelectric coefficient e{sub 31,f}. The e{sub 31,f} coefficient of PZT films were measured by substrate bending method. Furthermore, it was found that the e{sub 31,f} coefficient increases with increasing strain, which is favourable for the vibration energy harvesting.
Energy evaluation of protection effectiveness of anti-vibration gloves.
Hermann, Tomasz; Dobry, Marian Witalis
2017-09-01
This article describes an energy method of assessing protection effectiveness of anti-vibration gloves on the human dynamic structure. The study uses dynamic models of the human and the glove specified in Standard No. ISO 10068:2012. The physical models of human-tool systems were developed by combining human physical models with a power tool model. The combined human-tool models were then transformed into mathematical models from which energy models were finally derived. Comparative energy analysis was conducted in the domain of rms powers. The energy models of the human-tool systems were solved using numerical simulation implemented in the MATLAB/Simulink environment. The simulation procedure demonstrated the effectiveness of the anti-vibration glove as a method of protecting human operators of hand-held power tools against vibration. The desirable effect is achieved by lowering the flow of energy in the human-tool system when the anti-vibration glove is employed.
Energy-dependent collisional deactivation of vibrationally excited azulene
International Nuclear Information System (INIS)
Shi, J.; Barker, J.R.
1988-01-01
Collisional energy transfer parameters for highly vibrationally excited azulene have been deduced from new infrared fluorescence (IRF) emission lifetime data with an improved calibration relating IRF intensity to vibrational energy [J. Shi, D. Bernfeld, and J. R. Barker, J. Chem. Phys. 88, XXXX (1988), preceding paper]. In addition, data from previous experiments [M. J. Rossi, J. R. Pladziewicz, and J. R. Barker, J. Chem. Phys. 78, 6695 (1983)] have been reanalyzed based on the improved calibration. Inversion of the IRF decay curves produced plots of energy decay, which were analyzed to determine , the average energy transferred per collision. Master equation simulations reproduced both the original IRF decays and the deduced energy decays. A third (simple) method of determination agrees well with the other two. The results show to be nearly directly proportional to the vibrational energy of the excited azulene from ∼8000 to 33 000 cm -1 . At high energies, there are indications that the energy dependence may be slightly reduced
Vibrational Energy Relaxation in Water-Acetonitrile Mixtures
Cringus, Dan; Yeremenko, Sergey; Pshenichnikov, Maxim S.; Wiersma, Douwe A.; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De
2004-01-01
IR pump-probe spectroscopy is used to study the effect of hydrogen bonding on the vibrational energy relaxation pathways. Hydrogen bonding accelerates the population relaxation from 12ps in diluted acetonitrile solution to 700fs in bulk water.
A Novel Ropes-DrivenWideband Piezoelectric Vibration Energy Harvester
Directory of Open Access Journals (Sweden)
Jinhui Zhang
2016-12-01
Full Text Available This paper presents a novel piezoelectric vibration energy harvester (PVEH in which a high-frequency generating beam (HFGB is driven by an array of low-frequency driving beams (LFDBs using ropes. Two mechanisms based on frequency upconversion and multimodal harvesting work together to broaden the frequency bandwidth of the proposed vibration energy harvester (VEH. The experimental results show that the output power of generating beam (GB remains unchanged with the increasing number of driving beams (DBs, compared with the traditional arrays of beams vibration energy harvester (AB-VEH, and the output power and bandwidth behavior can be adjusted by parameters such as acceleration, rope margin, and stiffness of LFDBs, which shows the potential to achieve unlimited wideband vibration energy-harvesting for a variable environment.
Heavy atom vibrational modes and low-energy vibrational autodetachment in nitromethane anions
International Nuclear Information System (INIS)
Thompson, Michael C.; Weber, J. Mathias; Baraban, Joshua H.; Matthews, Devin A.; Stanton, John F.
2015-01-01
We report infrared spectra of nitromethane anion, CH 3 NO 2 − , in the region 700–2150 cm −1 , obtained by Ar predissociation spectroscopy and electron detachment spectroscopy. The data are interpreted in the framework of second-order vibrational perturbation theory based on coupled-cluster electronic structure calculations. The modes in the spectroscopic region studied here are mainly based on vibrations involving the heavier atoms; this work complements earlier studies on nitromethane anion that focused on the CH stretching region of the spectrum. Electron detachment begins at photon energies far below the adiabatic electron affinity due to thermal population of excited vibrational states
Vibrational energy relaxation: proposed pathway of fast local chromatin denaturation
International Nuclear Information System (INIS)
Harder, D.; Greinert, R.
2002-01-01
The molecular mechanism responsible for the a component of exchange-type chromosome aberrations, of chromosome fragmentation and of reproductive cell death is one of the unsolved issues of radiation biology. Under review is whether vibrational energy relaxation in the constitutive biopolymers of chromatin, induced by inelastic energy deposition events and mediated via highly excited vibrational states, may provide a pathway of fast local chromatin denaturation, thereby producing the severe DNA lesion able to interact chemically with other, non-damaged chromatin. (author)
Directory of Open Access Journals (Sweden)
Sajid Rafique
2014-04-01
Full Text Available Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber. It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of 'electromechanical' TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel "electromechanical" TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry
International Nuclear Information System (INIS)
Rafique, S.; Shah, S.
2014-01-01
Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber). It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of electromechanical TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel electromechanical TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry. (author)
Vibrational spectroscopy and intramolecular energy transfer in isocyanic acid (HNCO)
International Nuclear Information System (INIS)
Coffey, M.J.; Berghout, H.L.; Woods, E. III; Crim, F.F.
1999-01-01
Room temperature photoacoustic spectra in the region of the first through the fourth overtones (2ν 1 to 5ν 1 ) and free-jet action spectra of the second through the fourth overtones (3ν 1 to 5ν 1 ) of the N - H stretching vibration permit analysis of the vibrational and rotational structure of HNCO. The analysis identifies the strong intramolecular couplings that control the early stages of intramolecular vibrational energy redistribution (IVR) and gives the interaction matrix elements between the zero-order N - H stretching states and the other zero-order states with which they interact. The experimentally determined couplings and zero-order state separations are consistent with ab initio calculations of East, Johnson, and Allen [J. Chem. Phys. 98, 1299 (1993)], and comparison with the calculation identifies the coupled states and likely interactions. The states most strongly coupled to the pure N - H stretching zero-order states are ones with a quantum of N - H stretching excitation (ν 1 ) replaced by different combinations of N - C - O asymmetric or symmetric stretching excitation (ν 2 or ν 3 ) and trans-bending excitation (ν 4 ). The two strongest couplings of the nν 1 state are to the states (n-1)ν 1 +ν 2 +ν 4 and (n-1)ν 1 +ν 3 +2ν 4 , and sequential couplings through a series of low order resonances potentially play a role. The analysis shows that if the pure N - H stretch zero-order state were excited, energy would initially flow out of that mode into the strongly coupled mode in 100 fs to 700 fs, depending on the level of initial excitation. copyright 1999 American Institute of Physics
Population of vibrational levels of carbon dioxide by cylindrical fast ionization wave
Levko, Dmitry
2017-09-08
The population of vibrational levels of carbon dioxide (CO2) by a cylindrical fast ionization wave is analyzed using a one-dimensional Particle-in-Cell Monte Carlo collisions model. The model takes into account the inelastic electron-neutral collisions as well as the super-elastic collisions between electrons and excited species. We observe an efficient population of only the first two levels of the symmetric and asymmetric vibrational modes of CO2 by means of a fast ionization wave. The excitation of other higher vibrational modes by the fast ionization wave is inefficient. Additionally, we observe a strong influence of the secondary electron emission on the population of vibrational states of CO2. This effect is associated with the kinetics of high energy electrons generated in the cathode sheath.
Spectroscopic probes of vibrationally excited molecules at chemically significant energies
Energy Technology Data Exchange (ETDEWEB)
Rizzo, T.R. [Univ. of Rochester, NY (United States)
1993-12-01
This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.
Directory of Open Access Journals (Sweden)
Min Zhang
2016-01-01
Full Text Available A rigid circular cylinder with two piezoelectric beams attached on has been tested through vortex-induced vibrations (VIV and wake-induced vibrations (WIV by installing a big cylinder fixed upstream, in order to study the influence of the different flow-induced vibrations (FIV types. The VIV test shows that the output voltage increases with the increases of load resistance; an optimal load resistance exists for the maximum output power. The WIV test shows that the vibration of the small cylinder is controlled by the vortex frequency of the large one. There is an optimal gap of the cylinders that can obtain the maximum output voltage and power. For a same energy harvesting device, WIV has higher power generation capacity; then the piezoelectric output characteristics can be effectively improved.
A vibration energy harvesting device with bidirectional resonance frequency tunability
International Nuclear Information System (INIS)
Challa, Vinod R; Prasad, M G; Shi Yong; Fisher, Frank T
2008-01-01
Vibration energy harvesting is an attractive technique for potential powering of wireless sensors and low power devices. While the technique can be employed to harvest energy from vibrations and vibrating structures, a general requirement independent of the energy transfer mechanism is that the vibration energy harvesting device operate in resonance at the excitation frequency. Most energy harvesting devices developed to date are single resonance frequency based, and while recent efforts have been made to broaden the frequency range of energy harvesting devices, what is lacking is a robust tunable energy harvesting technique. In this paper, the design and testing of a resonance frequency tunable energy harvesting device using a magnetic force technique is presented. This technique enabled resonance tuning to ± 20% of the untuned resonant frequency. In particular, this magnetic-based approach enables either an increase or decrease in the tuned resonant frequency. A piezoelectric cantilever beam with a natural frequency of 26 Hz is used as the energy harvesting cantilever, which is successfully tuned over a frequency range of 22–32 Hz to enable a continuous power output 240–280 µW over the entire frequency range tested. A theoretical model using variable damping is presented, whose results agree closely with the experimental results. The magnetic force applied for resonance frequency tuning and its effect on damping and load resistance have been experimentally determined
Electromagnetic Vibration Energy Harvesting Devices Architectures, Design, Modeling and Optimization
Spreemann, Dirk
2012-01-01
Electromagnetic vibration transducers are seen as an effective way of harvesting ambient energy for the supply of sensor monitoring systems. Different electromagnetic coupling architectures have been employed but no comprehensive comparison with respect to their output performance has been carried out up to now. Electromagnetic Vibration Energy Harvesting Devices introduces an optimization approach which is applied to determine optimal dimensions of the components (magnet, coil and back iron). Eight different commonly applied coupling architectures are investigated. The results show that correct dimensions are of great significance for maximizing the efficiency of the energy conversion. A comparison yields the architectures with the best output performance capability which should be preferably employed in applications. A prototype development is used to demonstrate how the optimization calculations can be integrated into the design–flow. Electromagnetic Vibration Energy Harvesting Devices targets the design...
Performance Study of Diagonally Segmented Piezoelectric Vibration Energy Harvester
Energy Technology Data Exchange (ETDEWEB)
Kim, Jae Eun [Catholic Univ. of Daegu, Daegu (Korea, Republic of)
2013-08-15
This study proposes a piezoelectric vibration energy harvester composed of two diagonally segmented energy harvesting units. An auxiliary structural unit is attached to the tip of a host structural unit cantilevered to a vibrating base, where the two components have beam axes in opposite directions from each other and matched short-circuit resonant frequencies. Contrary to the usual observations in two resonant frequency-matched structures, the proposed structure shows little eigenfrequency separation and yields a mode sequence change between the first two modes. These lead to maximum power generation around a specific frequency. By using commercial finite element software, it is shown that the magnitude of the output power from the proposed vibration energy harvester can be substantially improved in comparison with those from conventional cantilevered energy harvesters with the same footprint area and magnitude of a tip mass.
Vibrational energy on surfaces: Ultrafast flash-thermal conductance of molecular monolayers
Dlott, Dana
2008-03-01
Vibrational energy flow through molecules remains a perennial problem in chemical physics. Usually vibrational energy dynamics are viewed through the lens of time-dependent level populations. This is natural because lasers naturally pump and probe vibrational transitions, but it is also useful to think of vibrational energy as being conducted from one location in a molecule to another. We have developed a new technique where energy is driven into a specific part of molecules adsorbed on a metal surface, and ultrafast nonlinear coherent vibrational spectroscopy is used to watch the energy arrive at another part. This technique is the analog of a flash thermal conductance apparatus, except it probes energy flow with angstrom spatial and femtosecond temporal resolution. Specific examples to be presented include energy flow along alkane chains, and energy flow into substituted benzenes. Ref: Z. Wang, J. A. Carter, A. Lagutchev, Y. K. Koh, N.-H. Seong, D. G. Cahill, and D. D. Dlott, Ultrafast flash thermal conductance of molecular chains, Science 317, 787-790 (2007). This material is based upon work supported by the National Science Foundation under award DMR 0504038 and the Air Force Office of Scientific Research under award FA9550-06-1-0235.
Energy Technology Data Exchange (ETDEWEB)
Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, Californial 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)
2015-05-07
Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions.
Coherent excitation of vibrational levels using ultra short pulses
CSIR Research Space (South Africa)
De Clercq, LE
2009-07-01
Full Text Available population in a specific vibrational level. We used two approaches to do this, in the one model we used Von Neumann’s equations and the other the Optical Bloch equations (OBE’s). In this poster presentation the Optical Bloch model was used to do...
Cahill, Paul; Hazra, Budhaditya; Karoumi, Raid; Mathewson, Alan; Pakrashi, Vikram
2018-06-01
The application of energy harvesting technology for monitoring civil infrastructure is a bourgeoning topic of interest. The ability of kinetic energy harvesters to scavenge ambient vibration energy can be useful for large civil infrastructure under operational conditions, particularly for bridge structures. The experimental integration of such harvesters with full scale structures and the subsequent use of the harvested energy directly for the purposes of structural health monitoring shows promise. This paper presents the first experimental deployment of piezoelectric vibration energy harvesting devices for monitoring a full-scale bridge undergoing forced dynamic vibrations under operational conditions using energy harvesting signatures against time. The calibration of the harvesters is presented, along with details of the host bridge structure and the dynamic assessment procedures. The measured responses of the harvesters from the tests are presented and the use the harvesters for the purposes of structural health monitoring (SHM) is investigated using empirical mode decomposition analysis, following a bespoke data cleaning approach. Finally, the use of sequential Karhunen Loeve transforms to detect train passages during the dynamic assessment is presented. This study is expected to further develop interest in energy-harvesting based monitoring of large infrastructure for both research and commercial purposes.
International Nuclear Information System (INIS)
Shin, H.K.
1983-01-01
An explicit time dependent approach for simultaneous VT and VV energy transfer in diatom--diatom collisions is explored using the exponential form of ladder operators in the solution of the Schroedinger equation of motion. The collision of two hydrogen molecules is chosen to illustrate the extent of interference between VT and VV modes among various vibrational states. While vibrational energy transfer processes of nominally VT type can be treated with pure VT mode at low collision energies, the intermode coupling is found to be very important at collision energies of several hω. The occurrence of the coupling appears to be nearly universal in vibrational transitions at such energies. Exceptions to the coupling have been discussed
Passive and Active Vibration Control of Renewable Energy Structures
DEFF Research Database (Denmark)
Zhang, Zili
The present thesis deals with fundamental researches on passive and active vibration control of renewable energy structures, and provides useful models for practical applications. Effective and robust vibration control methods have been explored for mitigating the lightly damped edgewise blade...... solutions for wave energy point absorbers, in order to maximize the mean absorbed power and to deliver more smooth power to the grid. A novel suboptimal causal control law has been established for controlling the motion of the point absorber, and a new type of point absorber has also been proposed...
Isotope separation process by transfer of vibrational energy
International Nuclear Information System (INIS)
Angelie, C.; Cauchetier, M.; Paris, J.
1983-01-01
This process consists in exciting A molecules by absorption of a pulsed light beam, then in exciting until their dissociation X molecules, present in several isotopic forms, by a vibrational transfer between the A molecules and the X molecules, the A molecules having a dissociation energy greater than that of the X molecules, the duration and energy of the light pulses being such that the absorption time by the A molecules is less than the excitation time of the X molecules and the temperature conditions such that the thermal width of the vibration rays is at the most near the isotopic difference between the resonance rays of the two isotopic varieties [fr
Yoon, Heonjun; Kim, Miso; Park, Choon-Su; Youn, Byeng D.
2018-01-01
Piezoelectric vibration energy harvesting (PVEH) has received much attention as a potential solution that could ultimately realize self-powered wireless sensor networks. Since most ambient vibrations in nature are inherently random and nonstationary, the output performances of PVEH devices also randomly change with time. However, little attention has been paid to investigating the randomly time-varying electroelastic behaviors of PVEH systems both analytically and experimentally. The objective of this study is thus to make a step forward towards a deep understanding of the time-varying performances of PVEH devices under nonstationary random vibrations. Two typical cases of nonstationary random vibration signals are considered: (1) randomly-varying amplitude (amplitude modulation; AM) and (2) randomly-varying amplitude with randomly-varying instantaneous frequency (amplitude and frequency modulation; AM-FM). In both cases, this study pursues well-balanced correlations of analytical predictions and experimental observations to deduce the relationships between the time-varying output performances of the PVEH device and two primary input parameters, such as a central frequency and an external electrical resistance. We introduce three correlation metrics to quantitatively compare analytical prediction and experimental observation, including the normalized root mean square error, the correlation coefficient, and the weighted integrated factor. Analytical predictions are in an excellent agreement with experimental observations both mechanically and electrically. This study provides insightful guidelines for designing PVEH devices to reliably generate electric power under nonstationary random vibrations.
Directory of Open Access Journals (Sweden)
Vytautas Ostasevicius
2015-05-01
Full Text Available This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4–4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation.
Energy harvesting from vibration using a piezoelectric membrane
Energy Technology Data Exchange (ETDEWEB)
Ericka, M.; Vasic, D.; Costa, F.; Tliba, S. [Ecole Normale Superieure de Cachan, Systemes et Applications des Technologies de l' Information et de l' Energie (SATIE, UMR 8029), 94 - Cachan (France); Poulin, G. [Ecole Nationale Superieure d' Ingenieurs Electriciens de Grenoble, Laboratoire d' Automatique de Grenoble, 38 (France)
2005-09-01
In this paper we investigate the capability of harvesting the electric energy from mechanical vibrations in a dynamic environment through a piezoelectric membrane transducer. This transducer consists of 2 layers lead zirconate titanate (PZT)/brass, the brass layer is embedded over the whole circumference by epoxy adhesive. A very small vibration gives a consequent deformation of the membrane which generates electric energy. Due to the impedance matrices connecting the efforts and flows of the membrane, we have established the dynamic electric equivalent circuit of the transducer. In a first study and in order to validate theoretical results, we performed experiments with a vibrating machine moving a macroscopic 25 mm diameter piezoelectric membrane. A power of 1.8 mW was generated at the resonance frequency (2.58 kHz) across a 56 k{omega} optimal resistor and for a 2 g acceleration. (authors)
A low frequency vibration energy harvester using magnetoelectric laminate composite
International Nuclear Information System (INIS)
Ju, Suna; Chae, Song Hee; Choi, Yunhee; Lee, Seungjun; Ji, Chang-Hyeon; Lee, Hyang Woon
2013-01-01
In this paper, we present a vibration energy harvester using magnetoelectric laminate composite and a springless spherical permanent magnet as a proof mass. The harvester utilizes a freely movable spherical permanent magnet to transform external vibration into a time varying magnetic field applied to the magnetoelectric transducer. The laminate composite consists of a Ni–Mn–Ga-based MSMA (magnetic shape memory alloy) element and a PZT (lead zirconate titanate) plate. A proof-of-concept harvester has been fabricated and characterized at various input accelerations and frequencies. A maximum open circuit voltage of 1.18 V has been obtained in response to a 3g vibration at 17 Hz with the fabricated device. Moreover, a maximum output voltage of 10.24 V and output power of 4.1 μW have been achieved on a 950 Ω load, when the fabricated energy harvester was mounted on a smartphone and shaken by hand. (paper)
Direct observation of vibrational energy flow in cytochrome c.
Fujii, Naoki; Mizuno, Misao; Mizutani, Yasuhisa
2011-11-10
Vibrational energy flow in ferric cytochrome c has been examined by picosecond time-resolved anti-Stokes ultraviolet resonance Raman (UVRR) measurements. By taking advantage of the extremely short nonradiative excited state lifetime of heme in the protein (energy of 20000-25000 cm(-1) was optically deposited selectively at the heme site. Subsequent energy relaxation in the protein moiety was investigated by monitoring the anti-Stokes UVRR intensities of the Trp59 residue, which is a single tryptophan residue involved in the protein that is located close to the heme group. It was found from temporal changes of the anti-Stokes UVRR intensities that the energy flow from the heme to Trp59 and the energy release from Trp59 took place with the time constants of 1-3 and ~8 ps, respectively. These data are consistent with the time constants for the vibrational relaxation of the heme and heating of water reported for hemeproteins. The kinetics of the energy flow were not affected by the amount of excess energy deposited at the heme group. These results demonstrate that the present technique is a powerful tool for studying the vibrational energy flow in proteins.
Intermediate energy electron impact excitation of composite vibrational modes in phenol
Energy Technology Data Exchange (ETDEWEB)
Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Lopes, M. C. A.; Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, Minas Gerais (Brazil); Oliveira, E. M. de; Lima, M. A. P. [Instituto de Física ‘Gleb Wataghin,’ Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, C.P. 19044, 81531-990 Curitiba, Paraná (Brazil); Silva, G. B. da [Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)
2015-05-21
We report differential cross section results from an experimental investigation into the electron impact excitation of a number of the low-lying composite (unresolved) vibrational modes in phenol (C{sub 6}H{sub 5}OH). The measurements were carried out at incident electron energies in the range 15–40 eV and for scattered-electron angles in the range 10–90°. The energy resolution of those measurements was typically ∼80 meV. Calculations, using the GAMESS code, were also undertaken with a B3LYP/aug-cc-pVDZ level model chemistry, in order to enable us to assign vibrational modes to the features observed in our energy loss spectra. To the best of our knowledge, the present cross sections are the first to be reported for vibrational excitation of the C{sub 6}H{sub 5}OH molecule by electron impact.
MEMS-based thick film PZT vibrational energy harvester
DEFF Research Database (Denmark)
Lei, Anders; Xu, Ruichao; Thyssen, Anders
2011-01-01
We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechan......We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....
Vibrational zero point energy for H-doped silicon
Karazhanov, S. Zh.; Ganchenkova, M.; Marstein, E. S.
2014-05-01
Most of the studies addressed to computations of hydrogen parameters in semiconductor systems, such as silicon, are performed at zero temperature T = 0 K and do not account for contribution of vibrational zero point energy (ZPE). For light weight atoms such as hydrogen (H), however, magnitude of this parameter might be not negligible. This Letter is devoted to clarify the importance of accounting the zero-point vibrations when analyzing hydrogen behavior in silicon and its effect on silicon electronic properties. For this, we estimate the ZPE for different locations and charge states of H in Si. We show that the main contribution to the ZPE is coming from vibrations along the Si-H bonds whereas contributions from other Si atoms apart from the direct Si-H bonds play no role. It is demonstrated that accounting the ZPE reduces the hydrogen formation energy by ˜0.17 eV meaning that neglecting ZPE at low temperatures one can underestimate hydrogen solubility by few orders of magnitude. In contrast, the effect of the ZPE on the ionization energy of H in Si is negligible. The results can have important implications for characterization of vibrational properties of Si by inelastic neutron scattering, as well as for theoretical estimations of H concentration in Si.
MEMS-Based Waste Vibrational Energy Harvesters
2013-06-01
MEMS energy- harvesting device. Although PZT is used more prevalently due to its higher piezoelectric coefficient and dielectric constant, AlN has...7 1. Lead Zirconium Titanate ( PZT ) .........................................................7 2. Aluminum...Laboratory PiezoMUMPS Piezoelectric Multi-User MEMS Processes PZT Lead Zirconate Titanate SEM Scanning Electron Microscopy SiO2 Silicon
Simultaneous Vibration Suppression and Energy Harvesting
2013-08-15
of the coupling coefficient in the feed back control law resulting from the PZT nonlinearity. A minimum energy control law was developed...these control laws we also discovered that the high voltages commanded by our control laws result in the piezoelectric coupling coefficient being...non constant. Thus we also had to implement an adaptive control law (exponential actually) to account for the change in coupling coefficient as the
Energy expenditure and substrate utilization during whole body vibration
Directory of Open Access Journals (Sweden)
Ravena Santos Raulino
2015-04-01
Full Text Available INTRODUCTION AND OBJECTIVE: the aim of this study was to investigate whether the addition of vibration during interval training would raise oxygen consumption VO2 to the extent necessary for weight management and to evaluate the influence of the intensity of the vibratory stimulus for prescribing the exercise program in question. METHODS: VO2, measured breath by breath, was evaluated at rest and during the four experimental conditions to determine energy expenditure, metabolic equivalent MET, respiratory exchange ratio RER, % Kcal from fat, and rate of fat oxidation. Eight young sedentary females age 22±1 years, height 163.88± 7.62 cm, body mass 58.35±10.96 kg, and VO2 max 32.75±3.55 mLO2.Kg-1.min-1 performed interval training duration = 13.3 min to the upper and lower limbs both with vibration 35 Hz and 2 mm, 40 Hz and 2 mm, 45 Hz and 2 mm and without vibration. The experimental conditions were randomized and balanced at an interval of 48 hours. RESULTS: the addition of vibration to exercise at 45 Hz and 2 mm resulted in an additional increase of 17.77±12.38% of VO2 compared with exercise without vibration. However, this increase did not change the fat oxidation rate p=0.42 because intensity of exercise 29.1±3.3 %VO2max, 2.7 MET was classified as mild to young subjects. CONCLUSION: despite the influence of vibration on VO2 during exercise, the increase was insufficient to reduce body weight and did not reach the minimum recommendation of exercise prescription for weight management for the studied population.
Piezoelectric Wind Energy Harvesting from Self-Excited Vibration of Square Cylinder
Directory of Open Access Journals (Sweden)
Junlei Wang
2016-01-01
Full Text Available Self-excited vibration of a square cylinder has been considered as an effective way in harvesting piezoelectric wind energy. In present work, both of the vortex-induced vibration and unstable galloping phenomenon process are investigated in a reduced velocity (Ur=U/ωn·D range of 4≤Ur≤20 with load resistance ranging in 100 Ω≤R≤1 MΩ. The vortex-induced vibration covers presynchronization, synchronization, and postsynchronization branches. An aeroelectromechanical model is given to describe the coupling of the dynamic equation of the fluid-structure interaction and the equation of Gauss law. The effects of load resistance are investigated in both the open-circuit and close-circuit system by a linear analysis, which covers the parameters of the transverse displacement, aerodynamic force, output voltage, and harvested power utilized to measure the efficiency of the system. The highest level of the transverse displacement and the maximum value of harvested power of synchronization branch during the vortex-induced vibration and galloping are obtained. The results show that the large-amplitude galloping at high wind speeds can generate energy. Additionally, energy can be harvested by utilization of the lock-in phenomenon of vortex-induced vibration under low wind speed.
Electromagnetic energy harvesting from vibrations of multiple frequencies
International Nuclear Information System (INIS)
Yang Bin; Lee Chengkuo; Xie Jin; Han He, Johnny; Kotlanka, Rama Krishna; Feng Hanhua; Xiang Wenfeng; Low, Siew Ping
2009-01-01
A novel multi-frequency energy harvester has been designed and fabricated, which consists of three permanent magnets, three sets of two-layer copper coils and a supported beam of acrylic, while these coils are made of thin fire resistant 4 (FR4) substrates using a standard printed circuit board. The energy under the first, second and third resonant modes can be harvested, corresponding to the resonant frequencies of 369 Hz, 938 Hz and 1184 Hz, respectively. The maximum output voltage and power of the first and second vibration modes are 1.38 mV, 0.6 µW and 3.2 mV, 3.2 µW for a 14 µm exciting vibration amplitude and a 0.4 mm gap between the magnet and coils, respectively. The feasibility study results are in good agreement with the theoretical calculations and show promising application potentials
A MEMS Energy Harvesting Device for Vibration with Low Acceleration
DEFF Research Database (Denmark)
Triches, Marco; Wang, Fei; Crovetto, Andrea
2012-01-01
We propose a polymer electret based energy harvesting device in order to extract energy from vibration sources with low acceleration. With MEMS technology, a silicon structure is fabricated which can resonate in 2D directions. Thanks to the excellent mechanical properties of the silicon material......, the proof mass could be successfully driven by an external vibrations with acceleration as low as 0.014g (∼0.14 m/s2). A root mean square (RMS) power output of 1.17μW under 0.014g RMS acceleration at 75Hz is measured when an optimal load of 20.3 MΩ is applied. The frequency response of the device is also...
Architecture-independent power bound for vibration energy harvesters
International Nuclear Information System (INIS)
Halvorsen, E; Le, C P; Mitcheson, P D; Yeatman, E M
2013-01-01
The maximum output power of energy harvesters driven by harmonic vibrations is well known for a range of specific harvester architectures. An architecture-independent bound based on the mechanical input-power also exists and gives a strict limit on achievable power with one mechanical degree of freedom, but is a least upper bound only for lossless devices. We report a new theoretical bound on the output power of vibration energy harvesters that includes parasitic, linear mechanical damping while still being architecture independent. This bound greatly improves the previous bound at moderate force amplitudes and is compared to the performance of established harvester architectures which are shown to agree with it in limiting cases. The bound is a hard limit on achievable power with one mechanical degree of freedom and can not be circumvented by transducer or power-electronic-interface design
A review of vibration-based MEMS piezoelectric energy harvesters
Energy Technology Data Exchange (ETDEWEB)
Saadon, Salem; Sidek, Othman [Collaborative Microelectronic Design Excellence Center (CEDEC), School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)
2011-01-15
The simplicity associated with the piezoelectric micro-generators makes it very attractive for MEMS applications, especially for remote systems. In this paper we reviewed the work carried out by researchers during the last three years. The improvements in experimental results obtained in the vibration-based MEMS piezoelectric energy harvesters show very good scope for MEMS piezoelectric harvesters in the field of power MEMS in the near future. (author)
Energy Technology Data Exchange (ETDEWEB)
Meier, Patrick; Oschetzki, Dominik; Rauhut, Guntram, E-mail: rauhut@theochem.uni-stuttgart.de [Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany); Berger, Robert [Clemens-Schöpf Institut für Organische Chemie and Biochemie, Technische Universität Darmstadt, Petersenstrasse 22, 64287 Darmstadt (Germany)
2014-05-14
A transformation of potential energy surfaces (PES) being represented by multi-mode expansions is introduced, which allows for the calculation of anharmonic vibrational spectra of any isotopologue from a single PES. This simplifies the analysis of infrared spectra due to significant CPU-time savings. An investigation of remaining deviations due to truncations and the so-called multi-level approximation is provided. The importance of vibrational-rotational couplings for small molecules is discussed in detail. In addition, an analysis is proposed, which provides information about the quality of the transformation prior to its execution. Benchmark calculations are provided for a set of small molecules.
On the Energy Conversion Efficiency of Piezoelectric Vibration Energy Harvesting Devices
Energy Technology Data Exchange (ETDEWEB)
Kim, Jae Eun [Catholic University of Daegu, Kyungsan (Korea, Republic of)
2015-05-15
To properly design and assess a piezoelectric vibration energy harvester, it is necessary to consider the application of an efficiency measure of energy conversion. The energy conversion efficiency is defined in this work as the ratio of the electrical output power to the mechanical input power for a piezoelectric vibration energy harvester with an impedance-matched load resistor. While previous research works employed the electrical output power for approximate impedance-matched load resistance, this work derives an efficiency measure considering optimally matched resistance. The modified efficiency measure is validated by comparing it with finite element analysis results for piezoelectric vibration energy harvesters with three different values of the electro-mechanical coupling coefficient. New findings on the characteristics of energy conversion and conversion efficiency are also provided for the two different impedance matching methods.
Wang, Xiao-Gang; Carrington, Tucker
2018-02-01
We compute numerically exact rovibrational levels of water dimer, with 12 vibrational coordinates, on the accurate CCpol-8sf ab initio flexible monomer potential energy surface [C. Leforestier et al., J. Chem. Phys. 137, 014305 (2012)]. It does not have a sum-of-products or multimode form and therefore quadrature in some form must be used. To do the calculation, it is necessary to use an efficient basis set and to develop computational tools, for evaluating the matrix-vector products required to calculate the spectrum, that obviate the need to store the potential on a 12D quadrature grid. The basis functions we use are products of monomer vibrational wavefunctions and standard rigid-monomer basis functions (which involve products of three Wigner functions). Potential matrix-vector products are evaluated using the F matrix idea previously used to compute rovibrational levels of 5-atom and 6-atom molecules. When the coupling between inter- and intra-monomer coordinates is weak, this crude adiabatic type basis is efficient (only a few monomer vibrational wavefunctions are necessary), although the calculation of matrix elements is straightforward. It is much easier to use than an adiabatic basis. The product structure of the basis is compatible with the product structure of the kinetic energy operator and this facilitates computation of matrix-vector products. Compared with the results obtained using a [6 + 6]D adiabatic approach, we find good agreement for the inter-molecular levels and larger differences for the intra-molecular water bend levels.
International Nuclear Information System (INIS)
Elfrink, R; Renaud, M; Kamel, T M; De Nooijer, C; Jambunathan, M; Goedbloed, M; Hohlfeld, D; Matova, S; Pop, V; Caballero, L; Van Schaijk, R
2010-01-01
This paper describes the characterization of thin-film MEMS vibration energy harvesters based on aluminum nitride as piezoelectric material. A record output power of 85 µW is measured. The parasitic-damping and the energy-harvesting performances of unpackaged and packaged devices are investigated. Vacuum and atmospheric pressure levels are considered for the packaged devices. When dealing with packaged devices, it is found that vacuum packaging is essential for maximizing the output power. Therefore, a wafer-scale vacuum package process is developed. The energy harvesters are used to power a small prototype (1 cm 3 volume) of a wireless autonomous sensor system. The average power consumption of the whole system is less than 10 µW, and it is continuously provided by the vibration energy harvester
Analyses of electromagnetic and piezoelectric systems for efficient vibration energy harvesting
Hadas, Z.; Smilek, J.; Rubes, O.
2017-05-01
The paper deals with analyses and evaluation of vibration energy harvesting systems which are based on electromagnetic and piezoelectric physical principles off electro-mechanical conversion. Energy harvesting systems are associated with wireless sensors and a monitoring of engineering objects. The most of engineering objects operate with unwanted mechanical vibrations. However, vibrations could provide an ambient source of energy which is converted into useful electricity. The use of electromagnetic and piezoelectric vibration energy harvesters is analyzed in this paper. Thee evaluated output power is used for a choice of the efficient system with respect to the character of vibrations and thee required power output.
Vibrational Energy Distribution Analysis (VEDA): Scopes and limitations
Jamróz, Michał H.
2013-10-01
The principle of operations of the VEDA program written by the author for Potential Energy Distribution (PED) analysis of theoretical vibrational spectra is described. Nowadays, the PED analysis is indispensible tool in serious analysis of the vibrational spectra. To perform the PED analysis it is necessary to define 3N-6 linearly independent local mode coordinates. Already for 20-atomic molecules it is a difficult task. The VEDA program reads the input data automatically from the Gaussian program output files. Then, VEDA automatically proposes an introductory set of local mode coordinates. Next, the more adequate coordinates are proposed by the program and optimized to obtain maximal elements of each column (internal coordinate) of the PED matrix (the EPM parameter). The possibility for an automatic optimization of PED contributions is a unique feature of the VEDA program absent in any other programs performing PED analysis.
Vibrational energy transfer in hydrogen liquid and its isotopes
International Nuclear Information System (INIS)
Gale, G.M.; Delalande, C.
1978-01-01
The transfer of vibrational energy (V-V) from H 2 to isotopic impurities (HD or D 2 ) has been studied in the liquid state, between 15 and 30 K. The subsequent ralaxation (V-T) of the excited impurity by the H 2 liquid host has also been measured and contrasted with the vibrational relaxation behaviour of pure H 2 and D 2 liquids. The isothermal density dependence of both V-V and V-T transfer has been investigated in the fluid state at 30 K. High density relaxation rates are also compared to the data in the pure gases and to other available gas phase results. Measurements in the solid, near the triple-point temperature, are equally reported for each process studied. (Auth.)
Skyrmion vibrational energies together with a generalized mass term
International Nuclear Information System (INIS)
Davies, Merlin C.; Marleau, Luc
2009-01-01
We study various properties of a one-parameter mass term for the Skyrme model, originating from the works of Kopeliovich, Piette and Zakrzewski [V. B. Kopeliovich, B. Piette, and W. J. Zakrzewski, Phys. Rev. D 73, 014006 (2006).], through the use of axially symmetric solutions obtained numerically by simulated-annealing. These solutions allow us to observe asymptotic behaviors of the B=2 binding energies that differ to those previously obtained [B. Piette and W. J. Zakrzewski, Phys. Rev. D 77, 074009 (2008).]. We also decipher the characteristics of three distinct vibrational modes that appear as eigenstates of the vibrational Hamiltonian. This analysis further examine the assertion that the one-parameter mass term offers a better account of baryonic matter than the traditional mass term.
Comparison of vibrational conductivity and radiative energy transfer methods
Le Bot, A.
2005-05-01
This paper is concerned with the comparison of two methods well suited for the prediction of the wideband response of built-up structures subjected to high-frequency vibrational excitation. The first method is sometimes called the vibrational conductivity method and the second one is rather known as the radiosity method in the field of acoustics, or the radiative energy transfer method. Both are based on quite similar physical assumptions i.e. uncorrelated sources, mean response and high-frequency excitation. Both are based on analogies with some equations encountered in the field of heat transfer. However these models do not lead to similar results. This paper compares the two methods. Some numerical simulations on a pair of plates joined along one edge are provided to illustrate the discussion.
Venkataramani, K.; Yonker, J. D.; Bailey, S. M.
2014-12-01
The 5.3μm emission from the vibrational levels of nitric oxide (NO) and the 15μm emission from CO2 are known to be the dominant sources of cooling in the thermosphere above 100 km. The 5.3μm emission is primarily produced by the radiative de-excitation of NO from its first vibrational level, which in turn is mainly populated by the collisions of NO with atomic oxygen. However, the reaction of atomic nitrogen (N(4S) and N(2D)) with O2 yields vibrationally excited NO with v>1, resulting in a radiative cascade which produces more than one 5.3μm photon per vibrationally excited NO molecule. This chemiluminescence is approximately 20% in magnitude of the emission produced by thermal collisions. These additional sources of the 5.3μm emission are introduced into a one dimensional photochemical model and the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) to assess their variability with latitude and solar activity, and to also understand their effect on the thermospheric energy budget. The results from the models are compared with data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment on-board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, which has been making measurements of the infrared radiative response of the mesosphere and thermosphere to solar inputs since 2002.
On the nature of intramolecular vibrational energy transfer in dense molecular environments
Energy Technology Data Exchange (ETDEWEB)
Benten, Rebekka S. von [Institut fuer Physikalische Chemie der Universitaet Goettingen, Tammannstrasse 6, D-37077 Goettingen (Germany); Abel, Bernd, E-mail: Bernd.Abel@uni-lepzig.de [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig, Linne-Strasse 2, D-04103 Leipzig (Germany)
2010-12-09
Graphical abstract: Mechanisms of IVR in multi-tiers of intramolecular energy levels in different molecular environments are investigated. - Abstract: Transient femtosecond-IR-pump-UV-absorption probe-spectroscopy has been employed to shed light on the nature of intramolecular vibrational energy transfer (IVR) in dense molecular environments ranging from the diluted gas phase to the liquid. A general feature in our experiments and those of others is that IVR proceeds via multiple timescales if overtones or combination vibrations of high frequency modes are excited. It has been found that collisions enhance IVR if its (slower) timescales can compete with collisions. This enhancement is, however, much more weaker and rather inefficient as opposed to the effect of collisions on intermolecular energy transfer which is well known. In a series of experiments we found that IVR depends not significantly on the average energy transferred in a collision but rather on the number of collisions. The collisions are much less efficient in affecting IVR than VET. We conclude that collision induced broadening of vibrational energy levels reduces the energy gaps and enhances existing couplings between tiers. The present results are an important step forward to rationalize and understand apparently different and not consistent results from different groups on different molecular systems between gas and liquid phases.
Vibrational excitation of D2 by low energy electrons
International Nuclear Information System (INIS)
Buckman, S.J.; Phelps, A.V.
1985-01-01
Excitation coefficients for the production of vibrationally exicted D 2 by low energy electrons have been determined from measurements of the intensity of infrared emission from mixtures of D 2 and small concentrations of CO 2 or CO. The measurements were made using the electron drift tube technique and covered electric field to gas density ratios (E/n) from (5 to 80) x 10 -21 V m 2 , corresponding to mean electron energies between 0.45 and 4.5 eV. The CO 2 and CO concentrations were chosen to allow efficient excitation transfer from the D 2 to the carbon containing molecule, but to minimize direct excitation of the CO 2 or CO. The measured infrared intensities were normalized to predicted values for N 2 --CO 2 and N 2 --CO mixtures at E/n where the efficiency of vibrational excitation is known to be very close to 100%. The experimental excitation coefficients are in satisfactory agreement with predictions based on electron--D 2 cross sections at mean electron energies below 1 eV, but are about 50% too high at mean energies above about 2 eV. Application of the technique to H 2 did not yield useful vibrational excitation coefficients. The effective coefficients in H 2 --CO 2 mixtures were a factor of about 3 times the predicted values. For our H 2 --CO mixtures the excitation of CO via excitation transfer from H 2 is small compared to direct electron excitation of CO molecules. Published experiments and theories on electron--H 2 and electron--D 2 collisions are reviewed to obtain the cross sections used in the predictions
Effects of Proof Mass Geometry on Piezoelectric Vibration Energy Harvesters
Directory of Open Access Journals (Sweden)
Abdul Hafiz Alameh
2018-05-01
Full Text Available Piezoelectric energy harvesters have proven to have the potential to be a power source in a wide range of applications. As the harvester dimensions scale down, the resonance frequencies of these devices increase drastically. Proof masses are essential in micro-scale devices in order to decrease the resonance frequency and increase the strain along the beam to increase the output power. In this work, the effects of proof mass geometry on piezoelectric energy harvesters are studied. Different geometrical dimension ratios have significant impact on the resonance frequency, e.g., beam to mass lengths, and beam to mass widths. A piezoelectric energy harvester has been fabricated and tested operating at a frequency of about 4 kHz within the audible range. The responses of various prototypes were studied, and an optimized T-shaped piezoelectric vibration energy harvester design is presented for improved performance.
Harvesting Energy from Vibrations of the Underlying Structure
DEFF Research Database (Denmark)
Han, Bo; Vssilaras, S; Papadias, C.B.
2013-01-01
to the long-term structural health of a building or bridge, but at the same time they can be exploited as a power source to power the wireless sensors that are monitoring this structural health. This paper presents a new energy harvesting method based on a vibration driven electromagnetic harvester. By using......The use of wireless sensors for structural health monitoring offers several advantages such as small size, easy installation and minimal intervention on existing structures. However the most significant concern about such wireless sensors is the lifetime of the system, which depends heavily...... on the type of power supply. No matter how energy efficient the operation of a battery operated sensor is, the energy of the battery will be exhausted at some point. In order to achieve a virtually unlimited lifetime, the sensor node should be able to recharge its battery in an easy way. Energy harvesting...
Novel piezoelectric bistable oscillator architecture for wideband vibration energy harvesting
International Nuclear Information System (INIS)
Liu, W Q; Badel, A; Formosa, F; Wu, Y P; Agbossou, A
2013-01-01
Bistable vibration energy harvesters are attracting more and more interest because of their capability to scavenge energy over a large frequency band. The bistable effect is usually based on magnetic interaction or buckled beams. This paper presents a novel architecture based on amplified piezoelectric structures. This buckled spring–mass architecture allows the energy of the dynamic mass to be converted into electrical energy in the piezoelectric materials as efficiently as possible. Modeling and design are performed and a normalized expression of the harvester behavior is given. Chirp and band-limited noise excitations are used to evaluate the proposed harvester’s performances. Simulation and experimental results are in good agreement. A method of using a spectrum plot for investigating the interwell motion is presented. The effect of the electric load impedance matching strategy is also studied. Results and comparisons with the literature show that the proposed device combines a large bandwidth and a high power density. (paper)
A Vibration Control Method for the Flexible Arm Based on Energy Migration
Directory of Open Access Journals (Sweden)
Yushu Bian
2015-01-01
Full Text Available A vibration control method based on energy migration is proposed to decrease vibration response of the flexible arm undergoing rigid motion. A type of vibration absorber is suggested and gives rise to the inertial coupling between the modes of the flexible arm and the absorber. By analyzing 1 : 2 internal resonance, it is proved that the internal resonance can be successfully created and the exchange of vibration energy is existent. Due to the inertial coupling, the damping enhancement effect is revealed. Via the inertial coupling, vibration energy of the flexible arm can be dissipated by not only the damping of the vibration absorber but also its own enhanced damping, thereby effectively decreasing vibration. Through numerical simulations and analyses, it is proven that this method is feasible in controlling nonlinear vibration of the flexible arm undergoing rigid motion.
Epistemic uncertainty propagation in energy flows between structural vibrating systems
Xu, Menghui; Du, Xiaoping; Qiu, Zhiping; Wang, Chong
2016-03-01
A dimension-wise method for predicting fuzzy energy flows between structural vibrating systems coupled by joints with epistemic uncertainties is established. Based on its Legendre polynomial approximation at α=0, both the minimum and maximum point vectors of the energy flow of interest are calculated dimension by dimension within the space spanned by the interval parameters determined by fuzzy those at α=0 and the resulted interval bounds are used to assemble the concerned fuzzy energy flows. Besides the proposed method, vertex method as well as two current methods is also applied. Comparisons among results by different methods are accomplished by two numerical examples and the accuracy of all methods is simultaneously verified by Monte Carlo simulation.
Homogeneity Analysis of a MEMS-based PZT Thick Film Vibration Energy Harvester Manufacturing Process
DEFF Research Database (Denmark)
Lei, Anders; Xu, Ruichao; Borregaard, Louise M.
2012-01-01
This paper presents a homogeneity analysis of a high yield wafer scale fabrication of MEMS-based unimorph silicon/PZT thick film vibration energy harvesters aimed towards vibration sources with peak vibrations in the range of around 300Hz. A wafer with a yield of 91% (41/45 devices) has been...
Vibration energy harvesting in railway tunnels with a wireless sensor node application
Energy Technology Data Exchange (ETDEWEB)
Wischke, Martin
2012-07-01
Vibration harvesting is a promising concept to prolong the lifetime of batterypowered stand-alone systems, or even to enable their energy-autonomy. This thesis focuses on ambient vibrations converted by electromechanical transducers into electricity. The final goal is energy scavenging from train-induced vibrations in railway tunnels. This is achieved via the development of a suitable harvester for this environment and the practical demonstration of a vibrationpowered wireless sensor node (WSN). At the beginning of this thesis, extensive vibration measurements were performed in several traffic tunnels. The obtained unique data set formed the basis for the design and test of several harvesters. The railway sleeper was chosen as usable harvester location. A shock-resistant double-side suspended piezoelectric cantilever was developed. Several cantilevers with different eigenfrequencies are combined in an array, creating a robust harvester with a broad bandwidth. A field test of 7 days in the Loetschbergbasis-tunnel verified that, on average the sufficient energy for powering a virtual wireless sensor node was scavenged. For application in a real WSN, the harvester array was scaled up to 10 cantilevers. The power management for the sensor node was developed concurrently. The central component is a power switch that monitors the energy level in the system's storage capacitor and only triggers the wireless interface when sufficient energy is available. Combined with a train detection circuit, the presented energy-autonomous WSN reliably reports every passing vehicle. In addition to the development of an energy-autonomous fully integrated WSN, this work investigates nonlinear properties of PZT ceramics. Consideration of the elastostriction and the electrostriction enables a more precises prediction of the tip displacement of a piezoelectric cantilever actuator. Further, the elastostriction is exploited to modify the resonance frequency of a bimorph cantilever. Basing
Vibrational energy transfer in selectively excited diatomic molecules
International Nuclear Information System (INIS)
Dasch, C.J.
1978-09-01
Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295 0 K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295 0 K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ΔJ transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references
Schwenke, David W.; Truhlar, Donald G.
1988-04-01
We present new ab initio calculations of the HF-HF interaction potential for the case where both molecules are simultaneously displaced from their equilibrium internuclear distance. These and previous ab initio calculations are then fit to a new analytic representation which is designed to be efficient to evaluate and to provide an especially faithful account of the forces along the vibrational coordinates. We use the new potential for two sets of quantal scattering calculations for collisions in three dimensions with total angular momentum zero. First we test that the angular harmonic representation of the anisotropy is adequate by comparing quantal rigid rotator calculations to those carried out for potentials involving higher angular harmonics and for which the expansion in angular harmonics is systematically increased to convergence. Then we carry out large-scale quantal calculations of vibration-vibration energy transfer including the coupling of both sets of vibrational and rotational coordinates. These calculations indicate that significant rotational energy transfer accompanies the vibration-to-vibration energy transfer process.
Anharmonic vibrational properties in periodic systems: energy, electron-phonon coupling, and stress
Monserrat, Bartomeu; Drummond, N. D.; Needs, R. J.
2013-01-01
A unified approach is used to study vibrational properties of periodic systems with first-principles methods and including anharmonic effects. Our approach provides a theoretical basis for the determination of phonon-dependent quantities at finite temperatures. The low-energy portion of the Born-Oppenheimer energy surface is mapped and used to calculate the total vibrational energy including anharmonic effects, electron-phonon coupling, and the vibrational contribution to the stress tensor. W...
Zou, Hong-Xiang; Zhang, Wen-Ming; Li, Wen-Bo; Wei, Ke-Xiang; Hu, Kai-Ming; Peng, Zhi-Ke; Meng, Guang
2018-03-01
The combination of nonlinear bistable and flextensional mechanisms has the advantages of wide operating frequency and high equivalent piezoelectric constant. In this paper, three magnetically coupled flextensional vibration energy harvesters (MF-VEHs) are designed from three magnetically coupled vibration systems which utilize a magnetic repulsion, two symmetrical magnetic attractions and multi-magnetic repulsions, respectively. The coupled dynamic models are developed to describe the electromechanical transitions. Simulations under harmonic excitation and random excitation are carried out to investigate the performance of the MF-VEHs with different parameters. Experimental validations of the MF-VEHs are performed under different excitation levels. The experimental results verify that the developed mathematical models can be used to accurately characterize the MF-VEHs for various magnetic coupling modes. A comparison of three MF-VEHs is provided and the results illustrate that a reasonable arrangement of multiple magnets can reduce the threshold excitation intensity and increase the harvested energy.
Harvesting vibrational energy due to intermodal systems via nano coated piezo electric devices.
2015-12-01
Vibrational energy resulting from intermodal transport systems can be recovered through the use of energy harvesting system consisting of PZT piezo electric material as the primary energy harvesting component. The ability of traditional PZT piezo ele...
Energy Technology Data Exchange (ETDEWEB)
Kunimatsu, S; Jinguji, M [National Institute for Resources and Environment, Tsukuba (Japan); Yamada, M; Hirai, T [Newjec Inc., Osaka (Japan); Durucan, S; Farsangi, M
1997-10-22
With an objective to assess environmental influence induced by blast vibration, a study has been carried out on a method to predict vibration levels. The study has discussed a method to calculate vibration levels, in which vibration propagating characteristics are sought on blast vibration generated from an open-cut limestone mine from acceleration waveforms in the vicinity of the blast source and residential housings by using an octave analysis, and waveforms are predicted. The shortest straight line distance from the blast position to a housing is about 150 m, and the height difference is about 30 to 40 meters. The measuring instruments include a vibration level meter used for pollution measurement and a data recorder, with signals lower than 1 Hz and higher than 90 Hz being interrupted. The environmental influence assessment discusses not only the maximum value of the vibration level, but also sizes of values of each band by using a frequency analysis. The result of the discussions revealed that the prediction of the vibration levels is little affected by phase characteristics, and that no problems are caused in the measurement accuracy even if the vibration levels are predicted by using relative decay amount according to a one-third octave analysis for the propagation characteristics. 5 figs., 4 tabs.
Piezoelectric energy harvesting from flow-induced vibration
International Nuclear Information System (INIS)
Wang, D-A; Ko, H-H
2010-01-01
A new piezoelectric energy harvester for harnessing energy from flow-induced vibration is developed. It converts flow energy into electrical energy by piezoelectric conversion with oscillation of a piezoelectric film. A finite element model is developed in order to estimate the generated voltage of the piezoelectric laminate subjected to a distributed load. Prototypes of the energy harvester are fabricated and tested. Experimental results show that an open circuit output voltage of 2.2 V pp and an instantaneous output power of 0.2 µW are generated when the excitation pressure oscillates with an amplitude of 1.196 kPa and a frequency of about 26 Hz. The solution of the generated voltage based on the finite element model agrees well with the experiments. Based on the finite element model, the effects of the piezoelectric film dimensions, the fluid pressure applied to the harvester and types of piezoelectric layer on the output voltage of the harvester can be investigated.
Report of workshop on vibration related to fluid in atomic energy field. 4
International Nuclear Information System (INIS)
1993-01-01
This is the fourth workshop on the vibration related to fluid in atomic energy field of Yayoi research group. This time, two topics were taken up. One is edgetone phenomena and the liquid surface vibration phenomena due to flow. Another is the introduction of the experience in light water reactors. The workshop was held on August 30 and 31, 1993 at Nuclear Engineering Research Laboratory, University of Tokyo. At the workshop, lectures were given on the mechanism of occurrence of edgetone, the theoretical analysis of edgetone and edgenoise, the self-excited vibration of free liquid surface due to vertical plane jet and vertical cylindrical jet, the research on flow instability phenomena in parallel loop system, the irregular vibration behavior of U-shaped tubes excited by flow, the research on the vibration of cyclindrical weir due to fluid discharge, the examples of the vibration related to fluid in LWRs, the estimation of fatigue phenomena in bearing rings, the vibration of rotary vanes and verifying test, the analysis of flow in isolated phase bus plate vane and the measurement of velocity distribution, flow in piping and the behavior of valve vibration, the condition for the occurrence of flow vibration in the main steam separation valve of BWR, the vibration of piping due to orifice, the analysis of flow in two-dimensional vibrating cascade, and the subjects of fluid vibration assessment in atomic energy. (K.I.)
A modal approach to modeling spatially distributed vibration energy dissipation.
Energy Technology Data Exchange (ETDEWEB)
Segalman, Daniel Joseph
2010-08-01
The nonlinear behavior of mechanical joints is a confounding element in modeling the dynamic response of structures. Though there has been some progress in recent years in modeling individual joints, modeling the full structure with myriad frictional interfaces has remained an obstinate challenge. A strategy is suggested for structural dynamics modeling that can account for the combined effect of interface friction distributed spatially about the structure. This approach accommodates the following observations: (1) At small to modest amplitudes, the nonlinearity of jointed structures is manifest primarily in the energy dissipation - visible as vibration damping; (2) Correspondingly, measured vibration modes do not change significantly with amplitude; and (3) Significant coupling among the modes does not appear to result at modest amplitudes. The mathematical approach presented here postulates the preservation of linear modes and invests all the nonlinearity in the evolution of the modal coordinates. The constitutive form selected is one that works well in modeling spatially discrete joints. When compared against a mathematical truth model, the distributed dissipation approximation performs well.
A method for regulating strong nonlinear vibration energy of the flexible arm
Directory of Open Access Journals (Sweden)
Yushu Bian
2015-07-01
Full Text Available For an oscillating system, large amplitude indicates strong vibration energy. In this article, modal interaction is used as a useful means to regulate strong nonlinear vibration energy of the flexible arm undergoing rigid motion. A method is put forward to migrate and dissipate vibration energy based on modal interaction. By means of multiple-scale perturbation analysis, it is proven that internal resonance can be successfully established between modes of the flexible arm and the vibration absorber. Through examples and analyses, it is verified that this control method is effective in regulating strong vibration energy and can be used to suppress strong nonlinear vibration of the flexible arm undergoing rigid motion.
Directory of Open Access Journals (Sweden)
Elie-Jacques Fares
Full Text Available There is increasing recognition about the importance of enhancing energy expenditure (EE for weight control through increases in low-intensity physical activities comparable with daily life (1.5-4 METS. Whole-body vibration (WBV increases EE modestly and could present both a useful adjuvant for obesity management and tool for metabolic phenotyping. However, it is unclear whether a "dose-response" exists between commonly-used vibration frequencies (VF and EE, nor if WBV influences respiratory quotient (RQ, and hence substrate oxidation. We aimed to investigate the EE-VF and RQ-VF relationships across three different frequencies (30, 40, and 50Hz.EE and RQ were measured in 8 healthy young adults by indirect calorimetry at rest, and subsequently during side-alternating WBV at one of 3 VFs (30, 40, and 50 Hz. Each frequency was assessed over 5 cycles of intermittent WBV (30s vibration/30s rest, separated by 5 min seated rest. During the WBV participants stood on the platform with knees flexed sufficiently to maintain comfort, prevent transmission of vibration to the upper body, and minimise voluntary physical exertion. Repeatability was assessed across 3 separate days in a subset of 4 individuals. In order to assess any sequence/habituation effect, an additional group of 6 men underwent 5 cycles of intermittent WBV (30s vibration/30s rest at 40 Hz, separated by 5 min seated rest.Side-alternating WBV increased EE relative to standing, non-vibration levels (+36%, p<0.001. However, no differences in EE were observed across VFs. Similarly, no effect of VF on RQ was found, nor did WBV alter RQ relative to standing without vibration.No relationship could be demonstrated between EE and VF in the range of 30-50Hz, and substrate oxidation did not change in response to WBV. Furthermore, the thermogenic effect of intermittent WBV, whilst robust, was quantitatively small (<2 METS.
Homotopy analysis approach for nonlinear piezoelectric vibration energy harvesting
Directory of Open Access Journals (Sweden)
Shahlaei-Far Shahram
2016-01-01
Full Text Available Piezoelectric energy harvesting from a vertical geometrically nonlinear cantilever beam with a tip mass subject to transverse harmonic base excitations is analyzed. One piezoelectric patch is placed on the slender beam to convert the tension and compression into electrical voltage. Applying the homotopy analysis method to the coupled electromechanical governing equations, we derive analytical solutions for the horizontal displacement of the tip mass and consequently the output voltage from the piezoelectric patch. Analytical approximation for the frequency response and phase of the geometrically forced nonlinear vibration system are also obtained. The research aims at a rigorous analytical perspective on a nonlinear problem which has previously been solely investigated by numerical and experimental methods.
A theoretical analysis on vibrational-energy transfers in gases
International Nuclear Information System (INIS)
Mastrocinque, G.
1981-01-01
In order to investigate the relationships between three-dimensional and colinear molecular-collision models with particular emphasis on the role of repulsive and attractive forces in vibrational-energy transfers in gases, a theoretical analysis is developed in this paper. A few known results - mainly the Cottrell and Ream equation, the Takayanagi and the Shin expressions of the transfer probability - relevant to repulsive-force-dominated processes are obtained and/or discussed in the proposed frame. Light is also given on long-range, attractive-forces-dominated processes. The main result of this investigation is that, when a suitable hypothesis is done on the transfer probability, centrifugal effects on the intermolecular trajectories due to standard potentials are negligible in the low-temperature range. A quasi-colinear collision model, which is found to be correlated to the Cottrell and Ream expression for the transfer probability, is regained from a three-dimensional geometry in these conditions. (author)
New DRIE-Patterned Electrets for Vibration Energy Harvesting
Directory of Open Access Journals (Sweden)
Chaillout J.-J.
2012-10-01
Full Text Available This paper is about a new manufacturing process aimed at developing stable SiO2/Si3N4 patterned electrets using a Deep Reactive Ion Etching (DRIE step for an application in electret-based Vibration Energy Harvesters (e-VEH. This process consists in forming continuous layers of SiO2/Si3N4 electrets in order to limit surface conduction phenomena and is a new way to see the problem of electret patterning. Experimental results prove that patterned electrets charged by a positive corona discharge show excellent stability with high surface charge densities that may reach 5mC/m2 on 1.1μm-thick layers, even with fine patterning and harsh temperature conditions (up to 250°C. This paves the way to new e-VEH designs and manufacturing processes.
Energy Technology Data Exchange (ETDEWEB)
Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.
2013-07-01
Formal journal article Experimental analysis of a piezoelectric energy harvesting system for harmonic, random, and sine on random vibration Abstract: Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Additionally, the implications of source vibration characteristics on harvester design are discussed. Studies in vibration harvesting have yielded numerous alternatives for harvesting electrical energy from vibrations but piezoceramics arose as the most compact, energy dense means of energy transduction. The rise in popularity of harvesting energy from ambient vibrations has made piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. In this manuscript, variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. We characterize the source vibration by its acceleration response for repeatability and transcription to general application. The results agree with numerical and theoretical predictions for in previous literature that load optimal resistance varies with transducer natural frequency and source type, and the findings demonstrate that significant gains are seen with lower tuned transducer natural frequencies for similar source amplitudes. Going beyond idealized steady state sinusoidal and simplified random vibration input, SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibrational sources significantly alter power generation and power processing
Nammari, Abdullah; Caskey, Logan; Negrete, Johnny; Bardaweel, Hamzeh
2018-03-01
This article presents a non-resonant magneto-mechanical vibration energy harvester. When externally excited, the energy harvester converts vibrations into electric charge using a guided levitated magnet oscillating inside a multi-turn coil that is fixed around the exterior of the energy harvester. The levitated magnet is guided using four oblique mechanical springs. A prototype of the energy harvester is fabricated using additive manufacturing. Both experiment and model are used to characterize the static and dynamic behavior of the energy harvester. Measured restoring forces show that the fabricated energy harvester retains a mono-stable potential energy well with desired stiffness nonlinearities. Results show that magnetic spring results in hardening effect which increases the resonant frequency of the energy harvester. Additionally, oblique mechanical springs introduce geometric, negative, nonlinear stiffness which improves the harvester's response towards lower frequency spectrum. The unique design can produce a tunable energy harvester with multi-well potential energy characteristics. A finite element model is developed to estimate the average radial flux density experienced by the multi-turn coil. Also, a lumped parameter model of the energy harvester is developed and validated against measured data. Both upward and downward frequency sweeps are performed to determine the frequency response of the harvester. Results show that at higher excitation levels hardening effects become more apparent, and the system dynamic response turns into non-resonant. Frequency response curves exhibit frequency jump phenomena as a result of coexistence of multiple energy states at the frequency branch. The fabricated energy harvester is hand-held and measures approximately 100.5 [cm3] total volume. For a base excitation of 1.0 g [m/s2], the prototype generates a peak voltage and normalized power density of approximately 3.5 [V] and 0.133 [mW/cm3 g2], respectively, at 15.5 [Hz].
Energy harvesting from vibration with cross-linked polypropylene piezoelectrets
Directory of Open Access Journals (Sweden)
Xiaoqing Zhang
2015-07-01
Full Text Available Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP, followed by proper corona charging. Young’s modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d33 coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d33 ⋅ g33 for a more typical d33 value of 400 pC/N is about 11.2 GPa−1. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm2 and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.
Energy harvesting from vibration with cross-linked polypropylene piezoelectrets
Energy Technology Data Exchange (ETDEWEB)
Zhang, Xiaoqing [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Institute for Telecommunications Technology, Merckstrasse 25, 64283 Darmstadt (Germany); Wu, Liming [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Sessler, Gerhard M., E-mail: g.sessler@nt.tu-darmstadt.de [Institute for Telecommunications Technology, Merckstrasse 25, 64283 Darmstadt (Germany)
2015-07-15
Piezoelectret films are prepared by modification of the microstructure of polypropylene foam sheets cross-linked by electronic irradiation (IXPP), followed by proper corona charging. Young’s modulus, relative permittivity, and electromechanical coupling coefficient of the fabricated films, determined by dielectric resonance spectra, are about 0.7 MPa, 1.6, and 0.08, respectively. Dynamic piezoelectric d{sub 33} coefficients up to 650 pC/N at 200 Hz are achieved. The figure of merit (FOM, d{sub 33} ⋅ g{sub 33}) for a more typical d{sub 33} value of 400 pC/N is about 11.2 GPa{sup −1}. Vibration-based energy harvesting with one-layer and two-layer stacks of these films is investigated at various frequencies and load resistances. At an optimum load resistance of 9 MΩ and a resonance frequency of 800 Hz, a maximum output power of 120 μW, referred to the acceleration g due to gravity, is obtained for an energy harvester consisting of a one-layer IXPP film with an area of 3.14 cm{sup 2} and a seismic mass of 33.7 g. The output power can be further improved by using two-layer stacks of IXPP films in electric series. IXPP energy harvesters could be used to energize low-power electronic devices, such as wireless sensors and LED lights.
Nearest neighbor spacing distributions of low-lying levels of vibrational nuclei
International Nuclear Information System (INIS)
Abul-Magd, A.Y.; Simbel, M.H.
1996-01-01
Energy-level statistics are considered for nuclei whose Hamiltonian is divided into intrinsic and collective-vibrational terms. The levels are described as a random superposition of independent sequences, each corresponding to a given number of phonons. The intrinsic motion is assumed chaotic. The level spacing distribution is found to be intermediate between the Wigner and Poisson distributions and similar in form to the spacing distribution of a system with classical phase space divided into separate regular and chaotic domains. We have obtained approximate expressions for the nearest neighbor spacing and cumulative spacing distribution valid when the level density is described by a constant-temperature formula and not involving additional free parameters. These expressions have been able to achieve good agreement with the experimental spacing distributions. copyright 1996 The American Physical Society
Topology optimization and fabrication of low frequency vibration energy harvesting microdevices
International Nuclear Information System (INIS)
Deng, Jiadong; Rorschach, Katherine; Baker, Evan; Sun, Cheng; Chen, Wei
2015-01-01
Topological design of miniaturized resonating structures capable of harvesting electrical energy from low frequency environmental mechanical vibrations encounters a particular physical challenge, due to the conflicting design requirements: low resonating frequency and miniaturization. In this paper structural static stiffness to resist undesired lateral deformation is included into the objective function, to prevent the structure from degenerating and forcing the solution to be manufacturable. The rational approximation of material properties interpolation scheme is introduced to deal with the problems of local vibration and instability of the low density area induced by the design dependent body forces. Both density and level set based topology optimization (TO) methods are investigated in their parameterization, sensitivity analysis, and applicability for low frequency energy harvester TO problems. Continuum based variation formulations for sensitivity analysis and the material derivative based shape sensitivity analysis are presented for the density method and the level set method, respectively; and their similarities and differences are highlighted. An external damper is introduced to simulate the energy output of the resonator due to electrical damping and the Rayleigh proportional damping is used for mechanical damping. Optimization results for different scenarios are tested to illustrate the influences of dynamic and static loads. To demonstrate manufacturability, the designs are built to scale using a 3D microfabrication method and assembled into vibration energy harvester prototypes. The fabricated devices based on the optimal results from using different TO techniques are tested and compared with the simulation results. The structures obtained by the level set based TO method require less post-processing before fabrication and the structures obtained by the density based TO method have resonating frequency as low as 100 Hz. The electrical voltage response
The impact of accelerometer mounting methods on the level of vibrations recorded at ground surface
Directory of Open Access Journals (Sweden)
Krzysztof Czech
2014-08-01
Full Text Available The paper presents the results of field research based on the measurements of accelerations recorded at ground surface. The source of the vibration characterized by high repetition rate of pulse parameters was light falling weight deflectometer ZFG-01. Measurements of vibrations have been carried out using top quality high-precision measuring system produced by Brüel&Kiær. Accelerometers were mounted on a sandy soil surface at the measuring points located radially at 5-m and 10-m distances from the source of vibration. The paper analyses the impact that the method of mounting accelerometers on the ground has on the level of the recorded values of accelerations of vibrations. It has been shown that the method of attaching the sensor to the surface of the ground is crucial for the credibility of the performed measurements.[b]Keywords[/b]: geotechnics, surface vibrations, ground, vibration measurement
Vibration piezoelectric energy harvester with multi-beam
Energy Technology Data Exchange (ETDEWEB)
Cui, Yan, E-mail: yanc@dlut.edu.cn; Zhang, Qunying, E-mail: zhangqunying89@126.com; Yao, Minglei, E-mail: yaomingleiok@126.com [Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Dong, Weijie, E-mail: dongwj@dlut.edu.cn [School of Electronic and Information Engineering, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Gao, Shiqiao, E-mail: gaoshq@bit.edu.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, 100081, Beijing Province (China)
2015-04-15
This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film were measured; XRD (X-ray diffraction) pattern and AFM (Atomic Force Microscope) image of the PZT thin film were measured, and show that the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film is highly (110) crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 μC/cm{sup 2}, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d{sub 33} is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency. .
Computation of expectation values from vibrational coupled-cluster at the two-mode coupling level
DEFF Research Database (Denmark)
Zoccante, Alberto; Seidler, Peter; Christiansen, Ove
2011-01-01
In this work we show how the vibrational coupled-cluster method at the two-mode coupling level can be used to calculate zero-point vibrational averages of properties. A technique is presented, where any expectation value can be calculated using a single set of Lagrangian multipliers computed...
Reviving Vibration Energy Harvesting and Self-Powered Sensing by a Triboelectric Nanogenerator
Chen, Jun
2017-10-10
Vibration energy harvesting and sensing is a traditional and growing research field in which various working mechanisms and designs have been developed for an improved performance. Relying on a coupling effect of contact electrification and electrostatic induction, in the past 5 years, triboelectric nanogenerator (TENG) has been applied as a fundamentally new technology to revive the field of vibration energy harvesting and self-powered sensing, especially for low-frequency vibrations such as human motion, automobile, machine, and bridge vibrations. The demonstrated instantaneous energy conversion efficiency of ∼70% and a total efficiency up to 85% distinguished TENG from traditional techniques. In this article, both TENG-enabled vibration energy harvesting and self-powered active sensing are comprehensively reviewed. Moving toward future development, problems pressing for solutions and onward research directions are also posed to deliver a coherent picture.
Directory of Open Access Journals (Sweden)
Jackson W. Cryns
2013-01-01
Full Text Available Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random, and sine on random (SOR input vibration scenarios; the implications of source vibration characteristics on harvester design are discussed. The rise in popularity of harvesting energy from ambient vibrations has made compact, energy dense piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. Variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. The results agree with numerical and theoretical predictions in the previous literature for optimal power harvesting in sinusoidal and flat broadband vibration scenarios. Going beyond idealized steady-state sinusoidal and flat random vibration input, experimental SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibration sources significantly alter power generation and processing requirements by varying harvested power, shifting optimal conditioning impedance, inducing voltage fluctuations, and ultimately rendering idealized sinusoidal and random analyses incorrect.
Gardner, Adrian M.; Tuttle, William Duncan; Whalley, Laura E.; Claydon, Andrew; Carter, Joseph H.; Wright, Timothy G.
2017-06-01
The S_{1} electronic state and ground state of the cation of para-fluorotoluene (pFT) have been investigated using resonance-enhanced multiphoton ionization (REMPI) spectroscopy and zero-kinetic-energy (ZEKE) spectroscopy. Here we focus on the low wavenumber region where a number of "pure" torsional, fundamental vibrational and vibration-torsional levels are expected; assignments of observed transitions are discussed, which are compared to results of published work on toluene (methylbenzene) from the Lawrance group. The similarity in the activity observed in the excitation spectrum of the two molecules is striking. A. M. Gardner, W. D. Tuttle, L. Whalley, A. Claydon, J. H. Carter and T. G. Wright, J. Chem. Phys., 145, 124307 (2016). J. R. Gascooke, E. A. Virgo, and W. D. Lawrance J. Chem. Phys., 143, 044313 (2015).
DEFF Research Database (Denmark)
Van Assche, P. H. M.; Baader, H. A.; Koch, H. R.
1971-01-01
The low-energy spectrum of the 55Mn(n,γ)56 Mn reaction has been studied with a γ-diffraction spectrometer. These data allowed the construction of a level scheme for 56Mn with two previously unobserved doublets. High-energy γ-transitions to the low-energy states have been measured for different...
Directory of Open Access Journals (Sweden)
Yushu Bian
2013-01-01
Full Text Available Due to the presence of system flexibility, impact can excite severe large amplitude vibration responses of the flexible robotic manipulator. This impact vibration exhibits characteristics of remarkable nonlinearity and strong energy. The main goal of this study is to put forward an energy-based control method to absorb and attenuate large amplitude impact vibration of the flexible robotic manipulator. The method takes advantage of internal resonance and is implemented through a vibration absorber based on the transfer and dissipation of energy. The addition of the vibration absorber to the flexible arm generates a coupling effect between vibration modes of the system. By means of analysis on 2:1 internal resonance, the exchange of energy is proven to be existent. The impact vibrational energy can be transferred from the arm to the absorber and dissipated through the damping of the absorber. The results of numerical simulations are promising and preliminarily verify that the method is feasible and can be used to combat large amplitude impact vibration of the flexible manipulator undergoing rigid motion.
Design and fabrication of an energy-harvesting device using vibration absorber
Heidari, Hamidreza; Afifi, Arash
2017-05-01
Energy-harvesting devices collect energy that is being wasted and convert to the electrical energy. For this reason, this type of devices is considered as a convenient alternative to traditional batteries. In this paper, experimental examinations were performed to investigate the application of harvesting device for the reduction of the vibration amplitude in a vibration system and also increase the efficiency of energy-harvesting device. This study focuses on the energy-harvesting device as both producing electrical device and a vibration disabled absorber. In this regard, a motion-based energy-harvesting device is designed to produce electrical energy and also eliminate vibrations of a two joint-end beam which is located under the harmonic excitation force. Then, the governing equations of the forced motion on the main beam are derived and energy-harvesting system are simulated. In addition, the system designed by MATLAB simulation is explained and its results are expressed. Finally, a prototype of the system was made and the ability of the energy-harvesting device to absorb the original system vibrations, as well as parameters impact on the efficiency of energy harvesting is investigated. Experimental results show that the energy-harvesting device, in addition to producing electric current with a maximum value of 1.5V, reduces 94% of the original system vibrations.
Vibrational energy transfer in gas phase water and ammonia
Energy Technology Data Exchange (ETDEWEB)
Hovis, F.E. Jr.
1979-09-01
The V ..-->.. T, R relaxation rate for NH/sub 3/ (..nu../sub 2/) was studied from 198/sup 0/K to 398/sup 0/K by the method of laser-excited vibrational fluorescence. The self-deactivation rate constant decreases from 2.4 ..mu..sec torr/sup -1/ at 198/sup 0/K to 0.65 ..mu..sec/sup -1/ torr/sup -1/ at 398/sup 0/K. The rate constants for deactivation by He, Ar, N/sub 2/, and O/sub 2/ are much smaller and show a weak temperature dependence in the opposite direction. The vibrational relaxation rates of the coupled ..nu../sub 1/, ..nu../sub 3/ stretching level manifold and of the 2..nu../sub 2/ bending level in H/sub 2//sup 18/O was studied from 250/sup 0/K to 400/sup 0/K using th same method as for NH/sub 3/. The ..nu../sub 1/, ..nu../sub 3/ self-deactivation rate goes from 1.4 ..mu..sec/sup -1/ torr/sup -1/ at 250/sup 0/K to 0.48 ..mu..sec-/sup 1/ torr-/sup 1/ at 400/sup 0/K. For 2..nu../sub 2/ it goes from 4.5 ..mu..sec-/sup 1/ torr to 1.9 ..mu..sec/sup -1/ torr/sup -1/. The temperature dependence of the deactivation of both levels by He and Ar is much weaker and the rates are several hundred times slower. Deactivation of ..nu../sub 1/, ..nu../sub 3/ by N/sub 2/, O/sub 2/, and CO/sub 2/ is measured only at 293/sup 0/K. N/sub 2/ and O/sub 2/ deactivate ..nu../sub 1/, ..nu../sub 3/ about 5 and CO/sub 2/ about 50 times faster than He or Ar.
STUDY OF THE VIBRATION LEVEL IN CASE OF MANUFACTURING ON A CNC MACHINE-TOOL
Directory of Open Access Journals (Sweden)
Ioan Călin ROȘCA
2015-12-01
Full Text Available The paper presents the results of an experimental research performed on a CNC machine tool type ISEL-GFV considering the vibration level developed during the manufacturing of different pieces of particleboard at six processing regimes. There were recorded signals on both time and frequency domains on the three main directions. Based on recorded data there are presented the main conclusions referring to the level of vibrations and the frequencies associated to the highest levels.
Control of 2D Flexible Structures by Confinement of Vibrations and Regulation of Their Energy Flow
Directory of Open Access Journals (Sweden)
Fakhreddine Landolsi
2009-01-01
Full Text Available In this paper, we investigate the control of 2D flexible structures by vibration confinement and the regulation of their energy flow along prespecified spatial paths. A discretized-model-based feedback strategy, aiming at confining and suppressing simultaneously the vibration, is proposed. It is assumed that the structure consists of parts that are sensitive to vibrations. The control design introduces a new pseudo-modal matrix derived from the computed eigenvectors of the discretized model. Simulations are presented to show the efficacy of the proposed control law. A parametric study is carried out to examine the effects of the different control parameters on the simultaneous confinement and suppression of vibrations. In addition, we conducted a set of simulations to investigate the flow control of vibrational energy during the confinement-suppression process. We found that the energy flow can be regulated via a set of control parameters for different confinement configurations.
Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine
Energy Technology Data Exchange (ETDEWEB)
Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Ellis-Gibbings, L.; García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); School of Biology, Chemistry and Forensic Science, University of Wolverhampton, Wolverhampton WV1 1LY (United Kingdom); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)
2015-09-07
We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energy condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.
Self-powered autonomous wireless sensor node using vibration energy harvesting
International Nuclear Information System (INIS)
Torah, R; Glynne-Jones, P; Tudor, M; Beeby, S; O'Donnell, T; Roy, S
2008-01-01
This paper reports the development and implementation of an energy aware autonomous wireless condition monitoring sensor system (ACMS) powered by ambient vibrations. An electromagnetic (EM) generator has been designed to harvest sufficient energy to power a radio-frequency (RF) linked accelerometer-based sensor system. The ACMS is energy aware and will adjust the measurement/transmit duty cycle according to the available energy; this is typically every 3 s at 0.6 m s −2 rms acceleration and can be as low as 0.2 m s −2 rms with a duty cycle around 12 min. The EM generator has a volume of only 150 mm 3 producing an average power of 58 µW at 0.6 m s −2 rms acceleration at a frequency of 52 Hz. In addition, a voltage multiplier circuit is shown to increase the electrical damping compared to a purely resistive load; this allows for an average power of 120 µW to be generated at 1.7 m s −2 rms acceleration. The ACMS has been successfully demonstrated on an industrial air compressor and an office air conditioning unit, continuously monitoring vibration levels and thereby simulating a typical condition monitoring application
Effect of collision energy and vibrational excitation on endothermic ion-molecule reactions
International Nuclear Information System (INIS)
Turner, T.P.
1984-07-01
This thesis is divided into two major parts. In the first part an experimental study of proton and deuteron transfer in H 2 + + He and HD + + He has been carried out as a function of kinetic and vibrational energy. The data gives evidence that at lower kinetic energies, the spectator stripping mechanism indeed plays an important role when H 2 + or HD + is vibrationally excited. The second half of this thesis examines the relative efficiencies between the excitation of C-C stretching vibration and collision energy on the promotion of the H atom transfer reaction of C 2 H 2 + + H 2 → C 2 H 3 + + H
Directory of Open Access Journals (Sweden)
Jae Eun Kim
2013-07-01
Full Text Available We propose a vibration energy harvester consisting of an auxiliary frequency-tuned mass unit and a piezoelectric vibration energy harvesting unit for enhancing output power. The proposed integrated system is so configured that its out-of-phase mode can appear at the lowest eigenfrequency unlike in the conventional system using a tuned unit. Such an arrangement makes the resulting system distinctive: enhanced output power at or near the target operating frequency and very little eigenfrequency separation, not observed in conventional eigenfrequency-tuned vibration energy harvesters. The power enhancement of the proposed system is theoretically examined with and without tip mass normalization or footprint area normalization.
Vibration energy harvesting system for railroad safety based on running vehicles
International Nuclear Information System (INIS)
Tianchen, Yuan; Jian, Yang; Ruigang, Song; Xiaowei, Liu
2014-01-01
This research is focused on energy harvesting from track vibration in order to provide power for the wireless sensors which monitor railroad health. Considering that track vibration has vibration energy, a new method is proposed in the paper to harvest energy based on the piezoelectric effect. The piezoelectric generator called drum transducer is the key part for track vibration energy harvesting. The model of drum transducer is established and the simulation results show that it can generate 100 mW in real track situation. In addition, an experiment rig is developed and its vibration model is also established. The simulation and experiment results show that peak open-circuit voltage of piezoelectric generator is about 50–70 V at the full load of the train. The whole track vibration energy harvesting system is analytically modeled, numerically simulated, and experimentally realized to demonstrate the feasibility and the reliability of the theoretical model. This paper is the theoretical basis of harvesting, recovering and recycling of the track vibration energy for track safety. (paper)
Enhancing Bone Accretion Using Short Duration, Low-Level Mechanical Vibrations
National Research Council Canada - National Science Library
Judex, Stefan
2005-01-01
.... In this second annual report, data are presented that indicate that the efficacy of extremely low-level whole-body mechanical vibrations can be enhanced by altering the number of daily loading...
Population of vibrational levels of carbon dioxide by cylindrical fast ionization wave
Levko, Dmitry; Pachuilo, Michael; Raja, Laxminarayan L.
2017-01-01
The population of vibrational levels of carbon dioxide (CO2) by a cylindrical fast ionization wave is analyzed using a one-dimensional Particle-in-Cell Monte Carlo collisions model. The model takes into account the inelastic electron
International Nuclear Information System (INIS)
Duque, H. V.; Chiari, L.; Jones, D. B.; Pettifer, Z.; Silva, G. B. da; Limão-Vieira, P.; Blanco, F.; García, G.; White, R. D.; Lopes, M. C. A.; Brunger, M. J.
2014-01-01
Differential and integral cross section measurements, for incident electron energies in the 20–50 eV range, are reported for excitation of several composite vibrational modes in α-tetrahydrofurfuryl alcohol (THFA). Optimisation and frequency calculations, using GAUSSIAN 09 at the B3LYP/aug-cc-pVDZ level, were also undertaken for the two most abundant conformers of THFA, with results being reported for their respective mode classifications and excitation energies. Those calculations assisted us in the experimental assignments of the composite features observed in our measured energy loss spectra. There are, to the best of our knowledge, no other experimental or theoretical data currently available in the literature against which we can compare the present results
Energy Technology Data Exchange (ETDEWEB)
Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Chiari, L.; Jones, D. B.; Pettifer, Z. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, G. [Instituto de Física Fundamental, CSIC, Madrid E-28006 (Spain); White, R. D. [School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia)
2014-06-07
Differential and integral cross section measurements, for incident electron energies in the 20–50 eV range, are reported for excitation of several composite vibrational modes in α-tetrahydrofurfuryl alcohol (THFA). Optimisation and frequency calculations, using GAUSSIAN 09 at the B3LYP/aug-cc-pVDZ level, were also undertaken for the two most abundant conformers of THFA, with results being reported for their respective mode classifications and excitation energies. Those calculations assisted us in the experimental assignments of the composite features observed in our measured energy loss spectra. There are, to the best of our knowledge, no other experimental or theoretical data currently available in the literature against which we can compare the present results.
International Nuclear Information System (INIS)
Chen Zhongsheng; Yang Yongmin; Lu Zhimiao; Luo Yanting
2013-01-01
Nowadays broadband vibration energy harvesting using piezoelectric effect has become a research hotspot. The innovation in this paper is the widening of the resonant bandwidth of a piezoelectric harvester based on phononic band gaps, which is called one-dimensional phononic piezoelectric cantilever beams (PPCBs). Broadband characteristics of one-dimensional PPCBs are analyzed deeply and the vibration band gap can be calculated. The effects of different parameters on the vibration band gap are presented by both numerical and finite element simulations. Finally experimental tests are conducted to validate the proposed method. It can be concluded that it is feasible to use the PPCB for broadband vibration energy harvesting and there should be a compromise among related parameters for low-frequency vibrations.
Energy Technology Data Exchange (ETDEWEB)
Chen Zhongsheng, E-mail: czs_study@sina.com [Key Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China); Yang Yongmin; Lu Zhimiao; Luo Yanting [Key Laboratory of Science and Technology on Integrated Logistics Support, College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073 (China)
2013-02-01
Nowadays broadband vibration energy harvesting using piezoelectric effect has become a research hotspot. The innovation in this paper is the widening of the resonant bandwidth of a piezoelectric harvester based on phononic band gaps, which is called one-dimensional phononic piezoelectric cantilever beams (PPCBs). Broadband characteristics of one-dimensional PPCBs are analyzed deeply and the vibration band gap can be calculated. The effects of different parameters on the vibration band gap are presented by both numerical and finite element simulations. Finally experimental tests are conducted to validate the proposed method. It can be concluded that it is feasible to use the PPCB for broadband vibration energy harvesting and there should be a compromise among related parameters for low-frequency vibrations.
Vibrational effects on surface energies and band gaps in hexagonal and cubic ice
International Nuclear Information System (INIS)
Engel, Edgar A.; Needs, Richard J.; Monserrat, Bartomeu
2016-01-01
Surface energies of hexagonal and cubic water ice are calculated using first-principles quantum mechanical methods, including an accurate description of anharmonic nuclear vibrations. We consider two proton-orderings of the hexagonal and cubic ice basal surfaces and three proton-orderings of hexagonal ice prism surfaces, finding that vibrations reduce the surface energies by more than 10%. We compare our vibrational densities of states to recent sum frequency generation absorption measurements and identify surface proton-orderings of experimental ice samples and the origins of characteristic absorption peaks. We also calculate zero point quantum vibrational corrections to the surface electronic band gaps, which range from −1.2 eV for the cubic ice basal surface up to −1.4 eV for the hexagonal ice prism surface. The vibrational corrections to the surface band gaps are up to 12% smaller than for bulk ice.
Directory of Open Access Journals (Sweden)
Lyashenko Mikhail
2017-01-01
Full Text Available This paper proposes mechanism and control algorithm for pneumatic relaxation system of suspension with vibration energy recuperation applied to standard vehicle operator seat (“Sibeko” company. Mathematical model of the seat pneumatic relaxation suspension with two additional air volumes was created. Pneumatic motor – recuperator activated by means of air flow from the one additional volume to another is installed in air piping between additional volumes. Computational research was made in Matlab/Simulink. Amplitude-frequency characteristics of transmission coefficient for standard and proposed suspensions were plotted for preliminary evaluation of vibration protection properties of seat suspension. Performed comparative analysis of amplitude-frequency characteristics shows that noticeable improvement of vibration protection properties of pneumatic relaxation suspension system with vibration energy recuperation in comparison with standard system both in region of resonance disturbances and in above-resonance region. Main ways for further improvement of vibration protection properties of proposed system were marked out.
Clingman, Dan J.; Thiesen, Jack
2017-04-01
Historically, piezoelectric vibration energy harvesters have been limited to operation at a single, structurally resonant frequency. A piezoceramic energy harvester, such as a bimorph beam, operating at structural resonance exchanges energy between dynamic and strain regimes. This energy exchange increases the coupling between piezoceramic deformation and electrical charge generation. Two BVEH mechanisms are presented that exploit strain energy management to reduce inertial forces needed to deform the piezoceramic, thus increasing the coupling between structural and electrical energy conversion over a broadband vibration spectrum. Broadband vibration excitation produces a non-sinusoidal electrical wave form from the BVEH device. An adaptive energy conversion circuit was developed that exploits a buck converter to capture the complex waveform energy in a form easily used by standard electrical components.
Vibration energy absorption in the whole-body system of a tractor operator.
Szczepaniak, Jan; Tanaś, Wojciech; Kromulski, Jacek
2014-01-01
Many people are exposed to whole-body vibration (WBV) in their occupational lives, especially drivers of vehicles such as tractor and trucks. The main categories of effects from WBV are perception degraded comfort interference with activities-impaired health and occurrence of motion sickness. Absorbed power is defined as the power dissipated in a mechanical system as a result of an applied force. The vibration-induced injuries or disorders in a substructure of the human system are primarily associated with the vibration power absorption distributed in that substructure. The vibration power absorbed by the exposed body is a measure that combines both the vibration hazard and the biodynamic response of the body. The article presents measurement method for determining vibration power dissipated in the human whole body system called Vibration Energy Absorption (VEA). The vibration power is calculated from the real part of the force-velocity cross-spectrum. The absorbed power in the frequency domain can be obtained from the cross-spectrum of the force and velocity. In the context of the vibration energy transferred to a seated human body, the real component reflects the energy dissipated in the biological structure per unit of time, whereas the imaginary component reflects the energy stored/released by the system. The seated human is modeled as a series/parallel 4-DOF dynamic models. After introduction of the excitation, the response in particular segments of the model can be analyzed. As an example, the vibration power dissipated in an operator has been determined as a function of the agricultural combination operating speed 1.39 - 4.16 ms(-1).
Vibration energy absorption in the whole-body system of a tractor operator
Directory of Open Access Journals (Sweden)
Jan Szczepaniak
2014-06-01
Full Text Available Many people are exposed to whole-body vibration (WBV in their occupational lives, especially drivers of vehicles such as tractor and trucks. The main categories of effects from WBV are perception degraded comfort interference with activities-impaired health and occurrence of motion sickness. Absorbed power is defined as the power dissipated in a mechanical system as a result of an applied force. The vibration-induced injuries or disorders in a substructure of the human system are primarily associated with the vibration power absorption distributed in that substructure. The vibration power absorbed by the exposed body is a measure that combines both the vibration hazard and the biodynamic response of the body. The article presents measurement method for determining vibration power dissipated in the human whole body system called Vibration Energy Absorption (VEA. The vibration power is calculated from the real part of the force-velocity cross-spectrum. The absorbed power in the frequency domain can be obtained from the cross-spectrum of the force and velocity. In the context of the vibration energy transferred to a seated human body, the real component reflects the energy dissipated in the biological structure per unit of time, whereas the imaginary component reflects the energy stored/released by the system. The seated human is modeled as a series/parallel 4-DOF dynamic models. After introduction of the excitation, the response in particular segments of the model can be analyzed. As an example, the vibration power dissipated in an operator has been determined as a function of the agricultural combination operating speed 1.39 – 4.16 ms[sup] -1 [/sup].
Measurements of vibrational excitation of N2, CO, and NO by low energy proton impact
International Nuclear Information System (INIS)
Krutein, J.; Linder, F.
1979-01-01
Differential scattering experiments are reported for proton impact on N 2 , CO, and NO in the energy range E/sub lab/=30--80 eV. The measurements include the range of very small scattering angles around 0 0 as well as the rainbow region. The vibrationally resolved energy-loss spectra show a relatively low vibrational inelasticity for all three systems. Differential cross sections, transition probabilities, and the mean vibrational energy transfer are presented. Rotational excitation is indicated by the broadening of the energy-loss peaks which is most significant for H + --NO. The small-angle scattering data for vibrational excitation in CO show good agreement with the impact parameter theory using the known long-range interactions for this system
Reviving Vibration Energy Harvesting and Self-Powered Sensing by a Triboelectric Nanogenerator
Chen, Jun; Wang, Zhong Lin
2017-01-01
Vibration energy harvesting and sensing is a traditional and growing research field in which various working mechanisms and designs have been developed for an improved performance. Relying on a coupling effect of contact electrification
International Nuclear Information System (INIS)
Huang, Dongmei; Xu, Wei; Shi, Lingling
2016-01-01
Highlights: • The nonlinear modified positive position feedback (NMPPF) scheme and the real-power form of restoring and damping forces are combined to improve the response performance of a vibration isolation system. • The primary resonance, dynamical stability and energy transmissibility of the real-power vibration isolation system are studied. • The sensitivity of the controller parameters on the responses has been analyzed. • In order to suppress the amplitude peak, the feedback parameters have been determined by the frequency response. • The energy transmissibility is investigated. - Abstract: In this paper, the nonlinear modified positive position feedback (NMPPF) scheme and the real-power form of restoring and damping forces are combined to improve the response performance of a vibration isolation system. Based on the method of multiple scales, the frequency response, the stability and the energy transmissibility of the real-power vibration isolation system are studied. It is found that the controlled isolation system exhibits a softening behavior for sub-linear restoring force, while it exhibits the two peak response characteristic rather than a hardening behavior for over-linear restoring force. Further, the sensitivity of the feedback parameters on the responses is discussed. The results, compared to the conventional PPF and IRC methods, show that the proposed method is significantly more effective in controlling the steady-state response, and slightly advantageous for the steady-state dynamics control. The effectiveness of this method is also verified by time domain analysis. Then, the suitable feedback and controller parameters are derived by simulation results in which the amplitude peak is suppressed and the resonance stability is maintained. Finally, the energy transmissibility of the vibration isolation system is investigated. The results show that the feedback gain can reduce the whole transmissibility level and greatly suppress vibration
Bettens, Ryan P A
2003-01-15
Collins' method of interpolating a potential energy surface (PES) from quantum chemical calculations for reactive systems (Jordan, M. J. T.; Thompson, K. C.; Collins, M. A. J. Chem. Phys. 1995, 102, 5647. Thompson, K. C.; Jordan, M. J. T.; Collins, M. A. J. Chem. Phys. 1998, 108, 8302. Bettens, R. P. A.; Collins, M. A. J. Chem. Phys. 1999, 111, 816) has been applied to a bound state problem. The interpolation method has been combined for the first time with quantum diffusion Monte Carlo calculations to obtain an accurate ground state zero-point energy, the vibrationally average rotational constants, and the vibrationally averaged internal coordinates. In particular, the system studied was fluoromethane using a composite method approximating the QCISD(T)/6-311++G(2df,2p) level of theory. The approach adopted in this work (a) is fully automated, (b) is fully ab initio, (c) includes all nine nuclear degrees of freedom, (d) requires no assumption of the functional form of the PES, (e) possesses the full symmetry of the system, (f) does not involve fitting any parameters of any kind, and (g) is generally applicable to any system amenable to quantum chemical calculations and Collins' interpolation method. The calculated zero-point energy agrees to within 0.2% of its current best estimate. A0 and B0 are within 0.9 and 0.3%, respectively, of experiment.
International Nuclear Information System (INIS)
Donovan, Robert J.; Lawley, Kenneth P.; Ridley, Trevor
2015-01-01
We report the identification of heavy Rydberg resonances in the ion-pair spectra of I 2 , Cl 2 , ICl, and IBr. Extensive vibrational progressions are analysed in terms of the energy dependence of the quantum defect δ(E b ) rather than as Dunham expansions. This is shown to define the heavy Rydberg region, providing a more revealing fit to the data with fewer coefficients and leads just as easily to numbering data sets separated by gaps in the observed vibrational progressions. Interaction of heavy Rydberg states with electronic Rydberg states at avoided crossings on the inner wall of the ion-pair potential is shown to produce distinctive changes in the energy dependence of δ(E b ), with weak and strong interactions readily distinguished. Heavy Rydberg behaviour is found to extend well below near-dissociation states, down to vibrational levels ∼18 000-20 000 cm −1 below dissociation. The rapid semi-classical calculation of δ(E b ) for heavy Rydberg states is emphasised and shows their absolute magnitude to be essentially the volume of phase space excluded from the vibrational motion by avoiding core-core penetration of the ions
Sensitivity of molecular vibrational dynamics to energy exchange rate constants
International Nuclear Information System (INIS)
Billing, G D; Coletti, C; Kurnosov, A K; Napartovich, A P
2003-01-01
The sensitivity of molecular vibrational population dynamics, governing the CO laser operated in fundamental and overtone transitions, to vibration-to-vibration rate constants is investigated. With this aim, three rate constant sets have been used, differing in their completeness (i.e. accounting for single-quantum exchange only, or for multi-quantum exchange with a limited number of rate constants obtained by semiclassical calculations, and, finally, with an exhaustive set of rate constants including asymmetric exchange processes, as well) and in the employed interaction potential. The most complete set among these three is introduced in this paper. An existing earlier kinetic model was updated to include the latter new data. Comparison of data produced by kinetic modelling with the above mentioned sets of rate constants shows that the vibrational distribution function, and, in particular, the CO overtone laser characteristics, are very sensitive to the choice of the model. The most complete model predicts slower evolution of the vibrational distribution, in qualitative agreement with experiments
Morgan, Sarah E.; Cole, Daniel J.; Chin, Alex W.
2016-11-01
Collective protein modes are expected to be important for facilitating energy transfer in the Fenna-Matthews-Olson (FMO) complex of photosynthetic green sulphur bacteria, however to date little work has focussed on the microscopic details of these vibrations. The nonlinear network model (NNM) provides a computationally inexpensive approach to studying vibrational modes at the microscopic level in large protein structures, whilst incorporating anharmonicity in the inter-residue interactions which can influence protein dynamics. We apply the NNM to the entire trimeric FMO complex and find evidence for the existence of nonlinear discrete breather modes. These modes tend to transfer energy to the highly connected core pigments, potentially opening up alternative excitation energy transfer routes through their influence on pigment properties. Incorporating localised modes based on these discrete breathers in the optical spectra calculations for FMO using ab initio site energies and excitonic couplings can substantially improve their agreement with experimental results.
Perfetto, Sara; Rohlfing, Jens; Infante, Francesco; Mayer, Dirk; Herold, Sven
2016-01-01
Piezoelectric transducers can be used to harvest electrical energy from structural vibrations in order to power continuously operating condition monitoring systems local to where they operate. However, excessive vibrations can compromise the safe operation of mechanical systems. Therefore, absorbers are commonly used to control vibrations. With an integrated device, the mechanical energy that otherwise would be dissipated can be converted via piezoelectric transducers. Vibration absorbers are...
Study of the levels of serum cortisol and gastrin in dogs with vibration-induced injury
International Nuclear Information System (INIS)
Wei Zikun
2005-01-01
Objective: To study the changes of levels of serum cortisol and gastrin in dogs with vibration-induced injury for providing better treatment regimen. Methods: In this experiment, 8 or 10 domestic dogs were placed on each of four sites away from explosion center about 0, 100, 200, 300 meters respectively. The dogs were standing uncontrolled or lying right side down under anesthesia. Serum cortisol and gastrin levels were detected with RIA both before and after explosion. Results: The levels of serum cortisol and gastrin began to fall about 24 hours after explosion. The serum levels of cortisol were still decreased significantly after 9 days and 17 days. Conclusion: The levels of the serum cortisol declined when the animals were injured by vibration. Detection of serum cortisol levels might lead to definitive diagnosis and supplemental treatment with cortical hormones for vibration-induced injury. (authors)
Electrostatic vibration energy harvester with 2.4-GHz Cockcroft-Walton rectenna start-up
Takhedmit, Hakim; Saddi, Zied; Karami, Armine; Basset, Philippe; Cirio, Laurent
2017-02-01
In this paper, we propose the design, fabrication and experiments of a macro-scale electrostatic vibration energy harvester (e-VEH), pre-charged wirelessly for the first time with a 2.4-GHz Cockcroft-Walton rectenna. The rectenna is designed and optimized to operate at low power densities and provide high voltage levels: 0.5 V at 0.76 μW/cm2 and 1 V at 1.53 μW/cm2. The e-VEH uses a Bennet doubler as a conditioning circuit. Experiments show a 23-V voltage across the transducer terminal, when the harvester is excited at 25 Hz by 1.5 g of external acceleration. An accumulated energy of 275 μJ and a maximum available power of 0.4 μW are achieved. xml:lang="fr"
Solar-pumped electronic-to-vibrational energy transfer lasers
Harries, W. L.; Wilson, J. W.
1981-01-01
The possibility of using solar-pumped lasers as solar energy converters is examined. The absorbing media considered are halogens or halogen compounds, which are dissociated to yield excited atoms, which then hand over energy to a molecular lasing medium. Estimates of the temperature effects for a Br2-CO2-He system with He as the cooling gas are given. High temperatures can cause the lower energy levels of the CO2 laser transition to be filled. The inverted populations are calculated and lasing should be possible. However, the efficiency is less than 0.001. Examination of other halogen-molecular lasant combinations (where the rate coefficients are known) indicate efficiencies in all cases of less than 0.005.
Tiwari, Vivek; Peters, William K.; Jonas, David M.
2017-10-01
Non-adiabatic vibrational-electronic resonance in the excited electronic states of natural photosynthetic antennas drastically alters the adiabatic framework, in which electronic energy transfer has been conventionally studied, and suggests the possibility of exploiting non-adiabatic dynamics for directed energy transfer. Here, a generalized dimer model incorporates asymmetries between pigments, coupling to the environment, and the doubly excited state relevant for nonlinear spectroscopy. For this generalized dimer model, the vibrational tuning vector that drives energy transfer is derived and connected to decoherence between singly excited states. A correlation vector is connected to decoherence between the ground state and the doubly excited state. Optical decoherence between the ground and singly excited states involves linear combinations of the correlation and tuning vectors. Excitonic coupling modifies the tuning vector. The correlation and tuning vectors are not always orthogonal, and both can be asymmetric under pigment exchange, which affects energy transfer. For equal pigment vibrational frequencies, the nonadiabatic tuning vector becomes an anti-correlated delocalized linear combination of intramolecular vibrations of the two pigments, and the nonadiabatic energy transfer dynamics become separable. With exchange symmetry, the correlation and tuning vectors become delocalized intramolecular vibrations that are symmetric and antisymmetric under pigment exchange. Diabatic criteria for vibrational-excitonic resonance demonstrate that anti-correlated vibrations increase the range and speed of vibronically resonant energy transfer (the Golden Rule rate is a factor of 2 faster). A partial trace analysis shows that vibronic decoherence for a vibrational-excitonic resonance between two excitons is slower than their purely excitonic decoherence.
Tiwari, Vivek; Jonas, David M.
2018-02-01
Vibrational-electronic resonance in photosynthetic pigment-protein complexes invalidates Förster's adiabatic framework for interpreting spectra and energy transfer, thus complicating determination of how the surrounding protein affects pigment properties. This paper considers the combined effects of vibrational-electronic resonance and inhomogeneous variations in the electronic excitation energies of pigments at different sites on absorption, emission, circular dichroism, and hole-burning spectra for a non-degenerate homodimer. The non-degenerate homodimer has identical pigments in different sites that generate differences in electronic energies, with parameters loosely based on bacteriochlorophyll a pigments in the Fenna-Matthews-Olson antenna protein. To explain the intensity borrowing, the excited state vibrational-electronic eigenvectors are discussed in terms of the vibrational basis localized on the individual pigments, as well as the correlated/anti-correlated vibrational basis delocalized over both pigments. Compared to those in the isolated pigment, vibrational satellites for the correlated vibration have the same frequency and precisely a factor of 2 intensity reduction through vibrational delocalization in both absorption and emission. Vibrational satellites for anti-correlated vibrations have their relaxed emission intensity reduced by over a factor 2 through vibrational and excitonic delocalization. In absorption, anti-correlated vibrational satellites borrow excitonic intensity but can be broadened away by the combination of vibronic resonance and site inhomogeneity; in parallel, their vibronically resonant excitonic partners are also broadened away. These considerations are consistent with photosynthetic antenna hole-burning spectra, where sharp vibrational and excitonic satellites are absent. Vibrational-excitonic resonance barely alters the inhomogeneously broadened linear absorption, emission, and circular dichroism spectra from those for a
Energy Technology Data Exchange (ETDEWEB)
Hirata, A. [Kumamoto Industries Univ, Kumamoto (Japan); Yamamoto, M. [Asahi Chemical Industry Co. Ltd., Tokyo (Japan); Inaba, C. [Nishimatsu Construction Co. Ltd., Kanagawa (Japan); Kaneko, K. [Hokkaido Univ (Japan)
1997-08-01
For avoiding the generation of public hazard due to ground vibration causes by blasting in tunneling, it is important to devise a blasting method for ensuring the level of the ground vibration caused thereby under a limit, and an exact predication of ground vibration before blasting is desirable. In this study, the characteristics of the ground vibration caused by tunnel blasting are analyzed, and a summary of amplitude spectra calculating method is described. A theoretical analysis method for predicting the vibration level is proposed based on spectrum-multiplicative method. Vibration caused by multistage blasting in tunneling is most strong and deemed as important. When observing the process of elastic wave motion caused by multistage blasting being measured, the process can be divided into three element processes in frequency area as vibration source spectrum, transmission attenuation spectrum and frequency response function vibrating test, and, with the multiplication of them, the amplitude spectra at an observation portion can be estimated. 12 refs., 12 figs.
Report of workshop on vibration related to fluid in atomic energy field. 7
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-12-31
Because of the nonlinearity of the equation that governs flow, sometimes vibration occurs in an unexpected system, and it causes trouble. This 7th workshop on vibration related to fluid in atomic energy field was held at Nuclear Engineering Research Laboratory of University of Tokyo on August 25 and 26, 1997. Two themes were ``Vibration of liquid surface by flow`` and ``Numerical analysis of coupled vibration of fluid-structures``. The former is related to the problem in the development of a demonstration FBR, and the latter is related to the numerical analysis technology such as the handling of boundary conditions and the method of taking position, moving velocity and acceleration into account. This workshop aims at thoroughly discussing a small number of themes, and deepening the understanding. In this report, the summaries of 17 papers are collected, of which the titles are as follows. Liquid surface self-exciting vibration by flow, vibration of upper plenum liquid surface of fast reactor, stability analysis of multiple liquid surfaces, flow instability phenomena of multi-loop system, sloshing in a vessel in which fluid flows, the mechanism of occurrence of self-exciting sloshing in a vessel elucidated by numerical analysis, numerical analysis of manometer vibration excited by flow, numerical analysis of flutter phenomena of aircraft, numerical analysis of aerodynamic elastic problem, mechanism of in-line excitation, numerical analysis of hydrodynamic elastic vibration of tube nest and so on. (K.I.)
Effect of temperature-dependent energy-level shifts on a semiconductor's Peltier heat
International Nuclear Information System (INIS)
Emin, D.
1984-01-01
The Peltier heat of a charge carrier in a semiconductor is calculated for the situation in which the electronic energy levels are temperature dependent. The temperature dependences of the electronic energy levels, generally observed optically, arise from their dependences on the vibrational energy of the lattice (e.g., as caused by thermal expansion). It has been suggested that these temperature dependences will typically have a major effect on the Peltier heat. The Peltier heat associated with a given energy level is a thermodynamic quantity; it is the product of the temperature and the change of the entropy of the system when a carrier is added in that level. As such, the energy levels cannot be treated as explicitly temperature dependent. The electron-lattice interaction causing the temperature dependence must be expressly considered. It is found that the carrier's interaction with the atomic vibrations lowers its electronic energy. However, the interaction of the carrier with the atomic vibrations also causes an infinitesimal lowering (approx.1/N) of each of the N vibrational frequencies. As a result, there is a finite carrier-induced increase in the average vibrational energy. Above the Debye temperature, this cancels the lowering of the carrier's electronic energy. Thus, the standard Peltier-heat formula, whose derivation generally ignores the temperature dependence of the electronic energy levels, is regained. This explains the apparent success of the standard formula in numerous analyses of electronic transport experiments
Characterization of Friction Joints Subjected to High Levels of Random Vibration
deSantos, Omar; MacNeal, Paul
2012-01-01
This paper describes the test program in detail including test sample description, test procedures, and vibration test results of multiple test samples. The material pairs used in the experiment were Aluminum-Aluminum, Aluminum- Dicronite coated Aluminum, and Aluminum-Plasmadize coated Aluminum. Levels of vibration for each set of twelve samples of each material pairing were gradually increased until all samples experienced substantial displacement. Data was collected on 1) acceleration in all three axes, 2) relative static displacement between vibration runs utilizing photogrammetry techniques, and 3) surface galling and contaminant generation. This data was used to estimate the values of static friction during random vibratory motion when "stick-slip" occurs and compare these to static friction coefficients measured before and after vibration testing.
A velocity-amplified electromagnetic energy harvester for small amplitude vibration
Klein, J.; Zuo, L.
2017-09-01
Dedicated, self-powered wireless sensors are widely being studied for use throughout many industries to monitor everyday operations, maintain safety, and report performance characteristics. To enable sensors to power themselves, harvesting energy from machine vibration has been studied, however, its overall effectiveness can be hampered due to small vibration amplitudes and thus limited harvestable energy density. This paper addresses the issue by proposing a novel vibration energy harvester architecture in which a compliant mechanism and proof mass system is used to amplify the vibrational velocity of machine vibration for a linear electromagnetic generator. A prototype has been fabricated and experimentally characterized to verify its effectiveness. When operating at its natural frequency in a low base amplitude, 0.001 inch (25.4 μm) at 19.4 Hz, during lab tests, the harvester has been shown to produce up to 0.91 V AC open voltage, and a maximum power of 2 mW, amplifying the relative proof mass velocity by approximately 5.4 times. This method of locally increasing the machine vibrational velocity has been shown to be a viable option for increasing the potential power output of an energy harvester. In addition, a mathematical model is created based on pseudo-rigid-body dynamics and the analysis matches closely with experiments.
The influence of molecular rotation on vibration--translation energy transfer
International Nuclear Information System (INIS)
McKenzie, R.L.
1977-01-01
The role of molecular rotations in the exchange of vibrational and translational energy is investigated for collisions between anharmonic diatomic molecules and structureless atoms. A three-dimensional, semiclassical, impact parameter description is applied with emphasis directed towards the influence of rotational coupling on the net rate of vibrational energy transfer summed over all final rotational states. These results are then related to the predictions of an equivalent collinear collision model, and their comparison allows an evaluation of the collinear approximation. The mechanisms of vibrational energy transfer including rotational transitions are shown to be separable into three classes, with the molecules belonging to each class identified first and foremost by their ratio of fundamental vibrational and rotational frequencies, ω/sub e//B/sub e/, and second by the proximity of their initial state to a near-resonant vibration--rotation transition with a small change in angular momentum. While the dynamics of molecules with ω/sub e//B/sub e/ ratios that are comparable to the range of angular momentum transitions having strong coupling are found to require a complete three-dimensional description, the rates of vibrational energy transfer in molecules with large ω/sub e//B/sub e/ ratios appear to be well approximated by a collinear collision model
Surface vibrational spectroscopy
International Nuclear Information System (INIS)
Erskine, J.L.
1984-01-01
A brief review of recent studies which combine measurements of surface vibrational energies with lattice dynamical calculations is presented. These results suggest that surface vibrational spectroscopy offers interesting prospects for use as a molecular-level probe of surface geometry, adsorbate bond distances and molecular orientations
Vibrational analysis of HOCl up to 98% of the dissociation energy with a Fermi resonance Hamiltonian
International Nuclear Information System (INIS)
Jost, R.; Joyeux, M.; Skokov, S.; Bowman, J.
1999-01-01
We have analyzed the vibrational energies and wave functions of HOCl obtained from previous ab initio calculations [J. Chem. Phys. 109, 2662 (1998); 109, 10273 (1998)]. Up to approximately 13 and h;000 cm -1 , the normal modes are nearly decoupled, so that the analysis is straightforward with a Dunham model. In contrast, above 13 and h;000 cm -1 the Dunham model is no longer valid for the levels with no quanta in the OH stretch (v 1 =0). In addition to v 1 , these levels can only be assigned a so-called polyad quantum number P=2v 2 +v 3 , where 2 and 3 denote, respectively, the bending and OCl stretching normal modes. In contrast, the levels with v 1 ≥2 remain assignable with three v i quantum numbers up to the dissociation (D 0 =19 and h;290 and h;cm -1 ). The interaction between the bending and the OCl stretch (ω 2 congruent 2ω 3 ) is well described with a simple, fitted Fermi resonance Hamiltonian. The energies and wave functions of this model Hamiltonian are compared with those obtained from ab initio calculations, which in turn enables the assignment of many additional ab initio vibrational levels. Globally, among the 809 bound levels calculated below dissociation, 790 have been assigned, the lowest unassigned level, No. 736, being located at 18 and h;885 cm -1 above the (0,0,0) ground level, that is, at about 98% of D 0 . In addition, 84 resonances located above D 0 have also been assigned. Our best Fermi resonance Hamiltonian has 29 parameters fitted with 725 ab initio levels, the rms deviation being of 5.3 cm -1 . This set of 725 fitted levels includes the full set of levels up to No. 702 at 18 and h;650 cm -1 . The ab initio levels, which are assigned but not included in the fit, are reasonably predicted by the model Hamiltonian, but with a typical error of the order of 20 cm -1 . The classical analysis of the periodic orbits of this Hamiltonian shows that two bifurcations occur at 13 and h;135 and 14 and h;059 cm -1 for levels with v 1 =0. Above each
An Enhanced Piezoelectric Vibration Energy Harvesting System with Macro Fiber Composite
Directory of Open Access Journals (Sweden)
Shuwen Zhang
2015-01-01
Full Text Available Self-power supply is a promising project in various applied conditions. Among this research area, piezoelectric material-based energy harvesting (EH method has been researched in recent years due to its advantages. With the limitation of energy form acceptance range of EH circuit system, a sum of energy is not accessible to be obtained. To enlarge the EH quantity from the vibration, an enhanced piezoelectric vibration EH structure with piezoelectric film is developed in this work. Piezoelectric-based energy harvesting mechanism is primarily proposed in this work. The special-designed electric circuit for EH from macro fiber composite (MFC is proposed and then analyzed. When the structure vibrates in its modes of frequencies, the experiments are developed to measure the EH effect. The energy harvested from the vibrating structure is analyzed and the enhanced effect is presented. The results indicate that, with the enhanced EH structure in this work, vibration energy from structure is obtained in a larger range, and the general EH quantity is enlarged.
Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y.
2010-01-01
We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezo...
Energy harvesting by means of flow-induced vibrations on aerospace vehicles
Li, Daochun; Wu, Yining; Da Ronch, Andrea; Xiang, Jinwu
2016-10-01
This paper reviews the design, implementation, and demonstration of energy harvesting devices that exploit flow-induced vibrations as the main source of energy. Starting with a presentation of various concepts of energy harvesters that are designed to benefit from a general class of flow-induced vibrations, specific attention is then given at those technologies that may offer, today or in the near future, a potential benefit to extend the operational capabilities and to monitor critical parameters of unmanned aerial vehicles. Various phenomena characterized by flow-induced vibrations are discussed, including limit cycle oscillations of plates and wing sections, vortex-induced and galloping oscillations of bluff bodies, vortex-induced vibrations of downstream structures, and atmospheric turbulence and gusts. It was found that linear or linearized modeling approaches are commonly employed to support the design phase of energy harvesters. As a result, highly nonlinear and coupled phenomena that characterize flow-induced vibrations are neglected in the design process. The Authors encourage a shift in the current design paradigm: considering coupled nonlinear phenomena, and adequate modeling tools to support their analysis, from a design limitation to a design opportunity. Special emphasis is placed on identifying designs and implementations applicable to aircraft configurations. Application fields of flow-induced vibrations-based energy harvesters are discussed including power supply for wireless sensor networks and simultaneous energy harvest and control. A large body of work on energy harvesters is included in this review journal. Whereas most of the references claim direct applications to unmanned aerial vehicles, it is apparent that, in most of the cases presented, the working principles and characteristics of the energy harvesters are incompatible with any aerospace applications. Finally, the challenges that hold back the integration of energy harvesting
Zhang, Yulong; Wang, Tianyang; Zhang, Ai; Peng, Zhuoteng; Luo, Dan; Chen, Rui; Wang, Fei
2016-12-01
In this paper, we present design and test of a broadband electrostatic energy harvester with a dual resonant structure, which consists of two cantilever-mass subsystems each with a mass attached at the free edge of a cantilever. Comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies. Furthermore, when one of the cantilever-masses is oscillating at resonance, the vibration amplitude is large enough to make it collide with the other mass, which provides strong mechanical coupling between the two subsystems. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range. During the measurement, continuous power output up to 6.2-9.8 μW can be achieved under external vibration amplitude of 9.3 m/s 2 at a frequency range from 36.3 Hz to 48.3 Hz, which means the bandwidth of the device is about 30% of the central frequency. The broad bandwidth of the device provides a promising application for energy harvesting from the scenarios with random vibration sources. The experimental results indicate that with the dual resonant structure, the vibration-to-electricity energy conversion efficiency can be improved by 97% when an external random vibration with a low frequency filter is applied.
A Smart Load Interface and Voltage Regulator for Electrostatic Vibration Energy Harvester
Bedier, Mohammed; Basset, Philippe; Galayko, Dimitri
2016-11-01
This paper presents a new implementation in ams 0.35μm HV technology of a complete energy management system for an electrostatic vibrational energy harvester (e-VEH). It is based on the Bennet's doubler architecture and includes a load voltage regulator (LVR) and a smart Load Interface (LI) that are self-controlled with internal voltages for maximum power point tracking (MMPT). The CMOS implementation makes use of an energy harvester that is capable of producing up to 1.8μW at harmonic excitation, given its internal voltage is kept within its optimum. An intermediate LI stage and its controller makes use of a high side switch with zero static power level shifter, and a low power hysteresis comparator. A full circuit level simulation with a VHDL-AMS model of the e-VEH presented was successfully achieved, indicating that the proposed load interface controller consumes less than 100nW average power. Moreover, a LVR regulates the buffer and discharge the harvested energy into a generic resistive load maintaining the voltage within a nominal value of 2 Volts.
International Nuclear Information System (INIS)
Challa, Vinod R; Prasad, M G; Fisher, Frank T
2011-01-01
Future deployment of wireless sensor networks will ultimately require a self-sustainable local power source for each sensor, and vibration energy harvesting is a promising approach for such applications. A requirement for efficient vibration energy harvesting is to match the device and source frequencies. While techniques to tune the resonance frequency of an energy harvesting device have recently been described, in many applications optimization of such systems will require the energy harvesting device to be able to autonomously tune its resonance frequency. In this work a vibration energy harvesting device with autonomous resonance frequency tunability utilizing a magnetic stiffness technique is presented. Here a piezoelectric cantilever beam array is employed with magnets attached to the free ends of cantilever beams to enable magnetic force resonance frequency tuning. The device is successfully tuned from − 27% to + 22% of its untuned resonance frequency while outputting a peak power of approximately 1 mW. Since the magnetic force tuning technique is semi-active, energy is only consumed during the tuning process. The developed prototype consumed maximum energies of 3.3 and 3.9 J to tune to the farthest source frequencies with respect to the untuned resonance frequency of the device. The time necessary for this prototype device to harvest the energy expended during its most energy-intensive (largest resonant frequency adjustment) tuning operation is 88 min in a low amplitude 0.1g vibration environment, which could be further optimized using higher efficiency piezoelectric materials and system components
Energy Technology Data Exchange (ETDEWEB)
Do, T. P. T. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); School of Education, Can Tho University, Campus II, 3/2 Street, Xuan Khanh, Ninh Kieu, Can Tho City (Viet Nam); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Konovalov, D. A.; White, R. D. [College of Science, Technology and Engineering, James Cook University, Townsville (Australia); Brunger, M. J., E-mail: michael.brunger@flinders.edu.au, E-mail: darryl.jones@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Jones, D. B., E-mail: michael.brunger@flinders.edu.au, E-mail: darryl.jones@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)
2015-03-28
We report differential cross sections (DCSs) for electron-impact vibrational-excitation of tetrahydrofuran, at intermediate incident electron energies (15-50 eV) and over the 10°-90° scattered electron angular range. These measurements extend the available DCS data for vibrational excitation for this species, which have previously been obtained at lower incident electron energies (≤20 eV). Where possible, our data are compared to the earlier measurements in the overlapping energy ranges. Here, quite good agreement was generally observed where the measurements overlapped.
International Nuclear Information System (INIS)
Fan Kang-Qi; Ming Zheng-Feng; Xu Chun-Hui; Chao Feng-Bo
2013-01-01
As an alternative power solution for low-power devices, harvesting energy from the ambient mechanical vibration has received increasing research interest in recent years. In this paper we study the transient dynamic characteristics of a piezoelectric energy harvesting system including a piezoelectric energy harvester, a bridge rectifier, and a storage capacitor. To accomplish this, this energy harvesting system is modeled, and the charging process of the storage capacitor is investigated by employing the in-phase assumption. The results indicate that the charging voltage across the storage capacitor and the gathered power increase gradually as the charging process proceeds, whereas the charging rate slows down over time as the charging voltage approaches to the peak value of the piezoelectric voltage across the piezoelectric materials. In addition, due to the added electrical damping and the change of the system natural frequency when the charging process is initiated, a sudden drop in the vibration amplitude is observed, which in turn affects the charging rate. However, the vibration amplitude begins to increase as the charging process continues, which is caused by the decrease in the electrical damping (i.e., the decrease in the energy removed from the mechanical vibration). This electromechanical coupling characteristic is also revealed by the variation of the vibration amplitude with the charging voltage. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Elfrink, R.; Renaud, M.; Kamel, T.M.; Nooijer, C. de; Jambunathan, M.; Goedbloed, M.; Hohlfeld, D.; Matova, S.; Pop, V.; Caballero, L.; Schaijk, R. van
2010-01-01
This paper describes the characterization of thin-film MEMS vibration energy harvesters based on aluminum nitride as piezoelectric material. A record output power of 85 μW is measured. The parasitic-damping and the energy-harvesting performances of unpackaged and packaged devices are investigated.
Energy-autonomous wireless vibration sensor for condition-based maintenance of machinery
Wang, Z.; Bouwens, F.; Vullers, R.; Petré, F.; Devos, S.
2011-01-01
This paper addresses the development of an energy-autonomous wireless vibration sensor for condition-based monitoring of machinery. Such technology plays an increasingly important role in modern manufacturing industry. In this work, energy harvesting is realized by resorting to a custom designed
Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting
DEFF Research Database (Denmark)
Xu, R.; Lei, A.; Christiansen, T. L.
2011-01-01
We present a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The most common piezoelectric energy harvesting devices utilize a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric material...
Electrostatic Vibration Energy Harvester Pre-charged Wirelessly at 2.45 GHz
Saddi, Z.; Takhedmit, H.; Karami, A.; Basset, P.; Cirio, L.
2016-11-01
This paper reports the design, fabrication and experiments of an electrostatic vibration harvester (e-VEH), pre-charged wirelessly for the first time by using an electromagnetic waves harvester at 2.4 GHz. The rectenna uses the Cockcroft-Walton voltage doubler rectifier. It is designed and optimized to operate at low power densities and provides high voltage levels: 0.5 V at 0.5 μW/cm2 and 0.8 V at 1 μW/cm2 The e-VEH uses the Bennet doubler as conditioning circuit. Experiments show 23 V voltage across the transducer terminal when the harvester is excited at 25 Hz by 1.5 g of external acceleration. An accumulated energy of 275 μJ and a maximum power of 0.4 μW are available for the load.
Electrostatic Vibration Energy Harvester Pre-charged Wirelessly at 2.45 GHz
International Nuclear Information System (INIS)
Saddi, Z.; Takhedmit, H.; Basset, P.; Cirio, L.; Karami, A.
2016-01-01
This paper reports the design, fabrication and experiments of an electrostatic vibration harvester (e-VEH), pre-charged wirelessly for the first time by using an electromagnetic waves harvester at 2.4 GHz. The rectenna uses the Cockcroft-Walton voltage doubler rectifier. It is designed and optimized to operate at low power densities and provides high voltage levels: 0.5 V at 0.5 μW/cm 2 and 0.8 V at 1 μW/cm 2 The e-VEH uses the Bennet doubler as conditioning circuit. Experiments show 23 V voltage across the transducer terminal when the harvester is excited at 25 Hz by 1.5 g of external acceleration. An accumulated energy of 275 μJ and a maximum power of 0.4 μW are available for the load. (paper)
Vibration-based Energy Harvesting Systems Characterization Using Automated Electronic Equipment
Directory of Open Access Journals (Sweden)
Ioannis KOSMADAKIS
2015-04-01
Full Text Available A measurement bench has been developed to fully automate the procedure for the characterization of a vibration-based energy scavenging system. The measurement system is capable of monitoring all important characteristics of a vibration harvesting system (input and output voltage, current, and other parameters, frequency and acceleration values, etc.. It is composed of a PC, typical digital measuring instruments (oscilloscope, waveform generator, etc., certain sensors and actuators, along with a microcontroller based automation module. The automation of the procedure and the manipulation of the acquired data are performed by LabVIEW software. Typical measurements of a system consisting of a vibrating source, a vibration transducer and an active rectifier are presented.
Ahmed, Riaz; Mir, Fariha; Banerjee, Sourav
2017-08-01
The principal objective of this article is to categorically review and compare the state of the art vibration based energy harvesting approaches. To evaluate the contemporary methodologies with respect to their physics, average power output and operational frequencies, systematically divided and easy readable tables are presented followed by the description of the energy harvesting methods. Energy harvesting is the process of obtaining electrical energy from the surrounding vibratory mechanical systems through an energy conversion method using smart structures, like, piezoelectric, electrostatic materials. Recent advancements in low power electronic gadgets, micro electro mechanical systems, and wireless sensors have significantly increased local power demand. In order to circumvent the energy demand; to allow limitless power supply, and to avoid chemical waste from conventional batteries, low power local energy harvesters are proposed for harvesting energy from different ambient energy sources. Piezoelectric materials have received tremendous interest in energy harvesting technology due to its unique ability to capitalize the ambient vibrations to generate electric potential. Their crystalline configuration allows the material to convert mechanical strain energy into electrical potential, and vice versa. This article discusses the various approaches in vibration based energy scavenging where piezoelectric materials are employed as the energy conversion medium.
A Hybrid Indoor Ambient Light and Vibration Energy Harvester for Wireless Sensor Nodes
Directory of Open Access Journals (Sweden)
Hua Yu
2014-05-01
Full Text Available To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.
Energy Technology Data Exchange (ETDEWEB)
Lan, C. B.; Qin, W. Y. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)
2014-09-15
This letter investigates the energy harvesting from the horizontal coherent resonance of a vertical cantilever beam subjected to the vertical base excitation. The potential energy of the system has two symmetric potential wells. So, under vertical excitation, the system can jump between two potential wells, which will lead to the large vibration in horizontal direction. Two piezoelectric patches are pasted to harvest the energy. From experiment, it is found that the vertical excitation can make the beam turn to be bistable. The system can transform vertical vibration into horizontal vibration of low frequency when excited by harmonic motion. The horizontal coherence resonance can be observed when excited by a vertical white noise. The corresponding output voltages of piezoelectric films reach high values.
A low-frequency vibration energy harvester based on diamagnetic levitation
Kono, Yuta; Masuda, Arata; Yuan, Fuh-Gwo
2017-04-01
This article presents 3-degree-of-freedom theoretical modeling and analysis of a low-frequency vibration energy harvester based on diamagnetic levitation. In recent years, although much attention has been placed on vibration energy harvesting technologies, few harvesters still can operate efficiently at extremely low frequencies in spite of large potential demand in the field of structural health monitoring and wearable applications. As one of the earliest works, Liu, Yuan and Palagummi proposed vertical and horizontal diamagnetic levitation systems as vibration energy harvesters with low resonant frequencies. This study aims to pursue further improvement along this direction, in terms of expanding maximum amplitude and enhancing the flexibility of the operation direction for broader application fields by introducing a new topology of the levitation system.
International Nuclear Information System (INIS)
Gu, Lei; Livermore, Carol
2011-01-01
This paper presents experiments and models of an energy harvesting device in which a low frequency resonator impacts a high frequency energy harvesting resonator, resulting in energy harvesting predominantly at the system's coupled vibration frequency. Analysis shows that a reduced mechanical damping ratio during coupled vibration enables increased electrical power generation as compared with conventional technology. Experiments demonstrate that the efficiency of electrical power transfer is significantly improved with the coupled vibration approach. An average power output of 0.43 mW is achieved under 0.4g acceleration at 8.2 Hz, corresponding to a power density of 25.5 µW cm −3 . The measured power and power density at the resonant frequency are respectively 4.8 times and 13 times the measured peak values for a conventional harvester created from a low frequency beam alone
Lin, Zhiming; Yang, Jin; Zhao, Jiangxin; Zhao, Nian; Liu, Jun; Wen, Yumei; Li, Ping
2016-07-01
In this work, we present a multimodal wideband vibration energy harvester designed to scavenge energy from ambient vibrations over a wide frequency range. The harvester consists of a folded cantilever, three magnetoelectric (ME) transducers, and two magnetic circuits. The folded cantilever enables multi-resonant response formed by bending of each stage, and the nonlinear magnetic forces acting on the folded cantilever beam allow further broadening of the frequency response. We also investigate the effects of the position of the ME transducer on the electrical output in order to achieve optimal performance. The experimental results show that the vibration energy harvester exhibited three resonance peaks in a range of 5 Hz to 30 Hz, a wider working bandwidth of 10.1 Hz, and a maximum average power value of 31.58 μW at an acceleration of 0.6 g (with g = 9.8 m/s2).
Halász, Gábor J; Csehi, András; Vibók, Ágnes; Cederbaum, Lorenz S
2014-12-26
Previous works have shown that dressing of diatomic molecules by standing or by running laser waves gives rise to the appearance of so-called light-induced conical intersections (LICIs). Because of the strong nonadiabatic couplings, the existence of such LICIs may significantly change the dynamical properties of a molecular system. In our former paper (J. Phys. Chem. A 2013, 117, 8528), the photodissociation dynamics of the D(2)(+) molecule were studied in the LICI framework starting the initial vibrational nuclear wave packet from the superposition of all the vibrational states initially produced by ionizing D(2). The present work complements our previous investigation by letting the initial nuclear wave packets start from different individual vibrational levels of D(2)(+), in particular, above the energy of the LICI. The kinetic energy release spectra, the total dissociation probabilities, and the angular distributions of the photofragments are calculated and discussed. An interesting phenomenon has been found in the spectra of the photofragments. Applying the light-induced adiabatic picture supported by LICI, explanations are given for the unexpected structure of the spectra.
Simpkins, Blake S.; Fears, Kenan P.; Dressick, Walter J.; Dunkelberger, Adam D.; Spann, Bryan T.; Owrutsky, Jeffrey C.
2016-09-01
Coherent coupling between an optical transition and confined optical mode have been investigated for electronic-state transitions, however, only very recently have vibrational transitions been considered. Here, we demonstrate both static and dynamic results for vibrational bands strongly coupled to optical cavities. We experimentally and numerically describe strong coupling between a Fabry-Pérot cavity and carbonyl stretch ( 1730 cm 1) in poly-methylmethacrylate and provide evidence that the mixed-states are immune to inhomogeneous broadening. We investigate strong and weak coupling regimes through examination of cavities loaded with varying concentrations of a urethane monomer. Rabi splittings are in excellent agreement with an analytical description using no fitting parameters. Ultrafast pump-probe measurements reveal transient absorption signals over a frequency range well-separated from the vibrational band, as well as drastically modified relaxation rates. We speculate these modified kinetics are a consequence of the energy proximity between the vibration-cavity polariton modes and excited state transitions and that polaritons offer an alternative relaxation path for vibrational excitations. Varying the polariton energies by angle-tuning yields transient results consistent with this hypothesis. Furthermore, Rabi oscillations, or quantum beats, are observed at early times and we see evidence that these coherent vibration-cavity polariton excitations impact excited state population through cavity losses. Together, these results indicate that cavity coupling may be used to influence both excitation and relaxation rates of vibrations. Opening the field of polaritonic coupling to vibrational species promises to be a rich arena amenable to a wide variety of infrared-active bonds that can be studied in steady state and dynamically.
Design and experimental analysis of broadband energy harvesting from vortex-induced vibrations
Zhang, L. B.; Abdelkefi, A.; Dai, H. L.; Naseer, R.; Wang, L.
2017-11-01
In this paper, an operable strategy to enhance the output power of piezoelectric energy harvesting from vortex-induced vibration (VIV) using nonlinear magnetic forces is proposed for the first time. Two introduced small magnets with a repulsive force are, respectively, attached on a lower support and the bottom of a circular cylinder which is subjected to a uniform wind speed. Experiments show that the natural frequency of the VIV-based energy harvester is significantly changed by varying the relative position of the two magnets and hence the synchronization region is shifted. It is observed that the proposed energy harvester displays a softening behavior due to the impact of nonlinear magnetic forces, which greatly increases the performance of the VIV-based energy harvesting system, showing a wider synchronization region and a higher level of the harvested power by 138% and 29%, respectively, compared to the classical configuration. This proposed design can provide the groundwork to promote the output power of conventional VIV-based piezoelectric generators, further enabling to realize self-powered systems.
Assements of Level of Comfort on a Vibrating Structure
DEFF Research Database (Denmark)
Pedersen, Lars
2008-01-01
on the floor are asked to rate the level of discomfort on a scale from 1 to 10, and to assess the size of floor displacement (the initial amplitude of the decay). Tests are carried out with different numbers of people present on the test floor, and with different initial amplitudes of the decay. The paper...
Piezoelectric Vibration Energy Harvesting Device Combined with Damper
Directory of Open Access Journals (Sweden)
Hung-I Lu
2014-05-01
Full Text Available Piezoelectricity is a type of material that enables mechanical energy and electrical energy to be interchangeable, which can be divided into positive piezoelectric effect and inverse piezoelectric effect. The positive piezoelectric effect is that the electric dipole moment of material generates changes when the piezoelectric material is subjected to pressure, resulting in electrical energy. Conversely, the inverse piezoelectric effect is the process of electrical energy converted into mechanical energy.
Dual resonant structure for energy harvesting from random vibration sources at low frequency
Directory of Open Access Journals (Sweden)
Shanshan Li
2016-01-01
Full Text Available We introduce a design with dual resonant structure which can harvest energy from random vibration sources at low frequency range. The dual resonant structure consists of two spring-mass subsystems with different frequency responses, which exhibit strong coupling and broad bandwidth when the two masses collide with each other. Experiments with piezoelectric elements show that the energy harvesting device with dual resonant structure can generate higher power output than the sum of the two separate devices from random vibration sources.
El Aroudi, Abdelali
2014-05-01
Recently, nonlinearities have been shown to play an important role in increasing the extracted energy of vibration-based energy harvesting systems. In this paper, we study the dynamical behavior of a piecewise linear (PWL) spring-mass-damper system for vibration-based energy harvesting applications. First, we present a continuous time single degree of freedom PWL dynamical model of the system. Different configurations of the PWL model and their corresponding state-space regions are derived. Then, from this PWL model, extensive numerical simulations are carried out by computing time-domain waveforms, state-space trajectories and frequency responses under a deterministic harmonic excitation for different sets of system parameter values. Stability analysis is performed using Floquet theory combined with Filippov method, Poincaré map modeling and finite difference method (FDM). The Floquet multipliers are calculated using these three approaches and a good concordance is obtained among them. The performance of the system in terms of the harvested energy is studied by considering both purely harmonic excitation and a noisy vibrational source. A frequency-domain analysis shows that the harvested energy could be larger at low frequencies as compared to an equivalent linear system, in particular, for relatively low excitation intensities. This could be an advantage for potential use of this system in low frequency ambient vibrational-based energy harvesting applications. © 2014 World Scientific Publishing Company.
Efficient cooling of quantized vibrations using a four-level configuration
Yan, Lei-Lei; Zhang, Jian-Qi; Zhang, Shuo; Feng, Mang
2016-12-01
Cooling vibrational degrees of freedom down to ground states is essential to observation of quantum properties of systems with mechanical vibration. We propose two cooling schemes employing four internal levels of the systems, which achieve the ground-state cooling in an efficient fashion by completely deleting the carrier and first-order blue-sideband transitions. The schemes, based on quantum interference and Stark-shift gates, are robust to fluctuations of laser intensity and frequency. The feasibility of the schemes is justified using current laboratory technology. In practice, our proposal readily applies to a nanodiamond nitrogen-vacancy center levitated in an optical trap or attached to a cantilever.
Estimation of sound pressure levels of voiced speech from skin vibration of the neck
Svec, JG; Titze, IR; Popolo, PS
How accurately can sound pressure levels (SPLs) of speech be estimated from skin vibration of the neck? Measurements using a small accelerometer were carried out in 27 subjects (10 males and 17 females) who read Rainbow and Marvin Williams passages in soft, comfortable, and loud voice, while skin
Vibrational energy transfer kinetics in molecular disequilibrium. Final technical report
International Nuclear Information System (INIS)
Rich, J.W.
1982-09-01
The present Calspan experiments have shown direct evidence of preferential vibrational pumping of two heavy isotopes of CO: 13 C 16 O and 12 C 18 O. The nature of the enhancement is generally consistent with the predictions of theoretical modeling. These are the first direct experimental demonstrations of this isotope selection method. The potential advantages of such a means of isotope separation are inherent in the V-V pumping process itself. Summarizing these: (1) Selectivity actually increases at higher reactant pressures, since the selection mechanism is collisional. Accordingly, rather high throughputs are possible, unlike other techniques in which molecular collisions actually decrease selectivity. (2) A variety of excitation methods can potentially be used - electric discharge, optical excitation by coherent or incoherent sources, or chemical excitation; laser excitation is not critical to the process. (3) The method can be applied to many isotopes of the lighter atoms. It is not inherently species-specific
Grabham, N. J.; Harden, C.; Vincent, D.; Beeby, S. P.
2016-11-01
A wirelessly powered remote sensor node is presented along with its design process. The purpose of the node is the further expansion of the sensing capabilities of the commercial Perpetuum system used for condition monitoring on trains and rolling stock which operates using vibration energy harvesting. Surplus harvested vibration energy is transferred wirelessly to a remote satellite sensor to allow measurements over a wider area to be made. This additional data is to be used for long term condition monitoring. Performance measurements made on the prototype remote sensor node are reported and advantages and disadvantages of using the same RF frequency for power and data transfer are identified.
Energy Technology Data Exchange (ETDEWEB)
Dhote, Sharvari, E-mail: sharvari.dhote@mail.utoronto.ca; Zu, Jean; Zhu, Yang [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario M5S-3G8 (Canada)
2015-04-20
In this paper, a nonlinear wideband multi-mode piezoelectric vibration-based energy harvester (PVEH) is proposed based on a compliant orthoplanar spring (COPS), which has an advantage of providing multiple vibration modes at relatively low frequencies. The PVEH is made of a tri-leg COPS flexible structure, where three fixed-guided beams are capable of generating strong nonlinear oscillations under certain base excitation. A prototype harvester was fabricated and investigated through both finite-element analysis and experiments. The frequency response shows multiple resonance which corresponds to a hardening type of nonlinear resonance. By adding masses at different locations on the COPS structure, the first three vibration modes are brought close to each other, where the three hardening nonlinear resonances provide a wide bandwidth for the PVEH. The proposed PVEH has enhanced performance of the energy harvester in terms of a wide frequency bandwidth and a high-voltage output under base excitations.
Engineering Vibrationally Assisted Energy Transfer in a Trapped-Ion Quantum Simulator
Gorman, Dylan J.; Hemmerling, Boerge; Megidish, Eli; Moeller, Soenke A.; Schindler, Philipp; Sarovar, Mohan; Haeffner, Hartmut
2018-01-01
Many important chemical and biochemical processes in the condensed phase are notoriously difficult to simulate numerically. Often, this difficulty arises from the complexity of simulating dynamics resulting from coupling to structured, mesoscopic baths, for which no separation of time scales exists and statistical treatments fail. A prime example of such a process is vibrationally assisted charge or energy transfer. A quantum simulator, capable of implementing a realistic model of the system of interest, could provide insight into these processes in regimes where numerical treatments fail. We take a first step towards modeling such transfer processes using an ion-trap quantum simulator. By implementing a minimal model, we observe vibrationally assisted energy transport between the electronic states of a donor and an acceptor ion augmented by coupling the donor ion to its vibration. We tune our simulator into several parameter regimes and, in particular, investigate the transfer dynamics in the nonperturbative regime often found in biochemical situations.
A Method to Assess Transverse Vibration Energy of Ship Propeller Shaft for Diagnostic Purposes
Directory of Open Access Journals (Sweden)
Korczewski Zbigniew
2017-12-01
Full Text Available The article discusses a key problem of ship propulsion system vibration diagnostics, which concerns assessing this part of mechanical energy transmitted from the main engine to the ship propeller which is dissipated due to propeller shaft vibration. A simplified calculation model is proposed which allows the total energy of the generated torsional vibration to be assessed from the shaft deflection amplitude measured at the mind-span point between the supports. To verify the developed model, pilot tests were performed on the laboratory rotational mechanical system test rig. In those tests, cyclic bending moment was applied to a unified (cylindrical material sample, which modelled, at an appropriate scale, structural and functional properties of a real propeller shaft.
Zhao, Nian; Yang, Jin; Yu, Qiangmo; Zhao, Jiangxin; Liu, Jun; Wen, Yumei; Li, Ping
2016-01-01
This work has demonstrated a novel piezoelectric energy harvester without a complex structure and appended component that is capable of scavenging vibration energy from arbitrary directions with multiple resonant frequencies. In this harvester, a spiral-shaped elastic thin beam instead of a traditional thin cantilever beam was adopted to absorb external vibration with arbitrary direction in three-dimensional (3D) spaces owing to its ability to bend flexibly and stretch along arbitrary direction. Furthermore, multiple modes in the elastic thin beam contribute to a possibility to widen the working bandwidth with multiple resonant frequencies. The experimental results show that the harvester was capable of scavenging the vibration energy in 3D arbitrary directions; they also exhibited triple power peaks at about 16 Hz, 21 Hz, and 28 Hz with the powers of 330 μW, 313 μW, and 6 μW, respectively. In addition, human walking and water wave energies were successfully converted into electricity, proving that our harvester was practical to scavenge the time-variant or multi-directional vibration energies in our daily life.
International Nuclear Information System (INIS)
Zhao, Nian; Yang, Jin; Yu, Qiangmo; Zhao, Jiangxin; Liu, Jun; Wen, Yumei; Li, Ping
2016-01-01
This work has demonstrated a novel piezoelectric energy harvester without a complex structure and appended component that is capable of scavenging vibration energy from arbitrary directions with multiple resonant frequencies. In this harvester, a spiral-shaped elastic thin beam instead of a traditional thin cantilever beam was adopted to absorb external vibration with arbitrary direction in three-dimensional (3D) spaces owing to its ability to bend flexibly and stretch along arbitrary direction. Furthermore, multiple modes in the elastic thin beam contribute to a possibility to widen the working bandwidth with multiple resonant frequencies. The experimental results show that the harvester was capable of scavenging the vibration energy in 3D arbitrary directions; they also exhibited triple power peaks at about 16 Hz, 21 Hz, and 28 Hz with the powers of 330 μW, 313 μW, and 6 μW, respectively. In addition, human walking and water wave energies were successfully converted into electricity, proving that our harvester was practical to scavenge the time-variant or multi-directional vibration energies in our daily life
Zhao, Nian; Yang, Jin; Yu, Qiangmo; Zhao, Jiangxin; Liu, Jun; Wen, Yumei; Li, Ping
2016-01-01
This work has demonstrated a novel piezoelectric energy harvester without a complex structure and appended component that is capable of scavenging vibration energy from arbitrary directions with multiple resonant frequencies. In this harvester, a spiral-shaped elastic thin beam instead of a traditional thin cantilever beam was adopted to absorb external vibration with arbitrary direction in three-dimensional (3D) spaces owing to its ability to bend flexibly and stretch along arbitrary direction. Furthermore, multiple modes in the elastic thin beam contribute to a possibility to widen the working bandwidth with multiple resonant frequencies. The experimental results show that the harvester was capable of scavenging the vibration energy in 3D arbitrary directions; they also exhibited triple power peaks at about 16 Hz, 21 Hz, and 28 Hz with the powers of 330 μW, 313 μW, and 6 μW, respectively. In addition, human walking and water wave energies were successfully converted into electricity, proving that our harvester was practical to scavenge the time-variant or multi-directional vibration energies in our daily life.
Directory of Open Access Journals (Sweden)
Kyung Ho Sun
2014-10-01
Full Text Available While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm3, which was designed for a target frequency of as low as 100 Hz.
Energy Technology Data Exchange (ETDEWEB)
Sun, Kyung Ho; Kim, Young-Cheol [Department of System Dynamics, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343 (Korea, Republic of); Kim, Jae Eun, E-mail: jekim@cu.ac.kr [School of Mechanical and Automotive Engineering, Catholic University of Daegu, 13-13 Hayang-Ro, Hayang-Eup, Gyeongsan-Si, Gyeongsangbuk-Do 712-702 (Korea, Republic of)
2014-10-15
While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm{sup 3}, which was designed for a target frequency of as low as 100 Hz.
Energy Technology Data Exchange (ETDEWEB)
Zhao, Nian; Yang, Jin, E-mail: yangjin@cqu.edu.cn; Yu, Qiangmo; Zhao, Jiangxin; Liu, Jun; Wen, Yumei; Li, Ping [Department of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)
2016-01-15
This work has demonstrated a novel piezoelectric energy harvester without a complex structure and appended component that is capable of scavenging vibration energy from arbitrary directions with multiple resonant frequencies. In this harvester, a spiral-shaped elastic thin beam instead of a traditional thin cantilever beam was adopted to absorb external vibration with arbitrary direction in three-dimensional (3D) spaces owing to its ability to bend flexibly and stretch along arbitrary direction. Furthermore, multiple modes in the elastic thin beam contribute to a possibility to widen the working bandwidth with multiple resonant frequencies. The experimental results show that the harvester was capable of scavenging the vibration energy in 3D arbitrary directions; they also exhibited triple power peaks at about 16 Hz, 21 Hz, and 28 Hz with the powers of 330 μW, 313 μW, and 6 μW, respectively. In addition, human walking and water wave energies were successfully converted into electricity, proving that our harvester was practical to scavenge the time-variant or multi-directional vibration energies in our daily life.
International Nuclear Information System (INIS)
Nakagawa, Hideyuki
2000-01-01
Synchrotron radiation is expected to be the sharp infrared light source for the advanced experiments on IR and FIR spectroscopy in wide research fields. Especially, synchronized use of SR with VIS and/or UV laser light is to be a promising technique for the research on the dynamical properties of the photo-excited states in condensed materials. Some proposals are attempted for high resolution IR spectroscopy to elucidate fine interaction of molecular ions in crystalline solids with their environmental field and for time-resolved IR spectroscopic studies on the electronic and vibrational energy relaxation by using laser pulses synchronized with IR-SR pulses. Several experimental results are presented in relevance to the subjects; on high-resolution FTIR spectra of cyanide ions and metal cyanide complexes in cadmium halide crystals, on the energy up-conversion process among the vibrational levels of cyanide ions in alkali halide crystals, and on the electronic-to-vibrational energy conversion process in metal cyanide complexes. (author)
Vibrational relaxation and energy transfer of matrix isolated HCl and DCl
Energy Technology Data Exchange (ETDEWEB)
Wiesenfeld, J.M.
1977-12-01
Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 ..mu..s, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N/sub 2/ and O/sub 2/ matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data.
Vibrational relaxation and energy transfer of matrix isolated HCl and DCl
International Nuclear Information System (INIS)
Wiesenfeld, J.M.
1977-12-01
Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1 μs, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N 2 and O 2 matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data
Directory of Open Access Journals (Sweden)
Zhongsheng Chen
2016-01-01
Full Text Available Nonlinear magnetic forces are always used to enlarge resonant bandwidth of vibration energy harvesting systems with piezoelectric cantilever beams. However, how to determine properly the distance between two magnets is one of the key engineering problems. In this paper, the Melnikov theory is introduced to overcome it. Firstly, the Melnikov state-space model of the nonlinear piezoelectric vibration energy harvesting (PVEH system is built. Based on it, chaotic dynamics mechanisms of achieving broadband PVEH by nonlinearity are exposed by potential function of the unperturbed nonlinear PVEH system. Then the corresponding Melnikov function of the nonlinear PVEH system is defined, based on which two Melnikov necessary conditions of determining the distance are obtained. Finally, numerical simulations are done to testify the theoretic results. The results demonstrate that the distance is closely related to the excitation amplitude and frequency once geometric and material parameters are fixed. Under a single-frequency excitation, the nonlinear PVEH system can generate a periodic vibration around a stable point, a large-amplitude vibration around two stable points, or a chaotic vibration. The proposed method is very valuable for optimally designing and utilizing nonlinear broadband PVEH devices in engineering applications.
Zero-point energy, tunnelling, and vibrational adiabaticity in the Mu + H2 reaction
Mielke, Steven L.; Garrett, Bruce C.; Fleming, Donald G.; Truhlar, Donald G.
2015-01-01
Isotopic substitution of muonium for hydrogen provides an unparalleled opportunity to deepen our understanding of quantum mass effects on chemical reactions. A recent topical review in this journal of the thermal and vibrationally state-selected reaction of Mu with H2 raises a number of issues that are addressed here. We show that some earlier quantum mechanical calculations of the Mu + H2 reaction, which are highlighted in this review, and which have been used to benchmark approximate methods, are in error by as much as 19% in the low-temperature limit. We demonstrate that an approximate treatment of the Born-Oppenheimer diagonal correction that was used in some recent studies is not valid for treating the vibrationally state-selected reaction. We also discuss why vibrationally adiabatic potentials that neglect bend zero-point energy are not a useful analytical tool for understanding reaction rates, and why vibrationally non-adiabatic transitions cannot be understood by considering tunnelling through vibrationally adiabatic potentials. Finally, we present calculations on a hierarchical family of potential energy surfaces to assess the sensitivity of rate constants to the quality of the potential surface.
Electric Power Self-Supply Module for WSN Sensor Node Based on MEMS Vibration Energy Harvester
Directory of Open Access Journals (Sweden)
Wenyang Zhang
2018-04-01
Full Text Available This paper proposes an electric power self-supply module for the wireless sensor network (WSN sensor node. The module includes an electromagnetic vibration energy harvester based on micro-electro-mechanical system (MEMS technology and a processing circuit. The vibration energy harvester presented in this paper is fabricated by an integrated microfabrication process and consists of four similar and relatively independent beam vibration elements. The main functions of the processing circuit are to convert the output of the harvester from unstable alternating current (AC to stable direct current (DC, charge the super capacitor, and ensure the stable output of the super capacitor. The preliminary test results of the harvester chip show that the chip can output discontinuous pulse voltage, and the range of the voltage value is from tens to hundreds of millivolts in the vibration frequency range of 10–90 Hz. The maximum value that can be reached is 563 mV (at the vibration frequency of 18 Hz. The results of the test show that the harvester can output a relatively high voltage, which can meet the general electric power demand of a WSN sensor node.
A reduced energy supply strategy in active vibration control
Ichchou, M. N.; Loukil, T.; Bareille, O.; Chamberland, G.; Qiu, J.
2011-12-01
In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings.
A reduced energy supply strategy in active vibration control
International Nuclear Information System (INIS)
Ichchou, M N; Loukil, T; Bareille, O; Chamberland, G; Qiu, J
2011-01-01
In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings
International Nuclear Information System (INIS)
Siddique, Abu Raihan Mohammad; Mahmud, Shohel; Van Heyst, Bill
2017-01-01
Highlights: • A T-shaped cantilever type electromagnetic vibration based MPG has been described. • The designed EVMPG is useful for low frequency based vibration sources. • Both experimental tests and theoretical analysis have been performed. • The final compact prototype was tested at different conditions of human movements. • The prototype can generate 35.2 mV and 0.22 mW at 7 Hz with 5.6 Ω. - Abstract: The design, development, and analyses of low-frequency vibration based T-shaped cantilever type electromagnetic micro power generators (EVMPGs) are presented in this paper. Four different configurations (Configurations A to D) of EVMPGs were designed and fabricated and subsequently characterized using detailed experimental and limited analytical techniques. Configuration A and B consisted of a single and a double cylindrical moving magnets (NdFeB), respectively, while Configuration C consisted of four rectangular moving magnets with respect to a fixed copper coil. In contrast, Configuration D used a moving coil between four rectangular magnets with a back-iron bar. The open circuit RMS voltage output was observed to be a maximum from Configuration D (98.2 mV at 6.29 Hz) with a base vibration acceleration of 0.8 m s"−"2. Therefore, Configuration D was selected for further experimental investigations, which included changing the back-iron bar thickness, changing the base acceleration level, and changing the air gap separation between the magnets in order to optimize this configuration. The maximum load RMS voltage and power outputs of Configuration D were 105.4 mV and 1.35 mW at 6.29 Hz for load resistance 8.2 Ω and a base acceleration of 0.8 m s"−"2 with a 4.2 mm back-iron bar when the air gap between the magnets was 20 mm. Finally, a small portable EVMPG prototype was developed based on the Configuration D and was tested at different human movement conditions (i.e., walking, quick walking, and running). The developed EVMPG prototype was capable of
Shin, Seungha
All energy conversion inefficiencies begin with emission of resonant atomic motions, e.g., vibrations, and are declared as waste heat once these motions thermalize to equilibrium. The nonequilibrium energy occupancy of the vibrational modes can be targeted as a harvestable, low entropy energy source for direct conversion to electric energy. Since the lifetime of these resonant vibrations is short, special nanostructures are required with the appropriate tuning of the kinetics. These in turn require multiscale, multiphysics treatments. Atomic vibration is described with quasiparticle phonon in solid, and the optical phonon emission is dominant relaxation channel in semiconductors. These optical modes become over-occupied when their emission rate becomes larger than their decay rate, thus hindering energy relaxation and transport in devices. Effective removal of these phonons by drifting electrons is investigated by manipulating the electron distribution to have higher population in the low-energy states, thus allowing favorable phonon absorption. This is done through introduction, design and analysis of a heterobarrier conducting current, where the band gap is controlled by alloying, thus creating a spatial variation which is abrupt followed by a linear gradient (to ensure directed current). Self-consistent ensemble Monte Carlo simulations based on interaction kinetics between electron and phonon show that up to 19% of the phonon energy is converted to electric potential with an optimized GaAs/AlxGa1-xAs barrier structure over a range of current and electron densities, and this system is also verified through statistical entropy analysis. This direct energy conversion improves the device performance with lower operation temperature and enhances overall energy conversion efficiency. Through this study, the paradigm for harvesting the resonant atomic vibration is proposed, reversing the general role of phonon as only causing electric potential drop. Fundamentals
Effects of reagent translational and vibrational energy on the dynamics of endothermic reactions
International Nuclear Information System (INIS)
Krajnovich, D.; Zhang, Z.; Huisken, F.; Shen, Y.R.; Lee, Y.T.
1981-07-01
The endothermic reactions Br + CH 3 I → CH 3 + IBr (ΔH 0 0 = 13 kcal/mole) and Br + CF 3 I → CF 3 + IBr (ΔH 0 0 = 11 kcal/mole) have been studied by the crossed molecular beams method. Detailed center-of-mass contour maps of the IBr product flux as a function of recoil velocity and scattering angle are derived. For both systems it is found that the IBr product is sharply backward scattered with respect to the incident Br dirction, and that most of the available energy goes into product translation. Vibrational enhancement of the Br + CF 3 I reaction was investigated by using the infrared multiphoton absorption process to prepare highly vibrationally excited CF 3 I. At a collision energy of 31 kcal/mole (several times the barrier height), reagent vibrational energy appears to be less effective than an equivalent amount of (additional) translational energy in promoting reaction. More forward scattered IBr is produced in reactions of Br with vibrationally hot CF 3 I
«Green» Energy Harvesting by Means of Piezoflexogeneration from Vibration or Similar Processes
Directory of Open Access Journals (Sweden)
Timofey G. Lupeiko
2013-01-01
Full Text Available The piezoelectric systems of electric energy harvesting with an adaptive low-frequency resonance are developed. These systems allowed to obtain electricity from low-frequency vibration. The availability of their application for adaptation to other periodic processes including pedestrians and vehicles movement is shown.
Loendersloot, Richard; Ooijevaar, T.H.; Warnet, Laurent; Akkerman, Remko; de Boer, Andries; Meguid, S.A.; Gomes, J.F.S.
2009-01-01
The feasibility of a vibration based damage identification method is investigated. The Modal Strain Energy method is applied to a T–beam structure. The dynamic response of an intact structure and a damaged, delaminated structure is analysed employing a commercially available Finite Element package.
Effects of reagent translational and vibrational energy on the dynamics of endothermic reactions
Energy Technology Data Exchange (ETDEWEB)
Krajnovich, D.; Zhang, Z.; Huisken, F.; Shen, Y.R.; Lee, Y.T.
1981-07-01
The endothermic reactions Br + CH/sub 3/I ..-->.. CH/sub 3/ + IBr (..delta..H/sub 0//sup 0/ = 13 kcal/mole) and Br + CF/sub 3/I ..-->.. CF/sub 3/ + IBr (..delta..H/sub 0//sup 0/ = 11 kcal/mole) have been studied by the crossed molecular beams method. Detailed center-of-mass contour maps of the IBr product flux as a function of recoil velocity and scattering angle are derived. For both systems it is found that the IBr product is sharply backward scattered with respect to the incident Br dirction, and that most of the available energy goes into product translation. Vibrational enhancement of the Br + CF/sub 3/I reaction was investigated by using the infrared multiphoton absorption process to prepare highly vibrationally excited CF/sub 3/I. At a collision energy of 31 kcal/mole (several times the barrier height), reagent vibrational energy appears to be less effective than an equivalent amount of (additional) translational energy in promoting reaction. More forward scattered IBr is produced in reactions of Br with vibrationally hot CF/sub 3/I.
Vibrational-state-selected ion--molecule reaction cross sections at thermal energies
Pijkeren, D. van; Boltjes, E.; Eck, J. van; Niehaus, A.
1984-01-01
A method designed to measure relative ion—molecule reaction rates at thermal collision energies for selected reactant ion vibrational states is described. Relative reaction rates are determined for the three endothermic reactions: H2+ (υ)(He,H)HeH+, H2+ (υ)(Ne,H)NeH+, D2+(υ)(Ne, D)NeD+, and for the
Analysis of Wind Energy Potential and Vibrations Caused by Wind Turbine on Its Basement
Czech Academy of Sciences Publication Activity Database
Kaláb, Z.; Hanslian, David; Stolárik, M.; Pinka, M.
2014-01-01
Roč. 19, č. 3 (2014), s. 151-159 ISSN 1335-1788 Institutional support: RVO:68378289 Keywords : wind turbine * wind energy potential * wind map * wind map * experimental measurement * vibration velocity Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 0.329, year: 2014 http://actamont.tuke.sk/pdf/2014/n3/6kalab.pdf
A resonant electromagnetic vibration energy harvester for intelligent wireless sensor systems
Energy Technology Data Exchange (ETDEWEB)
Qiu, Jing, E-mail: jingqiu@cqu.edu.cn; Wen, Yumei; Li, Ping; Liu, Xin; Chen, Hengjia; Yang, Jin [Sensors and Instruments Research Center, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)
2015-05-07
Vibration energy harvesting is now receiving more interest as a means for powering intelligent wireless sensor systems. In this paper, a resonant electromagnetic vibration energy harvester (VEH) employing double cantilever to convert low-frequency vibration energy into electrical energy is presented. The VEH is made up of two cantilever beams, a coil, and magnetic circuits. The electric output performances of the proposed electromagnetic VEH have been investigated. With the enhancement of turns number N, the optimum peak power of electromagnetic VEH increases sharply and the resonance frequency deceases gradually. When the vibration acceleration is 0.5 g, we obtain the optimum output voltage and power of 9.04 V and 50.8 mW at frequency of 14.9 Hz, respectively. In a word, the prototype device was successfully developed and the experimental results exhibit a great enhancement in the output power and bandwidth compared with other traditional electromagnetic VEHs. Remarkably, the proposed resonant electromagnetic VEH have great potential for applying in intelligent wireless sensor systems.
Surface energy effect on free vibration of nano-sized piezoelectric double-shell structures
Fang, Xue-Qian; Zhu, Chang-Song; Liu, Jin-Xi; Liu, Xiang-Lin
2018-01-01
Combining Goldenveizer-Novozhilov shell theory, thin plate theory and electro-elastic surface theory, the size-dependent vibration of nano-sized piezoelectric double-shell structures under simply supported boundary condition is presented, and the surface energy effect on the natural frequencies is discussed. The displacement components of the cylindrical nano-shells and annular nano-plates are expanded as the superposition of standard Fourier series based on Hamilton's principle. The total stresses with consideration of surface energy effect are derived, and the total energy function is obtained by using Rayleigh-Ritz energy method. The free vibration equation is solved, and the natural frequency is analyzed. In numerical examples, it is found that the surface elastic constant, piezoelectric constant and surface residual stress show different effects on the natural frequencies. The effect of surface piezoelectric constant is the maximum. The effect of dimensions of the double-shell under different surface material properties is also examined.
Development of Non-Conservative Joints in Beam Networks for Vibration Energy Flow Analysis
Directory of Open Access Journals (Sweden)
Jee-Hun Song
2007-01-01
Full Text Available Our work aims to find a general solution for the vibrational energy flow through a plane network of beams on the basis of an energy flow analysis. A joint between two semi-infinite beams are modeled by three sets of springs and dashpots. Thus, the results can incorporate the case of complaint and non-conservative in all the three degrees of freedom. In the cases of finite coupled structures connected at a certain angle, the derived non-conservative joints and developed wave energy equation were applied. The joint properties, the frequency, the coupling angle, and the internal loss factor were changed to evaluate the proposed methods for predicting medium-to-high frequency vibrational energy and intensity distributions.
Mems-based pzt/pzt bimorph thick film vibration energy harvester
DEFF Research Database (Denmark)
Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian
2011-01-01
We describe fabrication and characterization of a significantly improved version of a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical...... support materials since only PZT is strained, and thus it has a potential for significantly higher output power. An improved process scheme for the energy harvester resulted in a robust fabrication process with a record high fabrication yield of 98.6%. Moreover, the robust fabrication process allowed...... a high pressure treatment of the screen printed PZT thick films prior to sintering, improving the PZT thick film performance and harvester power output reaches 37.1 μW at 1 g....
Clarke, Peter; Varghese, Philip; Goldstein, David
2018-01-01
A discrete velocity method is developed for gas mixtures of diatomic molecules with both rotational and vibrational energy states. A full quantized model is described, and rotation-translation and vibration-translation energy exchanges are simulated using a Larsen-Borgnakke exchange model. Elastic and inelastic molecular interactions are modeled during every simulated collision to help produce smooth internal energy distributions. The method is verified by comparing simulations of homogeneous relaxation by our discrete velocity method to numerical solutions of the Jeans and Landau-Teller equations, and to direct simulation Monte Carlo. We compute the structure of a 1D shock using this method, and determine how the rotational energy distribution varies with spatial location in the shock and with position in velocity space.
Influence of collision energy and vibrational excitation on the ...
Indian Academy of Sciences (India)
tions of potential energy surface (PES) for BrH2 system are more ... rier heights for both the exchange and abstraction are smaller than ... The complete picture on the dynamics of ..... Kurosaki Y and Takayanagi T private communication. 20.
Multi-resonant electromagnetic shunt in base isolation for vibration damping and energy harvesting
Pei, Yalu; Liu, Yilun; Zuo, Lei
2018-06-01
This paper investigates multi-resonant electromagnetic shunts applied to base isolation for dual-function vibration damping and energy harvesting. Two multi-mode shunt circuit configurations, namely parallel and series, are proposed and optimized based on the H2 criteria. The root-mean-square (RMS) value of the relative displacement between the base and the primary structure is minimized. Practically, this will improve the safety of base-isolated buildings subjected the broad bandwidth ground acceleration. Case studies of a base-isolated building are conducted in both the frequency and time domains to investigate the effectiveness of multi-resonant electromagnetic shunts under recorded earthquake signals. It shows that both multi-mode shunt circuits outperform traditional single mode shunt circuits by suppressing the first and the second vibration modes simultaneously. Moreover, for the same stiffness ratio, the parallel shunt circuit is more effective at harvesting energy and suppressing vibration, and can more robustly handle parameter mistuning than the series shunt circuit. Furthermore, this paper discusses experimental validation of the effectiveness of multi-resonant electromagnetic shunts for vibration damping and energy harvesting on a scaled-down base isolation system.
International Nuclear Information System (INIS)
Band, Y.B.; Freed, K.F.
1977-01-01
The full quantum theory of dissociation processes in polyatomic molecules is converted to a form enabling the isolation of a selected fragment vibration. This form enables the easy evaluation of the probability distribution for energy partitioning between this vibration and all other degrees of freedom that results from the sudden Franck--Condon rearrangement process. The resultant Franck--Condon factors involve the square of the one-dimensional overlap integral between effective oscillator wavefunctions and the wavefunctions for the selected fragment vibration, a form that resembles the simple golden rule model for polyatomic dissociation and reaction processes. The full quantum theory can, therefore, be viewed as providing both a rigorous justification for certain generic aspects of the simple golden rule model as well as providing a number of important generalizations thereof. Some of these involve dealing with initial bound state vibrational excitation, explicit molecule, fragment and energy dependence of the effective oscillator, and the incorporation of all isotopic dependence. In certain limiting situations the full quantum theory yields simple, readily usable analytic expressions for the frequency and equilibrium position of the effective oscillator. Specific applications are presented for the direct photodissociation of HCN, DCN, and CO 2 where comparisons between the full theory and the simple golden rule are presented. We also discuss the generalizations of the previous theory to enable the incorporation of effects of distortion in the normal modes as a function of the reaction coordinate on the repulsive potential energy surface
Obut, T A; Ovsiukova, M V; Egorova, S A; Érdynieva, T A; Dement'eva, T Iu; Obut, E T
2014-01-01
The experiments were performed on male rats, which were subjected to single and multiply repeated vibrations (low-frequency, horizontal, high-amplitude) analogous to the action of motor transport vibrations. It is established that the administration of retabolil produces a hypotensive effect and blocks the vibration-induced increase in the level of hypertensive hormone aldosterone. Under conditions of the multiply repeated action of vibrations, both effects were realized via micro-opioid receptors. In the case of a single action, these receptors were only involved in a hypotensive effect but not mediated in aldosterone suppression. Both these effects were absent in the control group of animals (not subjected to vibrations). Therefore, retabolil can be used as a hypotensive and aldosterone-blocking drug for vibration-induced hypertension in animals and, probably, in humans.
CSIR Research Space (South Africa)
de Clercq, L
2010-09-01
Full Text Available Coherent control of the upper vibrational level populations in the electronic ground state of a polyatomic molecule was simulated. Results indicate that selective excitation of a specific upper state level is possible...
Dhote, Sharvari
With advancement in technology, power requirements are reduced drastically for sensor nodes. The piezoelectric vibration energy harvesters generate sufficient power to low-powered sensor nodes. The main requirement of energy harvester is to provide a broad bandwidth. A conventional linear harvester does not satisfy this requirement. Therefore, the research focus is shifted to exploiting nonlinearity to widen the bandwidth of the harvester. Although nonlinear techniques are promising for broadening a bandwidth, reverse sweep shows reduced response as compared to the forward sweep. To overcome this issue, this thesis presents the design and development of a broadband piezoelectric vibration energy harvester based on a nonlinear multi-frequency compliant orthoplanar spring. This thesis is divided into three parts. The first part presents the design and experimental study of a tri-leg compliant orthoplanar spring for a broadband energy harvesting. The harvester performance is enhanced through the use of lightweight masses, which bring nonlinear vibration modes closer. The performance of the harvester is analyzed through development of a mathematical model based on the Duffing oscillator. The experimental and numerical results are in good agreement. The parametric study shows that an optimum performance is achieved by further reducing a gap in between the vibration modes using different weight masses. In the second part of the research, multiple (bi, quad and pent) leg compliant orthoplanar springs are designed to understand their role in expanding the bandwidth and reducing gap between vibration modes. The designed harvesters are compared by calculating the figure of merits. The quad-leg design provides a better performance in terms of power density and bandwidth among all the designs. The reverse sweep response is comparable to the forward sweep in terms of bandwidth. In the final part, a magnetic force is applied to the tri-leg harvester, which enhanced the voltage
Development of Vibration-Based Piezoelectric Raindrop Energy Harvesting System
Wong, Chin Hong; Dahari, Zuraini
2017-03-01
The trend of finding new means to harvest energy has triggered numerous researches to explore the potential of raindrop energy harvesting. This paper presents an investigation on raindrop energy harvesting which compares the performance of polyvinylidene fluoride (PVDF) cantilever and bridge structure transducers and the development of a raindrop energy harvesting system. The parameters which contribute to the output voltage such as droplet size, droplets released at specific heights and dimensions of PVDF transducers are analyzed. Based on the experimental results, the outcomes have shown that the bridge structure transducer generated a higher voltage than the cantilever. Several dimensions have been tested and it was found that the 30 mm × 4 mm × 25 μm bridge structure transducer generated a relatively high AC open-circuit voltage, which is 4.22 V. The power generated by the bridge transducer is 18 μW across a load of 330 kΩ. The transducer is able to drive up a standard alternative current (AC) to direct current (DC) converter (full-wave bridge rectifier). It generated a DC voltage, V DC of 8.7 mV and 229 pW across a 330 kΩ resistor per drop. It is also capable to generate 9.3 nJ in 20 s from an actual rain event.
Roles of the Excitation in Harvesting Energy from Vibrations.
Directory of Open Access Journals (Sweden)
Hui Zhang
Full Text Available The study investigated the role of excitation in energy harvesting applications. While the energy ultimately comes from the excitation, it was shown that the excitation may not always behave as a source. When the device characteristics do not perfectly match the excitation, the excitation alternately behaves as a source and a sink. The extent to which the excitation behaves as a sink determines the energy harvesting efficiency. Such contradictory roles were shown to be dictated by a generalized phase defined as the instantaneous phase angle between the velocity of the device and the excitation. An inductive prototype device with a diamagnetically levitated seismic mass was proposed to take advantage of the well established phase changing mechanism of vibro-impact to achieve a broader device bandwidth. Results suggest that the vibro-impact can generate an instantaneous, significant phase shift in response velocity that switches the role of the excitation. If introduced properly outside the resonance zone it could dramatically increase the energy harvesting efficiency.
Inelastic surface vibrations versus energy-dependent nucleus ...
Indian Academy of Sciences (India)
Limitations of the static Woods–Saxon potential and the applicability of the energy dependent Woods–Saxon potential (EDWSP) model within the framework of one-dimensional Wong formula to explore the sub-barrier fusion data are highlighted. The inelastic surface excitations of the fusing nuclei are found to be ...
Inelastic surface vibrations versus energy-dependent nucleus ...
Indian Academy of Sciences (India)
Abstract. Limitations of the static Woods–Saxon potential and the applicability of the energy- dependent Woods–Saxon potential (EDWSP) model within the framework of one-dimensional. Wong formula to explore the sub-barrier fusion data are highlighted. The inelastic surface exci- tations of the fusing nuclei are found to ...
Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures
Vlahopoulos, Nickolas; Schiller, Noah H.
2011-01-01
The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.
Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect
International Nuclear Information System (INIS)
Ju, S; Chae, S H; Choi, Y; Jun, S; Park, S M; Lee, S; Ji, C-H; Lee, H W
2013-01-01
This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken
Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect
Ju, S.; Chae, S. H.; Choi, Y.; Jun, S.; Park, S. M.; Lee, S.; Lee, H. W.; Ji, C.-H.
2013-12-01
This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57μW has been achieved for a 50kΩ load, when the fabricated energy harvester was hand-shaken.
Magnetostrictive clad steel plates for high-performance vibration energy harvesting
Yang, Zhenjun; Nakajima, Kenya; Onodera, Ryuichi; Tayama, Tsuyoki; Chiba, Daiki; Narita, Fumio
2018-02-01
Energy harvesting technology is becoming increasingly important with the appearance of the Internet of things. In this study, a magnetostrictive clad steel plate for harvesting vibration energy was proposed. It comprises a cold-rolled FeCo alloy and cold-rolled steel joined together by thermal diffusion bonding. The performances of the magnetostrictive FeCo clad steel plate and conventional FeCo plate cantilevers were compared under bending vibration; the results indicated that the clad steel plate construct exhibits high voltage and power output compared to a single-plate construct. Finite element analysis of the cantilevers under bending provided insights into the magnetic features of a clad steel plate, which is crucial for its high performance. For comparison, the experimental results of a commercial piezoelectric bimorph cantilever were also reported. In addition, the cold-rolled FeCo and Ni alloys were joined by thermal diffusion bonding, which exhibited outstanding energy harvesting performance. The larger the plate volume, the more the energy generated. The results of this study indicated not only a promising application for the magnetostrictive FeCo clad steel plate as an efficient energy harvester, related to small vibrations, but also the notable feasibility for the formation of integrated units to support high-power trains, automobiles, and electric vehicles.
Quantum localization and protein-assisted vibrational energy flow in cofactors
International Nuclear Information System (INIS)
Leitner, David M
2010-01-01
Quantum effects influence vibrational dynamics and energy flow in biomolecules, which play a central role in biomolecule function, including control of reaction kinetics. Lifetimes of many vibrational modes of proteins and their temperature dependence, as determined by quantum golden-rule-based calculations, exhibit trends consistent with experimental observation and distinct from estimates based on classical modeling. Particularly notable are quantum coherence effects that give rise to localization of vibrational states of sizable organic molecules in the gas phase. Even when such a molecule, for instance a cofactor, is embedded in a protein, remnants of quantum localization survive that influence vibrational energy flow and its dependence on temperature. We discuss these effects on the mode-damping rates of a cofactor embedded in a protein, using the green fluorescent protein chromophore as a specific example. We find that for cofactors of this size embedded in their protein and solvent environment at room temperature a golden-rule calculation often overestimates the mode-damping rate.
Iannacci, J.; Sordo, G.; Serra, E.; Kucera, M.; Schmid, U.
2015-05-01
In this work, we discuss the verification and preliminary experimental characterization of a MEMS-based vibration Energy Harvester (EH) design. The device, named Four-Leaf Clover (FLC), is based on a circular-shaped mechanical resonator with four petal-like mass-spring cascaded systems. This solution introduces several mechanical Degrees of Freedom (DOFs), and therefore enables multiple resonant modes and deformation shapes in the vibrations frequency range of interest. The target is to realize a wideband multi-modal EH-MEMS device, that overcomes the typical narrowband working characteristics of standard cantilevered EHs, by ensuring flexible and adaptable power source to ultra-low power electronics for integrated remote sensing nodes (e.g. Wireless Sensor Networks - WSNs) in the Internet of Things (IoT) scenario, aiming to self-powered and energy autonomous smart systems. Finite Element Method simulations of the FLC EH-MEMS show the presence of several resonant modes for vibrations up to 4-5 kHz, and level of converted power up to a few μW at resonance and in closed-loop conditions (i.e. with resistive load). On the other hand, the first experimental tests of FLC fabricated samples, conducted with a Laser Doppler Vibrometer (LDV), proved the presence of several resonant modes, and allowed to validate the accuracy of the FEM modeling method. Such a good accordance holds validity for what concerns the coupled field behavior of the FLC EH-MEMS, as well. Both measurements and simulations performed at 190 Hz (i.e. out of resonance) showed the generation of power in the range of nW (Root Mean Square - RMS values). Further steps of this work will include the experimental characterization in a full range of vibrations, aiming to prove the whole functionality of the FLC EH-MEMS proposed design concept.
Split energy level radiation detection
International Nuclear Information System (INIS)
Barnes, G.T.
1986-01-01
This patent describes an energy discriminating radiation detector comprising: (a) a first element comprising a first material of a kind which is preferentially responsive to penetrative radiation of a first energy range; (b) a second element comprising a second material different in kind from the first material and of a kind which is preferentially responsive to penetrative radiation of second energy range extending higher than the first energy range. The element is positioned to receive radiation which has penetrated through a portion of the first element; and (c) a filter of penetrative radiation interposed between the first and second elements
Coupled analysis of multi-impact energy harvesting from low-frequency wind induced vibrations
Zhu, Jin; Zhang, Wei
2015-04-01
Energy need from off-grid locations has been critical for effective real-time monitoring and control to ensure structural safety and reliability. To harvest energy from ambient environments, the piezoelectric-based energy-harvesting system has been proven very efficient to convert high frequency vibrations into usable electrical energy. However, due to the low frequency nature of the vibrations of civil infrastructures, such as those induced from vehicle impacts, wind, and waves, the application of a traditional piezoelectric-based energy-harvesting system is greatly restrained since the output power drops dramatically with the reduction of vibration frequencies. This paper focuses on the coupled analysis of a proposed piezoelectric multi-impact wind-energy-harvesting device that can effectively up-convert low frequency wind-induced vibrations into high frequency ones. The device consists of an H-shape beam and four bimorph piezoelectric cantilever beams. The H-shape beam, which can be easily triggered to vibrate at a low wind speed, is originated from the first Tacoma Narrows Bridge, which failed at wind speeds of 18.8 m s-1 in 1940. The multi-impact mechanism between the H-shape beam and the bimorph piezoelectric cantilever beams is incorporated to improve the harvesting performance at lower frequencies. During the multi-impact process, a series of sequential impacts between the H-shape beam and the cantilever beams can trigger high frequency vibrations of the cantilever beams and result in high output power with a considerably high efficiency. In the coupled analysis, the coupled structural, aerodynamic, and electrical equations are solved to obtain the dynamic response and the power output of the proposed harvesting device. A parametric study for several parameters in the coupled analysis framework is carried out including the external resistance, wind speed, and the configuration of the H-shape beam. The average harvested power for the piezoelectric cantilever
Feasible integration in asphalt of piezoelectric cymbals for vibration energy harvesting
International Nuclear Information System (INIS)
Moure, A.; Izquierdo Rodríguez, M.A.; Rueda, S. Hernández; Gonzalo, A.; Rubio-Marcos, F.; Cuadros, D. Urquiza; Pérez-Lepe, A.; Fernández, J.F.
2016-01-01
Graphical abstract: A system based on piezoelectric cymbals embedded in asphalt for the first time is used as harvester for wasted vibrational energy produced by traffic. Energy density in the range of other alternative sources is achieved, with an estimated projected cost that shows the feasibility of this harvesting energy system. - Highlights: • Piezoelectric cymbals have been directly integrated in asphalt for the first time. • Harvesting from wasted vibrational energy caused by vehicles is demonstrated to be feasible by this integration. • Energy density and cost are estimated to be competitive with other sources as photovoltaic. • A 10% of the energy generated in the Region of Madrid can be obtained by covering only the 0.6% of its roads. - Abstract: Piezoelectric cymbals with 29-mm diameter and different configurations are fabricated and tested to determine the best conditions to optimize the conversion of mechanical to electric energy. Then, the ones with the best results are integrated directly in asphalt to evaluate their performance as vibration energy harvesters in roads, in a test bench designed to characterize these parameters. The main cymbal parameters and their integration in the asphalt are determined. For the first time, the electrical energy that can be obtained with the embedment of cymbals in asphalt is evaluated. Each single piezoceramic cymbal recovers up to 16 μW for the pass of one heavy vehicle wheel. An extrapolation of the energy transformed by the integrated cymbals in roads with high vehicle densities, such as in a peri-urban motorway, is approached. Energy densities in the range of 40–50 MW h/m"2 can be obtained at 100 m of road (use of 30,000 cymbals), which could account for more than 65 MW h in a year. All this with a relatively low cost for an emerging technology (less than 2 €/kW h). The conversion of wasted and unused vibrational energy in roads by piezoelectric cymbals is thus proved as a real possibility of
A novel design of a map-tuning piezoelectric vibration energy harvester
International Nuclear Information System (INIS)
Huang, Shyh-Chin; Lin, Kao-An
2012-01-01
In this paper, a new design of a self-tuning bimorph PZT beam for maximum vibration energy harvesting is introduced. As is well known, a PZT beam harvester captures the most energy as it resonates with the ambient vibration. The ambient excitation frequency varies in nature so that proper tracking of the ambient frequency and adjusting the harvester’s resonance frequency accordingly would assure the most energy retrieved. The harvester introduced in the paper is composed of an elastic beam partially covered with two-sided PZT patches, the same as most others, but the method of tuning its resonance frequency is novel. A movable intermediate rigid support is attached to the beam and by adjusting the support’s position according to the sensed ambient frequency, the beam’s resonance frequency will coincide with the ambient frequency such that the harvested vibration energy is maximized. The theoretical analysis employs Hamilton’s principle, the assumed-mode method, and the receptance method. Numerical results are obtained and compared with the experimental ones. They show excellent agreement in a frequency versus support’s position chart. The most significant feature is that there can be up to ±35% of resonance frequency tunability. This achievement provides substantial advantages in power-harvesting applications. An experiment for base excitation to simulate the ambient vibration is setup as well and the results show that as little as 5% excitation frequency variation would cause more than 70% output voltage drop if there were no tuning ability. The novel design could significantly enhance the harvested energy in a short duration of time. (paper)
Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams
Energy Technology Data Exchange (ETDEWEB)
Zhang, Xiaoyong, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn; Yan, Xiaojun, E-mail: zhangxy@buaa.edu.cn, E-mail: yanxiaojun@buaa.edu.cn [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China); Collaborative Innovation Center of Advanced Aero-Engine, Beijing 100191 (China); National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics, Beijing 100191 (China); Beijing Key Laboratory of Aero-Engine Structure and Strength, Beijing 100191 (China); Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)
2016-06-15
This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.
Molecular-level mechanisms of vibrational frequency shifts in a polar liquid.
Morales, Christine M; Thompson, Ward H
2011-06-16
A molecular-level analysis of the origins of the vibrational frequency shifts of the CN stretching mode in neat liquid acetonitrile is presented. The frequency shifts and infrared spectrum are calculated using a perturbation theory approach within a molecular dynamics simulation and are in good agreement with measured values reported in the literature. The resulting instantaneous frequency of each nitrile group is decomposed into the contributions from each molecule in the liquid and by interaction type. This provides a detailed picture of the mechanisms of frequency shifts, including the number of surrounding molecules that contribute to the shift, the relationship between their position and relative contribution, and the roles of electrostatic and van der Waals interactions. These results provide insight into what information is contained in infrared (IR) and Raman spectra about the environment of the probed vibrational mode. © 2011 American Chemical Society
Note: A component-level frequency tunable isolator for vibration-sensitive chips using SMA beams
International Nuclear Information System (INIS)
Zhang, Xiaoyong; Yan, Xiaojun; Ding, Xin; Wu, Di; Qi, Junlei; Wang, Ruixin; Lu, Siwei
2016-01-01
This note presents a component-level frequency tunable isolator for vibration-sensitive chips. The isolator employed 8 U-shaped shape memory alloy (SMA) beams to support an isolation island (used for mounting chips). Due to the temperature-induced Young’s modulus variation of SMA, the system stiffness of the isolator can be controlled through heating the SMA beams. In such a way, the natural frequency of the isolator can be tuned. A prototype was fabricated to evaluate the concept. The test results show that the natural frequency of the isolator can be tuned in the range of 64 Hz–97 Hz by applying different heating strategies. Moreover, resonant vibration can be suppressed significantly (the transmissibility decreases about 65% near the resonant frequency) using a real-time tuning method.
International Nuclear Information System (INIS)
Suzuki, M; Takahashi, T; Aoyagi, S
2014-01-01
We have been developing small power generation device of capacitance-type to be converted to electrical energy vibration energy using an electret. In this Study, dielectric nanoparticles were mixed with an electret made of fluorocarbon polymer. As a result, implanted charge density of the electret was successfully enhanced thanks to the mixing of particles. A small sized vibration energy harvester (VEH) was fabricated using the fluorocarbon mixed with dielectric nano-particles. As a result of applying vibration (20 Hz, 0.65 G) to the fabricated VEH, The maximum generated power of approximately 50 μW was obtained
Exploring the vibrational fingerprint of the electronic excitation energy via molecular dynamics
International Nuclear Information System (INIS)
Deyne, Andy Van Yperen-De; Pauwels, Ewald; Ghysels, An; Waroquier, Michel; Van Speybroeck, Veronique; Hemelsoet, Karen; De Meyer, Thierry; De Clerck, Karen
2014-01-01
A Fourier-based method is presented to relate changes of the molecular structure during a molecular dynamics simulation with fluctuations in the electronic excitation energy. The method implies sampling of the ground state potential energy surface. Subsequently, the power spectrum of the velocities is compared with the power spectrum of the excitation energy computed using time-dependent density functional theory. Peaks in both spectra are compared, and motions exhibiting a linear or quadratic behavior can be distinguished. The quadratically active motions are mainly responsible for the changes in the excitation energy and hence cause shifts between the dynamic and static values of the spectral property. Moreover, information about the potential energy surface of various excited states can be obtained. The procedure is illustrated with three case studies. The first electronic excitation is explored in detail and dominant vibrational motions responsible for changes in the excitation energy are identified for ethylene, biphenyl, and hexamethylbenzene. The proposed method is also extended to other low-energy excitations. Finally, the vibrational fingerprint of the excitation energy of a more complex molecule, in particular the azo dye ethyl orange in a water environment, is analyzed
Aldegunde, J.; Jambrina, P. G.; García, E.; Herrero, V. J.; Sáez-Rábanos, V.; Aoiz, F. J.
2013-11-01
The advent of very precise measurements of rate coefficients in reactions of muonium (Mu), the lightest hydrogen isotope, with H2 in its ground and first vibrational state and of kinetic isotope effects with respect to heavier isotopes has triggered a renewed interests in the field of muonic chemistry. The aim of the present article is to review the most recent results about the dynamics and mechanism of the reaction Mu+H2 to shed light on the importance of quantum effects such as tunnelling, the preservation of the zero point energy, and the vibrational adiabaticity. In addition to accurate quantum mechanical (QM) calculations, quasiclassical trajectories (QCT) have been run in order to check the reliability of this method for this isotopic variant. It has been found that the reaction with H2(v=0) is dominated by the high zero point energy (ZPE) of the products and that tunnelling is largely irrelevant. Accordingly, both QCT calculations that preserve the products' ZPE as well as those based on the Ring Polymer Molecular Dynamics methodology can reproduce the QM rate coefficients. However, when the hydrogen molecule is vibrationally excited, QCT calculations fail completely in the prediction of the huge vibrational enhancement of the reactivity. This failure is attributed to tunnelling, which plays a decisive role breaking the vibrational adiabaticity when v=1. By means of the analysis of the results, it can be concluded that the tunnelling takes place through the ν1=1 collinear barrier. Somehow, the tunnelling that is missing in the Mu+H2(v=0) reaction is found in Mu+H2(v=1).
International Nuclear Information System (INIS)
Renaud, M; Goedbloed, M; De Nooijer, C; Van Schaijk, R; Fujita, T
2014-01-01
Current commercial wireless tire pressure monitoring systems (TPMS) require a battery as electrical power source. The battery limits the lifetime of the TPMS. This limit can be circumvented by replacing the battery by a vibration energy harvester. Autonomous wireless TPMS powered by MEMS electret based vibration energy harvester have been demonstrated. A remaining technical challenge to attain the grade of commercial product with these autonomous TPMS is the mechanical reliability of the MEMS harvester. It should survive the harsh conditions imposed by the tire environment, particularly in terms of mechanical shocks. As shown in this article, our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, several types of shock absorbing structures are investigated. With the best proposed solution, the shock resilience of the harvesters is brought above 2500 g
The benefits of noise and nonlinearity: Extracting energy from random vibrations
Energy Technology Data Exchange (ETDEWEB)
Gammaitoni, Luca, E-mail: luca.gammaitoni@pg.infn.it [NiPS Laboratory, Universita di Perugia, I-06100 Perugia (Italy); Neri, Igor; Vocca, Helios [NiPS Laboratory, Universita di Perugia, I-06100 Perugia (Italy)
2010-10-05
Nonlinear behavior is the ordinary feature of the vast majority of dynamical systems and noise is commonly present in any finite temperature physical and chemical system. In this article we briefly review the potentially beneficial outcome of the interplay of noise and nonlinearity by addressing the novel field of vibration energy harvesting. The role of nonlinearity in a piezoelectric harvester oscillator dynamics is modeled with nonlinear stochastic differential equation.
2017-04-04
comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE...µm in order to facilitate the flow diagnostics. The center jet flow issues through a CNC- machined stainless nozzle, which can be replaced to provide...the mixing in the shear layer, which will be used to compare with the relaxation time of the vibrational energy, was defined as the eddy turnover time
Performance studies of the vibration wire monitor on the test stand with low energy electron beam
International Nuclear Information System (INIS)
Okabe, Kota; Yoshimoto, Masahiro; Kinsho, Michikazu
2015-01-01
In the high intensity proton accelerator as the Japan Proton Accelerator Research Complex (J-PARC) accelerators, serious radiation and residual dose is induced by a small beam loss such a beam halo. Therefore, diagnostics of the beam halo formation is one of the most important issues to control the beam loss. For the beam halo monitor, the vibration wire monitor (VWM) has a potential for investigating the beam halo and weak beam scanning. The VWM has a wide dynamic range, high resolution and the VWM is not susceptible to secondary electrons and electric noises. We have studied the VWM features as a new beam-halo monitor on the test stand with low energy electron gun. The frequency shift of the irradiated vibration wire was confirmed about wire material and the electron beam profile measured by using the VWM was consistent with the results of the Faraday cup measurement. Also we calculated a temperature distribution on the vibration wire which is irradiated by the electron beam with the numerical simulation. The simulations have been fairly successful in reproducing the transient of the irradiated vibration wire frequency measured by test stand experiments. In this paper, we will report a result of performance evaluation for the VWM on the test stands and discuss the VWM for beam halo diagnostic. (author)
Qian, Feng; Zhou, Wanlu; Kaluvan, Suresh; Zhang, Haifeng; Zuo, Lei
2018-04-01
Vibration energy harvesting has been extensively studied in recent years to explore a continuous power source for sensor networks and low-power electronics. Torsional vibration widely exists in mechanical engineering; however, it has not yet been well exploited for energy harvesting. This paper presents a theoretical model and an experimental validation of a torsional vibration energy harvesting system comprised of a shaft and a shear mode piezoelectric transducer. The piezoelectric transducer position on the surface of the shaft is parameterized by two variables that are optimized to obtain the maximum power output. The piezoelectric transducer can work in d 15 mode (pure shear mode), coupled mode of d 31 and d 33, and coupled mode of d 33, d 31 and d 15, respectively, when attached at different angles. Approximate expressions of voltage and power are derived from the theoretical model, which gave predictions in good agreement with analytical solutions. Physical interpretations on the implicit relationship between the power output and the position parameters of the piezoelectric transducer is given based on the derived approximate expression. The optimal position and angle of the piezoelectric transducer is determined, in which case, the transducer works in the coupled mode of d 15, d 31 and d 33.
Directory of Open Access Journals (Sweden)
Wenbin Gu
2015-01-01
Full Text Available As an important parameter in blasting design, charging structure directly influences blasting effect. Due to complex conditions of this blasting and excavating engineering in Jiangsu, China, the authors carried out comparative researches with coupling structure, air-decoupling structure, and water-decoupling structure. After collecting, comparing, and analyzing produced signals on blasting vibration, the authors summarized that when proportional distances are the same, water-decoupling structure can reduce instantaneous energy of blasting vibration more effectively with more average rock fragmentation and less harm of dust. From the perspective of impedance matching, the present paper analyzed influence of charging structure on blasting vibration energy, demonstrating that impedance matching relationship between explosive and rock changes because of different charging structures. Through deducing relationship equation that meets the impedance matching of explosive and rock under different charging structures, the research concludes that when blasting rocks with high impedance, explosive with high impedance can better transmits blasting energy. Besides, when employing decoupling charging, there exists a reasonable decoupling coefficient helping realize impedance matching of explosive and rock.
Parametric Study and Optimization of a Piezoelectric Energy Harvester from Flow Induced Vibration
Ashok, P.; Jawahar Chandra, C.; Neeraj, P.; Santhosh, B.
2018-02-01
Self-powered systems have become the need of the hour and several devices and techniques were proposed in favour of this crisis. Among the various sources, vibrations, being the most practical scenario, is chosen in the present study to investigate for the possibility of harvesting energy. Various methods were devised to trap the energy generated by vibrating bodies, which would otherwise be wasted. One such concept is termed as flow-induced vibration which involves the flow of a fluid across a bluff body that oscillates due to a phenomenon known as vortex shedding. These oscillations can be converted into electrical energy by the use of piezoelectric patches. A two degree of freedom system containing a cylinder as the primary mass and a cantilever beam as the secondary mass attached with a piezoelectric circuit, was considered to model the problem. Three wake oscillator models were studied in order to determine the one which can generate results with high accuracy. It was found that Facchinetti model produced better results than the other two and hence a parametric study was performed to determine the favourable range of the controllable variables of the system. A fitness function was formulated and optimization of the selected parameters was done using genetic algorithm. The parametric optimization led to a considerable improvement in the harvested voltage from the system owing to the high displacement of secondary mass.
International Nuclear Information System (INIS)
Perfetto, S; Rohlfing, J; Infante, F; Mayer, D; Herold, S
2016-01-01
Piezoelectric transducers can be used to harvest electrical energy from structural vibrations in order to power continuously operating condition monitoring systems local to where they operate. However, excessive vibrations can compromise the safe operation of mechanical systems. Therefore, absorbers are commonly used to control vibrations. With an integrated device, the mechanical energy that otherwise would be dissipated can be converted via piezoelectric transducers. Vibration absorbers are designed to have high damping factors. Hence, the integration of transducers would lead to a low energy conversion. Efficient energy harvesters usually have low damping capabilities; therefore, they are not effective for vibration suppression. Thus, the design of an integrated device needs to consider the two conflicting requirements on the damping. This study focuses on the development of a laboratory test rig with a host structure and a vibration absorber with tunable damping via an active relative velocity feedback. A voice coil actuator is used for this purpose. To overcome the passive damping effects of the back electromagnetic force a novel voltage feedback control is proposed, which has been validated both in simulation and experimentally. The aim of this study is to have a test rig ready for the introduction of piezo-transducers and available for future experimental evaluations of the damping effect on the effectiveness of vibration reduction and energy harvesting efficiency. (paper)
Perfetto, S.; Rohlfing, J.; Infante, F.; Mayer, D.; Herold, S.
2016-09-01
Piezoelectric transducers can be used to harvest electrical energy from structural vibrations in order to power continuously operating condition monitoring systems local to where they operate. However, excessive vibrations can compromise the safe operation of mechanical systems. Therefore, absorbers are commonly used to control vibrations. With an integrated device, the mechanical energy that otherwise would be dissipated can be converted via piezoelectric transducers. Vibration absorbers are designed to have high damping factors. Hence, the integration of transducers would lead to a low energy conversion. Efficient energy harvesters usually have low damping capabilities; therefore, they are not effective for vibration suppression. Thus, the design of an integrated device needs to consider the two conflicting requirements on the damping. This study focuses on the development of a laboratory test rig with a host structure and a vibration absorber with tunable damping via an active relative velocity feedback. A voice coil actuator is used for this purpose. To overcome the passive damping effects of the back electromagnetic force a novel voltage feedback control is proposed, which has been validated both in simulation and experimentally. The aim of this study is to have a test rig ready for the introduction of piezo-transducers and available for future experimental evaluations of the damping effect on the effectiveness of vibration reduction and energy harvesting efficiency.
Directory of Open Access Journals (Sweden)
J. P. Burrows
2012-09-01
Full Text Available Measurements of the OH Meinel emissions in the terrestrial nightglow are one of the standard ground-based techniques to retrieve upper mesospheric temperatures. It is often assumed that the emission peak altitudes are not strongly dependent on the vibrational level, although this assumption is not based on convincing experimental evidence. In this study we use Envisat/SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY observations in the near-IR spectral range to retrieve vertical volume emission rate profiles of the OH(3-1, OH(6-2 and OH(8-3 Meinel bands in order to investigate whether systematic differences in emission peak altitudes can be observed between the different OH Meinel bands. The results indicate that the emission peak altitudes are different for the different vibrational levels, with bands originating from higher vibrational levels having higher emission peak altitudes. It is shown that this finding is consistent with the majority of the previously published results. The SCIAMACHY observations yield differences in emission peak altitudes of up to about 4 km between the OH(3-1 and the OH(8-3 band. The observations are complemented by model simulations of the fractional population of the different vibrational levels and of the vibrational level dependence of the emission peak altitude. The model simulations reproduce the observed vibrational level dependence of the emission peak altitude well – both qualitatively and quantitatively – if quenching by atomic oxygen as well as multi-quantum collisional relaxation by O2 is considered. If a linear relationship between emission peak altitude and vibrational level is assumed, then a peak altitude difference of roughly 0.5 km per vibrational level is inferred from both the SCIAMACHY observations and the model simulations.
Directory of Open Access Journals (Sweden)
Salar Chamanian
2014-10-01
Full Text Available This paper presents a wireless sensor node (WSN system where an electromagnetic (EM energy harvester is utilized for charging its rechargeable batteries while the system is operational. The capability and the performance of an in-house low-frequency EM energy harvester for charging rechargeable NiMH batteries were experimentally verified in comparison to a regular battery charger. Furthermore, the power consumption of MicaZ motes, used as the WSN, was evaluated in detail for different operation conditions. The battery voltage and current were experimentally monitored during the operation of the MicaZ sensor node equipped with the EM vibration energy harvester. A compact (24.5 cm3 in-house EM energy harvester provides approximately 65 µA charging current to the batteries when excited by 0.4 g acceleration at 7.4 Hz. It has been shown that the current demand of the MicaZ mote can be compensated for by the energy harvester for a specific low-power operation scenario, with more than a 10-fold increase in the battery lifetime. The presented results demonstrate the autonomous operation of the WSN, with the utilization of a vibration-based energy harvester.
Ansari, M. H.; Karami, M. Amin
2016-03-01
This paper studies energy harvesting from heartbeat vibrations for powering leadless pacemakers. Unlike traditional pacemakers, leadless pacemakers are implanted inside the heart and the pacemaker is in direct contact with the myocardium. A leadless pacemaker is in the shape of a cylinder. Thus, in order to utilize the available 3-dimensional space for the energy harvester, we choose a fan-folded 3D energy harvester. The proposed device consists of several piezoelectric beams stacked on top of each other. The volume of the energy harvester is 1 cm3 and its dimensions are 2 cm × 0.5 cm × 1 cm. Although high natural frequency is generally a major concern with micro-scale energy harvesters, by utilizing the fan-folded geometry and adding tip mass and link mass to the configuration, we reduced the natural frequency to the desired range. This fan-folded design makes it possible to generate more than 10 μ W of power per cubic centimeter. The proposed device is compatible with Magnetic Resonance Imaging. Although the proposed device is a linear energy harvester, it is relatively insensitive to the heart rate. The natural frequencies and the mode shapes of the device are calculated analytically. The accuracy of the analytical model is verified by experimental investigations. We use a closed loop shaker system to precisely replicate heartbeat vibrations in vitro.
DEFF Research Database (Denmark)
Liang, Shanshan; Crovetto, Andrea; Peng, Zhuoteng
2016-01-01
and experiments with piezoelectric elements show that the energy harvesting device with the bi-resonant structure can generate higher power output than that of the sum of the two separate devices from random vibration sources at low frequency, and hence significantly improves the vibration-to- electricity......This paper reports on a bi-resonant structure of piezoelectric PVDF films energy harvester (PPEH), which consists of two cantilevers with resonant frequencies of 15 Hz and 22 Hz. With increased acceleration, the vibration amplitudes of the two cantilever-mass structures are increased and collision...
International Nuclear Information System (INIS)
Abouhnik, Abdelnasser; Albarbar, Alhussein
2012-01-01
Highlights: ► We used finite element method to model wind turbine induced vibration characteristics. ► We developed a technique for eliminating wind turbine’s vibration modulation problems. ► We use empirical mode decomposition to decompose the vibration into its fundamental elements. ► We show the area under shaft speed is a good indicator for assessing wind blades condition. ► We validate the technique under different wind turbine speeds and blade (cracks) conditions. - Abstract: Vibration based monitoring techniques are well understood and widely adopted for monitoring the condition of rotating machinery. However, in the case of wind turbines the measured vibration is complex due to the high number of vibration sources and modulation phenomenon. Therefore, extracting condition related information of a specific element e.g. blade condition is very difficult. In the work presented in this paper wind turbine vibration sources are outlined and then a three bladed wind turbine vibration was simulated by building its model in the ANSYS finite element program. Dynamic analysis was performed and the fundamental vibration characteristics were extracted under two healthy blades and one blade with one of four cracks introduced. The cracks were of length (10 mm, 20 mm, 30 mm and 40 mm), all had a consistent 3 mm width and 2 mm depth. The tests were carried out for three rotation speeds; 150, 250 and 360 r/min. The effects of the seeded faults were revealed by using a novel approach called empirically decomposed feature intensity level (EDFIL). The developed EDFIL algorithm is based on decomposing the measured vibration into its fundamental components and then determines the shaft rotational speed amplitude. A real model of the simulated wind turbine was constructed and the simulation outcomes were compared with real-time vibration measurements. The cracks were seeded sequentially in one of the blades and their presence and severity were determined by decomposing
Design of a hybrid power system based on solar cell and vibration energy harvester
Zhang, Bin; Li, Mingxue; Zhong, Shaoxuan; He, Zhichao; Zhang, Yufeng
2018-03-01
Power source has become a serious restriction of wireless sensor network. High efficiency, self-energized and long-life renewable source is the optimum solution for unmanned sensor network applications. However, single renewable power source can be easily affected by ambient environment, which influences stability of the system. In this work, a hybrid power system consists of a solar panel, a vibration energy harvester and a lithium battery is demonstrated. The system is able to harvest multiple types of ambient energy, which extends its applicability and feasibility. Experiments have been conducted to verify performance of the system.
Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting
DEFF Research Database (Denmark)
Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian
2012-01-01
We present a microelectromechanical system (MEMS) based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. Most piezoelectric energy harvesting devices use a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric...... elements. We show experimental results from two types PZT/PZT harvesting devices, one where the Pb(ZrxTi1−x)O3 (PZT) thick films are high pressure treated during the fabrication and the other where the treatment is omitted. We find that with the high pressure treatment prior to PZT sintering, the films...
First-Principles Vibrational Electron Energy Loss Spectroscopy of β -Guanine
Radtke, G.; Taverna, D.; Lazzeri, M.; Balan, E.
2017-07-01
A general approach to model vibrational electron energy loss spectra obtained using an electron beam positioned away from the specimen is presented. The energy-loss probability of the fast electron is evaluated using first-principles quantum mechanical calculations (density functional theory) of the dielectric response of the specimen. The validity of the method is assessed using recently measured anhydrous β -guanine, an important molecular solid used by animals to produce structural colors. The good agreement between theory and experiments lays the basis for a quantitative interpretation of this spectroscopy in complex systems.
Atomic energy levels and Grotrian diagrams
Bashkin, Stanley
1975-01-01
Atomic Energy Levels and Grotrian Diagrams, Volume I: Hydrogen I - Phosphorus XV presents diagrams of various elements that show their energy level and electronic transitions. The book covers the first 15 elements according to their atomic number. The text will be of great use to researchers and practitioners of fields such as astrophysics that requires pictorial representation of the energy levels and electronic transitions of elements.
Excitation of vibrational quanta in furfural by intermediate-energy electrons
Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; García, G.; Blanco, F.; Brunger, M. J.
2015-12-01
We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°-90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.
Energy Technology Data Exchange (ETDEWEB)
Montanini, Roberto, E-mail: rmontanini@unime.it; Quattrocchi, Antonino, E-mail: aquattrocchi@unime.it [University of Messina, Dept. of Engineering, Contrada di Dio, Messina (Italy)
2016-06-28
A cantilever-type resonant piezoelectric generator (RPG) has been designed by gluing a PZT patch working in d{sub 31} mode onto a glass fibre reinforced composite cantilever beam with a discrete mass applied on its free end. The electrical and dynamic behaviour of the RPG prototype has been investigated by carrying out laboratory tests aimed to assess the effect of definite design parameters, specifically the electric resistance load and the excitation frequency. Results showed that an optimum resistance load exists, at which power generation is maximized. Moreover, it has been showed that power generation is strongly influenced by the vibration frequency highlighting that, at resonance, output power can be increased by more than one order of magnitude. Possible applications include inertial resonant harvester for energy recovery from vibrating machines, sea waves or wind flux and self-powering of wireless sensor nodes.
Vibration mitigation of a bridge cable using a nonlinear energy sink: design and experiment
Directory of Open Access Journals (Sweden)
Weiss Mathieu
2015-01-01
Full Text Available This work deals with the design and experiment of a cubic nonlinear energy sink (NES for horizontal vibration mitigation of a bridge cable. Modal analysis of horizontal linear modes of the cable is experimentally performed using accelerometers and displacement sensors. A theoretical simplified 2-dof model of the coupled cable-NES system is used to analytically design the NES by mean of multi-time scale systems behaviours and detection its invariant manifold, equilibrium and singular points which stand for periodic and strongly modulated regimes, respectively. Numerical integration is used to confirm the efficiency of the designed NES for the system under step release excitation. Then, the prototype system is built using geometrical cubic nonlinearity as the potential of the NES. Efficiency of the prototype system for mitigation of horizontal vibrations of the cable under for step release and forced excitations is experimentally demonstrated.
Excitation of vibrational quanta in furfural by intermediate-energy electrons
Energy Technology Data Exchange (ETDEWEB)
Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, MG (Brazil); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, MG (Brazil); Costa, R. F. da [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, 09210-580 São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo, São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); and others
2015-12-14
We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°–90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.
Excitation of vibrational quanta in furfural by intermediate-energy electrons
International Nuclear Information System (INIS)
Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; Costa, R. F. da; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; García, G.
2015-01-01
We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°–90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule
A Vibration-Based MEMS Piezoelectric Energy Harvester and Power Conditioning Circuit
Directory of Open Access Journals (Sweden)
Hua Yu
2014-02-01
Full Text Available This paper presents a micro-electro-mechanical system (MEMS piezoelectric power generator array for vibration energy harvesting. A complete design flow of the vibration-based energy harvester using the finite element method (FEM is proposed. The modal analysis is selected to calculate the resonant frequency of the harvester, and harmonic analysis is performed to investigate the influence of the geometric parameters on the output voltage. Based on simulation results, a MEMS Pb(Zr,TiO3 (PZT cantilever array with an integrated large Si proof mass is designed and fabricated to improve output voltage and power. Test results show that the fabricated generator, with five cantilever beams (with unit dimensions of about 3 × 2.4 × 0.05 mm3 and an individual integrated Si mass dimension of about 8 × 12.4 × 0.5 mm3, produces a output power of 66.75 μW, or a power density of 5.19 μW∙mm−3∙g−2 with an optimal resistive load of 220 kΩ from 5 m/s2 vibration acceleration at its resonant frequency of 234.5 Hz. In view of high internal impedance characteristic of the PZT generator, an efficient autonomous power conditioning circuit, with the function of impedance matching, energy storage and voltage regulation, is then presented, finding that the efficiency of the energy storage is greatly improved and up to 64.95%. The proposed self-supplied energy generator with power conditioning circuit could provide a very promising complete power supply solution for wireless sensor node loads.
A vibration-based MEMS piezoelectric energy harvester and power conditioning circuit.
Yu, Hua; Zhou, Jielin; Deng, Licheng; Wen, Zhiyu
2014-02-19
This paper presents a micro-electro-mechanical system (MEMS) piezoelectric power generator array for vibration energy harvesting. A complete design flow of the vibration-based energy harvester using the finite element method (FEM) is proposed. The modal analysis is selected to calculate the resonant frequency of the harvester, and harmonic analysis is performed to investigate the influence of the geometric parameters on the output voltage. Based on simulation results, a MEMS Pb(Zr,Ti)O3 (PZT) cantilever array with an integrated large Si proof mass is designed and fabricated to improve output voltage and power. Test results show that the fabricated generator, with five cantilever beams (with unit dimensions of about 3 × 2.4 × 0.05 mm3) and an individual integrated Si mass dimension of about 8 × 12.4 × 0.5 mm3, produces a output power of 66.75 μW, or a power density of 5.19 μW∙mm-3∙g-2 with an optimal resistive load of 220 kΩ from 5 m/s2 vibration acceleration at its resonant frequency of 234.5 Hz. In view of high internal impedance characteristic of the PZT generator, an efficient autonomous power conditioning circuit, with the function of impedance matching, energy storage and voltage regulation, is then presented, finding that the efficiency of the energy storage is greatly improved and up to 64.95%. The proposed self-supplied energy generator with power conditioning circuit could provide a very promising complete power supply solution for wireless sensor node loads.
Dynamics of Transition Regime in Bi-stable Vibration Energy Harvesters
Ibrahim, Alwathiqbellah
2017-04-20
Vibration energy harvesting can be an effective method for scavenging wasted mechanical energy for use by wireless sensors that have limited battery life. Two major goals in designing energy harvesters are enhancing the power scavenged at low frequency and improving efficiency by increasing the frequency bandwidth. To achieve these goals, we derived a magneto-elastic beam operated at the transition between mono- and bi-stable regions. By improving the mathematical model of the interaction of magnetic force and beam dynamics, we obtained a precise prediction of natural frequencies as the distance of magnets varies. Using the shooting technique for the improved model, we present a fundamental understanding of interesting combined softening and hardening responses that happen at the transition between the two regimes. The transition regime is proposed as the optimal region for energy conversion in terms of frequency bandwidth and output voltage. Using this technique, low frequency vibration energy harvesting at around 17 Hz was possible. The theoretical results were in good agreement with the experimental results. The target application is to power wildlife bio-logging devices from bird flights that have consistent high power density around 16 Hz [1].
Dynamics of Transition Regime in Bi-stable Vibration Energy Harvesters
Ibrahim, Alwathiqbellah; Towfighian, Shahrzad; Younis, Mohammad I.
2017-01-01
Vibration energy harvesting can be an effective method for scavenging wasted mechanical energy for use by wireless sensors that have limited battery life. Two major goals in designing energy harvesters are enhancing the power scavenged at low frequency and improving efficiency by increasing the frequency bandwidth. To achieve these goals, we derived a magneto-elastic beam operated at the transition between mono- and bi-stable regions. By improving the mathematical model of the interaction of magnetic force and beam dynamics, we obtained a precise prediction of natural frequencies as the distance of magnets varies. Using the shooting technique for the improved model, we present a fundamental understanding of interesting combined softening and hardening responses that happen at the transition between the two regimes. The transition regime is proposed as the optimal region for energy conversion in terms of frequency bandwidth and output voltage. Using this technique, low frequency vibration energy harvesting at around 17 Hz was possible. The theoretical results were in good agreement with the experimental results. The target application is to power wildlife bio-logging devices from bird flights that have consistent high power density around 16 Hz [1].
International Nuclear Information System (INIS)
Dai, Zuyang; Gao, Shuming; Wang, Jia; Mo, Yuxiang
2014-01-01
The torsional energy levels of CH 3 OH + , CH 3 OD + , and CD 3 OD + have been determined for the first time using one-photon zero kinetic energy photoelectron spectroscopy. The adiabatic ionization energies for CH 3 OH, CH 3 OD, and CD 3 OD are determined as 10.8396, 10.8455, and 10.8732 eV with uncertainties of 0.0005 eV, respectively. Theoretical calculations have also been performed to obtain the torsional energy levels for the three isotopologues using a one-dimensional model with approximate zero-point energy corrections of the torsional potential energy curves. The calculated values are in good agreement with the experimental data. The barrier height of the torsional potential energy without zero-point energy correction was calculated as 157 cm −1 , which is about half of that of the neutral (340 cm −1 ). The calculations showed that the cation has eclipsed conformation at the energy minimum and staggered one at the saddle point, which is the opposite of what is observed in the neutral molecule. The fundamental C–O stretch vibrational energy level for CD 3 OD + has also been determined. The energy levels for the combinational excitation of the torsional vibration and the fundamental C–O stretch vibration indicate a strong torsion-vibration coupling
Dai, Zuyang; Gao, Shuming; Wang, Jia; Mo, Yuxiang
2014-10-14
The torsional energy levels of CH3OH(+), CH3OD(+), and CD3OD(+) have been determined for the first time using one-photon zero kinetic energy photoelectron spectroscopy. The adiabatic ionization energies for CH3OH, CH3OD, and CD3OD are determined as 10.8396, 10.8455, and 10.8732 eV with uncertainties of 0.0005 eV, respectively. Theoretical calculations have also been performed to obtain the torsional energy levels for the three isotopologues using a one-dimensional model with approximate zero-point energy corrections of the torsional potential energy curves. The calculated values are in good agreement with the experimental data. The barrier height of the torsional potential energy without zero-point energy correction was calculated as 157 cm(-1), which is about half of that of the neutral (340 cm(-1)). The calculations showed that the cation has eclipsed conformation at the energy minimum and staggered one at the saddle point, which is the opposite of what is observed in the neutral molecule. The fundamental C-O stretch vibrational energy level for CD3OD(+) has also been determined. The energy levels for the combinational excitation of the torsional vibration and the fundamental C-O stretch vibration indicate a strong torsion-vibration coupling.
Miller, Lindsay Margaret
Wireless sensor networks (WSNs) have the potential to transform engineering infrastructure, manufacturing, and building controls by allowing condition monitoring, asset tracking, demand response, and other intelligent feedback systems. A wireless sensor node consists of a power supply, sensor(s), power conditioning circuitry, radio transmitter and/or receiver, and a micro controller. Such sensor nodes are used for collecting and communicating data regarding the state of a machine, system, or process. The increasing demand for better ways to power wireless devices and increase operation time on a single battery charge drives an interest in energy harvesting research. Today, wireless sensor nodes are typically powered by a standard single-charge battery, which becomes depleted within a relatively short timeframe depending on the application. This introduces tremendous labor costs associated with battery replacement, especially when there are thousands of nodes in a network, the nodes are remotely located, or widely-distributed. Piezoelectric vibration energy harvesting presents a potential solution to the problems associated with too-short battery life and high maintenance requirements, especially in industrial environments where vibrations are ubiquitous. Energy harvester designs typically use the harvester to trickle charge a rechargeable energy storage device rather than directly powering the electronics with the harvested energy. This allows a buffer between the energy harvester supply and the load where energy can be stored in a "tank". Therefore, the harvester does not need to produce the full required power at every instant to successfully power the node. In general, there are tens of microwatts of power available to be harvested from ambient vibrations using micro scale devices and tens of milliwatts available from ambient vibrations using meso scale devices. Given that the power requirements of wireless sensor nodes range from several microwatts to about one
Modeling and Tuning for Vibration Energy Harvesting using a Piezoelectric Bimorph
Cao, Yongqing
With the development of wireless sensors and other devices, the need for continuous power supply with high reliability is growing ever more. The traditional battery power supply has the disadvantage of limited duration of continuous power supply capability so that replacement for new batteries has to be done regularly. This can be quite inconvenient and sometimes quite difficult especially when the sensors are located in places not easily accessible such as the inside of a machine or wild field. This situation stimulates the development of renewable power supply which can harvest energy from the environment. The use of piezoelectric materials to converting environment vibration to electrical energy is one of the alternatives of which a broad range of research has been done by many researchers, focusing on different issues. The improvement of efficiency is one of the most important issues in vibration based energy harvesting. For this purpose different methods are devised and more accurate modeling of coupled piezoelectric mechanical systems is investigated. In the current paper, the research is focused on improving voltage generation of a piezoelectric bimorph on a vibration beam, as well as the analytical modeling of the same system. Also an initial study is conducted on the characteristics of the vibration of Zinc oxide (ZnO) nanowire, which is a promising material for its coupled semiconducting and piezoelectric properties. The effect on the voltage generation by different placement of the piezoelectric bimorph on the vibrating beam is investigated. The relation between the voltage output and the curvature is derived which is used to explain the effect of placement on voltage generation. The effect of adding a lumped mass on the modal frequencies of the beam and on the curvature distribution is investigated. The increased voltage output from the piezoelectric bimorph by using appropriately selected mass is proved analytically and also verified by experiment. For
Directory of Open Access Journals (Sweden)
Yingliang Liu
2017-07-01
Full Text Available Molecular couplings between DNA and water together with the accompanying processes of energy exchange are mapped via the ultrafast response of DNA backbone vibrations after OH stretch excitation of the water shell. Native salmon testes DNA is studied in femtosecond pump-probe experiments under conditions of full hydration and at a reduced hydration level with two water layers around the double helix. Independent of their local hydration patterns, all backbone vibrations in the frequency range from 940 to 1120 cm–1 display a quasi-instantaneous reshaping of the spectral envelopes of their fundamental absorption bands upon excitation of the water shell. The subsequent reshaping kinetics encompass a one-picosecond component, reflecting the formation of a hot ground state of the water shell, and a slower contribution on a time scale of tens of picoseconds. Such results are benchmarked by measurements with resonant excitation of the backbone modes, resulting in distinctly different absorption changes. We assign the fast changes of DNA absorption after OH stretch excitation to structural changes in the water shell which couple to DNA through the local electric fields. The second slower process is attributed to a flow of excess energy from the water shell into DNA, establishing a common heated ground state in the molecular ensemble. This interpretation is supported by theoretical calculations of the electric fields exerted by the water shell at different temperatures.
Hu, Junhui; Jong, Januar; Zhao, Chunsheng
2010-01-01
To increase the vibration energy-harvesting capability of the piezoelectric generator based on a cantilever beam, we have proposed a piezoelectric generator that not only uses the strain change of piezoelectric components bonded on a cantilever beam, but also employs the weights at the tip of the cantilever beam to hit piezoelectric components located on the 2 sides of weights. A prototype of the piezoelectric generator has been fabricated and its characteristics have been measured and analyzed. The experimental results show that the piezoelectric components operating in the hit mode can substantially enhance the energy harvesting of the piezoelectric generator on a cantilever beam. Two methods are used and compared in the management of rectified output voltages from different groups of piezoelectric components. In one of them, the DC voltages from rectifiers are connected in series, and then the total DC voltage is applied to a capacitor. In another connection, the DC voltage from each group is applied to different capacitors. It is found that 22.3% of the harvested energy is wasted due to the series connection. The total output electric energy of our piezoelectric generator at nonresonance could be up to 43 nJ for one vibration excitation applied by spring, with initial vibration amplitude (0-p) of 18 mm and frequency of 18.5 Hz, when the rectified voltages from different groups of piezoelectric components are connected to their individual capacitors. In addition, the motion and impact of the weights at the tip of the cantilever beam are theoretically analyzed, which well explains the experimental phenomena and suggests the measures to improve the generator.
Vibrational energy flow in the villin headpiece subdomain: Master equation simulations
International Nuclear Information System (INIS)
Leitner, David M.; Buchenberg, Sebastian; Brettel, Paul; Stock, Gerhard
2015-01-01
We examine vibrational energy flow in dehydrated and hydrated villin headpiece subdomain HP36 by master equation simulations. Transition rates used in the simulations are obtained from communication maps calculated for HP36. In addition to energy flow along the main chain, we identify pathways for energy transport in HP36 via hydrogen bonding between residues quite far in sequence space. The results of the master equation simulations compare well with all-atom non-equilibrium simulations to about 1 ps following initial excitation of the protein, and quite well at long times, though for some residues we observe deviations between the master equation and all-atom simulations at intermediate times from about 1–10 ps. Those deviations are less noticeable for hydrated than dehydrated HP36 due to energy flow into the water
Vibrational energy flow in the villin headpiece subdomain: Master equation simulations
Energy Technology Data Exchange (ETDEWEB)
Leitner, David M., E-mail: dml@unr.edu, E-mail: stock@physik.uni-freiburg.de [Department of Chemistry and Chemical Physics Program, University of Nevada, Reno, Nevada 89557 (United States); Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg (Germany); Buchenberg, Sebastian; Brettel, Paul [Biomolecular Dynamics, Institute of Physics, University of Freiburg, Freiburg (Germany); Stock, Gerhard, E-mail: dml@unr.edu, E-mail: stock@physik.uni-freiburg.de [Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg (Germany); Biomolecular Dynamics, Institute of Physics, University of Freiburg, Freiburg (Germany)
2015-02-21
We examine vibrational energy flow in dehydrated and hydrated villin headpiece subdomain HP36 by master equation simulations. Transition rates used in the simulations are obtained from communication maps calculated for HP36. In addition to energy flow along the main chain, we identify pathways for energy transport in HP36 via hydrogen bonding between residues quite far in sequence space. The results of the master equation simulations compare well with all-atom non-equilibrium simulations to about 1 ps following initial excitation of the protein, and quite well at long times, though for some residues we observe deviations between the master equation and all-atom simulations at intermediate times from about 1–10 ps. Those deviations are less noticeable for hydrated than dehydrated HP36 due to energy flow into the water.
Vibration Energy Harvesting on Vehicle Suspension Using Rotary and Linear Electromagnetic Generator
Directory of Open Access Journals (Sweden)
Arif Indro Sultoni
2013-04-01
Full Text Available In this paper, we discuss comparation of vehicle vibration energy harvesting between rotary and linear electromagnetic generator. We construct the two model of energy harvester mechanism and then analyze both of energy absorbtion and vehicle comfortability. Furthermore, we analyze both of energy absorbtion and vehicle comfortability. Vehicle is modeled as quarter car. Rotarty generator harvests 2.5 x 10-4 Watt. The other hand, linear generator has viscous characteristic and capable to generates 90 Watts with 12 Volt power supply for 0.03 m amplitude of bumpy road input. Linear generator reduces oscillation with 1.2 sec settling time. It is more comfort than the angular which has 3 sec in settling time. With unnevenees road input, mean power of this generator is 64 Watt.
Multi-level Simulation of a Real Time Vibration Monitoring System Component
Robertson, Bryan A.; Wilkerson, Delisa
2005-01-01
This paper describes the development of a custom built Digital Signal Processing (DSP) printed circuit board designed to implement the Advanced Real Time Vibration Monitoring Subsystem proposed by Marshall Space Flight Center (MSFC) Transportation Directorate in 2000 for the Space Shuttle Main Engine Advanced Health Management System (AHMS). This Real Time Vibration Monitoring System (RTVMS) is being developed for ground use as part of the AHMS Health Management Computer-Integrated Rack Assembly (HMC-IRA). The HMC-IRA RTVMS design contains five DSPs which are highly interconnected through individual communication ports, shared memory, and a unique communication router that allows all the DSPs to receive digitized data fiom two multi-channel analog boards simultaneously. This paper will briefly cover the overall board design but will focus primarily on the state-of-the-art simulation environment within which this board was developed. This 16-layer board with over 1800 components and an additional mezzanine card has been an extremely challenging design. Utilization of a Mentor Graphics simulation environment provided the unique board and system level simulation capability to ascertain any timing or functional concerns before production. By combining VHDL, Synopsys Software and Hardware Models, and the Mentor Design Capture Environment, multiple simulations were developed to verify the RTVMS design. This multi-level simulation allowed the designers to achieve complete operability without error the first time the RTVMS printed circuit board was powered. The HMC-IRA design has completed all engineering and deliverable unit testing. P
International Nuclear Information System (INIS)
Ashraf, K; Md Khir, M H; Baharudin, Z; Dennis, J O
2013-01-01
This paper presents a bounded vibration energy harvester to effectively harvest energy from a wide band of low-frequency environmental vibrations ranging from 10 to 18 Hz. Rigid mechanical stoppers are used to confine the seismic mass movement within the elastic limits of the spring. Experimental results show the effectiveness of the proposed technique in increasing the efficiency of the energy harvester. When excited at a frequency of 10 Hz with a peak acceleration of 1 g, the harvester responds at a higher frequency of 20 Hz and gives a peak power of 2.68 mW and a peak to peak voltage of 2.62 V across a load of 220 Ω. The average power density of 65.74 μW cm −3 obtained at 10 Hz 1 g excitation monotonically increases with frequency up to 341.86 μW cm −3 at 18 Hz. An analytical model describing the nonlinear dynamics of the proposed harvester is also presented. A simple technique to estimate the energy losses during impact and thereof a method to incorporate these losses in the model are suggested. The presented model not only predicts the experimental voltage waveform and frequency response of the device with good similarity but also predicts the RMS voltage from the harvester for the whole range of operating frequencies with an RMS error of 5.2%. (paper)
Directory of Open Access Journals (Sweden)
Song Hee Chae
2017-09-01
Full Text Available We present an electromagnetic linear vibration energy harvester with an array of rectangular permanent magnets as a springless proof mass. Instead of supporting the magnet assembly with spring element, ferrofluid has been used as a lubricating material. When external vibration is applied laterally to the harvester, magnet assembly slides back and forth on the channel with reduced friction and wear due to ferrofluid, which significantly improves the long-term reliability of the device. Electric power is generated across an array of copper windings formed at the bottom of the aluminum housing. A proof-of-concept harvester has been fabricated and tested with a vibration exciter at various input frequencies and accelerations. For the device where 5 μL of ferrofluid was used for lubrication, maximum output power of 493 μW has been generated, which was 4.37% higher than that without ferrofluid. Long-term reliability improvement due to ferrofluid lubrication has also been verified. For the device with ferrofluid, 1.02% decrease of output power has been observed, in contrast to 59.73% decrease of output power without ferrofluid after 93,600 cycles.
On the exponential energy gap law in He--I2 vibrational relaxation
International Nuclear Information System (INIS)
Maricq, M.M.
1990-01-01
A comparison between coupled states, infinite order sudden, and classical path calculations is used to elucidate the origin of an exponential energy gap law recently observed for vibrational relaxation from highly excited states in the B 0 + u state of I 2 due to collisions with He. All three methods provide relaxation cross sections in good agreement with experiment. Anharmonic effects play an important role, with accurate results obtained with a Morse, but not harmonic, oscillator description of the I * 2 molecule. The nearly exact agreement between rotationally summed coupled states cross sections and the IOSA is consistent with the view that the I * 2 molecule does not rotate significantly during a collision. A closed form solution of the forced harmonic oscillator, valid for highly excited states, predicts a J 2 |Δv| distribution of vibrationally relaxed states at a given collision angle and impact parameter. The vibrationally close coupled-infinite order sudden (VCC-IOSA) results bear this out and show that the observed exponential scaling law arises from a superposition of such distributions over θ and b
McCaffery, Anthony J.
2018-03-01
This study of near-resonant, vibration-vibration (V-V) gas-phase energy transfer in diatomic molecules uses the theoretical/computational method, of Marsh & McCaffery (Marsh & McCaffery 2002 J. Chem. Phys. 117, 503 (doi:10.1063/1.1489998)) The method uses the angular momentum (AM) theoretical formalism to compute quantum-state populations within the component molecules of large, non-equilibrium, gas mixtures as the component species proceed to equilibration. Computed quantum-state populations are displayed in a number of formats that reveal the detailed mechanism of the near-resonant V-V process. Further, the evolution of quantum-state populations, for each species present, may be followed as the number of collision cycles increases, displaying the kinetics of evolution for each quantum state of the ensemble's molecules. These features are illustrated for ensembles containing vibrationally excited N2 in H2, O2 and N2 initially in their ground states. This article is part of the theme issue `Modern theoretical chemistry'.
White Noise Responsiveness of an AlN Piezoelectric MEMS Cantilever Vibration Energy Harvester
International Nuclear Information System (INIS)
Jia, Y; Seshia, A A
2014-01-01
This paper reports the design, analysis and experimental characterisation of a piezoelectric MEMS cantilever vibration energy harvester, the enhancement of its power output by adding various values of end mass, as well as assessing the responsiveness towards white noise. Devices are fabricated using a 0.5 μm AlN on 10 μm doped Si process. Cantilevers with 5 mm length and 2 mm width were tested at either unloaded condition (MC0: f n 577 Hz) or subjected to estimated end masses of 2 mg (MC2: f n 129 Hz) and 5 mg (MC5: f n 80 Hz). While MC0 was able to tolerate a higher drive acceleration prior to saturation (7 g with 0.7 μW), MC5 exhibited higher peak power attainable at a lower input vibration (2.56 μW at 3 ms −2 ). MC5 was also subjected to band-limited (10 Hz to 2 kHz) white noise vibration, where the power response was only a fraction of its resonant counterpart for the same input: peak instantaneous power >1 μW was only attainable beyond 2 g of white noise, whereas single frequency resonant response only required 2.5 ms −2 . Both the first resonant response and the band-limited white noise response were also compared to a numerical model, showing close agreements
International Nuclear Information System (INIS)
Dudka, A; Galayko, D; Basset, P; Cottone, F; Blokhina, E
2013-01-01
This paper reports on an electrostatic Vibration Energy Harvester (e-VEH) system, for which the energy conversion process is initiated with a low bias voltage and is compatible with wideband stochastic external vibrations. The system employs the auto-synchronous conditioning circuit topology with the use of a novel dedicated integrated low-power high-voltage switch that is needed to connect the charge pump and flyback – two main parts of the used conditioning circuit. The proposed switch is designed and implemented in AMS035HV CMOS technology. Thanks to the proposed switch device, which is driven with a low-voltage ground-referenced logic, the e-VEH system may operate within a large voltage range, from a pre-charge low voltage up to several tens volts. With such a high-voltage e-VEH operation, it is possible to obtain a strong mechanical coupling and a high rate of vibration energy conversion. The used transducer/resonator device is fabricated with a batch-processed MEMS technology. When excited with stochastic vibrations having an acceleration level of 0.8 g rms distributed in the band 110–170 Hz, up to 0.75 μW of net electrical power has been harvested with our system. This work presents an important milestone in the challenge of designing a fully integrated smart conditioning interface for the capacitive e-VEHs
Regional level approach for increasing energy efficiency
International Nuclear Information System (INIS)
Viholainen, Juha; Luoranen, Mika; Väisänen, Sanni; Niskanen, Antti; Horttanainen, Mika; Soukka, Risto
2016-01-01
Highlights: • Comprehensive snapshot of regional energy system for decision makers. • Connecting regional sustainability targets and energy planning. • Involving local players in energy planning. - Abstract: Actions for increasing the renewable share in the energy supply and improving both production and end-use energy efficiency are often built into the regional level sustainability targets. Because of this, many local stakeholders such as local governments, energy producers and distributors, industry, and public and private sector operators require information on the current state and development aspects of the regional energy efficiency. The drawback is that an overall view on the focal energy system operators, their energy interests, and future energy service needs in the region is often not available for the stakeholders. To support the local energy planning and management of the regional energy services, an approach for increasing the regional energy efficiency is being introduced. The presented approach can be seen as a solid framework for gathering the required data for energy efficiency analysis and also evaluating the energy system development, planned improvement actions, and the required energy services at the region. This study defines the theoretical structure of the energy efficiency approach and the required steps for revealing such energy system improvement actions that support the regional energy plan. To demonstrate the use of the approach, a case study of a Finnish small-town of Lohja is presented. In the case example, possible actions linked to the regional energy targets were evaluated with energy efficiency analysis. The results of the case example are system specific, but the conducted study can be seen as a justified example of generating easily attainable and transparent information on the impacts of different improvement actions on the regional energy system.
Vibration control of an energy regenerative seat suspension with variable external resistance
Ning, Donghong; Sun, Shuaishuai; Du, Haiping; Li, Weihua; Zhang, Nong
2018-06-01
In this paper, an energy regenerative seat suspension with a variable external resistance is proposed and built, and a semi-active controller for its vibration control is also designed and validated. The energy regenerative seat suspension is built with a three-phase generator and a gear reducer, which are installed in the scissors structure centre of the seat suspension, and the vibration energy is directly harvested from the rotary movement of suspension's scissors structure. The electromagnetic torque of the semi-active seat suspension actuator is controlled by an external variable resistor. An integrated model including the seat suspension's kinematics and the generator is built and proven to match the test result very well. A simplified experimental phenomenon model is also built based on the test results for the controller design. A state feedback H∞ controller is proposed for the regenerative seat suspension's semi-active vibration control. The proposed regenerative seat suspension and its controller are validated with both simulations and experiments. A well-tuned passive seat suspension is applied to evaluate the regenerative seat's performance. Based on ISO 2631-1, the frequency-weighted root mean square (FW-RMS) acceleration of the proposed seat suspension has a 22.84% reduction when compared with the passive one, which indicates the improvement of ride comfort. At the same time, the generated RMS power is 1.21 W. The proposed regenerative seat suspension can greatly improve the driver's ride comfort and has the potential to be developed to a self-powered semi-active system.
Huynh, B. H.; Tjahjowidodo, T.; Zhong, Z.-W.; Wang, Y.; Srikanth, N.
2018-01-01
Vortex induced vibration based energy harvesting systems have gained interests in these recent years due to its potential as a low water current energy source. However, the effectiveness of the system is limited only at a certain water current due to the resonance principle that governs the concept. In order to extend the working range, a bistable spring to support the structure is introduced on the system. The improvement on the performance is essentially dependent on the bistable gap as one of the main parameters of the nonlinear spring. A sufficiently large bistable gap will result in a significant performance improvement. Unfortunately, a large bistable gap might also increase a chance of chaotic responses, which in turn will result in diminutive harvested power. To mitigate the problem, an appropriate control structure is required to stabilize the chaotic vibrations of a VIV energy converter with the bistable supporting structure. Based on the nature of the double-well potential energy in a bistable spring, the ideal control structure will attempt to drive the responses to inter-well periodic vibrations in order to maximize the harvested power. In this paper, the OGY control algorithm is designed and implemented to the system. The control strategy is selected since it requires only a small perturbation in a structural parameter to execute the control effort, thus, minimum power is needed to drive the control input. Facilitated by a wake oscillator model, the bistable VIV system is modelled as a 4-dimensional autonomous continuous-time dynamical system. To implement the controller strategy, the system is discretized at a period estimated from the subspace hyperplane intersecting to the chaotic trajectory, whereas the fixed points that correspond to the desired periodic orbits are estimated by the recurrence method. Simultaneously, the Jacobian and sensitivity matrices are estimated by the least square regression method. Based on the defined fixed point and the
A quality control method by ultrasonic vibration energy and diagnosis system at trimming process
International Nuclear Information System (INIS)
Suh, Chang Min; Song, Gil Ho; Pyoun, Young Shik
2007-01-01
In this paper, the characteristics in mechanical properties of ultrasonic cold forging treatment (UCFT) used for the trimming knife and the effects of ultrasonic vibration energy (UVE) into the trimming process on the state of the strip cutting face were studied. And a diagnosis system to quality control for trimming knife and strip cutting face was developed and installed in plant. By the plant application of UCFT, service life of knife was more increased over 100% than that of conventional knife and using the developed diagnosis system, the knife breakage and saw ear have been perfectly detected and quality control of trimming face is effectively obtained
Manzoor, Ali; Rafique, Sajid; Usman Iftikhar, Muhammad; Mahmood Ul Hassan, Khalid; Nasir, Ali
2017-08-01
Piezoelectric vibration energy harvester (PVEH) consists of a cantilever bimorph with piezoelectric layers pasted on its top and bottom, which can harvest power from vibrations and feed to low power wireless sensor nodes through some power conditioning circuit. In this paper, a non-linear conditioning circuit, consisting of a full-bridge rectifier followed by a buck-boost converter, is employed to investigate the issues of electrical side of the energy harvesting system. An integrated mathematical model of complete electromechanical system has been developed. Previously, researchers have studied PVEH with sophisticated piezo-beam models but employed simplistic linear circuits, such as resistor, as electrical load. In contrast, other researchers have worked on more complex non-linear circuits but with over-simplified piezo-beam models. Such models neglect different aspects of the system which result from complex interactions of its electrical and mechanical subsystems. In this work, authors have integrated the distributed parameter-based model of piezo-beam presented in literature with a real world non-linear electrical load. Then, the developed integrated model is employed to analyse the stability of complete energy harvesting system. This work provides a more realistic and useful electromechanical model having realistic non-linear electrical load unlike the simplistic linear circuit elements employed by many researchers.
Energy Technology Data Exchange (ETDEWEB)
Sharpes, Nathan; Kumar, Prashant [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Abdelkefi, Abdessattar; Abdelmoula, Hichem [Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States); Adler, Jan [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Institute of Dynamics and Vibration Research (IDS), Leibniz Universität, Hannover 30167 (Germany); Priya, Shashank [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, Virginia 24061 (United States)
2016-07-18
Mode shapes in the design of mechanical energy harvesters, as a means of performance increase, have been largely overlooked. Currently, the vast majority of energy harvester designs employ some variation of a single-degree-of-freedom cantilever, and the mode shapes of such beams are well known. This is especially true for the first bending mode, which is almost exclusively the chosen vibration mode for energy harvesting. Two-dimensional beam shapes (those which curve, meander, spiral, etc., in a plane) have recently gained research interest, as they offer freedom to modify the vibration characteristics of the harvester beam for achieving higher power density. In this study, the second bending mode shape of the “Elephant” two-dimensional beam shape is examined, and its interaction with the first bending mode is evaluated. A combinatory mode shape created by using mass loading structural modification to lower the second bending modal frequency was found to interact with the first bending mode. This is possible since the first two bending modes do not share common areas of displacement. The combined mode shape is shown to produce the most power of any of the considered mode shapes.
State-Level Benefits of Energy Efficiency
Energy Technology Data Exchange (ETDEWEB)
Tonn, Bruce Edward [ORNL
2007-02-01
This report describes benefits attributable to state-level energy efficiency programs. Nationwide, state-level energy efficiency programs have targeted all sectors of the economy and have employed a wide range of methods to promote energy efficiency. Standard residential and industrial programs typically identify between 20 to 30% energy savings in homes and plants, respectively. Over a 20 year period of time, an average state that aggressively pursues even a limited array of energy efficiency programs can potentially reduce total state energy use by as much as 20%. Benefit-cost ratios of effective energy efficiency programs typically exceed 3 to 1 and are much higher when non-energy and macroeconomic benefits are included. Indeed, energy efficiency and associated programs and investments can create significant numbers of new jobs and enhance state tax revenues. Several states have incorporated energy efficiency into their economic development programs. It should also be noted that increasing amounts of venture capital are being invested in the energy sector in general and in specific technologies like solar power in particular. Well-designed energy efficiency programs can be expected to help overcome numerous barriers to the market penetration of energy efficient technologies and accelerate the market penetration of the technologies.
State-level benefits of energy efficiency
International Nuclear Information System (INIS)
Tonn, Bruce; Peretz, Jean H.
2007-01-01
This paper describes benefits attributable to state-level energy efficiency programs. Nationwide, state-level energy efficiency programs have targeted all sectors of the economy and have employed a wide range of methods to promote energy efficiency. Standard residential and industrial programs typically identify between 20% and 30% energy savings in homes and plants, respectively. Over a 20-year period of time, an average state that aggressively pursues even a limited array of energy efficiency programs can potentially reduce total state energy use by as much as 20%. Well-designed energy efficiency programs can be expected to help overcome numerous barriers to the market penetration of energy efficient technologies and accelerate the market penetration of the technologies. Energy efficiency programs are cost-effective; typical benefit-cost ratios exceed 3:1 and are much higher when non-energy and macroeconomic benefits are included. Indeed, energy efficiency and associated programs and investments can create significant numbers of new jobs and enhance state tax revenues. Several states have incorporated energy efficiency into their economic development programs. It should also be noted that increasing amounts of venture capital are being invested in the energy sector in general and in specific technologies like solar power in particular. (author)
Analysis of crack initiation and growth in the high level vibration test at Tadotsu
International Nuclear Information System (INIS)
Kassir, M.K.; Park, Y.J.; Hofmayer, C.H.; Bandyopadhyay, K.K.; Shteyngart, S.
1993-08-01
The High Level Vibration Test data are used to assess the accuracy and usefulness of current engineering methodologies for predicting crack initiation and growth in a cast stainless steel pipe elbow under complex, large amplitude loading. The data were obtained by testing at room temperature a large scale modified model of one loop of a PWR primary coolant system at the Tadotsu Engineering Laboratory in Japan. Fatigue crack initiation time is reasonably predicted by applying a modified local strain approach (Coffin-Mason-Goodman equation) in conjunction with Miner's rule of cumulative damage. Three fracture mechanics methodologies are applied to investigate the crack growth behavior observed in the hot leg of the model. These are: the ΔK methodology (Paris law), ΔJ concepts and a recently developed limit load stress-range criterion. The report includes a discussion on the pros and cons of the analysis involved in each of the methods, the role played by the key parameters influencing the formulation and a comparison of the results with the actual crack growth behavior observed in the vibration test program. Some conclusions and recommendations for improvement of the methodologies are also provided
Vibration and Energy Dissipation of Nanocomposite Laminates for Below Ballistic Impact Loading
Directory of Open Access Journals (Sweden)
G. Balaganesan
Full Text Available Abstract Composite laminates are made of glass woven roving mats of 610gsm, epoxy resin and nano clay which are subjected to projectile impact. Nano clay dispersion is varied from 1% to 5%. Impact tests are conducted in a gas gun setup with a spherical nose cylindrical projectile of diameter 9.5 mm of mass 7.6 g. The energy absorbed by the laminates when subjected to impact loading is studied, the velocity range is below ballistic limit. The effect of nano clay on energy absorption in vibration, delamination and matrix crack is studied for different weight % of nano clay and for different thickness values of the laminates. The natural frequencies and damping factors are obtained for the laminates during impact and the effect of nano clay is studied. The results show considerable improvement in energy absorption due to the presence of nano clay
On the Nonlinear Behavior of the Piezoelectric Coupling on Vibration-Based Energy Harvesters
Directory of Open Access Journals (Sweden)
Luciana L. Silva
2015-01-01
Full Text Available Vibration-based energy harvesting with piezoelectric elements has an increasing importance nowadays being related to numerous potential applications. A wide range of nonlinear effects is observed in energy harvesting devices and the analysis of the power generated suggests that they have considerable influence on the results. Linear constitutive models for piezoelectric materials can provide inconsistencies on the prediction of the power output of the energy harvester, mainly close to resonant conditions. This paper investigates the effect of the nonlinear behavior of the piezoelectric coupling. A one-degree of freedom mechanical system is coupled to an electrical circuit by a piezoelectric element and different coupling models are investigated. Experimental tests available in the literature are employed as a reference establishing the best matches of the models. Subsequently, numerical simulations are carried out showing different responses of the system indicating that nonlinear piezoelectric couplings can strongly modify the system dynamics.
Directory of Open Access Journals (Sweden)
Lutao Yan
2013-01-01
Full Text Available This paper presents a new vibration based electromagnetic power generator to transfer energy from stationary to rotating equipment, which can be a new attempt to substitute slip ring in rotational systems. The natural frequencies and modes are simulated in order to have a maximum and steady power output from the device. Parameters such as piezoelectric disk location and relative motion direction of the magnet are theoretically and experimentally analyzed. The results show that the position that is close to the fixed end of the cantilever and the relative motion along the long side gives higher power output. Moreover, the capability of the energy harvester to extract power from lower energy environment is experimentally validated. The voltage and power output are measured at different excitation frequencies.
Graph theory applied to noise and vibration control in statistical energy analysis models.
Guasch, Oriol; Cortés, Lluís
2009-06-01
A fundamental aspect of noise and vibration control in statistical energy analysis (SEA) models consists in first identifying and then reducing the energy flow paths between subsystems. In this work, it is proposed to make use of some results from graph theory to address both issues. On the one hand, linear and path algebras applied to adjacency matrices of SEA graphs are used to determine the existence of any order paths between subsystems, counting and labeling them, finding extremal paths, or determining the power flow contributions from groups of paths. On the other hand, a strategy is presented that makes use of graph cut algorithms to reduce the energy flow from a source subsystem to a receiver one, modifying as few internal and coupling loss factors as possible.
Palosaari, Jaakko; Leinonen, Mikko; Juuti, Jari; Jantunen, Heli
2018-06-01
In this research four piezoelectric bimorph type cantilevers for energy harvesting were manufactured, measured and analyzed to study the effects of substrate layer thickness on energy harvesting efficiency and durability under different accelerations. The cantilevers had the same dimensions of the piezoelectric ceramic components, but had different thicknesses of the steel substrate (no steel, 30 μm, 50 μm and 75 μm). The cantilevers were tuned to the same resonance frequency with different sizes of tip mass (2.13 g, 3.84 g, 4.17 g and 5.08 g). The energy harvester voltage outputs were then measured across an electrical load near to the resonance frequency (∼40 Hz) with sinusoidal vibrations under different accelerations. The stress exhibited by the four cantilevers was compared and analyzed and their durability was tested with accelerations up to 2.5 g-forces.
A review of the recent research on vibration energy harvesting via bistable systems
International Nuclear Information System (INIS)
Harne, R L; Wang, K W
2013-01-01
The investigation of the conversion of vibrational energy into electrical power has become a major field of research. In recent years, bistable energy harvesting devices have attracted significant attention due to some of their unique features. Through a snap-through action, bistable systems transition from one stable state to the other, which could cause large amplitude motion and dramatically increase power generation. Due to their nonlinear characteristics, such devices may be effective across a broad-frequency bandwidth. Consequently, a rapid engagement of research has been undertaken to understand bistable electromechanical dynamics and to utilize the insight for the development of improved designs. This paper reviews, consolidates, and reports on the major efforts and findings documented in the literature. A common analytical framework for bistable electromechanical dynamics is presented, the principal results are provided, the wide variety of bistable energy harvesters are described, and some remaining challenges and proposed solutions are summarized. (topical review)
Orientation of bluff body for designing efficient energy harvesters from vortex-induced vibrations
International Nuclear Information System (INIS)
Dai, H. L.; Abdelkefi, A.; Yang, Y.; Wang, L.
2016-01-01
The characteristics and performances of four distinct vortex-induced vibrations (VIVs) piezoelectric energy harvesters are experimentally investigated and compared. The difference between these VIV energy harvesters is the installation of the cylindrical bluff body at the tip of cantilever beam with different orientations (bottom, top, horizontal, and vertical). Experiments show that the synchronization regions of the bottom, top, and horizontal configurations are almost the same at low wind speeds (around 1.5 m/s). The vertical configuration has the highest wind speed for synchronization (around 3.5 m/s) with the largest harvested power, which is explained by its highest natural frequency and the smallest coupled damping. The results lead to the conclusion that to design efficient VIV energy harvesters, the bluff body should be aligned with the beam for low wind speeds (<2 m/s) and perpendicular to the beam at high wind speeds (>2 m/s)
Dai, Quanqi; Harne, Ryan L.
2017-04-01
Effective development of vibration energy harvesters is required to convert ambient kinetic energy into useful electrical energy as power supply for sensors, for example in structural health monitoring applications. Energy harvesting structures exhibiting bistable nonlinearities have previously been shown to generate large alternating current (AC) power when excited so as to undergo snap-through responses between stable equilibria. Yet, most microelectronics in sensors require rectified voltages and hence direct current (DC) power. While researchers have studied DC power generation from bistable energy harvesters subjected to harmonic excitations, there remain important questions as to the promise of such harvester platforms when the excitations are more realistic and include both harmonic and random components. To close this knowledge gap, this research computationally and experimentally studies the DC power delivery from bistable energy harvesters subjected to such realistic excitation combinations as those found in practice. Based on the results, it is found that the ability for bistable energy harvesters to generate peak DC power is significantly reduced by introducing sufficient amount of stochastic excitations into an otherwise harmonic input. On the other hand, the elimination of a low amplitude, coexistent response regime by way of the additive noise promotes power delivery if the device was not originally excited to snap-through. The outcomes of this research indicate the necessity for comprehensive studies about the sensitivities of DC power generation from bistable energy harvester to practical excitation scenarios prior to their optimal deployment in applications.
Energy Technology Data Exchange (ETDEWEB)
Dasch, C.J.
1978-09-01
Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.
Payne, Owen R.; Vandewater, Luke A.; Ung, Chandarin; Moss, Scott D.
2015-04-01
In this paper, a self-powered wireless sensor node utilising ambient vibrations for power is described. The device consists of a vibration energy harvester, power management system, microcontroller, accelerometer, RF transmitter/receiver and external LED indicators. The vibration energy harvester is adapted from a previously reported hybrid rotary-translational device and uses a pair of copper coil transducers to convert the mechanical energy of a magnetic sphere into usable electricity. The device requires less than 0.8 mW of power to operate continuously in its present setup (with LED indicators off) while measuring acceleration at a sample rate of 200 Hz, with the power source providing 39.7 mW of power from 500 mg excitations at 5.5 Hz. When usable input energy is removed, the device will continue to transmit data for more than 5 minutes.
Vibration Control of Structures using Vibro-Impact Nonlinear Energy Sinks
Directory of Open Access Journals (Sweden)
M. Ahmadi
2016-09-01
Full Text Available Using Vibro-Impact Nonlinear Energy Sinks (VI NESs is one of the novel strategies to control structural vibrations and mitigate their seismic response. In this system, a mass is tuned on the structure floor, so that it has a specific distance from an inelastic constraint connected to the floor mass. In case of structure stimulation, the displaced VI NES mass collides with the inelastic constraint and upon impacts, energy is dissipated. In the present work, VI NES is studied when its parameters, including clearance and stiffness ratio, are simultaneously optimized. Harmony search as a recent meta-heuristic algorithm is efficiently specialized and utilized for the aforementioned continuous optimization problem. The optimized attached VI NES is thus shown to be capable of interacting with the primary structure over a wide range of frequencies. The resulting controlled response is then investigated, in a variety of low and medium rise steel moment frames, via nonlinear dynamic time history analyses. Capability of the VI NES to dissipate siesmic input energy of earthquakes and their capabilitiy in reducing response of srtructures effectively, through vibro-impacts between the energy sink’s mass and the floor mass, is discussed by extracting several performance indices and the corresponding Fourier spectra. Results of the numerical simulations done on some structural model examples reveal that the optimized VI NES has caused successive redistribution of energy from low-frequency high-amplitude vibration modes to high-frequency low-amplitude modes, bringing about the desired attenuation of the structural responses.
Nonlinear vibration analysis of the high-efficiency compressive-mode piezoelectric energy harvester
Yang, Zhengbao; Zu, Jean
2015-04-01
Power source is critical to achieve independent and autonomous operations of electronic mobile devices. The vibration-based energy harvesting is extensively studied recently, and recognized as a promising technology to realize inexhaustible power supply for small-scale electronics. Among various approaches, the piezoelectric energy harvesting has gained the most attention due to its high conversion efficiency and simple configurations. However, most of piezoelectric energy harvesters (PEHs) to date are based on bending-beam structures and can only generate limited power with a narrow working bandwidth. The insufficient electric output has greatly impeded their practical applications. In this paper, we present an innovative lead zirconate titanate (PZT) energy harvester, named high-efficiency compressive-mode piezoelectric energy harvester (HC-PEH), to enhance the performance of energy harvesters. A theoretical model was developed analytically, and solved numerically to study the nonlinear characteristics of the HC-PEH. The results estimated by the developed model agree well with the experimental data from the fabricated prototype. The HC-PEH shows strong nonlinear responses, favorable working bandwidth and superior power output. Under a weak excitation of 0.3 g (g = 9.8 m/s2), a maximum power output 30 mW is generated at 22 Hz, which is about ten times better than current energy harvesters. The HC-PEH demonstrates the capability of generating enough power for most of wireless sensors.
Levels of vibration transmitted to the operator of the tractor equipped with front axle suspension
Directory of Open Access Journals (Sweden)
Daniele Pochi
2013-09-01
Full Text Available In recent years the comfort and the preservation of the health of the operators became central issues in the evolution of agricultural machinery and led to the introduction of devices aimed at improving working conditions. Thereby, for instance, the presence of air conditioner, soundproof cab and driver seat suspension became normal on agricultural tractors. The vibrations are one of the most complex issues to deal with, being determined by the characteristics and interaction of elements such as tyres, axles, mainframe, cab and seat suspension. In this respect, manufacturers are trying to improve their products, even integrating these elements with new devices such as the suspension on the front axle of the tractor, aimed at reducing the level of vibrations during the transfers at high speed. One of these underwent tests at CRA-ING. Since its purpose is to reduce the level of vibration transmitted to the driver, their measurements in different points of the tractor and in different operating conditions, were compared in order to evaluate the effectiveness of the device, expressed as time of exposure. The suspension system of the front axle is designed to absorb the oscillations (especially pitching determined by irregularities in the road surface, allowing an increased control of the vehicle at high speed, as demonstrated by the test results and confirmed by the driving impressions outlined by the operator. The action of the device under these conditions results in an increase of the exposure time, important fact because of the relevance of the road transfer operations of tractors with mounted implements or trailers to tow and of the tendency to increase the speed limit for the road tractors (in Germany were brought to 50 km h–1 for several years. The action just described is less evident with increasing irregularity of the road surface and with the decrease of the travel speed. Nevertheless, in such conditions, the device appears to
Dynamic Properties of the Painter Street Overpass at Different Levels of Vibration
DEFF Research Database (Denmark)
Ventura, C. E.; Brincker, Rune; Andersen, P.
2005-01-01
This paper describes the results from a series of ambient vibration studies conducted on the Painter Street Overpass in Rio Dell, California. Painter Street is a two-span, skewed reinforced concrete bridge with two single piers near the middle and monolithic abutments, typical of bridge overpasses...... from analyses of selected strong motion records. The magnitude of the events investigated ranges from ML=4.4 to ML=6.9, which produced accelerations of up to 0.54g at the free field site, 1.3g at the abutments, and 0.86g on the deck. The results of this study indicate that the overall dynamic...... properties of the bridge are very sensitive to the level of ground shaking and that soil-structure interaction is very important for this type structural system. Although the superstructure exhibited a nearly elastic response, the motions at the abutments and base of piers were significantly different...
Consistent post-reaction vibrational energy redistribution in DSMC simulations using TCE model
Borges Sebastião, Israel; Alexeenko, Alina
2016-10-01
The direct simulation Monte Carlo (DSMC) method has been widely applied to study shockwaves, hypersonic reentry flows, and other nonequilibrium flow phenomena. Although there is currently active research on high-fidelity models based on ab initio data, the total collision energy (TCE) and Larsen-Borgnakke (LB) models remain the most often used chemistry and relaxation models in DSMC simulations, respectively. The conventional implementation of the discrete LB model, however, may not satisfy detailed balance when recombination and exchange reactions play an important role in the flow energy balance. This issue can become even more critical in reacting mixtures involving polyatomic molecules, such as in combustion. In this work, this important shortcoming is addressed and an empirical approach to consistently specify the post-reaction vibrational states close to thermochemical equilibrium conditions is proposed within the TCE framework. Following Bird's quantum-kinetic (QK) methodology for populating post-reaction states, the new TCE-based approach involves two main steps. The state-specific TCE reaction probabilities for a forward reaction are first pre-computed from equilibrium 0-D simulations. These probabilities are then employed to populate the post-reaction vibrational states of the corresponding reverse reaction. The new approach is illustrated by application to exchange and recombination reactions relevant to H2-O2 combustion processes.
Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters
International Nuclear Information System (INIS)
Renaud, M; Goedbloed, M; De Nooijer, C; Van Schaijk, R; Fujita, T
2015-01-01
Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture. (paper)
Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters
Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.
2015-10-01
Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture.
Harne, Ryan L
2012-07-01
Conversion of ambient vibrational energy into electric power has been the impetus of much modern research. The traditional analysis has focused on absolute electrical power output from the harvesting devices and efficiency defined as the convertibility of an infinite resource of vibration excitation into power. This perspective has limited extensibility when applying resonant harvesters to host resonant structures when the inertial influence of the harvester is more significant. Instead, this work pursues a fundamental understanding of the coupled dynamics of a main mass-spring-damper system to which an electromagnetic or piezoelectric mass-spring-damper is attached. The governing equations are derived, a metric of efficiency is presented, and analysis is undertaken. It is found that electromagnetic energy harvesting efficiency and maximum power output is limited by the strength of the coupling such that no split system resonances are induced for a given mass ratio. For piezoelectric harvesters, only the coupling strength and certain design requirements dictate maximum power and efficiency achievable. Since the harvesting circuitry must "follow" the split resonances as the piezoelectric harvesters become more massive, the optimum design of piezoelectric harvesters appears to be more involved than for electromagnetic devices.
International Nuclear Information System (INIS)
Alyar, S.
2008-01-01
N-substituted sulfonamides are well known for their diuretic, antidiabetic, antibacterial and antifungal, anticancer e.g., and are widely used in the therapy of patients. These important bioactive properties are strongly affected by the special features of -CH 2 -SO 2 -NR-linker and intramolecular motion Thus, the studies of energetic and spatial properties on N-substituted sulfonamides are of great importance to improve our understanding of their biological activities and enhance abilities to predict new drugs. Density Functional Theory B3LYP /6-31G(d,p) level has been applied to obtain the vibrational force field for the most stable conformation of N,N'-etilenbis(p-toluensulfonamit)(ptsen)having sulfonamide moiety. The results of these calculation have been compared with spectroscopic data to verify accuracy of calculation and applicability of the DFT approach to ptsen. Additionally, complete normal coordinate analyses with quantum mechanical scaling (SQM) were performed to derive the potential energy distributions (PE)
Energy Levels of Hydrogen and Deuterium
SRD 142 NIST Energy Levels of Hydrogen and Deuterium (Web, free access) This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects.
Harne, R. L.; Zhang, Chunlin; Li, Bing; Wang, K. W.
2016-07-01
Impulsive energies are abundant throughout the natural and built environments, for instance as stimulated by wind gusts, foot-steps, or vehicle-road interactions. In the interest of maximizing the sustainability of society's technological developments, one idea is to capture these high-amplitude and abrupt energies and convert them into usable electrical power such as for sensors which otherwise rely on less sustainable power supplies. In this spirit, the considerable sensitivity to impulse-type events previously uncovered for bistable oscillators has motivated recent experimental and numerical studies on the power generation performance of bistable vibration energy harvesters. To lead to an effective and efficient predictive tool and design guide, this research develops a new analytical approach to estimate the electroelastic response and power generation of a bistable energy harvester when excited by an impulse. Comparison with values determined by direct simulation of the governing equations shows that the analytically predicted net converted energies are very accurate for a wide range of impulse strengths. Extensive experimental investigations are undertaken to validate the analytical approach and it is seen that the predicted estimates of the impulsive energy conversion are in excellent agreement with the measurements, and the detailed structural dynamics are correctly reproduced. As a result, the analytical approach represents a significant leap forward in the understanding of how to effectively leverage bistable structures as energy harvesting devices and introduces new means to elucidate the transient and far-from-equilibrium dynamics of nonlinear systems more generally.
Cao, Shuying; Sun, Shuaishuai; Zheng, Jiaju; Wang, Bowen; Wan, Lili; Pan, Ruzheng; Zhao, Ran; Zhang, Changgeng
2018-05-01
Galfenol traditional cantilever energy harvesters (TCEHs) have bigger electrical output only at resonance and exhibit nonlinear mechanical-magnetic-electric coupled (NMMEC) behaviors. To increase low-frequency broadband performances of a TCEH, an improved CEH (ICEH) with magnetic repulsive force is studied. Based on the magnetic dipole model, the nonlinear model of material, the Faraday law and the dynamic principle, a lumped parameter NMMEC model of the devices is established. Comparisons between the calculated and measured results show that the proposed model can provide reasonable data trends of TCEH under acceleration, bias field and different loads. Simulated results show that ICEH exhibits low-frequency resonant, hard spring and bistable behaviors, thus can harvest more low-frequency broadband vibration energy than TCEH, and can elicit snap-through and generate higher voltage even under weak noise. The proposed structure and model are useful for improving performances of the devices.
Interaction of low energy electrons with surface lattice vibrations. Final report
International Nuclear Information System (INIS)
Tong, S.Y.
1984-01-01
In carrying out the DOE contract, we have succeeded in constructing a new microscopic theory, with multiple scattering, for the inelastic scattering of electrons by surface vibrations. We have applied the theory to detailed studies of angle and energy variations of the inelastic cross-section for two important systems in surface physics: carbon monoxide molecules adsorbed on the (100) surface of a nickel crystal, and hydrogen atoms adsorbed on a reconstructed tungsten (100) surface. These calculations have outlined general trends that we expect to apply to a wide variety of systems. Also, we have discovered a series of new selection rules that apply to off-specular scattering. Particularly interesting are pseudo-selection rules which are not group theoretical in origin, but approximate statements that hold well when the electron scattering amplitude exhibits a slow energy variation. We have found and defined conditions for which these selection rules would hold and break down
Low-frequency and wideband vibration energy harvester with flexible frame and interdigital structure
Directory of Open Access Journals (Sweden)
Pengwei Li
2015-04-01
Full Text Available As an alternative to traditional cantilever beam structures and their evolutions, a flexible beam based, interdigital structure, vibration energy harvester has been presented and investigated. The proposed interdigital-shaped oscillator consists of a rectangular flexible frame and series of cantilever beams interdigitally bonded to it. In order to achieve low frequency and wide-bandwidth harvesting, Young’s modulus of materials, frame size and the amount of the cantilevers have been studied systematically. The measured frequency responses of the designed device (PDMS frame, quintuple piezoelectric cantilever beams show a 460% increase in bandwidth below 80Hz. When excited at an acceleration of 1.0 g, the energy harvester achieves to a maximum open-circuit voltage of 65V, and the maximum output power 4.5 mW.
Low-frequency and wideband vibration energy harvester with flexible frame and interdigital structure
Energy Technology Data Exchange (ETDEWEB)
Li, Pengwei, E-mail: lipengwei@tyut.edu.cn; Wang, Yanfen; Luo, Cuixian; Li, Gang; Hu, Jie; Zhang, Wendong [MicroNano System Research Center of College of Information Engineering and Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Liu, Ying [MicroNano System Research Center of College of Information Engineering and Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, Shanxi (China); Baicheng Ordnance Test Center of China, Baicheng 137000, Jilin (China); Liu, Wei [Baicheng Ordnance Test Center of China, Baicheng 137000, Jilin (China)
2015-04-15
As an alternative to traditional cantilever beam structures and their evolutions, a flexible beam based, interdigital structure, vibration energy harvester has been presented and investigated. The proposed interdigital-shaped oscillator consists of a rectangular flexible frame and series of cantilever beams interdigitally bonded to it. In order to achieve low frequency and wide-bandwidth harvesting, Young’s modulus of materials, frame size and the amount of the cantilevers have been studied systematically. The measured frequency responses of the designed device (PDMS frame, quintuple piezoelectric cantilever beams) show a 460% increase in bandwidth below 80Hz. When excited at an acceleration of 1.0 g, the energy harvester achieves to a maximum open-circuit voltage of 65V, and the maximum output power 4.5 mW.
Directory of Open Access Journals (Sweden)
Yao-Yun Feng
2017-03-01
Full Text Available A conductive direct-write process of multilayered coils for micro electromagnetic generators is proposed. This novel approach of using silver ink to form the conductive structures largely reduces the fabrication complexity, and it provides a faster alternative to the conventional semiconductor methods. Multi-layered coils with insulation were accurately layered on a micromachined cantilevered diaphragm by a dispenser. Coils several layers thick could be used to increase the power output and double coils were separated by a layer of insulation. Six prototypes, all capable of efficient conversion of vibrational energy into electrical energy, were fabricated. The experimental results, which include measurements of the electromotive force and power output, are presented. Prototypes with two coils and thicker conducting layers had less resistance and the power output was much more than that of a single-coil unit. This generator can produce 82 nW of power at a resonance frequency of 275 Hz under 5 g excitation.
Vibration energy harvester with low resonant frequency based on flexible coil and liquid spring
Wang, Y.; Zhang, Q.; Zhao, L.; Tang, Y.; Shkel, A.; Kim, E. S.
2016-11-01
This paper reports an electromagnetic vibration-energy harvester with low resonant frequency based on liquid spring composed of ferrofluid. Cylinder magnet array formed by four disc NdFeB magnets is suspended by ferrofluid in a laser-machined acrylic tube which is wrapped by flexible planar coil fabricated with microfabrication process. The magnet array and coil are aligned automatically by the ferrofluid. Restoring force when the magnet array is deviated from the balance position is proportional to the deviated distance, which makes the ferrofluid work as a liquid spring obeying Hook's law. Experimental results show that the electromagnetic energy harvester occupying 1.8 cc and weighing 5 g has a resonant frequency of 16 Hz and generates an induced electromotive force of Vrms = 2.58 mV (delivering 79 nW power into matched load of 21 Ω) from 3 g acceleration at 16 Hz.
Pancharoen, K.; Zhu, D.; Beeby, S. P.
2016-11-01
This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5kΩ generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 μW and 41.36 μW respectively..
The vibration-rotation-tunneling levels of N2-H2O and N2-D2O
Wang, Xiao-Gang; Carrington, Tucker
2015-07-01
In this paper, we report vibration-rotation-tunneling levels of the van der Waals clusters N2-H2O and N2-D2O computed from an ab initio potential energy surface. The only dynamical approximation is that the monomers are rigid. We use a symmetry adapted Lanczos algorithm and an uncoupled product basis set. The pattern of the cluster's levels is complicated by splittings caused by H-H exchange tunneling (larger splitting) and N-N exchange tunneling (smaller splitting). An interesting result that emerges from our calculation is that whereas in N2-H2O, the symmetric H-H tunnelling state is below the anti-symmetric H-H tunnelling state for both K = 0 and K = 1, the order is reversed in N2-D2O for K = 1. The only experimental splitting measurements are the D-D exchange tunneling splittings reported by Zhu et al. [J. Chem. Phys. 139, 214309 (2013)] for N2-D2O in the v2 = 1 region of D2O. Due to the inverted order of the split levels, they measure the sum of the K = 0 and K = 1 tunneling splittings, which is in excellent agreement with our calculated result. Other splittings we predict, in particular those of N2-H2O, may guide future experiments.
TLP Structural Health Monitoring Based on Vibration Signal of Energy Harvesting System
Directory of Open Access Journals (Sweden)
Vahid Jahangiri
Full Text Available Abstract Structural Health Monitoring (SHM of Tension Leg Platform (TLP is very crucial for preventing catastrophic and sudden collapse of the structures. One of the methods of monitoring these structures is implementing SHM sensors. Supplying energy for these sensors for a long period is a challenging problem. So, one of the new methods of supplying energy for SHM, is usage of mechanical energy. In this method, the piezoelectric material is employed to convert the mechanical energy which is resulted from vibration of structure, to electrical energy. The advantage of this method is based on not implementing the battery charging system. Therefore, in this paper, after modeling TLP structure, energy supplying of these sensors with piezoelectric converters is studied. Furthermore, fault diagnosis of these structures in the presence of different uncertainties is proposed by the features of voltage signal, produced from piezoelectric patches and fuzzy classification method. Results show that this method can diagnose faults of the structure with an acceptable success rate.
Directory of Open Access Journals (Sweden)
Wei Ken Chin
2017-09-01
Full Text Available Inspired by vortex induced vibration energy harvesting development as a new source of renewable energy, a T-shaped design vibration energy harvester is introduced with the aim of enhancing its performance through vortex induced vibration at near resonance conditions. The T-shaped structural model designed consists of a fixed boundary aluminum bluff splitter body coupled with a cantilever piezoelectric vibration energy harvesters (PVEH plate model which is a piezoelectric bimorph plate made of a brass plate sandwiched between 2 lead zirconate titanate (PZT plates. A 3-dimensional Fluid-Structure Interaction simulation analysis is carried out with Reynolds Stress Turbulence Model under wind speed of 7, 10, 12, 14, 16, 18, 19, 20, 22.5, and 25 m/s. The results showed that with 19 m/s wind speed, the model generates 75.758 Hz of vortex frequency near to the structural model’s natural frequency of 76.9 Hz. Resonance lock-in therefore occurred, generating a maximum displacement amplitude of 2.09 mm or a 49.76% increment relatively in vibrational amplitude. Under the effect of resonance at the PVEH plate’s fundamental natural frequency, it is able to generate the largest normalized power of 13.44 mW/cm3g2.
International Nuclear Information System (INIS)
Adamovich, Igor V.
2014-01-01
A three-dimensional, nonperturbative, semiclassical analytic model of vibrational energy transfer in collisions between a rotating diatomic molecule and an atom, and between two rotating diatomic molecules (Forced Harmonic Oscillator–Free Rotation model) has been extended to incorporate rotational relaxation and coupling between vibrational, translational, and rotational energy transfer. The model is based on analysis of semiclassical trajectories of rotating molecules interacting by a repulsive exponential atom-to-atom potential. The model predictions are compared with the results of three-dimensional close-coupled semiclassical trajectory calculations using the same potential energy surface. The comparison demonstrates good agreement between analytic and numerical probabilities of rotational and vibrational energy transfer processes, over a wide range of total collision energies, rotational energies, and impact parameter. The model predicts probabilities of single-quantum and multi-quantum vibrational-rotational transitions and is applicable up to very high collision energies and quantum numbers. Closed-form analytic expressions for these transition probabilities lend themselves to straightforward incorporation into DSMC nonequilibrium flow codes
Takeya, Kouichi; Sasaki, Eiichi; Kobayashi, Yusuke
2016-01-01
A bridge vibration energy harvester has been proposed in this paper using a tuned dual-mass damper system, named hereafter Tuned Mass Generator (TMG). A linear electromagnetic transducer has been applied to harvest and make use of the unused reserve of energy the aforementioned damper system absorbs. The benefits of using dual-mass systems over single-mass systems for power generation have been clarified according to the theory of vibrations. TMG parameters have been determined considering multi-domain parameters, and TMG has been tuned using a newly proposed parameter design method. Theoretical analysis results have shown that for effective energy harvesting, it is essential that TMG has robustness against uncertainties in bridge vibrations and tuning errors, and the proposed parameter design method for TMG has demonstrated this feature.
Acute Whole Body Vibration Decreases the Glucose Levels in Elderly Diabetic Women
Directory of Open Access Journals (Sweden)
Maíra Florentino Pessoa
2018-01-01
Full Text Available Type II diabetes (TIIDM is characterized by high levels of blood glucose followed by excessive insulin release so that the target cells become less sensitive, developing insulin resistance and maintaining hyperglycemic levels. Physical activity is the strongest element to prevent and to manage the TIIDM, and the majority of patients do not remain in regularly active levels, because the premature fatigue in these patients decreases the adherence to the training. Contrastingly, the whole body vibration (WBV training may improve the glucose metabolism in diabetic patients, reducing the peripheral blood sugar, decreasing the physical discomfort and perceived exertion. Therefore, the purpose of the study was to determine the effect of an acute WBV session as therapy to promote fasting decreases in insulin levels in peripheral blood in TIIDM when compared to healthy elderly. For this, fifteen healthy elderly women and fourteen diabetic elderly women, all sedentary, were allocated in diabetic or control groups, and we made an acute whole body session composed of 10 bouts lasting 2 minutes each one, separated by a 30-second rest period. The WBV was executed in a triaxial platform MY3 Power Plate® at 35 hertz and has been chosen a peak-to-peak displacement of 4 millimeters. After the protocol, both groups decreased the glycemic levels and increased lactate production in relation to the basal levels and when compared diabetic and control, where the most important results have been shown in diabetic women. This study revealed that WBV training in TIIDM has had significant beneficial effects on the control of glucose levels, still in an acute session. So that, the complete training probably will show better results about glycemic control and this finding could be especially important when prescribing exercise for elderly who are unable or unwilling to use traditional loads or who show poor exercise compliance.
Solleti, Ravi Teja; Harikrishna, Kyatham; Velmurugan, V.
Vibrations can be a good source of energy and can be harvested and utilized by simple design and fabrication using the MEMS technology. Energy harvesting provides unending sources of energy for low-power electronics devices where the use of batteries is not feasible. Piezoelectric energy harvesters are widely considered because of their compact design, compatibility to MEMS devices and ability to respond to a wide range of frequencies freely available in the environment. In this project, a rectangular model for cantilever-based piezoelectric energy harvester is proposed with different designs like two layer, two layer with proof mass, four layer and four layer with proof mass designed with dimensions as 50μm×50μm×1μm for each layer using COMSOL Multiphysics 5.0. Simulation results were obtained using silicon as substrate, aluminium as electrodes and PZT-5H and ZnO as piezoelectric materials and the respective stress and voltages were obtained by applying a force acting on foot, train, roller coaster and a general value of 10N/m2 on top of the cantilever. The effects of varying geometrical dimensions of the device were also investigated.
Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D
2013-09-01
The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.
Prediction of high level vibration test results by use of available inelastic analysis techniques
International Nuclear Information System (INIS)
Hofmayer, C.H.; Park, Y.J.; Costello, J.F.
1991-01-01
As part of a cooperative study between the United States and Japan, the US Nuclear Regulatory Commission and the Ministry of International Trade and Industry of Japan agreed to perform a test program that would subject a large scale piping model to significant plastic strains under excitation conditions much greater than the design condition for nuclear power plants. The objective was to compare the results of the tests with state-of-the-art analyses. Comparisons were done at different excitation levels from elastic to elastic-plastic to levels where cracking was induced in the test model. The program was called the high Level Vibration Test (HLVT). The HLVT was performed on the seismic table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center in Japan. The test model was constructed by modifying the 1/2.5 scale model of one loop of a PWR primary coolant system which was previously tested by NUPEC as part of their seismic proving test program. A comparison of various analysis techniques with test results shows a higher prediction error in the detailed strain values than in the overall response values. This prediction error is magnified as the plasticity in the test model increases. There is no significant difference in the peak responses between the simplified and the detailed analyses. A comparison between various detailed finite element model runs indicates that the material properties and plasticity modeling have a significant impact on the plastic strain responses under dynamic loading reversals. 5 refs., 12 figs
Role of energy exchange in vibrational dephasing processes in liquids and solids
International Nuclear Information System (INIS)
Marks, S.
1981-08-01
Three theories which claim relevance to the dephasing of molecular vibrations in condensed phase matter are presented. All of these theories predict (in certain limiting cases) that the widths and shifts of molecular vibrations will obey an Arrhenius temperature dependence. The basic tenets of the theories are detailed so that the differences between them may be used in an experiment to distinguish between them. One model, based on intermolecular energy exchange of low-frequency modes, results in dephasing the high-frequency modes when anharmonic coupling is present. A computer analysis of temperature dependent experimental lineshapes can result in the extraction of various parameters such as the anharmonic shifts and the exchange rates. It is shown that, in order to properly assess the relative validity of the three models, other evidence must be obtained such as the spectral parameters of the low-frequency modes, the combination bands, and the isotopic dilution behavior. This evidence is presented for d 14 -durene (perdeutero-1,2,4,5-tetramethylbenzene) and compared to previous data obtained on pure h 14 -durene. An extension of the (HSC) intermolecular energy exchange model which allows for the possibility of partial delocalization of the low-frequency modes gives an adequate description of the experimental evidence. Isotopic dilution experiments, in particular, have resulted in a detailed picture of the energy transfer dynamics of the low-frequency modes. A section in which some spontaneous Raman spectra support a model of inhomogeneous broadening in liquids based on results of picosecond stimulated Raman spectroscopy is presented. The model is that a distribution of environmental sites is created by a distribution in the local density and thus creates inhomogeneous broadening
Energy Technology Data Exchange (ETDEWEB)
Crozier, Peter A., E-mail: crozier@asu.edu [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States); Aoki, Toshihiro [LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ 85287-1704 (United States); Liu, Qianlang [School for the Engineering of Matter, Transport and Energy, Arizona State University, 501 E. Tyler Mall, Tempe, AZ 85287-6106 (United States)
2016-10-15
Understanding the role of water, hydrate and hydroxyl species on nanoparticle surfaces and interfaces is very important in both physical and life sciences. Detecting the presence of oxygen-hydrogen species with nanometer resolution is extremely challenging at present. Here we show that the recently developed vibrational electron energy-loss spectroscopy using subnanometer focused electron beams can be employed to spectroscopically identify the local presence and variation of OH species on nanoscale surfaces. The hydrogen-oxygen fingerprint can be correlated with highly localized structural and morphological information obtained from electron imaging. Moreover, the current approach exploits the aloof beam mode of spectral acquisition which does not require direct electron irradiation of the sample thus greatly reducing beam damage to the OH bond. These findings open the door for using electron microscopy to probe local hydroxyl and hydrate species on nanoscale organic and inorganic structures. - Highlights: • High spatial resolution spectroscopic detection of water related species in nanoparticles. • Detection of OH stretch modes with vibrational EELS. • Differentiation between hydrate and hydroxide species on or on nanoparticles. • Detection of hydrate on a single 60 nm oxide nanoparticle of MgO. • Use of aloof beam EELS to minimize radiation damage.
Reliability of vibration energy harvesters of metal-based PZT thin films
Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.
2014-11-01
This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s2. However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s2. The transverse piezoelectric coefficient (e31,f) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s2 and 36% at 25 m/s2 if we continue to excite the PVEHs for 30 years.
Reliability of vibration energy harvesters of metal-based PZT thin films
International Nuclear Information System (INIS)
Tsujiura, Y; Suwa, E; Kurokawa, F; Hida, H; Kanno, I
2014-01-01
This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O 3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s 2 . However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s 2 . The transverse piezoelectric coefficient (e 31,f ) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s 2 and 36% at 25 m/s 2 if we continue to excite the PVEHs for 30 years
Uncertainties in scaling factors for ab initio vibrational zero-point energies
Irikura, Karl K.; Johnson, Russell D.; Kacker, Raghu N.; Kessel, Rüdiger
2009-03-01
Vibrational zero-point energies (ZPEs) determined from ab initio calculations are often scaled by empirical factors. An empirical scaling factor partially compensates for the effects arising from vibrational anharmonicity and incomplete treatment of electron correlation. These effects are not random but are systematic. We report scaling factors for 32 combinations of theory and basis set, intended for predicting ZPEs from computed harmonic frequencies. An empirical scaling factor carries uncertainty. We quantify and report, for the first time, the uncertainties associated with scaling factors for ZPE. The uncertainties are larger than generally acknowledged; the scaling factors have only two significant digits. For example, the scaling factor for B3LYP/6-31G(d) is 0.9757±0.0224 (standard uncertainty). The uncertainties in the scaling factors lead to corresponding uncertainties in predicted ZPEs. The proposed method for quantifying the uncertainties associated with scaling factors is based upon the Guide to the Expression of Uncertainty in Measurement, published by the International Organization for Standardization. We also present a new reference set of 60 diatomic and 15 polyatomic "experimental" ZPEs that includes estimated uncertainties.
Energy Technology Data Exchange (ETDEWEB)
Uranga-Piña, L. [Facultad de Física, Universidad de la Habana, San Lázaro y L, Vedado, 10400 Havana (Cuba); Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, D-14195 Berlin (Germany); Tremblay, J. C., E-mail: jean.c.tremblay@gmail.com [Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, D-14195 Berlin (Germany)
2014-08-21
We investigate the effect of inter-mode coupling on the vibrational relaxation dynamics of molecules in weak dissipative environments. The simulations are performed within the reduced density matrix formalism in the Markovian regime, assuming a Lindblad form for the system-bath interaction. The prototypical two-dimensional model system representing two CO molecules approaching a Cu(100) surface is adapted from an ab initio potential, while the diatom-diatom vibrational coupling strength is systematically varied. In the weak system-bath coupling limit and at low temperatures, only first order non-adiabatic uni-modal coupling terms contribute to surface-mediated vibrational relaxation. Since dissipative dynamics is non-unitary, the choice of representation will affect the evolution of the reduced density matrix. Two alternative representations for computing the relaxation rates and the associated operators are thus compared: the fully coupled spectral basis, and a factorizable ansatz. The former is well-established and serves as a benchmark for the solution of Liouville-von Neumann equation. In the latter, a contracted grid basis of potential-optimized discrete variable representation is tailored to incorporate most of the inter-mode coupling, while the Lindblad operators are represented as tensor products of one-dimensional operators, for consistency. This procedure results in a marked reduction of the grid size and in a much more advantageous scaling of the computational cost with respect to the increase of the dimensionality of the system. The factorizable method is found to provide an accurate description of the dissipative quantum dynamics of the model system, specifically of the time evolution of the state populations and of the probability density distribution of the molecular wave packet. The influence of intra-molecular vibrational energy redistribution appears to be properly taken into account by the new model on the whole range of coupling strengths. It
Revised energy levels of singly ionized lanthanum
Güzelçimen, Feyza; Tonka, Mehdi; Uddin, Zaheer; Bhatti, Naveed Anjum; Windholz, Laurentius; Kröger, Sophie; Başar, Gönül
2018-05-01
Based on the experimental wavenumbers of 344 spectral lines from calibrated Fourier transform (FT) spectra as well as wavenumbers of 81 lines from the wavelength tables from literature, the energy of 115 fine structure levels of singly ionized lanthanum has been revised by weighted global fits. The classifications of the lines are provided by numerous previous investigations of lanthanum by different spectroscopic methods and authors. For the high accurate determination of the center of gravity wavenumbers from the experimental spectrum, the hyperfine constants of the involved levels have been taken into account, if possible. For the 94 levels with known hyperfine constants the accuracy of energy values is better than 0.01 cm-1. For 34 levels the magnetic dipole hyperfine constants A have been determined from FT spectra as part of this work. For four of these 34 levels even electric quadrupole hyperfine constants B could be estimated. For levels, which have experimentally unknown hyperfine constants and which are connected only by lines not found in the FT spectra but taken from literature, the uncertainties of energy values are about a factor of 10 higher. A list of all revised level energies together with a compilation of hyperfine structure data is given as well as a list of all lines used.
Directory of Open Access Journals (Sweden)
Chiao-Fang Hung
2017-02-01
Full Text Available In this paper, we demonstrate a miniature magnetic-force-based, three-axis, AC magnetic sensor with piezoelectric/vibrational energy-harvesting functions. For magnetic sensing, the sensor employs a magnetic–mechanical–piezoelectric configuration (which uses magnetic force and torque, a compact, single, mechanical mechanism, and the piezoelectric effect to convert x-axis and y-axis in-plane and z-axis magnetic fields into piezoelectric voltage outputs. Under the x-axis magnetic field (sine-wave, 100 Hz, 0.2–3.2 gauss and the z-axis magnetic field (sine-wave, 142 Hz, 0.2–3.2 gauss, the voltage output with the sensitivity of the sensor are 1.13–26.15 mV with 8.79 mV/gauss and 1.31–8.92 mV with 2.63 mV/gauss, respectively. In addition, through this configuration, the sensor can harness ambient vibrational energy, i.e., possessing piezoelectric/vibrational energy-harvesting functions. Under x-axis vibration (sine-wave, 100 Hz, 3.5 g and z-axis vibration (sine-wave, 142 Hz, 3.8 g, the root-mean-square voltage output with power output of the sensor is 439 mV with 0.333 μW and 138 mV with 0.051 μW, respectively. These results show that the sensor, using this configuration, successfully achieves three-axis magnetic field sensing and three-axis vibration energy-harvesting. Due to these features, the three-axis AC magnetic sensor could be an important design reference in order to develop future three-axis AC magnetic sensors, which possess energy-harvesting functions, for practical industrial applications, such as intelligent vehicle/traffic monitoring, processes monitoring, security systems, and so on.
Energy Technology Data Exchange (ETDEWEB)
Avram, C.N. [Faculty of Physics, West University of Timisoara, Bd. V. Parvan No. 4, 300223 Timisoara (Romania); Gruia, A.S., E-mail: adigruia@yahoo.com [Faculty of Physics, West University of Timisoara, Bd. V. Parvan No. 4, 300223 Timisoara (Romania); Brik, M.G. [College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, Ravila 14C, Tartu 50411 (Estonia); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, PL-42200 Czestochowa (Poland); Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Barb, A.M. [Faculty of Physics, West University of Timisoara, Bd. V. Parvan No. 4, 300223 Timisoara (Romania)
2015-12-01
Calculations of the Cr{sup 3+} energy levels, spin-Hamiltonian parameters and vibrational spectra for the layered CrCl{sub 3} crystals are reported for the first time. The crystal field parameters and the energy level scheme were calculated in the framework of the Exchange Charge Model of crystal field. The spin-Hamiltonian parameters (zero-field splitting parameter D and g-factors) for Cr{sup 3+} ion in CrCl{sub 3} crystals were obtained using two independent techniques: i) semi-empirical crystal field theory and ii) density functional theory (DFT)-based model. In the first approach, the spin-Hamiltonian parameters were calculated from the perturbation theory method and the complete diagonalization (of energy matrix) method. The infrared (IR) and Raman frequencies were calculated for both experimental and fully optimized geometry of the crystal structure, using CRYSTAL09 software. The obtained results are discussed and compared with the experimental available data.
Correlation of analysis with high level vibration test results for primary coolant piping
International Nuclear Information System (INIS)
Park, Y.J.; Hofmayer, C.H.; Costello, J.F.
1992-01-01
Dynamic tests on a modified 1/2.5-scale model of pressurized water reactor (PWR) primary coolant piping were performed using a large shaking table at Tadotsu, Japan. The High Level Vibration Test (HLVT) program was part of a cooperative study between the United States (Nuclear Regulatory Commission/Brookhaven National Laboratory, NRC/BNL) and Japan (Ministry of International Trade and Industry/Nuclear Power Engineering Center). During the test program, the excitation level of each test run was gradually increased up to the limit of the shaking table and significant plastic strains, as well as cracking, were induced in the piping. To fully utilize the test results, NRC/BNL sponsored a project to develop corresponding analytical predictions for the nonlinear dynamic response of the piping for selected test runs. The analyses were performed using both simplified and detailed approaches. The simplified approaches utilize a linear solution and an approximate formulation for nonlinear dynamic effects such as the use of a deamplification factor. The detailed analyses were performed using available nonlinear finite element computer codes, including the MARC, ABAQUS, ADINA and WECAN codes. A comparison of various analysis techniques with the test results shows a higher prediction error in the detailed strain values in the overall response values. A summary of the correlation analyses was presented before the BNL. This paper presents a detailed description of the various analysis results and additional comparisons with test results
Directory of Open Access Journals (Sweden)
Wenlong Tian
2017-09-01
Full Text Available Limited battery energy restricts the duration of the underwater operation of underwater mooring platforms (UMPs. In this paper, a flow-induced vibration energy converter (FIVEC is designed to produce power for the UMPs and extend their operational time. The FIVEC is equipped with a thin plate to capture the kinetic energy in the vortices shed from the surface of the UMP. A magnetic coupling (MC is applied for the non-contacting transmission of the plate torque to the generators so that the friction loss can be minimized. In order to quantify and evaluate the performance of the FIVEC, two-dimensional computational fluid dynamics (CFD simulations are performed. Simulations are based on the Reynolds Averaged Navier-Stokes (RANS equations and the shear stress transport (SST k-ω turbulent model is utilized. The CFD method is firstly validated using existing experimental data. Then the influences of plate length and system damping on the performance of the FIVEC are evaluated. The results show that the device has a maximum averaged power coefficient of 0.0520 (13.86 W in the considered situations. The results also demonstrate the feasibility of this energy converter plan.
Yuan, Ying; Zhang, Hulin; Wang, Jie; Xie, Yuhang; Khan, Saeed Ahmed; Jin, Long; Yan, Zhuocheng; Huang, Long; Pan, Taisong; Yang, Weiqing; Lin, Yuan
2018-01-01
Hybrid energy harvesters based on different physical effects is fascinating, but a rational design for multiple energy harvesting is challenging. In this work, a spring-magnet oscillator-based triboelectric-electromagnetic generator (EMG) with a solar cell cap is proposed. A power was produced by a triboelectric nanogenerator (TENG) and an EMG independently or simultaneously by using a shared spring-magnet oscillator. The oscillator configuration enables versatile energy harvesting with the excellent size scalability and self-packaged structure which can perform well at low frequency ranging from 3.5 to 5 Hz. The solar cell cap mounted above the oscillator can harvest solar energy. Under vibrations at the frequency of 4 Hz, the TENG and the EMG produced maximum output power of 5.46 nW cm-3 and 378.79 μW cm-3, respectively. The generated electricity by the hybrid nanogenerator can be stored in a capacitor or Li-ion battery, which is capable of powering a wireless locator for real-time locating data reporting to a personal cell phone. The light-weight and handy hybrid nanogenerator can directly light a caution light or play as a portable flashlight by shaking hands at night.
International Nuclear Information System (INIS)
Asanuma, H; Oguchi, H; Hara, M; Kuwano, H
2013-01-01
Aiming at longer stability of surface potential, we propose a ferroelectric dipole electret (FDE) prepared from hard ferroelectric material. We compared output power of electrostatic vibration energy harvester and surface potential stability between FDEs prepared from soft and hard PZT ceramics, as well as a CYTOP polymer electret. The hard FDE showed a seven-fold increase in output power over the soft FDE and nine-fold increase over the CYTOP polymer electret. The hard FDE also showed longer stability of surface potential than that of the soft FDE, whereas the stability of the hard FDE was not yet comparable to that of CYTOP polymer electret. A FDE prepared from harder PZT ceramic (with higher coercive electric field and Curie temperature) may provide more stability in surface potential
Vibration Energy Harvester with Bi-stable Curved Beam Spring Offset by Gravitational Acceleration
International Nuclear Information System (INIS)
Yamamoto, Koki; Fujita, Takayuki; Kanda, Kensuke; Maenaka, Kazusuke; Badel, Adrien; Formosa, Fabien
2015-01-01
We developed MEMS bi-stable spring for vibration energy harvester (VEH), which consists of intrinsically curved shape spring and gravitational acceleration. By applying the gravitational acceleration, the curved beam is offset to the gravity direction. It will make more symmetrical bi-stable motion and the symmetry is improved from 3.3 to 65.4%. We proposed that the combination between curved beam and gravity acceleration for decreasing snap- through acceleration. From the analytical result, we investigate the combination can effective to use for decreasing of snap-through force. We also fabricated the prototype device by using MEMS fabrication process. The frequency response for horizontal direction and the acceleration response for vertical direction are measured. The acceleration response shows that the gravitational acceleration improves the symmetry of snap-through force. (paper)
Optimal linear generator with Halbach array for harvesting of vibration energy during human walking
Directory of Open Access Journals (Sweden)
Joonsoo Jun
2016-05-01
Full Text Available In IT business, the capacity of the battery in smartphone was drastically improved to digest various functions such as communication, Internet, e-banking, and entertainment. Although the capacity of the battery is improved, it still needs to be upgraded due to customer’s demands. In this article, we optimize the design of the linear generator with the Halbach array to improve the efficiency of harvesting vibration energy during human walking for the battery capacitance. We propose the optimal design of the tubular permanent magnet with the linear generator that uses a Halbach array. The approximate model is established using generic algorithm. Furthermore, we performed electromagnetic finite element analysis to predict the induced voltage.
DEFF Research Database (Denmark)
Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian
2012-01-01
We describe the fabrication and characterization of a significantly improved version of a microelectromechanical system-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass; the harvester is fabricated in a fully monolithic process. The main advantage...... yield of 98%. The robust fabrication process allowed a high pressure treatment of the screen printed PZT thick films prior to sintering. The high pressure treatment improved the PZT thick film performance and increased the harvester power output to 37.1 μW at 1 g root mean square acceleration. We also...... characterize the harvester performance when only one of the PZT layers is used while the other is left open or short circuit....
International Nuclear Information System (INIS)
Zhou, Shengxi; Cao, Junyi; Wang, Wei; Liu, Shengsheng; Lin, Jing
2015-01-01
This paper presents a nonlinear doubly magnet-coupled energy harvesting system (DMEHS) which could exhibit co-bistable and monostable dynamic characteristics. Its various characteristic responses induced by the magnetic force can be conveniently obtained using the adjustable horizontal distance between two coupled harvesters in the DMEHS. In the case of appropriate relative positions, the DMEHS appears in a co-bistable structure which is different from the traditional bistable structure. Additionally, both the inclination angle of endmost magnets and the displacement perpendicular to the vibration direction are taken into account to calculate the nonlinear magnetic force in the nonlinear electromechanical equations. The numerical investigations show good agreement with experimental results with respect to the output voltage response. Each harvester without magnetic coupling is tested independently to compare with the DMEHS. Both numerical and experimental results also demonstrate the frequency bandwidth and performance enhancements by changing the horizontal distance between the two coupled harvesters. (paper)
Wang, Chen; Zhang, Qichang; Wang, Wei
2017-07-01
This work presents models and experiments of an impact-driven and frequency up-converted wideband piezoelectric-based vibration energy harvester with a quintuple-well potential induced by the combination effect of magnetic nonlinearity and mechanical piecewise-linearity. Analysis shows that the interwell motions during coupled vibration period enable to increase electrical power output in comparison to conventional frequency up-conversion technology. Besides, the quintuple-well potential with shallower potential wells could extend the harvester's operating bandwidth to lower frequencies. Experiments demonstrate our proposed approach can dramatically boost the measured power of the energy harvester as much as 35 times while its lower cut-off frequency is two times lower than that of a conventional counterpart. These results reveal our proposed approach shows promise for powering portable wireless smart devices from low-intensity, low-frequency vibration sources.
Occupation number dependence of molecular energy levels
International Nuclear Information System (INIS)
Giambiagi, M.S. de; Giambiagi, M.; Ferreira, R.
1977-08-01
The Roothaan expression for the energy of a closed-shell molecular system is generalized in order to apply to open shells. A continuous variation from 0 to 2 is supposed for each level's occupation number, extending to this range tbe correction due to the spurious repulsion appearing in the half-electron method. The characteristic equations of the Xα method are applied to the energy expressions. The one level case is discussed in detail. Ionic and excited states of the 1,3 transbutadiene π system are analyzed
Bajaj, Pushp; Wang, Xiao-Gang; Carrington, Tucker; Paesani, Francesco
2018-03-01
Full-dimensional vibrational spectra are calculated for both X-(H2O) and X-(D2O) dimers (X = F, Cl, Br, I) at the quantum-mechanical level. The calculations are carried out on two sets of recently developed potential energy functions (PEFs), namely, Thole-type model energy (TTM-nrg) and many-body energy (MB-nrg), using the symmetry-adapted Lanczos algorithm with a product basis set including all six vibrational coordinates. Although both TTM-nrg and MB-nrg PEFs are derived from coupled-cluster single double triple-F12 data obtained in the complete basis set limit, they differ in how many-body effects are represented at short range. Specifically, while both models describe long-range interactions through the combination of two-body dispersion and many-body classical electrostatics, the relatively simple Born-Mayer functions employed in the TTM-nrg PEFs to represent short-range interactions are replaced in the MB-nrg PEFs by permutationally invariant polynomials to achieve chemical accuracy. For all dimers, the MB-nrg vibrational spectra are in close agreement with the available experimental data, correctly reproducing anharmonic and nuclear quantum effects. In contrast, the vibrational frequencies calculated with the TTM-nrg PEFs exhibit significant deviations from the experimental values. The comparison between the TTM-nrg and MB-nrg results thus reinforces the notion that an accurate representation of both short-range interactions associated with electron density overlap and long-range many-body electrostatic interactions is necessary for a correct description of hydration phenomena at the molecular level.
Vibrational Surface Electron-Energy-Loss Spectroscopy Probes Confined Surface-Phonon Modes
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Hugo Lourenço-Martins
2017-12-01
Full Text Available Recently, two reports [Krivanek et al. Nature (London 514, 209 (2014NATUAS0028-083610.1038/nature13870, Lagos et al. Nature (London 543, 529 (2017NATUAS0028-083610.1038/nature21699] have demonstrated the amazing possibility to probe vibrational excitations from nanoparticles with a spatial resolution much smaller than the corresponding free-space phonon wavelength using electron-energy-loss spectroscopy (EELS. While Lagos et al. evidenced a strong spatial and spectral modulation of the EELS signal over a nanoparticle, Krivanek et al. did not. Here, we show that discrepancies among different EELS experiments as well as their relation to optical near- and far-field optical experiments [Dai et al. Science 343, 1125 (2014SCIEAS0036-807510.1126/science.1246833] can be understood by introducing the concept of confined bright and dark surface phonon modes, whose density of states is probed by EELS. Such a concise formalism is the vibrational counterpart of the broadly used formalism for localized surface plasmons [Ouyang and Isaacson Philos. Mag. B 60, 481 (1989PMABDJ1364-281210.1080/13642818908205921, García de Abajo and Aizpurua Phys. Rev. B 56, 15873 (1997PRBMDO0163-182910.1103/PhysRevB.56.15873, García de Abajo and Kociak Phys. Rev. Lett. 100, 106804 (2008PRLTAO0031-900710.1103/PhysRevLett.100.106804, Boudarham and Kociak Phys. Rev. B 85, 245447 (2012PRBMDO1098-012110.1103/PhysRevB.85.245447]; it makes it straightforward to predict or interpret phenomena already known for localized surface plasmons such as environment-related energy shifts or the possibility of 3D mapping of the related surface charge densities [Collins et al. ACS Photonics 2, 1628 (2015APCHD52330-402210.1021/acsphotonics.5b00421].
International Nuclear Information System (INIS)
Thomason, M.D.
1982-07-01
Rates for resonant vibrational and rotational energy transfer from the 001 state by CO 2 + CO 2 collisions have been measured. All data were obtained by double resonance spectroscopy with CO 2 lasers in a 2.5 meter absorption cell at 700 0 K. Results for rotation transfer include pumped-level relaxation and the response of other 001 levels with ΔJ up to 18. These data are compared to four relevant collision models via a 35-level rate equation analysis. Sequence-band (002 → 101) and hot-band (011 → 110) lasting have been used to observe resonant nu 3 -transfer relaxation involving 001 + 001 reversible 002 + 000, 001 + 100 reversible 101 + 000, and 001 + 010 reversible 011 + 000. A multilevel rate analysis has been utilized to determine the rate coefficients for 001 going to the 002, the 101, and the 011 levels. Part of the hot-band data has been interpreted as due to 110 + 000 reversible 100 + 010, and the associated rate constant has been estimated. The results of the study are compared to the theory and to other experiments
International Nuclear Information System (INIS)
Apkarian, V.A.; Weitz, E.
1979-01-01
The rare gas dependence of V--V rates can be used as a diagnostic technique to identify different mechanisms of vibrational energy transfer and determine the rate constants for individual kinetic steps. The method is especially useful for the identification and measurement of rates of resonant vibrational energy transfer processes. Analytical and numerical solutions of pertinent model equations are presented and their range of applicability is discussed. The technique is applied to CH 2 D 2 and CH 3 F. In CH 2 D 2 results of studies on ν 9 , [ν 1 , ν 6 ] and states in the 2000 cm -1 region are presented where the application of the technique has made it possible to identify the pathways leading to population of these states and to assign rate constants to some of the steps involved. In CH 3 F, by studying the Ar dependence of the V--V rates of the [ν 2 , ν 5 ] and [ν 1 , ν 4 ] states it has been possible to construct a complete map of energy transfer pathways which can explain all experimental observations for this system, to date. The general applicability of the technique and its potential application to other systems is also considered
Investigation of the performances of PZT vs rare earth (BaLaTiO3) vibration based energy harvester
Pak, Nehemiah; Aris, Hasnizah; Nadia Taib, Bibi
2017-11-01
This study proposes the investigation of two piezoelectric material namely PZT and Lanthanum Doped Barium Titanate (BaLaTiO3) performance as a vibration based energy harvester. The piezoelectric material when applied mechanical stress or strain produces electricity through the piezoelectric effect. The vibration energy would exude mechanical energy and thus apply mechanical force on the energy harvester. The energy harvester would be designed and simulated using the piezoelectric material individually. The studied outputs are divided to frequency response, the load dependence, and the acceleration dependence whereby measurement are observed and taken at maximum power output. The simulation is done using the cantilevers design which employs d31 type of constants. Three different simulations to study the dependence of output power on the resonant frequency response, load and acceleration have found that material that exhibit highest power generation was the BaLaTiO3.
Investigation of the performances of PZT vs rare earth (BaLaTiO3 vibration based energy harvester
Directory of Open Access Journals (Sweden)
Pak Nehemiah
2017-01-01
Full Text Available This study proposes the investigation of two piezoelectric material namely PZT and Lanthanum Doped Barium Titanate (BaLaTiO3 performance as a vibration based energy harvester. The piezoelectric material when applied mechanical stress or strain produces electricity through the piezoelectric effect. The vibration energy would exude mechanical energy and thus apply mechanical force on the energy harvester. The energy harvester would be designed and simulated using the piezoelectric material individually. The studied outputs are divided to frequency response, the load dependence, and the acceleration dependence whereby measurement are observed and taken at maximum power output. The simulation is done using the cantilevers design which employs d31 type of constants. Three different simulations to study the dependence of output power on the resonant frequency response, load and acceleration have found that material that exhibit highest power generation was the BaLaTiO3.
Kawamura, Y; Kanegae, R
2016-06-17
Cooling the vibration amplitude of a microcantilever as low as possible is important to improve the sensitivity and resolutions of various types of scanning type microscopes and sensors making use of it. When the vibration amplitude is controlled to be smaller using a feed back control system, it is known that the obtainable minimum amplitude of the vibration is limited by the floor noise level of the detection system. In this study, we demonstrated that the amplitude of the thermal vibration of a microcantilever was suppressed to be about 0.15 pmHz(-1/2), which is the same value with the floor noise level, without the assistance of external cryogenic cooling. We think that one of the reason why we could reach the smaller amplitude at room temperature is due to stiffer spring constant of the lever, which leads to higher natural frequency and consequently lower floor noise level. The other reason is considered to be due to the increase in the laser power for the diagnostics, which lead to the decrease in the signal to noise ratio determined by the optical shot noise.
Impurity energy level in the Haldane gap
International Nuclear Information System (INIS)
Wang Wei; Lu Yu
1995-11-01
An impurity bond J' in a periodic 1D antiferromagnetic spin 1 chain with exchange J is considered. Using the numerical density matrix renormalization group method, we find an impurity energy level in the Haldane gap, corresponding to a bound state near the impurity bond. When J' J. The impurity level appears only when the deviation dev = (J'- J)/J' is greater than B c , which is close to 0.3 in our calculation. (author). 15 refs, 4 figs
On expectation values for nuclear energy levels
International Nuclear Information System (INIS)
De Wet, J.A.
1978-01-01
The nuclear model is built up by constructing measured states, including the ground state, from the vacuum state. All states are, however, not accessible from the ground state so that selection rules may be found which at the same time impose even more stringent conditions on the labelling of energy levels. These are the subject of this paper
Vibrational and electronic excitation of hexatriacontane thin films by low energy electron impact
International Nuclear Information System (INIS)
Vilar, M.R.; Schott, M.; Pfluger, P.
1990-01-01
Thin polycrystalline films of hexatriacontane (HTC) were irradiated with low energy (E=0.5--15 eV) electrons, and off-specular backscattered electron spectra were measured. Below E∼7 eV, single and multiple vibrational excitations only are observed, which relax the electrons down to the bottom of the HTC conduction band. Due to the negative electron affinity of HTC, thermal electrons are emitted into vacuum. Structure in the backscattered electron current at kinetic energies about 1.5 and 4 eV are associated to conduction band density of states. Above E∼7 eV, the dominant losses correspond to electronic excitations, excitons, or above a threshold (energy of the electron inside the HTC film) at 9.2±0.1 eV, electron--hole pair generation. The latter process is very efficient and reaches a yield of the order of one ∼11 eV. Evidence for chemical reaction above E∼4 eV is observed
Yang, Yangyiwei; Li, Yuanbo; Guo, Yaqian; Xu, Bai-Xiang; Yang, Tongqing
2018-03-01
Vibration-based energy harvesting using piezoelectric circular diaphragms (PCDs) with a structure featuring the central mass (C-mass) configuration has drawn much attention in recent decades. In this work, we propose a new configuration with the annular proof mass (A-mass) where an improved energy harvesting is promised. The numerical analysis was employed using the circuit-coupled piezoelectric simulation, and the experimental validation was implemented using PCDs with the even-width annular electrodes. Samples with the different mass configurations as well as structural parameters ϖ 1 and ϖ 2, which indicate the ratio between the inner boundary radius and piezoelectric ceramic radius as well as the ratio between outer boundary radius and the substrate radius, respectively, were prepared and tested. The impedance-matched output power of full-electrode PCDs was also collected, and some distinct improvement was measured on samples with the certain structural parameters. The power increases from 14.1 mW to 19.0 mW after changing the configuration from C-mass to A-mass with the same parameters (ϖ 1, ϖ 2) = (0.16, 0.9), showing the considerable improvement in energy harvesting by using A-mass configuration.
Directory of Open Access Journals (Sweden)
Darius Zizys
2015-12-01
Full Text Available The piezoelectric transduction mechanism is a common vibration-to-electric energy harvesting approach. Piezoelectric energy harvesters are typically mounted on a vibrating host structure, whereby alternating voltage output is generated by a dynamic strain field. A design target in this case is to match the natural frequency of the harvester to the ambient excitation frequency for the device to operate in resonance mode, thus significantly increasing vibration amplitudes and, as a result, energy output. Other fundamental vibration modes have strain nodes, where the dynamic strain field changes sign in the direction of the cantilever length. The paper reports on a dimensionless numerical transient analysis of a cantilever of a constant cross-section and an optimally-shaped cantilever with the objective to accurately predict the position of a strain node. Total effective strain produced by both cantilevers segmented at the strain node is calculated via transient analysis and compared to the strain output produced by the cantilevers segmented at strain nodes obtained from modal analysis, demonstrating a 7% increase in energy output. Theoretical results were experimentally verified by using open-circuit voltage values measured for the cantilevers segmented at optimal and suboptimal segmentation lines.
International Nuclear Information System (INIS)
Valencich, T.; Hsieh, J.; Kwan, J.; Stewart, T.; Lenhardt, T.
1976-01-01
Agreement with experimental rate measurements for vibrational and translational effects on reactivity are shown to place stringent requirements on empirical potential energy surfaces. Classical trajectory dynamics on various surfaces show that Cl exchange reactions between isotopes of hydrogen require a barrier to agree with laser induced fluorescence experiments as well as molecular beam and thermal data. (orig.) [de
Analysis of crack initiation and growth in the high level vibration test at Tadotsu
International Nuclear Information System (INIS)
Kassir, M.K.; Hofmayer, C.H.; Bandyopadhyay, K.K.
1991-01-01
A High Level Vibration Test (HLVT) Program was carried out recently on the seismic table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Center (NUPEC) in Japan. The objective of the study being performed at Brookhaven National Laboratory is to use the HLVT data to assess the accuracy and usefulness of existing methods for predicting crack initiation and growth under complex, large amplitude loading. The work to be performed as part of this effort involves: (1) analysis of the stress/strain distribution in the vicinity of the crack, including the potential for residual stresses due to the weld repair; (2) analysis of the number of load cycles required for crack initiation, including estimates of the impact of the weld repair on the crack initiation behavior; (3) analysis of crack advance as a function of applied loading (classic fatigue versus cyclic tearing) taking into account the variable amplitude loading and the possible influence of the repair; and (4) material property testing to supplement the work performed as part of the HLVT, providing the materials data necessary to perform the analysis efforts. A summary of research progress for FY 1990 is presented. 2 refs
Spectrum and energy levels of Y VI
International Nuclear Information System (INIS)
Persson, W.; Reader, J.
1986-01-01
The spectrum of the five-times-ionized yttrium atom (Y VI), excited in a sliding-spark discharge, was studied in the 160--2500 A-circle range. About 900 Y VI lines were classified as transitions between 101 odd and 69 even energy levels.The energy-level system established includes almost all levels of the 4s 2 4p 4 , 4s4p 5 , 4s 2 4p 3 4d, 5d, 5s, 6s, and 5p configurations and a number of levels of the 7s, 4f, and 4s4p 4 4d configurations. The observed level system has been theoretically interpreted by means of Hartree--Fock calculations and least-squares parametric fits. Strong configuration mixings are found between the 4s4p 5 and 4s 2 4p 3 4d configurations, between the 4s 2 4p 3 5p and 4s4p 4 4d configurations, and between the 4s 2 4p 3 4f and 4s4p 4 4d configurations. From the optimized energy-level values, a system of Ritz-type wavelength standards with accuracies varying from 0.0003 to 0.003 A-circle in the range 179--500 A-circle has been determined. The ionization energy as determined from 4s 2 4p 3 ns levels (n = 5-7) is 737 110 +- 200 cm/sup -1/ (91.390 +- 0.025 eV)
Yin, Yuan; Shi, Deheng; Sun, Jinfeng; Zhu, Zunlue
2018-03-01
This work calculates the potential energy curves of 9 Λ-S and 28 Ω states of the NCl+ cation. The technique employed is the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. The Λ-S states are X2Π, 12Σ+, 14Π, 14Σ+, 14Σ-, 24Π, 14Δ, 16Σ+, and 16Π, which are yielded from the first two dissociation channels of NCl+ cation. The Ω states are generated from these Λ-S states. The 14Π, 14Δ, 16Σ+, and 16Π states are inverted with the spin-orbit coupling effect included. The 14Σ+, 16Σ+, and 16Π states are very weakly bound, whose well depths are only several-hundred cm- 1. One avoided crossing of PECs occurs between the 12Σ+ and 22Σ+ states. To improve the quality of potential energy curves, core-valence correlation and scalar relativistic corrections are included. The potential energies are extrapolated to the complete basis set limit. The spectroscopic parameters and vibrational levels are calculated. The transition dipole moments are computed. The Franck-Condon factors, Einstein coefficients, and radiative lifetimes of many transitions are determined. The spectroscopic approaches are proposed for observing these states according to the transition probabilities. The spin-orbit coupling effect on the spectroscopic and vibrational properties is evaluated. The spectroscopic parameters, vibrational levels, transition dipole moments, as well as transition probabilities reported in this paper could be considered to be very reliable.
FORECASTING OF DURABILITY OF ASPHALT PAVEMENT ON THE BASIS OF LEVELS OF THEIR VIBRATION LOADING
Directory of Open Access Journals (Sweden)
V. A. Osinovskaya
2015-01-01
Full Text Available The problem of low durability of flexible pavement is one of the most important problems of road economy. For example, the actual service life of asphalt pavement in Russia about 3 … 5 years. The bad condition of highways is an obstacle for the development of the national economy and leads to a significant annual economic losses.At present, this problem has no exact solution. Even at the seeming good road conditions of Europe and America the problem of low durability is no less important in these countries. And this problem becomes more and more actual every year.Our scientific researches allowed to make a hypothesis that the projected of pavements are not have the necessary durability yet not of a stage of designing because in strength calculations did not take into account the vibration of road constructions.Very actual the vibration loading becomes today as is now significantly changed the nature of loading of pavements. As a result the deflections of a pavements are reduced, but the increased vibration of pavements accelerated processes of destruction and significantly reduced durability.The theory of vibration destruction developed by the author allows to adjust the vibration, to form the vibration resistance pavements, and also to forecast a residual life of pavements that will more effectively develop repair actions.
Directory of Open Access Journals (Sweden)
Milad Derakhshanjazari
2016-03-01
Full Text Available Introduction: Taxi drivers’ exposure to repeat whole-body vibrations can cause back pain and digestive disorders. Since this type of vibration depends on the car components, this study was carried out to determine the influence of tire characteristics on the amount of whole-body vibrations transmitted to the Peugeot 405 taxi drivers. Methods: In this experimental study, vibration characteristics were measured according to the ISO2631-1 with each of the statuses: tubeless tires fixed and fluid in it (normal air or nitrogen and also the fluid in the tires fixed with tubes or tubeless on asphalt-paved road. Other variables including tire pressure, engine speed, road gradient, number of passengers, springs, and shock absorbers were kept constant. Then the effect of changes was analyzed using an appropriate statistical test. Results: After changing nitrogen to normal air and tubeless tires to tube, the average of RMS in Z-axis, eight-hour equivalent acceleration A(8 and crest factor were reduced (P 0.9 m/s2 to caution zone (0.45-0.9 m/s2 with a value of 0.8 m/s2. Conclusions: The amount of vibration transmitted to the whole body is sensitive to existence of tubes and tires inflation so that we can reduce the amount of whole-body vibration to lower than the upper limit of the health risk by changing the characteristics of the tire
Frontiers of controlling energy levels at interfaces
Koch, Norbert
The alignment of electron energy levels at interfaces between semiconductors, dielectrics, and electrodes determines the function and efficiency of all electronic and optoelectronic devices. Reliable guidelines for predicting the level alignment for a given material combination and methods to adjust the intrinsic energy landscape are needed to enable efficient engineering approaches. These are sufficiently understood for established electronic materials, e.g., Si, but for the increasing number of emerging materials, e.g., organic and 2D semiconductors, perovskites, this is work in progress. The intrinsic level alignment and the underlying mechanisms at interfaces between organic and inorganic semiconductors are discussed first. Next, methods to alter the level alignment are introduced, which all base on proper charge density rearrangement at a heterojunction. As interface modification agents we use molecular electron acceptors and donors, as well as molecular photochromic switches that add a dynamic aspect and allow device multifunctionality. For 2D semiconductors surface transfer doping with molecular acceptors/donors transpires as viable method to locally tune the Fermi-level position in the energy gap. The fundamental electronic properties of a prototypical 1D interface between intrinsic and p-doped 2D semiconductor regions are derived from local (scanning probe) and area-averaged (photoemission) spectroscopy experiments. Future research opportunities for attaining unsurpassed interface control through charge density management are discussed.
A bi-annular-gap magnetorheological energy absorber for shock and vibration mitigation
Bai, Xian-Xu; Wereley, Norman M.; Choi, Young-Tai; Wang, Dai-Hua
2012-04-01
For semi-active shock and vibration mitigation systems using magnetorheological energy absorbers (MREAs), the minimization of the field-off damper force of the MREA at high speed is of particular significance because the damper force due to the viscous damping at high speed becomes too excessive and thus the controllable dynamic force range that is defined by the ratio of the field-on damper force to the field-off damper force is significantly reduced. In this paper, a bi-annular-gap MREA with an inner-set permanent magnet is proposed to decrease the field-off damper force at high speed while keeping appropriate dynamic force range for improving shock and vibration mitigation performance. In the bi-annular-gap MREA, two concentric annular gaps are configured in parallel so as to decrease the baseline damper force and both magnetic activation methods using the electromagnetic coil winding and the permanent magnet are used to keep holding appropriate magnetic intensity in these two concentric annular gaps in the consideration of failure of the electric power supply. An initial field-on damper force is produced by the magnetic field bias generated from the inner-set permanent magnet. The initial damper force of the MREA can be increased (or decreased) through applying positive (or negative) current to the electromagnetic coil winding inside the bi-annular-gap MREA. After establishing the analytical damper force model of the bi-annular-gap MREA using a Bingham-plastic nonlinear fluid model, the principle and magnetic properties of the MREA are analytically validated and analyzed via electromagnetic finite element analysis (FEA). The performance of the bi-annular-gap MREA is also theoretically compared with that of a traditional single-annular- gap MREA with the constraints of an identical volume by the performance matrix, such as the damper force, dynamic force range, and Bingham number with respect to different excitation velocities.
A theoretical study on the mechanism of electronic to vibrational energy transfer in Hg/3P/ + CO
Kato, S.; Jaffe, R. L.; Komornicki, A.; Morokuma, K.
1983-01-01
The mechanism of electronic-to-vibrational (E-V) energy transfer in Hg(3P) + CO collisions has been studied theoretically. The configuration interaction (CI) method was employed to calculate potential energy surfaces of the collision system. A simplified theoretical model, based on the reaction coordinate concept and the calculated potential energy characteristics, was used to discuss the mechanism of the singlet-triplet transition and the energy disposal in the collision. The results obtained were that: (a) the quenching process processed via a collision complex mechanism; and that (b) the triplet-singlet transition occurs near the collinear geometry. A model classical trajectory calculation gives a product CO vibrational distribution in good agreement with the experimental result.
Energy Technology Data Exchange (ETDEWEB)
Tachikawa, Masanori [Quantum Chemistry Division, Graduate School of NanoBioScience, Yokohama City University, 22-2 Seto, Kanazawa, Yokohama 236-0027 (Japan)
2015-12-31
To theoretically demonstrate the binding of a positron to small polarized molecules, we have calculated the vibrational averaged positron affinity (PA) values along the local vibrational contribution with the configuration interaction level of multi-component molecular orbital method. This method can take the electron-positron correlation contribution into account through single electronic - single positronic excitation configurations. The PA values are enhanced by including the local vibrational contribution from vertical PA values due to the anharmonicity of the potential.
International Nuclear Information System (INIS)
Kardinal, I.
1998-01-01
The complementary techniques of HR-XPS and HREELS have been applied to two distinct problems. The first studies adsorption and dissociation of C 2 N 2 on Ni (110) at room temperature (RT) and at 90 K and its co-adsorption with CO. At RT C 2 N 2 dissociates and forms a c(2x2)-CN structure. The resulting CN is found to be bound in the grooves of the (110) surface yielding the lowest C-N vibrational energy yet observed. C 2 N 2 was found to dissociate even at 90 K however the resulting CN overlayer after warming to RT showed remarkable differences to that of the RT adsorption. As well as the in-groove species a number of adsorption sites on the ridges with a bond order higher have been identified. Preadsorbed CO is completely driven of the Ni (110) surface by co-adsorption of CN at RT. HREELS indicates that first CO is desorbed from the on-top-sites and then from the bridge-sites of the (110)-ridges involving a considerable increase of the HREELS cross section for the CO on the bridge-sites. Also the signal intensity of the coadsorbed CN is suppressed by the CO present on the surface. The second study investigated the adsorption of bithiophene (BiT) on clean Ni (110) and the S-modified c(2x2)-S-Ni (110) and p(4x1)-S-Ni (110). The latter provided a strongly structured substrate which forced the assembly of the adsorbed BiT-molecules. The high degree of order of this adsorbate/substrate system was obvious in both the HR-XPS results and the BREELS results with strong azimuthal anisotropy. This system was used to asses the ability to use the HREELS impact selection rules to determine molecular orientation of a reasonably complex adsorbate overlayer. (author)
Thibado, Paul; Kumar, Pradeep; Singh, Surendra
Internet-of-Things (IoT) is projected to become a multi-trillion-dollar market, but most applications cannot afford replacing batteries on such a large scale, driving the need for battery alternatives. We recently discovered that freestanding graphene membranes are in perpetual motion when held at room temperature. Surprisingly, the random up-down motion of the membrane does not follow classical Brownian motion, but instead is super-diffusive at short times and sub-diffusive at long times. Furthermore, the velocity probability distribution function is non-Gaussian and follows the heavy-tailed Cauchy-Lorentz distribution, consistent with Lévy flights. Molecular dynamics simulations reveal that mechanical buckling is spontaneously occurring, and that this is the mechanism responsible for the anomalous movement. Bucking in this system occurs when the local material suddenly flips from concave to convex. The higher kinetic energy associated with this motion is derived from the surrounding thermal waste heat, and it may be converted into an electrical current and used as the active component of small power generators known as ambient vibration energy harvesters. thibado@uark.edu.
International Nuclear Information System (INIS)
Malmskog, S.G.; Hoejeberg, M.; Berg, V.
1969-02-01
Gamma ray spectra in the decay of 185 Ta and 185m W have been studied with Ge (Li) detectors. The 185m W isomeric transition at 131.6 keV is shown to be of E3 multipolarity. A level scheme of 185 W is proposed with the following energy levels (energies in keV, spin and K quantum numbers in brackets): 0 (3/2 - 3/2), 23.5 (1/2 - 1/2), 65.9 (5/2 - 3/2), 93.5 (3/2 - 1/2) (uncertain), 173.9 (7/2 - 3/2), 188.1 (5/2 - 1/2), 197.5 (11/2 + 11/2) , 243.5 (7/2 - 7/2), and 390.8 (9/2 - 7/2)
Comparison of energy performance requirements levels
DEFF Research Database (Denmark)
Spiekman, Marleen; Thomsen, Kirsten Engelund; Rose, Jørgen
This summary report provides a synthesis of the work within the EU SAVE project ASIEPI on developing a method to compare the energy performance (EP) requirement levels among the countries of Europe. Comparing EP requirement levels constitutes a major challenge. From the comparison of for instance...... the present Dutch requirement level (EPC) of 0,8 with the present Flemish level of E80, it can easily be seen that direct comparison is not possible. The conclusions and recommendations of the study are presented in part A. These constitute the most important result of the project. Part B gives an overview...... of all other project material related to that topic, which allows to easily identify the most pertinent information. Part C lists the project partners and sponsors....
Bovino, S; Bodo, E; Yurtsever, E; Gianturco, F A
2008-06-14
The interaction between the triplet state of the lithium dimer, (7)Li(2), with (4)He is obtained from accurate ab initio calculations where the vibrational dependence of the potential is newly computed. Vibrational quenching dynamics within a coupled-channel quantum treatment is carried out at ultralow energies, and large differences in efficiency as a function of the initial vibrational state of the targets are found as one compares the triplet results with those of the singlet state of the same target.
International Nuclear Information System (INIS)
Zheng, Rui; Zheng, Limin; Yang, Minghui; Lu, Yunpeng
2015-01-01
Theoretical studies of the potential energy surface (PES) and bound states are performed for the N 2 –N 2 O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N 2 O monomer is near the N 2 monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency for intermolecular disrotation mode is 23.086 cm −1 , which is in good agreement with the available experimental data of 22.334 cm −1 . A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers 14 N 2 –N 2 O and 15 N 2 –N 2 O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters
International Nuclear Information System (INIS)
Zou, Hong-Xiang; Zhang, Wen-ming; Li, Wen-Bo; Wei, Ke-Xiang; Gao, Qiu-Hua; Peng, Zhi-Ke; Meng, Guang
2017-01-01
Highlights: • A magnetically coupled two-degree-of-freedom harvester for rotation is proposed. • The electromechanical coupling model is developed and validated experimentally. • The harvester can generate high voltage at low rotating speeds. • The harvester can harvest vibration energy in multiple frequency bands. - Abstract: Energy can be harvested from rotational motion for powering wireless autonomous electronic devices. The paper presents a magnetically coupled two-degree-of-freedom vibration energy harvester for rotary motion applications. The design consists of two inverted piezoelectric cantilever beams whose free ends point to the rotating shaft. The centrifugal force of the inverted cantilever beam is beneficial to producing large amplitude in a low speed range. The electromechanical coupling dynamical model is developed by the energy method from Hamilton’s principle and validated experimentally. The experimental results indicate that the presented harvester is suitable for low speed rotation and can harvest vibration energy in multiple frequency bands. The first and second resonant behaviors of voltage can be obtained at 420 r/min and 550 r/min, and the average output powers are 564 μW and 535.3 μW, respectively.
Two-dimensional concentrated-stress low-frequency piezoelectric vibration energy harvesters
Energy Technology Data Exchange (ETDEWEB)
Sharpes, Nathan [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Abdelkefi, Abdessattar [Department of Mechanical and Aerospace Engineering, New Mexico State University, Las Cruces, New Mexico 88003 (United States); Priya, Shashank [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, Virginia 24061 (United States)
2015-08-31
Vibration-based energy harvesters using piezoelectric materials have long made use of the cantilever beam structure. Surmounting the deficiencies in one-dimensional cantilever-based energy harvesters has been a major focus in the literature. In this work, we demonstrate a strategy of using two-dimensional beam shapes to harvest energy from low frequency excitations. A characteristic Zigzag-shaped beam is created to compare against the two proposed two-dimensional beam shapes, all of which occupy a 25.4 × 25.4 mm{sup 2} area. In addition to maintaining the low-resonance bending frequency, the proposed beam shapes are designed with the goal of realizing a concentrated stress structure, whereby stress in the beam is concentrated in a single area where a piezoelectric layer may be placed, rather than being distributed throughout the beam. It is shown analytically, numerically, and experimentally that one of the proposed harvesters is able to provide significant increase in power production, when the base acceleration is set equal to 0.1 g, with only a minimal change in the resonant frequency compared to the current state-of-the-art Zigzag shape. This is accomplished by eliminating torsional effects, producing a more pure bending motion that is necessary for high electromechanical coupling. In addition, the proposed harvesters have a large effective beam tip whereby large tip mass may be placed while retaining a low-profile, resulting in a low volume harvester and subsequently large power density.
International Nuclear Information System (INIS)
Kim, Miso; Hoegen, Mathias; Dugundji, John; Wardle, Brian L
2010-01-01
An electromechanically coupled model for a cantilevered piezoelectric energy harvester with a proof mass is presented. Proof masses are essential in microscale devices to move device resonances towards optimal frequency points for harvesting. Such devices with proof masses have not been rigorously modeled previously; instead, lumped mass or concentrated point masses at arbitrary points on the beam have been used. Thus, this work focuses on the exact vibration analysis of cantilevered energy harvester devices including a tip proof mass. The model is based not only on a detailed modal analysis, but also on a thorough investigation of damping ratios that can significantly affect device performance. A model with multiple degrees of freedom is developed and then reduced to a single-mode model, yielding convenient closed-form normalized predictions of device performance. In order to verify the analytical model, experimental tests are undertaken on a macroscale, symmetric, bimorph, piezoelectric energy harvester with proof masses of different geometries. The model accurately captures all aspects of the measured response, including the location of peak-power operating points at resonance and anti-resonance, and trends such as the dependence of the maximal power harvested on the frequency. It is observed that even a small change in proof mass geometry results in a substantial change of device performance due not only to the frequency shift, but also to the effect on the strain distribution along the device length. Future work will include the optimal design of devices for various applications, and quantification of the importance of nonlinearities (structural and piezoelectric coupling) for device performance
International Nuclear Information System (INIS)
Krajcar-Bronic, I.; Kimura, M.
1995-01-01
Electron thermalization in methane and argon--methane mixtures is studied by using the Boltzmann equation. The presence of low-lying vibrational excited states in methane significantly changes electron energy distribution functions and relaxation times. We found that (i) the mean electron energy just below the first vibrational excited state is reached faster by 1000 times when the vibrational states are taken into account, and (ii) electron energy distribution functions have distinct peaks at energy intervals equal to the vibrational threshold energies. Both these effects are due to large vibrational stopping cross section. The thermalization time in mixtures of argon--methane (without vibrational states) smoothly changes as the mixture composition varies, and no significant difference in the electron energy distribution function is observed. When the vibrational excited states are taken into account, thermalization is almost completely defined by CH 4 , even at very low fractional concentrations of CH 4 . The sensitivity of the electron energy distribution functions on the momentum transfer cross sections used in calculation on the thermalization is discussed. copyright 1995 American Institute of Physics
Wang, Guangqing; Liao, Wei-Hsin; Yang, Binqiang; Wang, Xuebao; Xu, Wentan; Li, Xiuling
2018-05-01
Bistable piezoelectric energy harvesters are being increasingly seen as an alternative to batteries in low-power devices. However, their energy harvesting characteristics are limited. To enhance these, we use a configuration including an elastic magnifier to amplify base excitation and provide sufficient kinetic energy to overcome potential well barriers, thus leading to large-amplitude bistable motion. We derive the distributed parameter mathematical model of this configuration by using Hamilton's principle. We then investigate the nonlinear dynamic behaviors and energetic characteristics and analyze the bifurcation for the equilibrium solution of the model. The simulations and experiments show high electromechanical responses and energy generation characteristics of the proposed system over a broad frequency band. The results suggest that, compared with a typical bistable piezoelectric energy harvester, the proposed energy harvester system with an elastic magnifier can provide higher output over a broader frequency band at lower excitation levels by adjusting the system's mass and stiffness ratios.
Ziemkiewicz, Michael P; Pluetzer, Christian; Nesbitt, David J; Scribano, Yohann; Faure, Alexandre; van der Avoird, Ad
2012-08-28
First results are reported on overtone (v(OH) = 2 ← 0) spectroscopy of weakly bound H(2)-H(2)O complexes in a slit supersonic jet, based on a novel combination of (i) vibrationally mediated predissociation of H(2)-H(2)O, followed by (ii) UV photodissociation of the resulting H(2)O, and (iii) UV laser induced fluorescence on the nascent OH radical. In addition, intermolecular dynamical calculations are performed in full 5D on the recent ab initio intermolecular potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)] in order to further elucidate the identity of the infrared transitions detected. Excellent agreement is achieved between experimental and theoretical spectral predictions for the most strongly bound van der Waals complex consisting of ortho (I = 1) H(2) and ortho (I = 1) H(2)O (oH(2)-oH(2)O). Specifically, two distinct bands are seen in the oH(2)-oH(2)O spectrum, corresponding to internal rotor states in the upper vibrational manifold of Σ and Π rotational character. However, none of the three other possible nuclear spin modifications (pH(2)-oH(2)O, pH(2)-pH(2)O, or oH(2)-pH(2)O) are observed above current signal to noise level, which for the pH(2) complexes is argued to arise from displacement by oH(2) in the expansion mixture to preferentially form the more strongly bound species. Direct measurement of oH(2)-oH(2)O vibrational predissociation in the time domain reveals lifetimes of 15(2) ns and <5(2) ns for the Σ and Π states, respectively. Theoretical calculations permit the results to be interpreted in terms of near resonant energy levels and intermolecular alignment of the H(2) and H(2)O wavefunctions, providing insight into predissociation dynamical pathways from these metastable levels.
International Nuclear Information System (INIS)
Uluşan, H; Gharehbaghi, K; Külah, H; Zorlu, Ö; Muhtaroğlu, A
2015-01-01
This study presents a novel hybrid system that combines the power generated simultaneously by a vibration-based Electromagnetic (EM) harvester and a UHF band RF harvester. The novel hybrid scavenger interface uses a power management circuit in 180 nm CMOS technology to step-up and to regulate the combined output. At the first stage of the system, the RF harvester generates positive DC output with a 7-stage threshold compensated rectifier, while the EM harvester generates negative DC output with a self-powered AC/DC negative doubler circuit. At the second stage, the generated voltages are serially added, stepped-up with an on-chip charge pump circuit, and regulated to a typical battery voltage of 3 V. Test results indicate that the hybrid operation enables generation of 9 μW at 3 V output for a wide range of input stimulations, which could not be attained with either harvesting mode by itself. Moreover the hybrid system behaves as a typical battery, and keeps the output voltage stable at 3 V up to 18 μW of output power. The presented system is the first battery-like harvester to our knowledge that generates energy from two independent sources and regulates the output to a stable DC voltage. (paper)
Energy level diagrams for black hole orbits
Levin, Janna
2009-12-01
A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy with atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed-form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.
Energy level diagrams for black hole orbits
International Nuclear Information System (INIS)
Levin, Janna
2009-01-01
A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy with atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed-form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.
Pietanza, L D; Colonna, G; Laporta, V; Celiberto, R; D'Ammando, G; Laricchiuta, A; Capitelli, M
2016-05-05
A new set of electron-vibrational (e-V) processes linking the first 10 vibrational levels of the symmetric mode of CO2 is derived by using a decoupled vibrational model and inserted in the Boltzmann equation for the electron energy distribution function (eedf). The new eedf and dissociation rates are in satisfactory agreement with the corresponding ones obtained by using the e-V cross sections reported in the database of Hake and Phelps (H-P). Large differences are, on the contrary, found when the experimental dissociation cross sections of Cosby and Helm are inserted in the Boltzman equation. Comparison of the corresponding rates with those obtained by using the low-energy threshold energy, reported in the H-P database, shows differences up to orders of magnitude, which decrease with the increasing of the reduced electric field. In all cases, we show the importance of superelastic vibrational collisions in affecting eedf and dissociation rates either in the direct electron impact mechanism or in the pure vibrational mechanism.
Chandrasekharan, Nataraj
Innovation in integrated circuit technology along with improved manufacturing processes has resulted in considerable reduction in power consumption of electromechanical devices. Majority of these devices are currently powered by batteries. However, the issues posed by batteries, including the need for frequent battery recharge/replacement has resulted in a compelling need for alternate energy to achieve self-sufficient device operation or to supplement battery power. Vibration based energy harvesting methods through piezoelectric transduction provides with a promising potential towards replacing or supplementing battery power source. However, current piezoelectric energy harvesters generate low specific power (power-to-weight ratio) when compared to batteries that the harvesters seek to replace or supplement. In this study, the potential of integrating lightweight cellular honeycomb structures with existing piezoelectric device configurations (bimorph) to achieve higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of a conventional piezoelectric bimorph with honeycomb structures of the same material results in a significant increase in power-to-weight ratio of the piezoelectric harvester. In order to maximize the electrical response of vibration based power harvesters, the natural frequency of these harvesters is designed to match the input driving frequency. The commonly used technique of adding a tip mass is employed to lower the natural frequency (to match driving frequency) of both, solid and honeycomb substrate bimorphs. At higher excitation frequency, the natural frequency of the traditional solid substrate bimorph can only be altered (to match driving frequency) through a change in global geometric design parameters, typically achieved by increasing the thickness of the harvester. As a result, the size of the harvester is increased and can be disadvantageous
Energy-Saving Vibration Impulse Coal Degradation at Finely Dispersed Coal-Water Slurry Preparation
Directory of Open Access Journals (Sweden)
Moiseev V.A.
2015-01-01
Full Text Available Theoretical and experimental research results of processes of finely dispersed coal-water slurry preparation for further generation of energetic gas in direct flow and vortex gas generator plants have been presented. It has been stated that frequency parameters of parabolic vibration impulse mill influence degradation degree. Pressure influence on coal parameters in grinding cavity has been proven. Experimental researches have proven efficiency of vibration impulse mill with unbalanced mass vibrator generator development. Conditions of development on intergranular walls of coal cracks have been defined.
International Nuclear Information System (INIS)
Ji, Hongli; Qiu, Jinhao; Xia, Pinqi; Inman, Daniel
2012-01-01
Modal coupling is an important issue in the analysis and control of structural systems with multi-degrees of freedom (MDOF). In this paper, modal coupling induced by energy conversion in the structural control of an MDOF system using a synchronized switch damping method is investigated theoretically and validated numerically. In the analysis, it is supposed that the voltage on the piezoelectric actuator is switched at the displacement extrema of a given mode. Two types of coupling in energy conversion are considered. The first is whether the switching action based on one mode induces energy conversion of the other modes. The second is whether the vibration of one mode affects the energy conversion of the other modes. The results indicate that the modal coupling in energy conversion is very complicated. In most cases the switching action based on one mode does induce energy conversion of another mode, but the efficiency depends on the frequency ratio of the two modes. The vibration of one mode affects the energy conversion of another mode only when the frequency ratio of the two modes takes some special values. Discussions are also given on the potential application of the theoretical results in the design of an energy harvesting device. (paper)
Energy Technology Data Exchange (ETDEWEB)
Zenkour, A. M.; Alnefaie, K. A.; Abu-Hamdeh, N. H.; Aljinaid, A. A.; Aifanti, E. C. [King Abdulaziz University, Jeddah (Saudi Arabia); Abouelregal, A. E. [Mansoura University, Mansoura (Egypt)
2015-07-15
In this article, an Euler-Bernoulli beam model based upon nonlocal thermoelasticity theory without energy dissipation is used to study the vibration of a nanobeam subjected to ramp-type heating. Classical continuum theory is inherently size independent, while nonlocal elasticity exhibits size dependence. Among other things, this leads to a new expression for the effective nonlocal bending moment as contrasted to its classical counterpart. The thermal problem is addressed in the context of the Green-Naghdi (GN) theory of heat transport without energy dissipation. The governing partial differential equations are solved in the Laplace transform domain by the state space approach of modern control theory. Inverse of Laplace transforms are computed numerically using Fourier expansion techniques. The effects of nonlocality and ramping time parameters on the lateral vibration, temperature, displacement and bending moment are discussed.
DEFF Research Database (Denmark)
Lei, Anders; Xu, Ruichao; Pedersen, C.M.
2011-01-01
This work presents a high yield wafer scale fabrication of MEMS-based unimorph silicon/PZT thick film vibrational energy harvesters aimed towards vibration sources with peak frequencies in the range of a few hundred Hz. By combining KOH etching with mechanical front side protection, SOI wafer...... to accurately define the thickness of the silicon part of the harvester and a silicon compatible PZT thick film screen-printing technique, we are able to fabricate energy harvesters on wafer scale with a yield higher than 90%. The characterization of the fabricated harvesters is focused towards the full wafer....../mass-production aspect; hence the analysis of uniformity in harvested power and resonant frequency....
Systematic vibration thermodynamic properties of bromine
Liu, G. Y.; Sun, W. G.; Liao, B. T.
2015-11-01
Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.
Robust energy harvesting from walking vibrations by means of nonlinear cantilever beams
Kluger, Jocelyn M.; Sapsis, Themistoklis P.; Slocum, Alexander H.
2015-04-01
In the present work we examine how mechanical nonlinearity can be appropriately utilized to achieve strong robustness of performance in an energy harvesting setting. More specifically, for energy harvesting applications, a great challenge is the uncertain character of the excitation. The combination of this uncertainty with the narrow range of good performance for linear oscillators creates the need for more robust designs that adapt to a wider range of excitation signals. A typical application of this kind is energy harvesting from walking vibrations. Depending on the particular characteristics of the person that walks as well as on the pace of walking, the excitation signal obtains completely different forms. In the present work we study a nonlinear spring mechanism that is composed of a cantilever wrapping around a curved surface as it deflects. While for the free cantilever, the force acting on the free tip depends linearly on the tip displacement, the utilization of a contact surface with the appropriate distribution of curvature leads to essentially nonlinear dependence between the tip displacement and the acting force. The studied nonlinear mechanism has favorable mechanical properties such as low frictional losses, minimal moving parts, and a rugged design that can withstand excessive loads. Through numerical simulations we illustrate that by utilizing this essentially nonlinear element in a 2 degrees-of-freedom (DOF) system, we obtain strongly nonlinear energy transfers between the modes of the system. We illustrate that this nonlinear behavior is associated with strong robustness over three radically different excitation signals that correspond to different walking paces. To validate the strong robustness properties of the 2DOF nonlinear system, we perform a direct parameter optimization for 1DOF and 2DOF linear systems as well as for a class of 1DOF and 2DOF systems with nonlinear springs similar to that of the cubic spring that are physically realized
2009-09-01
capacitor responsible for charge. Figure 25. Half Bridge Power Harvester with Leakage Resistance [From 70] The resistor accounts for the voltage...REV PAP, 1996. [63] M. Umeda, K. Nakamura, and S. Ueha, “Energy storage characteristics of a piezo - generator using impact induced vibration...Japanese journal of applied physics, vol. 36, pp. 3146–3151, 1997. [64] M. Kimura, “ Piezo -electricity generation device,” U.S. Patent 812070, September
Intramolecular Vibrational Energy Transfer and Bond-Selected Photochemistry in Liquids
National Research Council Canada - National Science Library
Crim, F
2001-01-01
.... In the gas phase experiments, one pulse excited the first overtone of the O-H stretching vibration in nitric acid and the second pulse probed the excited molecule by excitation to a dissociative...
Energy Dissipation from Vibrating Floor Slabs due to Human-Structure Interaction
Directory of Open Access Journals (Sweden)
James M.W. Brownjohn
2001-01-01
Full Text Available Lightweight pre-cast flooring systems using post-tensioning to increase strength but not stiffness are increasingly popular, and vibration serviceability problems tend to govern design of such floors where human occupants are increasingly concerned with vibrations. At the same time as inducing response, stationary human observers can also participate in the response as mitigating influence and it is clear that a human behaves as a highly effective damper, even when seated.
Vibration energy absorption in the whole-body system of a tractor operator
Jan Szczepaniak; Wojciech Tanaś; Jacek Kromulski
2014-01-01
Many people are exposed to whole-body vibration (WBV) in their occupational lives, especially drivers of vehicles such as tractor and trucks. The main categories of effects from WBV are perception degraded comfort interference with activities-impaired health and occurrence of motion sickness. Absorbed power is defined as the power dissipated in a mechanical system as a result of an applied force. The vibration-induced injuries or disorders in a substructure of the human system are primari...
Report of workshop on vibration related to fluid in atomic energy field. 6
International Nuclear Information System (INIS)
1996-01-01
The accident of the fast breeder prototype reactor, 'Monju' on sodium leakage in its second cooling system occurred on December 8, 1995 was broadcast widely through mass-communication such as newspaper, television and others. Because of suspicion of whether concealment of videotape taken the accident state was intended to not, a method of information opening was an argument point. In spite of this, technical details of the accident was not transferred to researchers of each specified field by formal state still yet. Informations expected by the specialists of flow relating vibration are, for example, objective data such as accurate shape, eigenfrequency, attenuation, and others of the thermometer well, flow conditions and so forth, by knowing which they could judge reason of occurring the accident. It seems to be meaningful to conduct the information exchange on even a scale of the 'Yayoi Research Group'. Therefore, the Research Group was received all of objective facts on eddy excitation vibration of Monju's secondary system thermometer well accurately from its interested persons, reviewed on the eddy excitation vibration at this accident once more, and argued with a method of future research. In this book, the following 14 reports are described; 1) Outline of the Monju secondary system sodium leakage accident, 2) Karman vortex, 3) Flow at circumference of vibrates, 4) Flowing power analysis of the thermometer, 5) Flowing power vibration water flow test of the thermometer well, 6) Water flow test on the flow excitation vibration of the Monju's thermometer well, and others. (G.K.)
Lu, Haohui; Chai, Tan; Cooley, Christopher G.
2018-03-01
This study investigates the vibration of a rotating piezoelectric device that consists of a proof mass that is supported by elastic structures with piezoelectric layers. Vibration of the proof mass causes deformation in the piezoelectric structures and voltages to power the electrical loads. The coupled electromechanical equations of motion are derived using Newtonian mechanics and Kirchhoff's circuit laws. The free vibration behavior is investigated for devices with identical (tuned) and nonidentical (mistuned) piezoelectric support structures and electrical loads. These devices have complex-valued, speed-dependent eigenvalues and eigenvectors as a result of gyroscopic effects caused by their constant rotation. The characteristics of the complex-valued eigensolutions are related to physical behavior of the device's vibration. The free vibration behaviors differ significantly for tuned and mistuned devices. Due to gyroscopic effects, the proof mass in the tuned device vibrates in either forward or backward decaying circular orbits in single-mode free response. This is proven analytically for all tuned devices, regardless of the device's specific parameters or operating speed. For mistuned devices, the proof mass has decaying elliptical forward and backward orbits. The eigenvalues are shown to be sensitive to changes in the electrical load resistances. Closed-form solutions for the eigenvalues are derived for open and close circuits. At high rotation speeds these devices experience critical speeds and instability.
Kamath, Aditya; Vargas-Hernández, Rodrigo A.; Krems, Roman V.; Carrington, Tucker; Manzhos, Sergei
2018-06-01
For molecules with more than three atoms, it is difficult to fit or interpolate a potential energy surface (PES) from a small number of (usually ab initio) energies at points. Many methods have been proposed in recent decades, each claiming a set of advantages. Unfortunately, there are few comparative studies. In this paper, we compare neural networks (NNs) with Gaussian process (GP) regression. We re-fit an accurate PES of formaldehyde and compare PES errors on the entire point set used to solve the vibrational Schrödinger equation, i.e., the only error that matters in quantum dynamics calculations. We also compare the vibrational spectra computed on the underlying reference PES and the NN and GP potential surfaces. The NN and GP surfaces are constructed with exactly the same points, and the corresponding spectra are computed with the same points and the same basis. The GP fitting error is lower, and the GP spectrum is more accurate. The best NN fits to 625/1250/2500 symmetry unique potential energy points have global PES root mean square errors (RMSEs) of 6.53/2.54/0.86 cm-1, whereas the best GP surfaces have RMSE values of 3.87/1.13/0.62 cm-1, respectively. When fitting 625 symmetry unique points, the error in the first 100 vibrational levels is only 0.06 cm-1 with the best GP fit, whereas the spectrum on the best NN PES has an error of 0.22 cm-1, with respect to the spectrum computed on the reference PES. This error is reduced to about 0.01 cm-1 when fitting 2500 points with either the NN or GP. We also find that the GP surface produces a relatively accurate spectrum when obtained based on as few as 313 points.
Ahmed, Md. Tusher; Hossain, Md. Tanver; Rahman, Md. Ashiqur
2017-06-01
Energy harvesting technology has the ability to create self-powered electronic systems that do not rely on battery power for their operation. Wind energy can be converted into electricity via a piezoelectric transducer during the air flow over a cylinder. The vortex-induced vibration over the cylinder causes the piezoelectric beam to vibrate. Thus useful electric energy at the range 0.2-0.3V is found which can be useful for self-powering small electronic devices. In the present study, prototypes of micro-energy harvester with a shape of 65 mm × 37 mm × 0.4 mm are developed and tested for airflow over D-shaped bluff body for diameters of 15, 20 and 28mm in an experimental setup consisting of a long wind tunnel of 57cm × 57cm with variable speeds of the motor for different flow velocities and the experimental setup is connected at the downstream where flow velocity is the maximum. Experimental results show that the velocity and induced voltage follows a regular linear pattern. A maximum electrical potential of 140 mV for velocity of 1.1 ms-1 at a bluff body diameter of 15 mm is observed in the energy harvester that can be applied in many practical cases for self-powering electronic devices. The simulation of this energy harvesting phenomena is then simulated using COMSOLE multi-physics. Diameter of the bluff bodies as well as flow velocity and size of cantilever beam are varied and the experimental findings are found to be in good agreement with the simulated ones. The simulations along with the experimental data show the possibility of generating electricity from vortex induced vibration and can be applied in many practical cases for self-powering electronic devices.
Renewable energy education at the University level
Energy Technology Data Exchange (ETDEWEB)
Bhattacharya, S.C. [Asian Institute of Technology, Pathumthani (Thailand). Energy Program
2001-03-01
The rapid growth in global enrolment of students for higher education observed in recent decades is expected to continue in the early next century. However, the role of the universities and their approach to education may undergo substantial transformation in the future. The Internet is expected to play a significant role in university-level education in general and renewable energy education (REE) in particular. Currently, REE at different universities is characterized by a lack of uniformity in terms of duration, coursework, emphasis on research, etc. There is a need to establish guidelines and standards regarding academic programs and to establish a system of accreditation, preferably global, of REE in different academic disciplines and departments. (author)
Directory of Open Access Journals (Sweden)
Zhenlong Xu
2017-06-01
Full Text Available Considering coil inductance and the spatial distribution of the magnetic field, this paper developed an approximate distributed-parameter model of a hybrid energy harvester (HEH. The analytical solutions were compared with numerical solutions. The effects of load resistances, electromechanical coupling factors, mechanical damping ratio, coil parameters and size scale on performance were investigated. A meso-scale HEH prototype was fabricated, tested and compared with a stand-alone piezoelectric energy harvester (PEH and a stand-alone electromagnetic energy harvester (EMEH. The peak output power is 2.93% and 142.18% higher than that of the stand-alone PEH and EMEH, respectively. Moreover, its bandwidth is 108%- and 122.7%-times that of the stand-alone PEH and EMEH, respectively. The experimental results agreed well with the theoretical values. It is indicated that the linearized electromagnetic coupling coefficient is more suitable for low-level excitation acceleration. Hybrid energy harvesting contributes to widening the frequency bandwidth and improving energy conversion efficiency. However, only when the piezoelectric coupling effect is weak or medium can the HEH generate more power than the single-mechanism energy harvester. Hybrid energy harvesting can improve output power even at the microelectromechanical systems (MEMS scale. This study presents a more effective model for the performance evaluation and structure optimization of the HEH.
International Nuclear Information System (INIS)
Yu, Hua-Gen
2015-01-01
We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An application is illustrated by calculating the infrared vibrational dipole transition spectrum of CH based on the ab initio T8 potential energy surface of Schwenke and Partridge and the low-order truncated ab initio dipole moment surfaces of Yurchenko and co-workers. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra
13C and 18O isotope enrichment by vibrational energy exchange pumping of CO
International Nuclear Information System (INIS)
Bergman, R.C.; Homicz, G.F.; Rich, J.W.; Wolk, G.L.
1983-01-01
Measurements of preferential vibration-to-vibration (V--V) pumping of high vibrational states of 13 C 16 O and 12 C 18 O in optically excited CO gas are reported. It is found that the v = 22, 25, 27, 30, and 32 states of 13 C 16 O and the v = 8, 10, and 12 states of 12 C 18 O are substantially overpopulated compared to the same states in 12 C 16 O in strongly V--V pumped CO. Such mixtures are observed to react, forming products enriched in 13 C. The results are in reasonable agreement with an analytical kinetic model of V--V pumping in binary mixtures of diatomic gases
Is there an optimum level for renewable energy?
International Nuclear Information System (INIS)
Moriarty, Patrick; Honnery, Damon
2011-01-01
Because continued heavy use of fossil fuel will lead to both global climate change and resource depletion of easily accessible fuels, many researchers advocate a rapid transition to renewable energy (RE) sources. In this paper we examine whether RE can provide anywhere near the levels of primary energy forecast by various official organisations in a business-as-usual world. We find that the energy costs of energy will rise in a non-linear manner as total annual primary RE output increases. In addition, increasing levels of RE will lead to increasing levels of ecosystem maintenance energy costs per unit of primary energy output. The result is that there is an optimum level of primary energy output, in the sense that the sustainable level of energy available to the economy is maximised at that level. We further argue that this optimum occurs at levels well below the energy consumption forecasts for a few decades hence. - Highlights: → We need to shift to renewable energy for climate change and fuel depletion reasons. → We examine whether renewable energy can provide the primary energy levels forecast. → The energy costs of energy rise non-linearly with renewable energy output. → There is thus an optimum level of primary energy output. → This optimum occurs at levels well below future official energy use forecasts.
CSIR Research Space (South Africa)
De Clercq, L
2010-09-01
Full Text Available al lbl d i I e I e dt ω ωρ ρ ρ − = − = −∑h (1) where, , .a b a bω ω ω= − , (2) ρab gives the elements of the density matrix, ωa the frequencies... of the individual vibrational levels, and Iab the matrix elements of the interaction Hamiltonian [2] which include the detailed time dependence of the shaped femtosecond pulse. 2. Simulation results A transform limited 150 femtosecond laser pulse with a...
Comparison of PZN-PT, PMN-PT single crystals and PZT ceramic for vibration energy harvesting
International Nuclear Information System (INIS)
Yang, Zhengbao; Zu, Jean
2016-01-01
Highlights: • Systematic analysis of PMN-PT and PZN-PT single crystals for energy harvesters. • Performance analysis and comparison under various conditions. • Discussion of the effect of the SSHI technique on single crystal energy harvesters. • Efficiency analysis in both on-resonance and off-resonance conditions. - Abstract: Vibration energy harvesting has a great potential to achieve self-powered operations for wireless sensors, wearable devices and medical electronics, and thus has attracted much attention in academia and industry. The majority of research into this subject has focused on the piezoelectric effect of synthetic materials, especially the perovskite PZT ceramics. Recently the new-generation piezoelectric materials PMN-PT and PZN-PT single crystals have gained significant interest because of their outstanding piezoelectric properties. They can be used to replace the widely-adopted PZT ceramics for improving energy harvesters’ performance substantially. However, there is little research on comparing PMN-PT and PZN-PT energy harvesters against PZT harvesters. In this paper, we present a systematic comparison between vibration energy harvesters using the PMN-PT, PZN-PT single crystals and those using the PZT ceramics. Key properties of the three materials are summarized and compared. The performance of the PMN-PT and PZN-PT energy harvesters is characterized under different conditions (beam length, resistance, frequency, excitation strength, and backward coupling effect), and is quantitatively compared with the PZT counterpart. Furthermore, the effect of the synchronized switch harvesting on inductor (SSHI) circuit on the three harvesters is discussed. The experimental results indicate that energy harvesters using the PMN-PT and PZN-PT single crystals can significantly outperform those using the PZT ceramics. This study provides a strong base for future research on high-performance energy harvesters using the new PMN-PT and PZN-PT single
Maurath, Dominic
2015-01-01
Chip-integrated power management solutions are a must for ultra-low power systems. This enables not only the optimization of innovative sensor applications. It is also essential for integration and miniaturization of energy harvesting supply strategies of portable and autonomous monitoring systems. The book particularly addresses interfaces for energy harvesting, which are the key element to connect micro transducers to energy storage elements. Main features of the book are: - A comprehensive technology and application review, basics on transducer mechanics, fundamental circuit and control design, prototyping and testing, up to sensor system supply and applications. - Novel interfacing concepts - including active rectifiers, MPPT methods for efficient tracking of DC as well as AC sources, and a fully-integrated charge pump for efficient maximum AC power tracking at sub-100µW ultra-low power levels. The chips achieve one of widest presented operational voltage range in standard CMOS technology: 0.44V to over...
Directory of Open Access Journals (Sweden)
Yukio Takahashi
2011-01-01
Full Text Available To investigate the contribution of body vibrations to the vibratory sensation induced by high-level, complex low-frequency noise, we conducted two experiments. In Experiment 1, eight male subjects were exposed to seven types of low-frequency noise stimuli: two pure tones [a 31.5-Hz, 100-dB(SPL tone and a 50-Hz, 100-dB(SPL tone] and five complex noises composed of the pure tones. For the complex noise stimuli, the sound pressure level of one tonal component was 100 dB(SPL and that of another one was either 90, 95, or 100 dB(SPL. Vibration induced on the body surface was measured at five locations, and the correlation with the subjective rating of the vibratory sensation at each site of measurement was examined. In Experiment 2, the correlation between the body surface vibration and the vibratory sensation was similarly examined using seven types of noise stimuli composed of a 25-Hz tone and a 50-Hz tone. In both the experiments, we found that at the chest and the abdomen, the rating of the vibratory sensation was in close correlation with the vibration acceleration level (VAL of the body surface vibration measured at each corresponding location. This was consistent with our previous results and suggested that at the trunk of the body (the chest and the abdomen, the mechanoreception of body vibrations plays an important role in the experience of the vibratory sensation in persons exposed to high-level low-frequency noise. At the head, however, no close correlation was found between the rating of the vibratory sensation and the VAL of body surface vibration. This suggested that at the head, the perceptual mechanisms of vibration induced by high-level low-frequency noise were different from those in the trunk of the body.
Stochastic Response of Energy Balanced Model for Vortex-Induced Vibration
DEFF Research Database (Denmark)
Nielsen, Søren R.K.; Krenk, S.
of lightly damped structures are found on two branches, with the highest amplification branch on the low-frequency branch. The effect free wind turbulence is to destabilize the vibrations on the high amplification branch, thereby reducing the oscillation amplitude. The effect is most pronounced for very...
Estimation of Oil Production Rates in Reservoirs Exposed to Focused Vibrational Energy
Jeong, Chanseok; Kallivokas, Loukas F.; Huh, Chun; Lake, Larry W.
2014-01-01
the production rate of remaining oil from existing oil fields. To date, there are few theoretical studies on estimating how much bypassed oil within an oil reservoir could be mobilized by such vibrational stimulation. To fill this gap, this paper presents a
Levelized Cost of Energy of the Weptos wave energy converter
DEFF Research Database (Denmark)
Pecher, Arthur; Kofoed, Jens Peter
This report presents the cost of energy calculations of a wave energy array of 90 MW, consisting of 25 x 3.6 MW Weptos wave energy converters. The calculation has been made in analogy with a publically available document presented by the UK government, covering the case of a similar size wind...
Energy Technology Data Exchange (ETDEWEB)
Boda, Łukasz, E-mail: lboda@chemia.uj.edu.pl; Boczar, Marek; Gług, Maciej; Wójcik, Marek J. [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków (Poland)
2015-11-28
Interaction energies, molecular structure and vibrational frequencies of the binary complex formed between H(D)Cl and dimethyl ether have been obtained using quantum-chemical methods. Equilibrium and vibrationally averaged structures, harmonic and anharmonic wavenumbers of the complex and its deuterated isotopomer were calculated using harmonic and anharmonic second-order perturbation theory procedures with Density Functional Theory B3LYP and B2PLYP-D and ab initio Møller-Plesset second-order methods, and a 6-311++G(3d,3p) basis set. A phenomenological model describing anharmonic-type vibrational couplings within hydrogen bonds was developed to explain the unique broadening and fine structure, as well as the isotope effect of the Cl–H and Cl–D stretching IR absorption bands in the gaseous complexes with dimethyl ether, as an effect of hydrogen bond formation. Simulations of the rovibrational structure of the Cl–H and Cl–D stretching bands were performed and the results were compared with experimental spectra.
International Nuclear Information System (INIS)
Blix, A.S.; Lentfer, J.W.
1992-01-01
Petroleum exploration and development are occurring in various locations in the Arctic, where there are important denning sites for polar bears. Petroleum activities usually coincide with winter denning activities by bears, who may abandon dens if subject to prolonged annoyance. A study was carried out to measure noise and vibration levels in artificial polar bear dens at Prudhoe's Bar, Alaska, resulting from seismic testing, drilling and transport. A microphone and an accelerometer were frozen to the floor of the dens, with leads passed through a consolidated snow filled entrance to a truck, tent or helicopter. Tests were carried out on land, sea ice, and next to a drilling tower on an artificial island, which was also used to measure noise levels resulting from a helicopter taking off. It was concluded that the dry and wind-beaten arctic snow muffles both sound and vibration extremely well, and it is unlikely that polar bears in their dens will be disturbed by the type of petroleum-related activities measured, provided they do not take place within 100 m of the dens. 8 refs., 7 figs., 1 tab
Zhao, Zhiqiang; Chen, Jun; Zhang, Zhaojun; Zhang, Dong H.; Wang, Xiao-Gang; Carrington, Tucker; Gatti, Fabien
2018-02-01
Quantum mechanical calculations of ro-vibrational energies of CH4, CHD3, CH3D, and CH3F were made with two different numerical approaches. Both use polyspherical coordinates. The computed energy levels agree, confirming the accuracy of the methods. In the first approach, for all the molecules, the coordinates are defined using three Radau vectors for the CH3 subsystem and a Jacobi vector between the remaining atom and the centre of mass of CH3. Euler angles specifying the orientation of a frame attached to CH3 with respect to a frame attached to the Jacobi vector are used as vibrational coordinates. A direct product potential-optimized discrete variable vibrational basis is used to build a Hamiltonian matrix. Ro-vibrational energies are computed using a re-started Arnoldi eigensolver. In the second approach, the coordinates are the spherical coordinates associated with four Radau vectors or three Radau vectors and a Jacobi vector, and the frame is an Eckart frame. Vibrational basis functions are products of contracted stretch and bend functions, and eigenvalues are computed with the Lanczos algorithm. For CH4, CHD3, and CH3D, we report the first J > 0 energy levels computed on the Wang-Carrington potential energy surface [X.-G. Wang and T. Carrington, J. Chem. Phys. 141(15), 154106 (2014)]. For CH3F, the potential energy surface of Zhao et al. [J. Chem. Phys. 144, 204302 (2016)] was used. All the results are in good agreement with experimental data.
Zhao, Zhiqiang; Chen, Jun; Zhang, Zhaojun; Zhang, Dong H; Wang, Xiao-Gang; Carrington, Tucker; Gatti, Fabien
2018-02-21
Quantum mechanical calculations of ro-vibrational energies of CH 4 , CHD 3 , CH 3 D, and CH 3 F were made with two different numerical approaches. Both use polyspherical coordinates. The computed energy levels agree, confirming the accuracy of the methods. In the first approach, for all the molecules, the coordinates are defined using three Radau vectors for the CH 3 subsystem and a Jacobi vector between the remaining atom and the centre of mass of CH 3 . Euler angles specifying the orientation of a frame attached to CH 3 with respect to a frame attached to the Jacobi vector are used as vibrational coordinates. A direct product potential-optimized discrete variable vibrational basis is used to build a Hamiltonian matrix. Ro-vibrational energies are computed using a re-started Arnoldi eigensolver. In the second approach, the coordinates are the spherical coordinates associated with four Radau vectors or three Radau vectors and a Jacobi vector, and the frame is an Eckart frame. Vibrational basis functions are products of contracted stretch and bend functions, and eigenvalues are computed with the Lanczos algorithm. For CH 4 , CHD 3 , and CH 3 D, we report the first J > 0 energy levels computed on the Wang-Carrington potential energy surface [X.-G. Wang and T. Carrington, J. Chem. Phys. 141(15), 154106 (2014)]. For CH 3 F, the potential energy surface of Zhao et al. [J. Chem. Phys. 144, 204302 (2016)] was used. All the results are in good agreement with experimental data.
Estimating the vibration level of an L-shaped beam using power flow techniques
Cuschieri, J. M.; Mccollum, M.; Rassineux, J. L.; Gilbert, T.
1986-01-01
The response of one component of an L-shaped beam, with point force excitation on the other component, is estimated using the power flow method. The transmitted power from the source component to the receiver component is expressed in terms of the transfer and input mobilities at the excitation point and the joint. The response is estimated both in narrow frequency bands, using the exact geometry of the beams, and as a frequency averaged response using infinite beam models. The results using this power flow technique are compared to the results obtained using finite element analysis (FEA) of the L-shaped beam for the low frequency response and to results obtained using statistical energy analysis (SEA) for the high frequencies. The agreement between the FEA results and the power flow method results at low frequencies is very good. SEA results are in terms of frequency averaged levels and these are in perfect agreement with the results obtained using the infinite beam models in the power flow method. The narrow frequency band results from the power flow method also converge to the SEA results at high frequencies. The advantage of the power flow method is that detail of the response can be retained while reducing computation time, which will allow the narrow frequency band analysis of the response to be extended to higher frequencies.
International Nuclear Information System (INIS)
Sim, Kyuho; Park, Jisu; Jang, Seon-Jun
2015-01-01
This paper proposes a floating-type wave energy conversion system that consists of a mechanical part (yo-yo vibrating system, motion rectifying system, and power transmission system) and electrical part (power generation system). The yo-yo vibrating system, which converts translational input to rotational motion, is modeled as a single degree-of-freedom system. It can amplify the wave input via the resonance phenomenon and enhance the energy conversion efficiency. The electromechanical model is established from impedance matching of the mechanical part to the electrical system. The performance was analyzed at various wave frequencies and damping ratios for a wave input acceleration of 0.14 g. The maximum output occurred at the resonance frequency and optimal load resistance, where the power conversion efficiency and electrical output power reached 48% and 290 W, respectively. Utilizing the resonance phenomenon was found to greatly enhance the performance of the wave energy converter, and there exists a maximum power point at the optimum load resistance
Directory of Open Access Journals (Sweden)
Eduard Dechant
2017-12-01
Full Text Available Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs. The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.
Energy Technology Data Exchange (ETDEWEB)
Sim, Kyuho; Park, Jisu [Seoul National University, Seoul (Korea, Republic of); Jang, Seon-Jun [Innovation KR, Seoul (Korea, Republic of)
2015-01-15
This paper proposes a floating-type wave energy conversion system that consists of a mechanical part (yo-yo vibrating system, motion rectifying system, and power transmission system) and electrical part (power generation system). The yo-yo vibrating system, which converts translational input to rotational motion, is modeled as a single degree-of-freedom system. It can amplify the wave input via the resonance phenomenon and enhance the energy conversion efficiency. The electromechanical model is established from impedance matching of the mechanical part to the electrical system. The performance was analyzed at various wave frequencies and damping ratios for a wave input acceleration of 0.14 g. The maximum output occurred at the resonance frequency and optimal load resistance, where the power conversion efficiency and electrical output power reached 48% and 290 W, respectively. Utilizing the resonance phenomenon was found to greatly enhance the performance of the wave energy converter, and there exists a maximum power point at the optimum load resistance.
Xu, Yao; Leitner, David M
2014-07-17
We calculate communication maps for green fluorescent protein (GFP) to elucidate energy transfer pathways between the chromophore and other parts of the protein in the ground and excited state. The approach locates energy transport channels from the chromophore to remote regions of the protein via residues and water molecules that hydrogen bond to the chromophore. We calculate the thermal boundary conductance between GFP and water over a wide range of temperature and find that the interface between the protein and the cluster of water molecules in the β-barrel poses negligible resistance to thermal flow, consistent with facile vibrational energy transfer from the chromophore to the β-barrel waters observed in the communication maps.
Vibrational lifetimes of protein amide modes
International Nuclear Information System (INIS)
Peterson, K.A.; Rella, C.A.
1995-01-01
Measurement of the lifetimes of vibrational modes in proteins has been achieved with a single frequency infrared pump-probe technique using the Stanford Picosecond Free-electron Laser, These are the first direct measurements of vibrational dynamics in the polyamide structure of proteins. In this study, modes associated with the protein backbone are investigated. Results for the amide I band, which consists mainly of the stretching motion of the carbonyl unit of the amide linkage, show that relaxation from the first vibrational excited level (v=1) to the vibrational ground state (v=0) occurs within 1.5 picoseconds with apparent first order kinetics. Comparison of lifetimes for myoglobin and azurin, which have differing secondary structures, show a small but significant difference. The lifetime for the amide I band of myoglobin is 300 femtoseconds shorter than for azurin. Further measurements are in progress on other backbone vibrational modes and on the temperature dependence of the lifetimes. Comparison of vibrational dynamics for proteins with differing secondary structure and for different vibrational modes within a protein will lead to a greater understanding of energy transfer and dissipation in biological systems. In addition, these results have relevance to tissue ablation studies which have been conducted with pulsed infrared lasers. Vibrational lifetimes are necessary for calculating the rate at which the energy from absorbed infrared photons is converted to equilibrium thermal energy within the irradiated volume. The very fast vibrational lifetimes measured here indicate that mechanisms which involve direct vibrational up-pumping of the amide modes with consecutive laser pulses, leading to bond breakage or weakening, are not valid
International Nuclear Information System (INIS)
Sato, T; Masuda, A; Sanada, T
2015-01-01
This paper presents an experimental verification of a self-excitation control of a resonance- type vibration energy harvester with a Duffing-type nonlinearity which is designed to perform effectively in a wide frequency range. For the conventional linear vibration energy harvester, the performance of the power generation at the resonance frequency and the bandwidth of the resonance peak are trade-off. The resonance frequency band can be expanded by introducing a Duffing-type nonlinear oscillator in order to enable the harvester to generate larger electric power in a wider frequency range. However, since such nonlinear oscillator can have multiple stable steady-state solutions in the resonance band, it is difficult for the nonlinear harvester to maintain the high performance of the power generation constantly. The principle of self-excitation and entrainment has been utilized to provide the global stability to the highest-energy solution by destabilizing other unexpected lower-energy solutions by introducing a switching circuit of the load resistance between positive and the negative values depending on the response amplitude of the oscillator. It has been experimentally validated that this control law imparts the self-excitation capability to the oscillator to show an entrainment into the highest-energy solution. (paper)
Simple Levelized Cost of Energy (LCOE) Calculator Documentation | Energy
;M, performance and fuel costs. Note that this doesn't include financing issues, discount issues ). This means that the LCOE is the minimum price at which energy must be sold for an energy project to the balance between debt-financing and equity-financing, and an assessment of the financial risk
Dynamic vibrations in wind energy systems: Application to vertical axis wind turbine
Mabrouk, Imen Bel; El Hami, Abdelkhalak; Walha, Lassâad; Zghal, Bacem; Haddar, Mohamed
2017-02-01
Dynamic analysis of Darrieus turbine bevel spur gear subjected to transient aerodynamic loads is carried out in the present study. The aerodynamic torque is obtained by solving the two dimensional unsteady incompressible Navies Stocks equation with the k-ω shear stress transport turbulence model. The results are presented for several values of tip speed ratio. The two-dimensional Computational Fluid Dynamics model is validated with experimental results. The optimum tip speed ratio is achieved, giving the best overall performance. In this study, we developed a lamped mass dynamic model with 14 degrees of freedom. This model is excited by external and internal issues sources. The main factors of these excitations are the periodic fluctuations of the gear meshes' stiffness and the unsteady aerodynamic torque oscillations. The vibration responses are obtained in time and frequency domains. The originality of our work is the correlation between the complexity of the aerodynamic phenomenon and the non-stationary dynamics vibration of the mechanical gearing system. The effect of the rotational speed on the dynamic behavior of the Darrieus turbine is also discussed. The present study shows that the variation of rotor rotational speed directly affects the torque production. However, there is a small change in the dynamic vibration of the studied gearing system.
Vibrational spectroscopy in the electron microscope.
Krivanek, Ondrej L; Lovejoy, Tracy C; Dellby, Niklas; Aoki, Toshihiro; Carpenter, R W; Rez, Peter; Soignard, Emmanuel; Zhu, Jiangtao; Batson, Philip E; Lagos, Maureen J; Egerton, Ray F; Crozier, Peter A
2014-10-09
Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage.
Matching renewable energy systems to village-level energy needs
Energy Technology Data Exchange (ETDEWEB)
Ashworth, J.H.; Neuendorffer, J.W.
1980-06-01
This report provides a five step process for matching alternative renewable energy technologies with energy needs in rural villages of developing countries. Analytic tools are given for each of the five steps as well as information that can be expected. Twelve characterization criteria are developed to assist in the matching process. Three of these criteria, called discrimination criteria, are used for preliminary screening of technology possibilities for each need. The other criteria address site-specific temporal, climatic, social, cultural, and environmental characteristics of the energy need, technology, and cost considerations. To illustrate the matching process, seven basic human needs for energy are matched with seven potential renewable energy technologies. The final portion of the paper discusses the advantages of such a matching process and the resources required to initiate such an effort within a development project. Specific recommendations are given for field-testing this process and actions that could be taken immediately in basic research and development, applied research and technology modification, demonstrations, and commercialization to assist in the future diffusion of renewable energy technologies to rural areas of developing countries.
Homayoon, Zahra
2014-09-28
A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO(+)(H2O) cluster is reported. The PES is based on fitting of roughly 32,000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO(+)(H2O) and NO(+)(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO(+)(H2O) and NO(+)(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO(+)(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.
Homayoon, Zahra
2014-09-01
A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO+(H2O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO+(H2O) and NO+(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO+(H2O) and NO+(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO+(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.
Energy Technology Data Exchange (ETDEWEB)
Homayoon, Zahra, E-mail: zhomayo@emory.edu [Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322 (United States)
2014-09-28
A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO{sup +}(H{sub 2}O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO{sup +}(H{sub 2}O) and NO{sup +}(D{sub 2}O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO{sup +}(H{sub 2}O) and NO{sup +}(D{sub 2}O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO{sup +}(H{sub 2}O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water “antisymmetric” stretching mode with the low-frequency intermolecular modes results in intensity borrowing.
International Nuclear Information System (INIS)
Homayoon, Zahra
2014-01-01
A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO + (H 2 O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO + (H 2 O) and NO + (D 2 O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO + (H 2 O) and NO + (D 2 O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO + (H 2 O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water “antisymmetric” stretching mode with the low-frequency intermolecular modes results in intensity borrowing
International Nuclear Information System (INIS)
Bellum, J.C.; McGuire, P.
1983-01-01
We investigate forms of the molecular system Hamiltonian valid for rigorous quantum-mechanical treatments of inelastic atom--diatom collisions characterized by exchange of energy between electronic, vibrational, and rotational degrees of freedom. We analyze this Hamiltonian in terms of various choices of independent coordinates which unambiguously specify the electronic and nuclear positions in the context of space-fixed and body-fixed reference frames. In particular we derive forms of the Hamiltonian in the context of the following four sets of independent coordinates: (1) a so-called space-fixed set, in which both electronic and nuclear positions are relative to the space-fixed frame; (2) a so-called mixed set, in which nuclear positions are relative to the body-fixed frame while electronic positions are relative to the space-fixed frame; (3) a so-called body-fixed set, in which both electronic and nuclear positions are relative to the body-fixed frame; and (4) another mixed set, in which nuclear positions are relative to the space-fixed frame while electronic positions are relative to the body-fixed frame. Based on practical considerations in accounting for electronic structure and nonadiabatic coupling of electronic states of the collision complex we find the forms of the Hamiltonian in the context of coordinate sets (3) and (4) above to be most appropriate, respectively, for body-fixed and space-fixed treatments of nuclear dynamics in collisional transfer of electronic, vibrational, and rotational energies
Golibrzuch, Kai; Shirhatti, Pranav R; Altschäffel, Jan; Rahinov, Igor; Auerbach, Daniel J; Wodtke, Alec M; Bartels, Christof
2013-09-12
Translational motion is believed to be a spectator degree of freedom in electronically nonadiabatic vibrational energy transfer between molecules and metal surfaces, but the experimental evidence available to support this view is limited. In this work, we have experimentally determined the translational inelasticity in collisions of NO molecules with a single-crystal Au(111) surface-a system with strong electronic nonadiabaticity. State-to-state molecular beam surface scattering was combined with an IR-UV double resonance scheme to obtain high-resolution time-of-flight data. The measurements include vibrationally elastic collisions (v = 3→3, 2→2) as well as collisions where one or two quanta of molecular vibration are excited (2→3, 2→4) or de-excited (2→1, 3→2, 3→1). In addition, we have carried out comprehensive measurements of the effects of rotational excitation on the translational energy of the scattered molecules. We find that under all conditions of this work, the NO molecules lose a large fraction (∼0.45) of their incidence translational energy to the surface. Those molecules that undergo vibrational excitation (relaxation) during the collision recoil slightly slower (faster) than vibrationally elastically scattered molecules. The amount of translational energy change depends on the surface temperature. The translation-to-rotation coupling, which is well-known for v = 0→0 collisions, is found to be significantly weaker for vibrationally inelastic than elastic channels. Our results clearly show that the spectator view of the translational motion in electronically nonadiabatic vibrational energy transfer between NO and Au(111) is only approximately correct.
Estimating Solar Energy Potential in Buildings on a Global Level
DEFF Research Database (Denmark)
Petrichenko, Ksenia
2015-01-01
This chapter contributes to the debate around net-zero energy concept from a global perspective. By means of comprehensive modelling, it analyses how much global building energy consumption could be reduced through utilisation of building-integrated solar energy technologies and energy......-efficiency improvements. Valuable insights on the locations and building types, in which it is feasible to achieve a net-zero level of energy performance through solar energy utilisation, are presented in world maps....
Low energy level density and surface instabilities in heavy transition nuclei
International Nuclear Information System (INIS)
Wieclawik, W. de; Foucher, R.; Dionisio, J.S.; Vieu, C.; Hoglund, A.; Watzig, W.
1975-01-01
A statistical analysis of Au, Pt, Hg nuclear levels was performed with Ericson's method. The odd mass gold experimental number of levels distributions are compared to the theoretical distributions corresponding to vibrational (Alaga and Kisslinger-Sorensen) and rotational (Stephens, Meyer-ter-Vehn) models. The Alaga model gives the most complete description of 193 Au, 195 Au levels and fits the lowest part of Gilbert-Cameron high energy distributions (deduced from the statistical model and neutron capture data). The Ericson's method shows other interesting features of Pt and Hg isotopes (i.e. level density dependence on nuclear shape and pairing correlations, evidence for phase transitions). Consequently, this method is a useful tool for guiding experimental as well as theoretical investigations of transition nuclei [fr
Nuclear energy levels and elementary particles
International Nuclear Information System (INIS)
de Wet, J.A.
1982-01-01
Considering only exchange forces, the binding energies and excited states of nuclei up to 24 Mg are predicted to within charge independence, and there is no reason why the model should not be extended to cover all of the elements. A comparison of theory with experiment shows that the energy of one exchange is 2.56 MeV. Moreover, there is an attractive well of depth 30 MeV, corresponding to the helium nucleus. before exchange forces become operative. A possible explanation of the origin of mesons is also presented
Cost optimal levels for energy performance requirements
DEFF Research Database (Denmark)
Thomsen, Kirsten Engelund; Aggerholm, Søren; Kluttig-Erhorn, Heike
This report summarises the work done within the Concerted Action EPBD from December 2010 to April 2011 in order to feed into the European Commission's proposal for a common European procedure for a Cost-Optimal methodology under the Directive on the Energy Performance of Buildings (recast) 2010/3...
International Nuclear Information System (INIS)
Kim, Jae Eum
2014-01-01
DC electrical outputs of a piezoelectric vibration energy harvester by nonlinear rectifying circuitry can hardly be obtained either by any mathematical models developed so far or by finite element analysis. To address the issue, this work used an equivalent electrical circuit model and newly developed an algorithm to efficiently identify relevant circuit parameters of arbitrarily-shaped cantilevered piezoelectric energy harvesters. The developed algorithm was then realized as a dedicated software module by adopting ANSYS finite element analysis software for the parameters identification and the Tcl/Tk programming language for a graphical user interface and linkage with ANSYS. For verifications, various AC electrical outputs by the developed software were compared with those by traditional finite element analysis. DC electrical outputs through rectifying circuitry were also examined for varying values of the smoothing capacitance and load resistance.
Energy Technology Data Exchange (ETDEWEB)
Kim, Jae Eum [Catholic University of Daegu, Gyeongsan (Korea, Republic of)
2014-10-15
DC electrical outputs of a piezoelectric vibration energy harvester by nonlinear rectifying circuitry can hardly be obtained either by any mathematical models developed so far or by finite element analysis. To address the issue, this work used an equivalent electrical circuit model and newly developed an algorithm to efficiently identify relevant circuit parameters of arbitrarily-shaped cantilevered piezoelectric energy harvesters. The developed algorithm was then realized as a dedicated software module by adopting ANSYS finite element analysis software for the parameters identification and the Tcl/Tk programming language for a graphical user interface and linkage with ANSYS. For verifications, various AC electrical outputs by the developed software were compared with those by traditional finite element analysis. DC electrical outputs through rectifying circuitry were also examined for varying values of the smoothing capacitance and load resistance.
International Nuclear Information System (INIS)
Jung, Hyung-Jo; Kim, In-Ho; Jang, Seon-Jun
2011-01-01
This paper proposes an electromagnetic energy harvesting system, which utilizes the wind-induced vibration of a stay cable, and investigates its feasibility for powering a wireless sensor node on the cable through numerical simulations as well as experimental tests. To this end, the ambient acceleration responses of a stay cable installed in an in-service cable-stayed bridge are measured, and then they are used as input excitations in cases of both numerical simulations and experimental tests to evaluate the performance of the proposed energy harvesting system. The results of the feasibility test demonstrate that the proposed system generates sufficient electricity for operation of a wireless sensor node attached on the cable under the moderate wind conditions
Chen, Wen-Chyuan; Chen, Yi-Ming; Huang, Chi-Chang; Tzeng, Yen-Dun
2016-01-01
Dehydroepiandrosterone (DHEA), the most abundant sex steroid, is primarily secreted by the adrenal gland and a precursor hormone used by athletes for performance enhancement. Whole-body vibration (WBV) is a well-known light-resistance exercise by automatic adaptations to rapid and repeated oscillations from a vibrating platform, which is also a simple and convenient exercise for older adults. However, the potential effects of DHEA supplementation combined with WBV training on to body composition, exercise performance, and hormone regulation are currently unclear. The objective of the study is to investigate the effects of DHEA supplementation combined with WBV training on body composition, exercise performance, and physical fatigue-related biochemical responses and testosterone content in young-adult C57BL/6 mice. In this study, male C57BL/6 mice were divided into four groups (n = 8 per group) for 6-weeks treatment: sedentary controls with vehicle (SC), DHEA supplementation (DHEA, 10.2 mg/kg), WBV training (WBV; 5.6 Hz, 2 mm, 0.13 g), and WBV training with DHEA supplementation (WBV+DHEA; WBV: 5.6 Hz, 2 mm, 0.13 g and DHEA: 10.2 mg/kg). Exercise performance was evaluated by forelimb grip strength and exhaustive swimming time, as well as changes in body composition and anti-fatigue levels of serum lactate, ammonia, glucose, creatine kinase (CK), and blood urea nitrogen (BUN) after a 15-min swimming exercise. In addition, the biochemical parameters and the testosterone content were measured at the end of the experiment. Six-week DHEA supplementation alone significantly increased mice body weight (BW), muscle weight, testosterone level, and glycogen contents (liver and muscle) when compared with SC group. DHEA supplementation alone had no negative impact on all tissue and biochemical profiles, but could not improve exercise performance. However, WBV+DHEA supplementation also significantly decreased BW, testosterone level and glycogen content of liver, as well as serum
Vibration-based energy harvesting with piezoelectrets having high d{sub 31} activity
Energy Technology Data Exchange (ETDEWEB)
Zhang, X. [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); School of Physics Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092 (China); Pondrom, P. [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); System Reliability and Machine Acoustics SzM, Technische Universität Darmstadt, Magdalenenstr. 4, 64289 Darmstadt (Germany); Wu, L. [School of Physics Science and Engineering, Tongji University, Siping Road 1239, Shanghai 200092 (China); Sessler, G. M., E-mail: g.sessler@nt.tu-darmstadt.de [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany)
2016-05-09
Sandwiched fluoroethylene propylene films with charged, parallel-tunnel voids between the layers, which exhibit high d{sub 31} piezoelectric activity, were designed. Stripes of such piezoelectrets were exposed to mechanical stress in length direction by a seismic mass excited to vibrations. Due to the piezoelectricity of the films, a current in a terminating resistor is generated. The harvested power across the resistor amounts to about 0.2 mW for a seismic mass of 2 g and an acceleration of 1 g. In comparison with other piezoelectret or with poly(vinylidene fluoride) harvesters, the generated power referred to equal acceleration and force, is significantly larger.
International Nuclear Information System (INIS)
Cady, W.A.; Clark, A.P.; Dickinson, A.S.
1975-01-01
Recently a near-adiabatic (perturbed stationary states) approximation was used in an investigation the collinear vibrational excitation of a harmonic oscillator. This approximation reduced the problem to that of obtaining transition probabilities for a harmonic oscillator with time-dependent forcing function. Cady derived an apparently exact solution for this problem. It is shown that this solution is not exact but that the solution results from making a further adiabatic approximation and a derivation is given that clearly shows the adiabatic character of this further approximation
Monge-Palacios, M; Corchado, J C; Espinosa-Garcia, J
2012-05-28
A detailed state-to-state dynamics study was performed to analyze the effects of vibrational excitation and translational energy on the dynamics of the Cl((2)P) + NH(3)(v) gas-phase reaction, effects which are connected to such issues as mode selectivity and Polanyi's rules. This reaction evolves along two deep wells in the entry and exit channels. At low and high collision energies quasi-classical trajectory calculations were performed on an analytical potential energy surface previously developed by our group, together with a simplified model surface in which the reactant well is removed to analyze the influence of this well. While at high energy the independent vibrational excitation of all NH(3)(v) modes increases the reactivity by a factor ≈1.1-2.9 with respect to the vibrational ground-state, at low energy the opposite behaviour is found (factor ≈ 0.4-0.9). However, when the simplified model surface is used at low energy the independent vibrational excitation of all NH(3)(v) modes increases the reactivity, showing that the behaviour at low energies is a direct consequence of the existence of the reactant well. Moreover, we find that this reaction exhibits negligible mode selectivity, first because the independent excitation of the N-H symmetric and asymmetric stretch modes, which lie within 200 cm(-1) of each other, leads to reactions with similar reaction probabilities, and second because the vibrational excitation of the reactive N-H stretch mode is only partially retained in the products. For this "late transition-state" reaction, we also find that vibrational energy is more effective in driving the reaction than an equivalent amount of energy in translation, consistent with an extension of Polanyi's rules. Finally, we find that the non-reactive events, Cl((2)P)+NH(3)(v) → Cl((2)P) + NH(3)(v'), lead to a great number of populated vibrational states in the NH(3)(v') product, even starting from the NH(3)(v = 0) vibrational ground state at low energies
Directory of Open Access Journals (Sweden)
Wan Sun
2015-01-01
Full Text Available This study focuses on the design, simulation, and load power optimization for the development of a novel frequency-tunable electromagnetic vibrational energy harvester. The unique characteristic of a magnetorheological elastomer (MRE is utilized, that the shear modulus can be varied by changing the strength of an applied magnetic field. The electromagnetic energy harvester is fabricated, the external electric circuit is connected, and the performance is evaluated through a series of experiments. The resonant frequencies and the parasitic damping constant are measured experimentally for different tuning magnet gap distances, which validate the application of the MRE to the development of a frequency-tunable energy harvesting system. The harvested energy of the system is measured by the voltage across the load resistor. The maximum load power is attained by optimizing the external circuit connected to the coil system. The analysis results are presented for harvesting the maximum load power in terms of the coil parameters and external circuit resistance. The optimality of the load resistance is validated by comparing the analytical results with experimental results. The optimal load resistances under various resonance frequencies are also found for the design and composition of the optimal energy harvesting circuit of the energy harvester system.
Sutradhar, S.; Samanta, B. R.; Samanta, A. K.; Reisler, H.
2017-07-01
The 205-230 nm photodissociation of vibrationally excited CO2 at temperatures up to 1800 K was studied using Resonance Enhanced Multiphoton Ionization (REMPI) and time-sliced Velocity Map Imaging (VMI). CO2 molecules seeded in He were heated in an SiC tube attached to a pulsed valve and supersonically expanded to create a molecular beam of rotationally cooled but vibrationally hot CO2. Photodissociation was observed from vibrationally excited CO2 with internal energies up to about 20 000 cm-1, and CO(X1Σ+), O(3P), and O(1D) products were detected by REMPI. The large enhancement in the absorption cross section with increasing CO2 vibrational excitation made this investigation feasible. The internal energies of heated CO2 molecules that absorbed 230 nm radiation were estimated from the kinetic energy release (KER) distributions of CO(X1Σ+) products in v″ = 0. At 230 nm, CO2 needs to have at least 4000 cm-1 of rovibrational energy to absorb the UV radiation and produce CO(X1Σ+) + O(3P). CO2 internal energies in excess of 16 000 cm-1 were confirmed by observing O(1D) products. It is likely that initial absorption from levels with high bending excitation accesses both the A1B2 and B1A2 states, explaining the nearly isotropic angular distributions of the products. CO(X1Σ+) product internal energies were estimated from REMPI spectroscopy, and the KER distributions of the CO(X1Σ+), O(3P), and O(1D) products were obtained by VMI. The CO product internal energy distributions change with increasing CO2 temperature, suggesting that more than one dynamical pathway is involved when the internal energy of CO2 (and the corresponding available energy) increases. The KER distributions of O(1D) and O(3P) show broad internal energy distributions in the CO(X1Σ+) cofragment, extending up to the maximum allowed by energy but peaking at low KER values. Although not all the observations can be explained at this time, with the aid of available theoretical studies of CO2 VUV
Energy security issues at household level in India
International Nuclear Information System (INIS)
Jain, Garima
2010-01-01
Energy security at the household level implies ensuring assured and regular supply of clean energy fuels at an affordable price for various household activities. Threat to physical availability of clean energy fuels for cooking and lighting is determined through various indicators such as dependence on traditional fuels and limited access to clean fuels. Energy insecurity translates into various adverse social impacts. Financial threat to energy security is indicated by expenses incurred on energy fuels and affordability of clean fuels. Households spend a major portion of their income on acquiring energy fuels; however, due to high price of clean fuels, they continue to depend on traditional and inefficient fuels. There is an urgent need to address factors that pose a threat to energy security at the household level. In this regard, measures taken by the government agencies and other institutions are also reviewed. The paper also suggests the regulatory and policy interventions required to address the energy security issues at the household level.
Fine-structure energy levels, oscillator strengths and lifetimes
Indian Academy of Sciences (India)
We have done relativistic calculations for the evaluation of energy levels, oscillator strengths, transition probabilities and lifetimes for Cr VIII ion. Use has been made of configuration interaction technique by including Briet–Pauli approximation. The energies of various levels from the ground state to excited levels of 3s3p6, ...
Kurouski, Dmitry; Dukor, Rina K; Lu, Xuefang; Nafie, Laurence A; Lednev, Igor K
2012-08-08
Fibrils are β-sheet-rich aggregates that are generally composed of several protofibrils and may adopt variable morphologies, such as twisted ribbons or flat-like sheets. This polymorphism is observed for many different amyloid associated proteins and polypeptides. In a previous study we proposed the existence of another level of amyloid polymorphism, namely, that associated with fibril supramolecular chirality. Two chiral polymorphs of insulin, which can be controllably grown by means of small pH variations, exhibit opposite signs of vibrational circular dichroism (VCD) spectra. Herein, using atomic force microscopy (AFM) and scanning electron microscopy (SEM), we demonstrate that indeed VCD supramolecular chirality is correlated not only by the apparent fibril handedness but also by the sense of supramolecular chirality from a deeper level of chiral organization at the protofilament level of fibril structure. Our microscopic examination indicates that normal VCD fibrils have a left-handed twist, whereas reversed VCD fibrils are flat-like aggregates with no obvious helical twist as imaged by atomic force microscopy or scanning electron microscopy. A scheme is proposed consistent with observed data that features a dynamic equilibrium controlled by pH at the protofilament level between left- and right-twist fibril structures with distinctly different aggregation pathways for left- and right-twisted protofilaments. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.
New energy level identifications in Kr VI
International Nuclear Information System (INIS)
Tauheed, A.; Pinnington, E.H.; Ansbacher, W.; Kernahan, J.A.
1990-01-01
Beam-foil delayed spectra from 89.0 to 101.0 nm are used to identify the intercombination lines connecting the 4s4p 2 4 P and 4s 2 4p 2 P levels in Kr VI. The existing analysis is extended to include the 4s 2 5s 2 S 1/2 , 4f 2 F 5/2 , 2 F 7/2 , 4p 3 2 D 3/2 , 2 D 5/2 , 2 P 3/2 , 4 S 3/2 and 4s4p 2 4 P 1/2 , 4 P 3/2 , 4 P 5/2 levels. Lifetime measurements for the 4s4p 2 4 P 1/2 , 4 P 5/2 , 4p 3 2 D 3/2 and 2 D 5/2 levels are also discussed in support of these assignments. (orig.)
International Nuclear Information System (INIS)
Kim, In-Ho; Jung, Hyung-Jo; Jang, Seon-Jun
2013-01-01
In this paper, an innovative strategy for improving the performance of a recently developed rotational energy harvester is proposed. Its performance can be considerably enhanced by replacing the electromagnetic induction part, consisting of moving permanent magnets and a fixed solenoid coil, with a moving mass and a rotational generator (i.e., an electric motor). The proposed system is easily tuned to the natural frequency of a target structure using the position change of a proof mass. Owing to the high efficiency of the rotational generator, the device can more effectively harness electrical energy from the wind-induced vibration of a stay cable. Also, this new configuration makes the device more compact and geometrically tunable. In order to validate the effectiveness of the new configuration, a series of laboratory and field tests are carried out with the prototype of the proposed device, which is designed and fabricated based on the dynamic characteristics of the vibration of a stay cable installed in an in-service cable-stayed bridge. From the field test, it is observed that the normalized output power of the proposed system is 35.67 mW (m s −2 ) −2 , while that of the original device is just 5.47 mW (m s −2 ) −2 . These results show that the proposed device generates much more electrical energy than the original device. Moreover, it is verified that the proposed device can generate sufficient electricity to power a wireless sensor node placed on a cable under gentle–moderate wind conditions. (paper)
Sugandi, Gandi; Mambu, Grace A.; Mulyadi, Dadang; Mulyana, Edi
2017-07-01
Planar spring as a mechanical resonator is very important in designing an electrodynamic vibration energy harvesting application (EVEH) to generate output power with high efficiency. Generally, component of the mechanical resonator is a cantilever beam that is designed using one cantilever with an inertial mass placed cantilever tip. In this study, a planar spring which has four arms cantilever beam was designed and fabricated using an extra-thin FR4-PCB material with a total thickness of 130 µm. There are four types of planar spring that were designed and fabricated in this research to produce resonant frequencies at about 30, 40, 50 and 60 Hz with 1 mm width cantilever arm and various length of 13.5, 11.2, 9.8 and 8.7 mm, respectively. FR4 resonator is fabricated using technology LASER-cutting in order to obtain results precisely. The resonant frequency generated by the mechanical resonator is characterized using vibrator system with certain acceleration. The resonant frequency of the planar spring was obtained at a frequency where the maximum induced voltage occurs. The resonant frequency generated by each type of planar spring was obtained at 24.81, 34.24, 40.2, and 46.8 Hz with three conditions of acceleration of 0.02, 0.06, and 0,1g (g=9.8 m/s2).
International Nuclear Information System (INIS)
Salvi, Jonathan; Giaralis, Agathoklis
2016-01-01
A novel dynamic vibration absorber (DVA) configuration is introduced for simultaneous vibration suppression and energy harvesting from oscillations typically exhibited by large-scale low-frequency engineering structures and structural components. The proposed configuration, termed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) comprises a mass grounded via an in-series electromagnetic motor (energy harvester)-inerter layout, and attached to the primary structure through linear spring and damper in parallel connection. The governing equations of motion are derived and solved in the frequency domain, for the case of harmonically-excited primary structures, here modelled as damped single-degree- of-freedom (SDOF) systems. Comprehensive parametric analyses proved that by varying the mass amplification property of the grounded inerter, and by adjusting the stiffness and the damping coefficients using simple optimum tuning formulae, enhanced vibration suppression (in terms of primary structure peak displacement) and energy harvesting (in terms of relative velocity at the terminals of the energy harvester) may be achieved concurrently and at nearresonance frequencies, for a fixed attached mass. Hence, the proposed EH-TMDI allows for relaxing the trade-off between vibration control and energy harvesting purposes, and renders a dual-objective optimisation a practically-feasible, reliable task. (paper)
Statistical interpretation of low energy nuclear level schemes
Energy Technology Data Exchange (ETDEWEB)
Egidy, T von; Schmidt, H H; Behkami, A N
1988-01-01
Nuclear level schemes and neutron resonance spacings yield information on level densities and level spacing distributions. A total of 75 nuclear level schemes with 1761 levels and known spins and parities was investigated. The A-dependence of level density parameters is discussed. The spacing distributions of levels near the groundstate indicate transitional character between regular and chaotic properties while chaos dominates near the neutron binding energy.
DEFF Research Database (Denmark)
Kuznetsov, A.M.; Ulstrup, Jens
2002-01-01
We present a new view and an analytical formalism of electron flow through a donor-acceptor molecule inserted between a pair of metal electrodes. The donor and acceptor levels are strongly coupled to an environmental nuclear continuum. The formalism applies to molecular donor-acceptor systems bot...
Lu, Y.; Cottone, F.; Boisseau, S.; Galayko, D.; Marty, F.; Basset, P.
2015-12-01
This paper reports for the first time a MEMS electrostatic vibration energy harvester (e-VEH) with corona-charged vertical electrets on its electrodes. The bandwidth of the 1-cm2 device is extended in low and high frequencies by nonlinear elastic stoppers. With a bias voltage of 46 V (electret@21 V + DC external source@25 V) between the electrodes, the RMS power of the device reaches 0.89 μW at 33 Hz and 6.6 μW at 428 Hz. The -3dB frequency band including the hysteresis is 223∼432 Hz, the one excluding the hysteresis 88∼166 Hz. We also demonstrate the charging of a 47 μF capacitor used for powering a wireless and autonomous temperature sensor node with a data transmission beyond 10 m at 868 MHz.
Jedidi, Abdesslem
2015-11-13
Vibrational fingerprints of small PtnP2n (n = 1–5) clusters were computed from their low-lying structures located from a global exploration of their DFT potential energy surfaces with the GSAM code. Five DFT methods were assessed from the CCSD(T) wavenumbers of PtP2 species and CCSD relative energies of Pt2P4 structures. The eight first PtnP2n isomers found are reported. The vibrational computations reveal (i) the absence of clear signatures made by overtone or combination bands due to very weak mechanical and electrical anharmonicities and (ii) some significant and recurrent vibrational fingerprints in correlation with the different PP bonding situations in the PtnP2n structures.
Jedidi, Abdesslem; Li, Rui; Fornasiero, Paolo; Cavallo, Luigi; Carbonniere, Philippe
2015-01-01
Vibrational fingerprints of small PtnP2n (n = 1–5) clusters were computed from their low-lying structures located from a global exploration of their DFT potential energy surfaces with the GSAM code. Five DFT methods were assessed from the CCSD(T) wavenumbers of PtP2 species and CCSD relative energies of Pt2P4 structures. The eight first PtnP2n isomers found are reported. The vibrational computations reveal (i) the absence of clear signatures made by overtone or combination bands due to very weak mechanical and electrical anharmonicities and (ii) some significant and recurrent vibrational fingerprints in correlation with the different PP bonding situations in the PtnP2n structures.
Directory of Open Access Journals (Sweden)
X.Z. Jiang
2014-07-01
Full Text Available Over the past few decades, wireless sensor networks have been widely used in the field of structure health monitoring of civil, mechanical, and aerospace systems. Currently, most wireless sensor networks are battery-powered and it is costly and unsustainable for maintenance because of the requirement for frequent battery replacements. As an attempt to address such issue, this article theoretically and experimentally studies a compression-based piezoelectric energy harvester using a multilayer stack configuration, which is suitable for civil infrastructure system applications where large compressive loads occur, such as heavily vehicular loading acting on pavements. In this article, we firstly present analytical and numerical modeling of the piezoelectric multilayer stack under axial compressive loading, which is based on the linear theory of piezoelectricity. A two-degree-of-freedom electromechanical model, considering both the mechanical and electrical aspects of the proposed harvester, was developed to characterize the harvested electrical power under the external electrical load. Exact closed-form expressions of the electromechanical models have been derived to analyze the mechanical and electrical properties of the proposed harvester. The theoretical analyses are validated through several experiments for a test prototype under harmonic excitations. The test results exhibit very good agreement with the analytical analyses and numerical simulations for a range of resistive loads and input excitation levels.
Comparing energy levels in isotropic and anisotropic potentials
Energy Technology Data Exchange (ETDEWEB)
Pikovski, Alexander, E-mail: alexander.pikovski@colorado.edu
2015-11-06
Qualitative information about the quantized energy levels of a system can be of great value. We study the relationship between the bound-state energies of an anisotropic potential and those of its spherical average. It is shown that the two ground-state energies satisfy an inequality, and there is a similar inequality for the first excited states. - Highlights: • Quantized energy levels in an arbitrary non-central potential are studied. • We derive inequalities between energies in a potential and its spherical average. • The results hold in three and two dimensions for any ground state and, with additional symmetry requirements for the first excited state.
Comparing energy levels in isotropic and anisotropic potentials
International Nuclear Information System (INIS)
Pikovski, Alexander
2015-01-01
Qualitative information about the quantized energy levels of a system can be of great value. We study the relationship between the bound-state energies of an anisotropic potential and those of its spherical average. It is shown that the two ground-state energies satisfy an inequality, and there is a similar inequality for the first excited states. - Highlights: • Quantized energy levels in an arbitrary non-central potential are studied. • We derive inequalities between energies in a potential and its spherical average. • The results hold in three and two dimensions for any ground state and, with additional symmetry requirements for the first excited state.
Wei, Qiu-Shi; Huang, Li; Chen, Xian-Hong; Wang, Hai-Bin; Sun, Wei-Shan; Huo, Shao-Chuan; Li, Zi-Qi; Deng, Wei-Min
2014-01-01
Studies have reported that whole body vibration (WBV) played a vital role in bone remodeling. Circulating serotonin is also involved in negative regulating bone mass in rodents and humans. However, both WBV and inhibition of serotonin biosynthesis may suppress receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclastogenesis in vitro. The purpose of the current study was to investigate the effect of WBV therapy on the levels of serum serotonin in ovariectomized rats. Thirty-six-month-old female Sprague Dawley rats weighing 276.15±37.75 g were ovariectomized to induce osteoporosis, and another ten rats underwent sham operation to establish sham control (SHAM) group. After 3 months, ovariectomized rats were divided into three subgroups and then separately treated with WBV, Alendronate (ALN) and normal saline (OVX), SHAM group was given normal saline. After 6 weeks of treatment, rats were sacrificed. Serum serotonin, RANKL, bone turnover markers, and bone mineral density (BMD), bone strength were evaluated. The serum serotonin level was significantly lower in WBV group than OVX and ALN groups (P<0.05 and P<0.001). RANKL levels significantly decreased in WBV and ALN groups compared to OVX group (P<0.001 for both). BMD and biomechanical parameters of femur significantly increased (P<0.05 for both) and bone turnover levels decreased (P<0.001 for both) in WBV group compared to OVX group. These data indicated that WBV enhanced the bone strength and BMD in ovariectomized rats most likely by reducing the levels of circulating serotonin.
Energy Technology Data Exchange (ETDEWEB)
Fujihashi, Yuta; Ishizaki, Akihito, E-mail: ishizaki@ims.ac.jp [Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585 (Japan); Fleming, Graham R. [Department of Chemistry, University of California, Berkeley and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2015-06-07
Recently, nuclear vibrational contribution signatures in two-dimensional (2D) electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. In this work, we address a dimer which produces little beating of electronic origin in the absence of vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the electronic-vibrational quantum mixtures are rather robust, even under the influence of the fluctuations and despite the small Huang-Rhys factors of the Franck-Condon active vibrational modes. This results in long-lasting beating behavior of vibrational origin in the 2D electronic spectra. At physiological temperatures, however, the fluctuations eradicate the mixing, and hence, the beating in the 2D spectra disappears. Further, it is demonstrated that such electronic-vibrational quantum mixtures do not necessarily play a significant role in electronic energy transfer dynamics, despite contributing to the enhancement of long-lived quantum beating in 2D electronic spectra, contrary to speculations in recent publications.
Information Geometry, Inference Methods and Chaotic Energy Levels Statistics
Cafaro, Carlo
2008-01-01
In this Letter, we propose a novel information-geometric characterization of chaotic (integrable) energy level statistics of a quantum antiferromagnetic Ising spin chain in a tilted (transverse) external magnetic field. Finally, we conjecture our results might find some potential physical applications in quantum energy level statistics.
High-Temperature Vibration Damper
Clarke, Alan; Litwin, Joel; Krauss, Harold
1987-01-01
Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.
Estimation of Oil Production Rates in Reservoirs Exposed to Focused Vibrational Energy
Jeong, Chanseok
2014-01-01
Elastic wave-based enhanced oil recovery (EOR) is being investigated as a possible EOR method, since strong wave motions within an oil reservoir - induced by earthquakes or artificially generated vibrations - have been reported to improve the production rate of remaining oil from existing oil fields. To date, there are few theoretical studies on estimating how much bypassed oil within an oil reservoir could be mobilized by such vibrational stimulation. To fill this gap, this paper presents a numerical method to estimate the extent to which the bypassed oil is mobilized from low to high permeability reservoir areas, within a heterogeneous reservoir, via wave-induced cross-flow oscillation at the interface between the two reservoir permeability areas. This work uses the finite element method to numerically obtain the pore fluid wave motion within a one-dimensional fluid-saturated porous permeable elastic solid medium embedded in a non-permeable elastic semi-infinite solid. To estimate the net volume of mobilized oil from the low to the high permeability area, a fluid flow hysteresis hypothesis is adopted to describe the behavior at the interface between the two areas. Accordingly, the fluid that is moving from the low to the high permeability areas is assumed to transport a larger volume of oil than the fluid moving in the opposite direction. The numerical experiments were conducted by using a prototype heterogeneous oil reservoir model, subjected to ground surface dynamic loading operating at low frequencies (1 to 50 Hz). The numerical results show that a sizeable amount of oil could be mobilized via the elastic wave stimulation. It is observed that certain wave frequencies are more effective than others in mobilizing the remaining oil. We remark that these amplification frequencies depend on the formation’s elastic properties. This numerical work shows that the wave-based mobilization of the bypassed oil in a heterogeneous oil reservoir is feasible, especially
Cultural energy analyses of dairy cattle receiving different concentrate levels
International Nuclear Information System (INIS)
Koknaroglu, Hayati
2010-01-01
Purpose of this study was to conduct cultural energy analyses of dairy cows receiving different levels of concentrate. Data were acquired by conducting a survey on 132 dairy farms selected by the stratified random sampling method. Dairy cattle farms were divided into three groups according to concentrate level and were analyzed. Accordingly concentrate levels were assigned as low (LLC) ( 50%, 44 farms). Cultural energy used for feed for cows was calculated by multiplying each ingredient with corresponding values of ingredients from literature. Transportation energy was also included in the analysis. Total cultural energy expended was highest for LLC (P < 0.05). Cultural energy expended for feed constituted more than half of the total cultural energy and was highest for LLC (P < 0.05). Cultural energy expended per kg milk and per Mcal protein energy was higher for LLC (P < 0.05). Efficiency defined as Mcal input/Mcal output was better for ILC and was worse for LLC (P < 0.05) and HLC was intermediate thus not differing from other groups. Results show that cultural energy use efficiency does not linearly increases as concentrate level increases and increasing concentrate level does not necessarily mean better efficiency. Thus optimum concentrate level not interfering cows performance should be sought for sustainable dairy production.
Energy Technology Data Exchange (ETDEWEB)
Hanson-Heine, Magnus W. D., E-mail: magnus.hansonheine@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)
2015-10-28
Carefully choosing a set of optimized coordinates for performing vibrational frequency calculations can significantly reduce the anharmonic correlation energy from the self-consistent field treatment of molecular vibrations. However, moving away from normal coordinates also introduces an additional source of correlation energy arising from mode-coupling at the harmonic level. The impact of this new component of the vibrational energy is examined for a range of molecules, and a method is proposed for correcting the resulting self-consistent field frequencies by adding the full coupling energy from connected pairs of harmonic and pseudoharmonic modes, termed vibrational self-consistent field (harmonic correlation). This approach is found to lift the vibrational degeneracies arising from coordinate optimization and provides better agreement with experimental and benchmark frequencies than uncorrected vibrational self-consistent field theory without relying on traditional correlated methods.
Elioff, Michael S.; Wall, Mark C.; Lemoff, Andrew S.; Mullin, Amy S.
1999-03-01
Energy dependent studies of the collisional relaxation of highly vibrationally excited pyrazine through collisions with CO2 were performed for initial pyrazine energies Evib=31 000-35 000 cm-1. These studies are presented along with earlier results for pyrazine with Evib=36 000-41 000