PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY
Ervin, Elizabeth K.
, such as stress, temperature, electric fieldby external stimuli, such as stress, temperature, electric field, piezoelectric materials are of great interest, as they are commonly used as sensors, actuators and memory for implementing the above coated PZT and plain PZT in power harvesting. Equipment and Experimental Set Up
A micropower programmable DSP powered using a MEMS-based vibration-to-electric energy converter
R. Amirtharajah; S. Meninger; J. O. Mur-Miranda; A. Chandrakasan; J. Lang
2000-01-01
An ultra-low-power programmable DSP for sensor applications enables systems to be powered by ambient vibration. The three-chip system consists of a MEMS transducer that converts vibration to a voltage delivered to a conversion IC. The conversion IC creates a stable power supply that provides energy to the sensor DSP load. The system exploits ambient mechanical vibration as its energy source
NASA Astrophysics Data System (ADS)
Beeby, Stephen P.; Wang, Leran; Zhu, Dibin; Weddell, Alex S.; Merrett, Geoff V.; Stark, Bernard; Szarka, Gyorgy; Al-Hashimi, Bashir M.
2013-07-01
The design of vibration energy harvesters (VEHs) is highly dependent upon the characteristics of the environmental vibrations present in the intended application. VEHs can be linear resonant systems tuned to particular frequencies or nonlinear systems with either bistable operation or a Duffing-type response. This paper provides detailed vibration data from a range of applications, which has been made freely available for download through the Energy Harvesting Networks online data repository. In particular, this research shows that simulation is essential in designing and selecting the most suitable vibration energy harvester for particular applications. This is illustrated through C-based simulations of different types of VEHs, using real vibration data from a diesel ferry engine, a combined heat and power pump, a petrol car engine and a helicopter. The analysis shows that a bistable energy harvester only has a higher output power than a linear or Duffing-type nonlinear energy harvester with the same Q-factor when it is subjected to white noise vibration. The analysis also indicates that piezoelectric transduction mechanisms are more suitable for bistable energy harvesters than electromagnetic transduction. Furthermore, the linear energy harvester has a higher output power compared to the Duffing-type nonlinear energy harvester with the same Q factor in most cases. The Duffing-type nonlinear energy harvester can generate more power than the linear energy harvester only when it is excited at vibrations with multiple peaks and the frequencies of these peaks are within its bandwidth. Through these new observations, this paper illustrates the importance of simulation in the design of energy harvesting systems, with particular emphasis on the need to incorporate real vibration data.
Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters
NASA Astrophysics Data System (ADS)
Amin Karami, M.; Inman, Daniel J.
2012-01-01
Linear and nonlinear piezoelectric devices are introduced to continuously recharge the batteries of the pacemakers by converting the vibrations from the heartbeats to electrical energy. The power requirement of a pacemaker is very low. However, after few years, patients require another surgical operation just to replace their pacemaker battery. Linear low frequency and nonlinear mono-stable and bi-stable energy harvesters are designed according to the especial signature of heart vibrations. The proposed energy harvesters are robust to variation of heart rate and can meet the power requirement of pacemakers.
Magneto-dipole radiation of quaking neutron star powered by energy of Alfven seismic vibrations
Bastrukov, S I; Xu, R X; Molodtsova, I V
2011-01-01
We compute characteristic parameters of magneto-dipole radiation of a neutron star undergoing torsional seismic vibrations under the action of Lorentz restoring force about axis of dipolar magnetic field experiencing decay. After brief outlook of general theoretical background of the model of vibration powered neutron star, we present numerical estimates of basic vibration and radiation characteristics, such as the oscillation frequency, lifetime, luminosity of radiation, and investigate their time dependence upon magnetic field decay. The presented analysis suggests that gradual decrease in frequencies of pulsating high-energy emission detected from a handful of currently monitoring AXP/SGR-like X-ray sources can be explained as being produced by vibration powered magneto-dipole radiation of quaking magnetars.
A vibration-based MEMS piezoelectric energy harvester and power conditioning circuit.
Yu, Hua; Zhou, Jielin; Deng, Licheng; Wen, Zhiyu
2014-01-01
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 ?W, or a power density of 5.19 ?W?mm-3?g-2 with an optimal resistive load of 220 k? 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. PMID:24556670
A Vibration-Based MEMS Piezoelectric Energy Harvester and Power Conditioning Circuit
Yu, Hua; Zhou, Jielin; Deng, Licheng; Wen, Zhiyu
2014-01-01
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 ?W, or a power density of 5.19 ?W·mm?3·g?2 with an optimal resistive load of 220 k? 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. PMID:24556670
Kim, Moonkeun; Lee, Sang-Kyun; Ham, Yong-Hyun; Yang, Yil Suk; Kwon, Jong-Kee; Kwon, Kwang-Ho
2012-08-01
We designed and fabricated a bimorph cantilever array for sustainable power with an integrated Cu proof mass to obtain additional power and current. We fabricated a cantilever system using single-crystal piezoelectric material and compared the calculations for single and arrayed cantilevers to those obtained experimentally. The vibration energy harvester had resonant frequencies of 60.4 and 63.2 Hz for short and open circuits, respectively. The damping ratio and quality factor of the cantilever device were 0.012 and 41.66, respectively. The resonant frequency at maximum average power was 60.8 Hz. The current and highest average power of the harvester array were found to be 0.728 mA and 1.61 mW, respectively. The sustainable maximum power was obtained after slightly shifting the short-circuit frequency. In order to improve the current and power using an array of cantilevers, we also performed energy conversion experiments. PMID:22962737
Fisher, Frank
the design and testing of a resonance frequency tunable energy harvesting device using magnetic forces a generic model for vibration to electrical energy power generation, and many researchers have demonstrated generators based on vibration energy were designed and developed by Roundy [2, 3], Miao [4], and Mitcheson [5
NASA Astrophysics Data System (ADS)
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.
Self-Powered Kinetic Energy Harvesters for Seek-Induced Vibrations in Hard Disk Drives
NASA Astrophysics Data System (ADS)
Chang, Jen-Yuan (James; Gutierrez, Mike
Energy harvesters with battery charging circuitry, which collect wasted kinetic energy from a magnetic disk drive's rotary actuator seek operations and flexible cable vibrations, are proposed, prototyped and presented in this paper. Depending on a disk drive's form factor and seek format, it is suggested by the present study that the harvested energy can be optimized by tuning the harvester's natural frequencies to major frequency content in the rotary actuator's excitation. It is demonstrated in this study that with prototype energy harvester systems, one can easily light up a regular LED. The work presented in this paper has implications in energy saving and recycling wasted mechanical energy for other low-power electronic applications in magnetic disk drive storage devices.
Downhole vibration sensing by vibration energy harvesting
Trimble, A. Zachary
2007-01-01
This thesis outlines the design of a prototype electromagnetic induction vibration energy harvesting device for use in a downhole environment. First order models of the necessary components for a generic vibration energy ...
Adaptive vibration energy harvesting
NASA Astrophysics Data System (ADS)
Behrens, Sam; Ward, John; Davidson, Josh
2007-04-01
By scavenging energy from their local environment, portable electronic devices such as 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 wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilise 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 adaption to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27 - 34%. However, simulations of a more electro-mechanical efficient and lightly damped transducer show conversion efficiencies in excess of 80%.
Vibration Testing of Stirling Power Convertors
NASA Technical Reports Server (NTRS)
Hughes, Bill; Goodnight, Thomas; McNelis, Mark E.; Suarez, Vicente J.; Schreiber, Jeff; Samorezov, Sergey
2003-01-01
The NASA John H. Glenn Research Center (GRC) and the U.S. Department of Energy (DOE) are currently developing a high efficient, long life, free piston Stirling convertor for use as an advanced spacecraft power system for future NASA missions. As part of this development, a Stirling Technology Demonstrator Convertor (TDC), developed by Stirling Technology Company (STC) for DOE, was vibration tested at GRC s Structural Dynamics Laboratory (SDU7735) in November- December 1999. This testing demonstrated that the Stirling TDC is able to withstand the harsh random vibration (20 to 2000 Hertz) seen during a typical spacecraft launch and survive with no structural damage or functional power performance degradation, thereby enabling its usage in future spacecraft power systems. The Stirling Vibration Test Team at NASA GRC and STC personnel conducted tests on a single 55 electric watt TDC. The purpose was to characterize the TDC s structural response to vibration and determine if the TDC could survive the vibration criteria established by the Jet Propulsion Laboratory (JPL) for launch environments. The TDC was operated at full-stroke and full power conditions during the vibration testing. The TDC was tested in two orientations, with the direction of vibration parallel and perpendicular to the TDC s moving components (displacer and piston). The TDC successfully passed a series of sine and random vibration tests. The most severe test was a 12.3 Grms random vibration test (peak vibration level of 0.2 g2/Hz from 50 to 250 Hertz) with test durations of 3 minutes per axis. The random vibration test levels were chosen to simulate, with margin, the maximum anticipated launch vibration conditions. As a result of this very successful vibration testing and successful evaluations in other key technical readiness areas, the Stirling power system is now considered a viable technology for future application for NASA spacecraft missions. Possible usage of the Stirling power system would be to supply on- board electric spacecraft power for future NASA Deep-Space Missions, performing as an attractive alternative to Radioisotope Thermoelectric Generators (RTG). Usage of the Stirling technology is also being considered as the electric power source for future Mars rovers, whose mission profiles may exclude the use of photovoltaic power systems (such as exploring at high Martian latitudes or for missions of lengthy durations). GRC s Thermo-Mechanical Systems Branch (5490) provides Stirling technology expertise under a Space Act Agreement with the DOE. Additional vibration testing, by GRC s Structural Systems Dynamics Branch (7733, is planned to continue to demonstrate the Stirling power system s vibration capability as its technology and flight system designs progress.
NASA Astrophysics Data System (ADS)
Tao, Kai; Liu, Shuwei; Woh Lye, Sun; Miao, Jianmin; Hu, Xiao
2014-06-01
A novel three-dimensional (3D) electret-based micro power generator with multiple vibration modes has been developed, which is capable of converting low-level ambient kinetic energy to electrical energy. The device is based on a rotational symmetrical resonator which consists of a movable disc-shaped seismic mass suspended by three sets of spiral springs. Experimental analysis shows that the proposed generator operates at an out-of-plane direction at mode I of 66 Hz and two in-plane directions at mode II of 75 Hz and mode III of 78.5 Hz with a phase difference of about 90°. A corona localized charging method is also proposed that employs a shadow mask and multiple discharge needles for the production of micro-sized electret array. From tests conducted at an acceleration of 0.05 g, the prototype can generate a maximum power of 4.8 nW, 0.67 nW and 1.2 nW at vibration modes of I, II and III, respectively. These values correspond to the normalized power densities of 16 µW cm-3 g-2, 2.2 µW cm-3 g-2 and 4 µW cm-3 g-2, respectively. The results show that the generator can potentially offer an intriguing alternative for scavenging low-level ambient energy from 3D vibration sources.
NASA Astrophysics Data System (ADS)
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 ?W 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.
Kim, Moonkeun; Lee, Sang-Kyun; Yang, Yil Suk; Jeong, Jaehwa; Min, Nam Ki; Kwon, Kwang-Ho
2013-12-01
We fabricated dual-beam cantilevers on the microelectromechanical system (MEMS) scale with an integrated Si proof mass. A Pb(Zr,Ti)O3 (PZT) cantilever was designed as a mechanical vibration energy-harvesting system for low power applications. The resonant frequency of the multilayer composition cantilevers were simulated using the finite element method (FEM) with parametric analysis carried out in the design process. According to simulations, the resonant frequency, voltage, and average power of a dual-beam cantilever was 69.1 Hz, 113.9 mV, and 0.303 microW, respectively, at optimal resistance and 0.5 g (gravitational acceleration, m/s2). Based on these data, we subsequently fabricated cantilever devices using dual-beam cantilevers. The harvested power density of the dual-beam cantilever compared favorably with the simulation. Experiments revealed the resonant frequency, voltage, and average power density to be 78.7 Hz, 118.5 mV, and 0.34 microW, respectively. The error between the measured and simulated results was about 10%. The maximum average power and power density of the fabricated dual-beam cantilever at 1 g were 0.803 microW and 1322.80 microW cm(-3), respectively. Furthermore, the possibility of a MEMS-scale power source for energy conversion experiments was also tested. PMID:24266167
Molecular vibrational energy flow
NASA Astrophysics Data System (ADS)
Gruebele, M.; Bigwood, R.
This article reviews some recent work in molecular vibrational energy flow (IVR), with emphasis on our own computational and experimental studies. We consider the problem in various representations, and use these to develop a family of simple models which combine specific molecular properties (e.g. size, vibrational frequencies) with statistical properties of the potential energy surface and wavefunctions. This marriage of molecular detail and statistical simplification captures trends of IVR mechanisms and survival probabilities beyond the abilities of purely statistical models or the computational limitations of full ab initio approaches. Of particular interest is IVR in the intermediate time regime, where heavy-atom skeletal modes take over the IVR process from hydrogenic motions even upon X H bond excitation. Experiments and calculations on prototype heavy-atom systems show that intermediate time IVR differs in many aspects from the early stages of hydrogenic mode IVR. As a result, IVR can be coherently frozen, with potential applications to selective chemistry.
Yuji Suzuki; Shigeo Kawasaki
2011-01-01
A MEMS electret generator for energy harvesting applications has been developed and its performance is examined in a series of experiments. In addition, an autonomous wireless sensor powered by the electret generator combined with a microwave wireless power transmission is proposed for the space transmission system
Fernando, Joseph S; Sun, Qiao
2013-11-01
A vibration harvester is usually designed to work in resonance responding to source vibration. Many existing types of harvesters use a single mechanical resonator to amplify the excitation vibrations. However, these harvesters are inherently limited in the amount of power that they can produce, due to their design, particularly in the limited number of design parameters. In our study, we propose a two-stage design to improve a harvester's performance both in power production and in bandwidth widening. In this paper, we demonstrate that a two-stage design can increase the power production when the device is intended to operate under a single frequency excitation. Harvester parameters are optimized to provide maximum power production. Power production comparisons between single-stage and two-stage harvesters are made through numerical simulation and experiments. PMID:24289422
Wireless Inductive Power Device Suppresses Blade Vibrations
NASA Technical Reports Server (NTRS)
Morrison, Carlos R.; Provenza, Andrew J.; Choi, Benjamin B.; Bakhle, Milind A.; Min, James B.; Stefko, George L.; Duffy, Kirsten P.; Fougers, Alan J.
2011-01-01
Vibration in turbomachinery can cause blade failures and leads to the use of heavier, thicker blades that result in lower aerodynamic efficiency and increased noise. Metal and/or composite fatigue in the blades of jet engines has resulted in blade destruction and loss of lives. Techniques for suppressing low-frequency blade vibration, such as gtuned circuit resistive dissipation of vibratory energy, h or simply "passive damping," can require electronics incorporating coils of unwieldy dimensions and adding unwanted weight to the rotor. Other approaches, using vibration-dampening devices or damping material, could add undesirable weight to the blades or hub, making them less efficient. A wireless inductive power device (WIPD) was designed, fabricated, and developed for use in the NASA Glenn's "Dynamic Spin Rig" (DSR) facility. The DSR is used to simulate the functionality of turbomachinery. The relatively small and lightweight device [10 lb (approx.=4.5 kg)] replaces the existing venerable and bulky slip-ring. The goal is the eventual integration of this technology into actual turbomachinery such as jet engines or electric power generators, wherein the device will facilitate the suppression of potentially destructive vibrations in fan blades. This technology obviates slip rings, which require cooling and can prove unreliable or be problematic over time. The WIPD consists of two parts: a remote element, which is positioned on the rotor and provides up to 100 W of electrical power to thin, lightweight piezoelectric patches strategically placed on/in fan blades; and a stationary base unit that wirelessly communicates with the remote unit. The base unit supplies inductive power, and also acts as an input and output corridor for wireless measurement, and active control command to the remote unit. Efficient engine operation necessitates minimal disturbance to the gas flow across the turbine blades in any effort to moderate blade vibration. This innovation makes it possible to moderate vibration on or in turbomachinery blades by providing 100 W of wireless electrical power and actuation control to thin, lightweight vibration-suppressing piezoelectric patches (eight actuation and eight sensor patches in this prototype, for a total of 16 channels) positioned strategically on the surface of, or within, titanium fan blades, or embedded in composite fan blades. This approach moves significantly closer to the ultimate integration of "active" vibration suppression technology into jet engines and other turbomachinery devices such as turbine electrical generators used in the power industry. The novel feature of this device is in its utilization of wireless technology to simultaneously sense and actively control vibration in rotating or stationary turbomachinery blades using piezoelectric patches. In the past, wireless technology was used solely for sensing and diagnostics. This technology, however, will accomplish much more, in terms of simultaneously sensing, suppressing blade vibration, and making it possible for detailed study of vibration impact in turbomachinery blades.
Adjustable Nonlinear Springs to Improve Efficiency of Vibration Energy Harvesters
S. Boisseau; G. Despesse; B. Ahmed Seddik
2015-06-01
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 shifts of ambient vibration frequencies and to increase the frequency band where energy can be harvested, one solution consists in using nonlinear springs. We present in this paper a model of adjustable nonlinear springs (H-shaped springs) and their benefits to improve velocity-damped vibration energy harvesters' (VEH) output powers. A simulation on a real vibration source proves that the output power can be higher in nonlinear devices compared to linear systems (up to +48%).
Energy scavenging from environmental vibration.
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 fabricated device currently generates a peak power of 25.9{micro}W and an average power of 1.21{micro}W from an input acceleration of 9.8m/s{sup -} at 10Hz. The device operates over a frequency range of 23Hz. The internal volume of the generator is 1.2cm{sup 3}.
Extremely low-loss rectification methodology for low-power vibration energy harvesters
NASA Astrophysics Data System (ADS)
Tiwari, R.; Ryoo, K.; Schlichting, A.; Garcia, E.
2013-06-01
Because of its promise for the generation of wireless systems, energy harvesting technology using smart materials is the focus of significant reported effort. Various techniques and methodologies for increasing power extraction have been tested. One of the key issues with the existing techniques is the use of diodes in the harvesting circuits with a typical voltage drop of 0.7 V. Since most of the smart materials, and other transducers, do not produce large voltage outputs, this voltage drop becomes significant in most applications. Hence, there is a need for designing a rectification method that can convert AC to DC with minimal losses. This paper describes a new mechanical rectification scheme, designed using reed switches, in a full-bridge configuration that shows the capability of working with signals from millivolts to a few hundred volts with extremely low losses. The methodology has been tested for piezoelectric energy harvesters undergoing mechanical excitation.
Vibration harvesting in traffic tunnels to power wireless sensor nodes
NASA Astrophysics Data System (ADS)
Wischke, M.; Masur, M.; Kröner, M.; Woias, P.
2011-08-01
Monitoring the traffic and the structural health of traffic tunnels requires numerous sensors. Powering these remote and partially embedded sensors from ambient energies will reduce maintenance costs, and improve the sensor network performance. This work reports on vibration levels detected in railway and road tunnels as a potential energy source for embedded sensors. The measurement results showed that the vibrations at any location in the road tunnel and at the wall in the railway tunnel are too small for useful vibration harvesting. In contrast, the railway sleeper features usable vibrations and sufficient mounting space. For this application site, a robust piezoelectric vibration harvester was designed and equipped with a power interface circuit. Within the field test, it is demonstrated that sufficient energy is harvested to supply a microcontroller with a radio frequency (RF) interface.
Vibration-to-electric energy conversion
Scott Meninger; Jose Oscar Mur-Miranda; Rajeevan Amirtharajah; Anantha Chandrakasan; Jeffrey Lang
1999-01-01
A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low-power electronic systems. The energy is transduced through the use of a variable capacitor, which has been designed with MEMS (microelectromechanical systems) tech- nology. A low-power controller IC has been fabricated in a 0 6µm CMOS pro- cess and has been tested and
Nonperturbative vibrational energy relaxation effects on vibrational line shapes
Cao, Jianshu
approach to vibrational phase and energy relaxation is based on perturbation theory and Fermi's golden rule quantum dynamics of solutes in a condensed phase is proposed to calculate linear and nonlinear vibrational between population relaxations of different vibrational states. These predictions cannot be reproduced
Harvesting vibrational energy using material work functions.
Varpula, Aapo; Laakso, Sampo J; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika
2014-01-01
Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications. PMID:25348004
Energy harvesting from wind-induced vibration of suspension bridges
Shi, Miao, M. Eng. Massachusetts Institute of Technology
2013-01-01
Recently, an extensive amount of research has been focused on energy harvesting from structural vibration sources for wireless self-powered microsystem applications. One method of energy harvesting is using electromagnetic ...
Vibration energy harvesting: fabrication, miniaturisation and applications
NASA Astrophysics Data System (ADS)
Beeby, S. P.; Zhu, D.
2015-05-01
This paper reviews work at the University of Southampton and its spin-out company Perpetuum towards the use of vibration energy harvesting in real applications. Perpetuum have successfully demonstrated vibration-powered condition monitoring systems for rail and industrial applications. They have pursued applications were volume is not a particular constraint and therefore sufficient power can be harvested. Harvester reliability and longevity is a key requirement and this can be a challenging task in high shock environments. The University of Southampton has investigated the miniaturization of the technology. MEMS electromagnetic harvesters were found to be unsuitable although miniaturized devices fabricated using bulk components did perform well. Screen printed piezoelectric harvesters were also found to perform well and were ideally suited to a low profile application where device thickness was limited. Screen printing was not only used to deposit the active piezoelectric material but also an inertial mass ink based on tungsten. This enables the device to be printed entirely by screen printing providing a low-cost route to manufacture. Finally, details of a simulation tool that can take real world vibrations and estimate vibration energy harvester output was presented. This was used to simulate linear and nonlinear harvesters and in many applications with a characteristic resonant frequency the linear approach was found to be the optimum. Bistable nonlinear harvesters were found to work better with more random vibration sources.
Microelectromechanical power generator and vibration sensor
Roesler, Alexander W. (Tijeras, NM); Christenson, Todd R. (Albuquerque, NM)
2006-11-28
A microelectromechanical (MEM) apparatus is disclosed which can be used to generate electrical power in response to an external source of vibrations, or to sense the vibrations and generate an electrical output voltage in response thereto. The MEM apparatus utilizes a meandering electrical pickup located near a shuttle which holds a plurality of permanent magnets. Upon movement of the shuttle in response to vibrations coupled thereto, the permanent magnets move in a direction substantially parallel to the meandering electrical pickup, and this generates a voltage across the meandering electrical pickup. The MEM apparatus can be fabricated by LIGA or micromachining.
Modeling and design of a MEMS piezoelectric vibration energy harvester
Du Toit, Noėl Eduard
2005-01-01
The modeling and design of MEMS-scale piezoelectric-based vibration energy harvesters (MPVEH) are presented. The work is motivated by the need for pervasive and limitless power for wireless sensor nodes that have application ...
Evaluating vehicular-induced bridge vibrations for energy harvesting applications
NASA Astrophysics Data System (ADS)
Reichenbach, Matthew; Fasl, Jeremiah; Samaras, Vasilis A.; Wood, Sharon; Helwig, Todd; Lindenberg, Richard
2012-04-01
Highway bridges are vital links in the transportation network in the United States. Identifying possible safety problems in the approximately 600,000 bridges across the country is generally accomplished through labor-intensive, visual inspections. Ongoing research sponsored by NIST seeks to improve inspection practices by providing real-time, continuous monitoring technology for steel bridges. A wireless sensor network with a service life of ten years that is powered by an integrated energy harvester is targeted. In order to achieve the target ten-year life for the monitoring system, novel approaches to energy harvesting for use in recharging batteries are investigated. Three main sources of energy are evaluated: (a) vibrational energy, (b) solar energy, and (c) wind energy. Assessing the energy produced from vehicular-induced vibrations and converted through electromagnetic induction is the focus of this paper. The goal of the study is to process acceleration data and analyze the vibrational response of steel bridges to moving truck loads. Through spectral analysis and harvester modeling, the feasibility of vibration-based energy harvesting for longterm monitoring can be assessed. The effects of bridge conditions, ambient temperature, truck traffic patterns, and harvester position on the power content of the vibrations are investigated. With sensor nodes continually recharged, the proposed real-time monitoring system will operate off the power grid, thus reducing life cycle costs and enhancing inspection practices for state DOTs. This paper will present the results of estimating the vibration energy of a steel bridge in Texas.
Harvesting vibration energy using two modal vibrations of a folded piezoelectric device
NASA Astrophysics Data System (ADS)
Gong, Li Jiao; Pan, Qiao Sheng; Li, Wei; Yan, Gang Yi; Liu, Yong Bin; Feng, Zhi Hua
2015-07-01
This letter reports a piezoelectric vibration energy harvester that uses the local lateral resonant modes of a folded structure to widen the operation frequency band. In addition, energy conversion efficiency is improved. A prototype energy harvester was fabricated and tested. The output power achieved two power peaks: 0.43 mW at 97 Hz and 6.64 mW at 120.9 Hz. The output power remained above 20 ?W within the operation frequency band that ranged from 88 Hz to 177 Hz when the energy harvester was driven with a vibration of 0.7 g peak acceleration. The output power remained higher than half of one of the maximum power peaks (0.43 mW) between 95 Hz and 101 Hz. Meanwhile, it remained higher than half of the other maximum power peak (6.64 mW) between 120.5 Hz and 123.8 Hz.
Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator
Wang, Zhong L.
Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator Weiqing Yang1 vibration energy, triple-cantilever, self-powered systems ABSTRACT Triboelectric nanogenerators (TENG a rationally designed triple-cantilever based TENG for harvesting vibration energy. With the assistance
Piezoelectric Power Requirements for Active Vibration Control
NASA Technical Reports Server (NTRS)
Brennan, Matthew C.; McGowan, Anna-Maria Rivas
1997-01-01
This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material non- linearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined.
Vibration energy harvesting from random force and motion excitations
NASA Astrophysics Data System (ADS)
Tang, Xiudong; Zuo, Lei
2012-07-01
A vibration energy harvester is typically composed of a spring-mass system with an electromagnetic or piezoelectric transducer connected in parallel with a spring. This configuration has been well studied and optimized for harmonic vibration sources. Recently, a dual-mass harvester, where two masses are connected in series by the energy transducer and a spring, has been proposed. The dual-mass vibration energy harvester is proved to be able to harvest more power and has a broader bandwidth than the single-mass configuration, when the parameters are optimized and the excitation is harmonic. In fact, some dual-mass vibration energy harvesters, such as regenerative vehicle suspensions and buildings with regenerative tuned mass dampers (TMDs), are subjected to random excitations. This paper is to investigate the dual-mass and single-mass vibration harvesters under random excitations using spectrum integration and the residue theorem. The output powers for these two types of vibration energy harvesters, when subjected to different random excitations, namely force, displacement, velocity and acceleration, are obtained analytically with closed-form expressions. It is also very interesting to find that the output power of the vibration energy harvesters under random excitations depends on only a few parameters in very simple and elegant forms. This paper also draws some important conclusions on regenerative vehicle suspensions and buildings with regenerative TMDs, which can be modeled as dual-mass vibration energy harvesters. It is found that, under white-noise random velocity excitation from road irregularity, the harvesting power from vehicle suspensions is proportional to the tire stiffness and road vertical excitation spectrum only. It is independent of the chassis mass, tire-wheel mass, suspension stiffness and damping coefficient. Under random wind force excitation, the power harvested from buildings with regenerative TMD will depends on the building mass only, not on the parameters of the TMD subsystem if the ratio of electrical and mechanical damping is constant.
NASA Technical Reports Server (NTRS)
Thieme, Lanny G.
2000-01-01
Stirling Technology Company (STC), as part of a Small Business Innovation Research contract Phase II with the NASA Glenn Research Center at Lewis Field, is developing an Adaptive Vibration Reduction System (AVRS) that will effectively eliminate vibrations for the Stirling radioisotope power system. The AVRS will reduce vibration levels for two synchronized, opposed Stirling converters by a factor of 10 or more under normal operating conditions. Even more importantly, the AVRS will be adaptive and will be able to adjust to any changing converter conditions over the course of a mission. The Stirling converter is being developed by NASA and the Department of Energy (DOE) as a high-efficiency option for a radioisotope power system to provide onboard electric power for NASA deep space missions. The high Stirling efficiency of over 25 percent for this application will reduce the required amount of isotope by more than a factor of 3 in comparison to the current radioisotope thermoelectric generators (RTG s). Stirling is the most developed converter option of the advanced power technologies under consideration.
Efficiency of piezoelectric mechanical vibration energy harvesting
NASA Astrophysics Data System (ADS)
Kim, Miso; Dugundji, John; Wardle, Brian L.
2015-05-01
Harvesting efficiency of a piezoelectric vibration energy harvesting system is investigated to provide design guidelines for harvesting devices with optimal performance. Harvesting power efficiency (?), defined as the ratio of device output power (Pout) to mechanical input power (Pin), is an essential but unexplored metric for comparison of harvesters operating in different power-input environments. Power extracted from piezoelectric harvesters has been of primary interest and proper accounting of mechanical input power and efficiency metrics has not been considered. Here, we present a closed form solution for harvesting efficiency that allows device comparison and furthermore, efficiency-optimized versus power-optimized electrical loading conditions are compared along with a case study. A key finding is that optimal design parameters for efficiency are quite different than optima for output power (e.g., a single optimum versus dual optima at different frequencies), requiring multi-objective design. These new findings provide guidelines on system parameters that can be manipulated for optimized performance in different ambient source conditions.
Vibration Monitoring of Power Distribution Poles
Clark Scott; Gail Heath; John Svoboda
2006-04-01
Some of the most visible and least monitored elements of our national security infrastructure are the poles and towers used for the distribution of our nations electrical power. Issues surrounding these elements within the United States include safety such as unauthorized climbing and access, vandalism such as nut/bolt removal or destructive small arms fire, and major vandalism such as the downing of power poles and towers by the cutting of the poles with a chainsaw or torches. The Idaho National Laboratory (INL) has an ongoing research program working to develop inexpensive and sensitive sensor platforms for the monitoring and characterization of damage to the power distribution infrastructure. This presentation covers the results from the instrumentation of a variety of power poles and wires with geophone assemblies and the recording of vibration data when power poles were subjected to a variety of stimuli. Initial results indicate that, for the majority of attacks against power poles, the resulting signal can be seen not only on the targeted pole but on sensors several poles away in the distribution network and a distributed sensor system can be used to monitor remote and critical structures.
Vibration characteristics about thermal variation of BFP in power plant
NASA Astrophysics Data System (ADS)
Song, A. H.; Song, J. D.; Kim, H. S.; Jung, G. C.
2012-11-01
BFPs(Boiler Feedwater Pump) in power plants are used for pumping high pressure and high temperature water. The pressure pulsation of high pressure pumps is the vibration caused by fluid forces. If the frequency of the exciting source is adjacent to one of the natural frequencies of the pump, it can cause high vibration by resonance. The natural vibration characteristics of pump depend on thermal variation. This paper examines vibration characteristics due to thermal variation experimentally and analytically.
Bilgen, Onur; Kenerson, John G; Akpinar-Elci, Muge; Hattery, Rebecca; Hanson, Lisbet M
2015-08-01
The World Health Organization has established recommendations for blood pressure measurement devices for use in low-resource venues, setting the "triple A" expectations of Accuracy, Affordability, and Availability. Because of issues related to training and assessment of proficiency, the pendulum has swung away from manual blood pressure devices and auscultatory techniques towards automatic oscillometric devices. As a result of power challenges in the developing world, there has also been a push towards semiautomatic devices that are not dependent on external power sources or batteries. Beyond solar solutions, disruptive technology related to solid-state vibrational energy harvesting may be the next iterative solution to attain the ultimate goal of a self-powered low-cost validated device that is simple to use and reliable. PMID:25913774
Theory of vibrational energy relaxation in liquids: Vibrational-vibrational energy transfer
NASA Astrophysics Data System (ADS)
Adelman, S. A.; Muralidhar, R.; Stote, R. H.
1993-07-01
A theoretical treatment of the vibrational-vibrational (VV) contribution to the vibrational energy relaxation time T1 of a solute normal mode in a molecular solvent, which extends a previous treatment [S. A. Adelman, R. H. Stote, and R. Muralidhar, J. Chem. Phys. 99, 1320 (1993), henceforth called Paper I] of the vibrational-translational-rotational (VTR) contribution to T1, is outlined and expressions for this VV contribution, valid for the infinitely dilute diatomic solution, are presented. The treatment is based on the formula T1=?-1(?l), where ?(?) is the friction kernel of the relaxing solute mode and where ?l is its liquid phase frequency. ?(?) is evaluated as the cosine transform of the autocorrelation function
Development of power supply package for electret vibration generator
NASA Astrophysics Data System (ADS)
Hattori, Yutaka
2014-11-01
Development of power supply package for electret vibration generator. To use the electret vibration generator widely in the market the power supply unit of the package where the circuit of making to direct current had been integrated with the control circuit was developed. And the application was examined.
Converged vibrational energy levels and quantum mechanical vibrational partition function of ethane
Truhlar, Donald G
Converged vibrational energy levels and quantum mechanical vibrational partition function of ethane function of ethane is calculated in the temperature range of 200600 K using well-converged energy levels25 In this article, we report converged vibrational levels and converged quantum mechanical vibrational partition
On Kinetics Modeling of Vibrational Energy Transfer
NASA Technical Reports Server (NTRS)
Gilmore, John O.; Sharma, Surendra P.; Cavolowsky, John A. (Technical Monitor)
1996-01-01
Two models of vibrational energy exchange are compared at equilibrium to the elementary vibrational exchange reaction for a binary mixture. The first model, non-linear in the species vibrational energies, was derived by Schwartz, Slawsky, and Herzfeld (SSH) by considering the detailed kinetics of vibrational energy levels. This model recovers the result demanded at equilibrium by the elementary reaction. The second model is more recent, and is gaining use in certain areas of computational fluid dynamics. This model, linear in the species vibrational energies, is shown not to recover the required equilibrium result. Further, this more recent model is inconsistent with its suggested rate constants in that those rate constants were inferred from measurements by using the SSH model to reduce the data. The non-linear versus linear nature of these two models can lead to significant differences in vibrational energy coupling. Use of the contemporary model may lead to significant misconceptions, especially when integrated in computer codes considering multiple energy coupling mechanisms.
A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources
Shen, Hui; Ji, Hongli; Zhu, Kongjun; Balsi, Marco; Giorgio, Ivan; dell'Isola, Francesco
2010-01-01
In the paper, a vibration damping system powered by harvested energy with implementation of the so-called SSDV (synchronized switch damping on voltage source) technique is designed and investigated. In the semi-passive approach, the piezoelectric element is intermittently switched from open-circuit to specific impedance synchronously with the structural vibration. Due to this switching procedure, a phase difference appears between the strain induced by vibration and the resulting voltage, thus creating energy dissipation. By supplying the energy collected from the piezoelectric materials to the switching circuit, a new low-power device using the SSDV technique is proposed. Compared with the original self-powered SSDI (synchronized switch damping on inductor), such a device can significantly improve its performance of vibration control. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results.
NASA Astrophysics Data System (ADS)
Ueno, Toshiyuki
2015-05-01
Vibration based power generation technology is utilized effectively in various fields. Author has invented novel vibrational power generation device using magnetostrictive material. The device is based on parallel beam structure consisting of a rod of iron-gallium alloy wound with coil and yoke accompanied with permanent magnet. When bending force is applied on the tip of the device, the magnetization inside the rod varies with induced stress due to the inverse magnetostrictive effect. In vibration, the time variation of the magnetization generates voltage on the wound coil. The magnetostrictive type is advantageous over conventional such using piezoelectric or moving magnet types in high efficiency and high robustness, and low electrical impedance. Here, author has established device configuration, simple, rigid, and high power output endurable for practical applications. In addition, the improved device is lower cost using less volume of Fe-Ga and permanent magnet compared to our conventional, and its assembly by soldering is easy and fast suitable for mass production. Average power of 3 mW/cm3 under resonant vibration of 212 Hz and 1.2 G was obtained in miniature prototype using Fe-Ga rod of 2 × 0.5× 7 mm3. Furthermore, the damping effect was observed, which demonstrates high energy conversion of the generator.
Potential system efficiencies for MEMS vibration energy harvesting
NASA Astrophysics Data System (ADS)
Behrens, S.
2007-01-01
Reliable power sources are needed for portable micro-electromechanical systems (MEMS) devices such as wireless automobile tire pressure sensors. Vibration is an ubiquitous energy source that maybe 'harvested' as electrical energy at the site of the MEMS device. Existing vibration energy harvesting systems use either a piezoelectric or an electromagnetic transducer to convert vibrations into electrical energy. This electrical energy is then conditioned using a passive rectifier dc-dc converter circuit. Such vibration harvesting techniques have focused on optimising circuit efficiency and, hence, have ignored the system efficiency i.e. mechanical-to-electrical efficiency. Results obtained in the laboratory can be extrapolated to predict potential system efficiencies for MEMS vibration energy harvesting systems. Results to date, using a standard speaker as the electromagnetic transducer, have demonstrated system efficiencies of greater than 14%. Initial estimates suggest a MEMS system efficiency of more than 80% could be achieved with a high performance transducer. Research is continuing to demonstrate these higher system efficiencies with the experimental apparatus.
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 requirements by increasing harvested power, shifting optimal conditioning impedance, inducing significant voltage supply fluctuations and ultimately rendering idealized sinusoidal and random analyses insufficient.
Wideband electromagnetic energy harvesting from ambient vibrations
NASA Astrophysics Data System (ADS)
Mallick, Dhiman; Podder, Pranay; Roy, Saibal
2015-06-01
Different bandwidth widening schemes of electromagnetic energy harvesters have been reported in this work. The devices are fabricated on FR4 substrate using laser micromachining techniques. The linear device operate in a narrow band around the resonance; in order to tune resonant frequency of the device electrically, two different types of complex load topologies are adopted. Using capacitive load, the resonant frequency is tuned in the low frequency direction whereas using inductive load, the resonant frequency is tuned in the high frequency direction. An overall tuning range of 2.4 Hz is obtained at 0.3g though the output power dropped significantly over the tuning range. In order to improve the off-resonance performance, nonlinear oscillation based systems are adopted. A specially designed spring arm with fixed-guided configuration produced single well nonlinear monostable configuration. With increasing input acceleration, wider bandwidth is obtained with such a system as large displacement, stretching nonlinearity comes into play and 9.55 Hz bandwidth is obtained at 0.5g. The repulsive force between one static and one vibrating oppositely polarized magnets are used to generate bistable nonlinear potential system. The distance between the mentioned magnets is varied between 4 to 10 mm to produce tunable nonlinearity with a maximum half power bandwidth over 3 Hz at 0.5g.
Vibrational energy transfer map for OCS
NASA Astrophysics Data System (ADS)
Mandich, M. L.; Flynn, G. W.
1980-08-01
The paper analyzes fluorescence detected from the OCS laser nu(1), nu(2), nu(3), 4nu(2), and 2nu(2) + nu(1) levels following initial excitation of the OCS bending overtone, 2nu(2), with a pulsed CO2 laser. Analysis of each time-dependent fluorescence produces multiple exponentials consistent with a simple energy transfer path; the excess population placed in the 2nu(2) by the laser rapidly equilibrates through ladder climbing processes with the rest of the nu(2) bending manifold at a near gas kinetic rate. The intermode vibrational energy transfer process is followed closely by overall relaxation of the vibrational energy into rotations and translations; vibrational relaxation from nu(2) to nu(1) may also occur. A model calculation of the probability for the 4nu(2) to nu(3) coupling based on long range attractive forces is about 3 times the measured value.
Damping and energy dissipation in soft tissue vibrations during running.
Khassetarash, Arash; Hassannejad, Reza; Enders, Hendrik; Ettefagh, Mir Mohammad
2015-01-21
It has been well accepted that the vibrations of soft tissue cannot be simulated by a single sinusoidal function. In fact, these vibrations are a combination of several vibration modes. In this study, these modes are extracted applying a recently developed method namely, partly ensemble empirical mode decomposition (PEEMD). Then, a methodology for estimating the damping properties and energy dissipation caused by damping for each mode is used. Applying this methodology on simulated signals demonstrates high accuracy. This methodology is applied to the acceleration signals of the gastrocnemius muscle during sprinting and the differences between the damping properties of different vibration modes were identified. The results were 1) the damping property of high-frequency mode was higher than that for low-frequency modes. 2) All identified modes were in under damped condition, therefore, the vibrations had an oscillatory nature. 3) The damping ratios of lower modes are about 100% increased compared to higher modes. 4) The energy dissipation occurred in lower modes were much more than that for higher mode; According to the power spectrum of the ground reaction force (GRF), which is the input force into the body, the recent finding supports the muscle tuning paradigm. It is suggested that the damping properties and energy dissipation can be used to distinguish between different running conditions (surface, fatigue, etc.). PMID:25527887
Vibration Power Flow In A Constrained Layer Damping Cylindrical Shell
NASA Astrophysics Data System (ADS)
Wang, Yun; Zheng, Gangtie
2012-07-01
In this paper, the vibration power flow in a constrained layer damping (CLD) cylindrical shell using wave propagation approach is investigated. The dynamic equations of the shell are derived with the Hamilton principle in conjunction with the Donnell shell assumption. With these equations, the dynamic responses of the system under a line circumferential cosine harmonic exciting force is obtained by employing the Fourier transform and the residue theorem. The vibration power flows inputted to the system and transmitted along the shell axial direction are both studied. The results show that input power flow varies with driving frequency and circumferential mode order, and the constrained damping layer can obviously restrict the exciting force from inputting power flow into the base shell especially for a thicker viscoelastic layer, a thicker or stiffer constraining layer (CL), and a higher circumferential mode order, can rapidly attenuate the vibration power flow transmitted along the base shell axial direction.
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.
NASA Astrophysics Data System (ADS)
Zaghari, Bahareh; Rustighi, Emiliano; Ghandchi Tehrani, Maryam
2015-03-01
Vibration energy harvesting is the transformation of vibration energy to electrical energy. The motivation of this work is to use vibration energy harvesting to power wireless sensors that could be used in inaccessible or hostile environments to transmit information for condition health monitoring. Although considerable work has been done in the area of energy harvesting, there is still a demand for making a robust and small vibration energy harvesters from random excitations in a real environment that can produce a reliable amount of energy. Parametrically excited harvesters can have time-varying stiffness. Parametric amplification is used to tune vibration energy harvesters to maximize energy gains at system superharmonics, often at twice the first natural frequency. In this paper the parametrically excited harvester with cubic and cubic parametric nonlinearity is introduced as a novel work. The advantages of having cubic and cubic nonlinearity are explained theoretically and experimentally.
Effect of electrode configurations on piezoelectric vibration energy harvesting performance
NASA Astrophysics Data System (ADS)
Kim, Miso; Dugundji, John; Wardle, Brian L.
2015-04-01
Piezoelectric vibration energy harvesting is an attractive technology for self-powered wireless sensor networks because of the potential to deliver power to the sensor nodes from mechanical vibration sources in the surrounding medium. Systematic device designs are required in order to increase performance along with materials development of high piezoelectric coefficients and design of circuits with high power transfer efficiency. In this work, we present refined structural and electrical modeling of interdigitated electrodes (IDEs) for piezoelectric vibration energy harvesting, followed by parametric case studies on MEMS devices. Differences in geometric parameters including the size of the electrode and the number of IDE fingers for given device dimensions lead to substantial changes in harvesting performance such as capacitance, system coupling, voltage and power. When compared with parallel plate electrodes, use of IDEs results in much higher voltage generation by a factor of ten times while similar power levels are observed for both {3-1} and {3-3} configurations at optimal electrical loading conditions.
Multi-link piezoelectric structure for vibration energy harvesting
NASA Astrophysics Data System (ADS)
Aryanpur, Rameen M.; White, Robert D.
2012-04-01
Work in piezoelectric vibration energy harvesting has typically focused on single member cantilevered structures with transverse tip displacement at a known frequency, taking advantage of the optimal coupling characteristics of piezoceramics in the 3-1 bending mode. Multi-member designs could be advantageous in delivering power to a load in environments with random or wide-band vibrations. The design presented in this work consists of two hinged piezoceramic (PZT-5A) beams x-poled for series operation. Each beam measures 31.8mm x 12.7mm x 0.38mm and consists of two layers of nickel-plated piezoceramic adhered to a brass center shim. The hinge device consists of two custom-machined aluminum attachments epoxied to the end of a beam and connected using a 1.59mm diameter alloy steel dowel. A stainless steel torsion spring is placed over the pin and attached to the aluminum body to provide a restoring torque when under rotation. The design is modeled using the piezoelectric constitutive equations to solve for voltage and power for a set of electromechanical boundary conditions. Experimental measurements on the design are achieved by bolting one end of the structure to a vibration shaker and fixing the other to a rigid framework of industrial aluminum framing material. For a given frequency of vibration, power output of the structure can be obtained by measuring voltage drop across a resistive load.
Efficiency enhancement of a cantilever-based vibration energy harvester.
Kubba, Ali E; Jiang, Kyle
2013-01-01
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 (V(ave)), and average normal strain in the piezoelectric transducer (?(ave)) 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 ?J/cycle). PMID:24366177
Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester
Kubba, Ali E.; Jiang, Kyle
2014-01-01
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 (?ave) 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 ?J/cycle). PMID:24366177
S. A. Adelman; R. H. Stote; R. Muralidhar
1993-01-01
The concepts underlying a theoretical treatment of the vibrational energy relaxation (VER) time T1 of a solute normal mode in a molecular solvent are summarized, and results for T1, valid for VER processes mediated by vibrationaltranslationalrotational energy transfer, obtained from this treatment are presented. These results are based on the formula T1=?TR?1(?l), where ?TR(?) is the translationalrotational branch of the
NASA Astrophysics Data System (ADS)
Loverich, J.; Geiger, R.; Frank, J.
2008-03-01
This paper addresses a particular type of power harvesting in which energy in the periodic movement of structures is parasitically converted to stored electric charge. In such applications, tuning of the vibration power harvesters' resonance frequency is often required to match the host structures' forcing frequency. This paper presents a method of adjusting the boundary conditions of nonlinear stiffness elements as a means of tuning the resonance frequency of piezoelectric vibration power harvesters (altering the deformation mode from bending to in-plane stretching). Using this tuning method, the resonance frequency was experimentally varied between 56 and 62 Hz. For a vibration level of 2 mm/s, the harvester has a similar Q to a linear system but its Q is reduced by one third at a vibration level of 10 mm/s. This behavior is important for applications where high sensitivity is required for low vibration levels but mechanical robustness is required for high vibration levels.
Energy harvester array using piezoelectric circular diaphragm for rail vibration
NASA Astrophysics Data System (ADS)
Wang, Wei; Huang, Rong-Jin; Huang, Chuan-Jun; Li, Lai-Feng
2014-12-01
Generating electric energy from mechanical vibration using a piezoelectric circular membrane array is presented in this paper. The electrical characteristics of the functional array consisted of three plates with varies tip masses are examined under dynamic conditions. With an optimal load resistor of 11 k?, an output power of 21.4 mW was generated from the array in parallel connection at 150 Hz under a pre-stress of 0.8 N and a vibration acceleration of 9.8 m/s2. Moreover, the broadband energy harvesting using this array still can be realized with different tip masses. Three obvious output power peaks can be obtained in a frequency spectra of 110 Hz to 260 Hz. The results show that using a piezoelectric circular diaphragm array can increase significantly the output of energy compared with the use of a single plate. And by optimizing combination of tip masses with piezoelectric elements in array, the frequency range can be tuned to meet the broadband vibration. This array may possibly be exploited to design the energy harvesting for practical applications such as future high speed rail.
Magnetostrictive vibration damper and energy harvester for rotating machinery
NASA Astrophysics Data System (ADS)
Deng, Zhangxian; Asnani, Vivake M.; Dapino, Marcelo J.
2015-04-01
Vibrations generated by machine driveline components can cause excessive noise and structural dam- age. Magnetostrictive materials, including Galfenol (iron-gallium alloys) and Terfenol-D (terbium-iron- dysprosium alloys), are able to convert mechanical energy to magnetic energy. A magnetostrictive vibration ring is proposed, which generates electrical energy and dampens vibration, when installed in a machine driveline. A 2D axisymmetric finite element (FE) model incorporating magnetic, mechanical, and electrical dynamics is constructed in COMSOL Multiphysics. Based on the model, a parametric study considering magnetostrictive material geometry, pickup coil size, bias magnet strength, flux path design, and electrical load is conducted to maximize loss factor and average electrical output power. By connecting various resistive loads to the pickup coil, the maximum loss factors for Galfenol and Terfenol-D due to electrical energy loss are identified as 0.14 and 0.34, respectively. The maximum av- erage electrical output power for Galfenol and Terfenol-D is 0.21 W and 0.58 W, respectively. The loss factors for Galfenol and Terfenol-D are increased to 0.59 and 1.83, respectively, by using an L-C resonant circuit.
Vibrationally assisted quantum energy pumps
NASA Astrophysics Data System (ADS)
Myers, C. R.; Milburn, G. J.; Twamley, J.
2015-09-01
We show that directed energy transport in a linear array of coupled quantum dots can be achieved by a coherent coupling of each dot to a single coherently driven mechanical mode. Recent work on light harvesting molecules have implicated the role of discrete mechanical modes in enhancing the energy transport through dipole arrays but say less about directed transport. The study of quantum ratchets indicates how directed energy transport is possible in quantum dot arrays. Inspired by these two apparently unrelated models we show how directed energy transport may be implemented in an engineered quantum systems using a single mechanical degree of freedom. This may have implications for nano-engineered artificial energy harvesting systems.
Multistable chain for ocean wave vibration energy harvesting
NASA Astrophysics Data System (ADS)
Harne, R. L.; Schoemaker, M. E.; Wang, K. W.
2014-03-01
The heaving of ocean waves is a largely untapped, renewable kinetic energy resource. Conversion of this energy into electrical power could integrate with solar technologies to provide for round-the-clock, portable, and mobile energy supplies usable in a wide variety of marine environments. However, the direct drive conversion methodology of gridintegrated wave energy converters does not efficiently scale down to smaller, portable architectures. This research develops an alternative power conversion approach to harness the extraordinarily large heaving displacements and long oscillation periods as an excitation source for an extendible vibration energy harvesting chain. Building upon related research findings and engineering insights, the proposed system joins together a series of dynamic cells through bistable interfaces. Individual impulse events are generated as the inertial mass of each cell is pulled across a region of negative stiffness to induce local snap through dynamics; the oscillating magnetic inertial mass then generates current in a coil which is connected to energy harvesting circuitry. It is shown that linking the cells into a chain transmits impulses through the system leading to cascades of vibration and enhancement of electrical energy conversion from each impulse event. This paper describes the development of the multistable chain and ways in which realistic design challenges were addressed. Numerical modeling and corresponding experiments demonstrate the response of the chain due to slow and large amplitude input motion. Lastly, experimental studies give evidence that energy conversion efficiency of the chain for wave energy conversion is much higher than using an equal number of cells without connections.
Harvesting energy from the natural vibration of human walking.
Yang, Weiqing; Chen, Jun; Zhu, Guang; Yang, Jin; Bai, Peng; Su, Yuanjie; Jing, Qingsheng; Cao, Xia; Wang, Zhong Lin
2013-12-23
The triboelectric nanogenerator (TENG), a unique technology for harvesting ambient mechanical energy based on the triboelectric effect, has been proven to be a cost-effective, simple, and robust approach for self-powered systems. However, a general challenge is that the output current is usually low. Here, we demonstrated a rationally designed TENG with integrated rhombic gridding, which greatly improved the total current output owing to the structurally multiplied unit cells connected in parallel. With the hybridization of both the contact-separation mode and sliding electrification mode among nanowire arrays and nanopores fabricated onto the surfaces of two contact plates, the newly designed TENG produces an open-circuit voltage up to 428 V, and a short-circuit current of 1.395 mA with the peak power density of 30.7 W/m(2). Relying on the TENG, a self-powered backpack was developed with a vibration-to-electric energy conversion efficiency up to 10.62(±1.19) %. And it was also demonstrated as a direct power source for instantaneously lighting 40 commercial light-emitting diodes by harvesting the vibration energy from natural human walking. The newly designed TENG can be a mobile power source for field engineers, explorers, and disaster-relief workers. PMID:24180642
Vibration behavior of fuel-element vibration suppressors for the advanced power reactor
NASA Technical Reports Server (NTRS)
Adams, D. W.; Fiero, I. B.
1973-01-01
Preliminary shock and vibration tests were performed on vibration suppressors for the advanced power reactor for space application. These suppressors position the fuel pellets in a pin type fuel element. The test determined the effect of varying axial clearance on the behavior of the suppressors when subjected to shock and vibratory loading. The full-size suppressor was tested in a mockup model of fuel and clad which required scaling of test conditions. The test data were correlated with theoretical predictions for suppressor failure. Good agreement was obtained. The maximum difference with damping neglected was about 30 percent. Neglecting damping would result in a conservative design.
Self-powered discrete time piezoelectric vibration damper
NASA Astrophysics Data System (ADS)
Konak, Michael J.; Powlesland, Ian G.; van der Velden, Stephen P.; Galea, Stephen C.
1997-11-01
Structural vibration suppression is of great interest to the aircraft industry as it can reduce the amplitude of excessive vibration in lightly damped panels caused by conditions in their operational environment. One technique of suppressing vibration is to use passive damping techniques such as constrained layered damping incorporating viscoelastic materials. However these techniques may not be acceptable because of weight concerns or extreme temperature variations. Over the past decade much work has been done by researchers on the use of piezoelectric ceramic devices, using passive and active techniques, for structural vibration suppression. The passive piezoelectric damping devices consist of a piezoelectric element and either a resistive or resonant shunt. The resonant circuit shunt, which is analogous to a mechanical vibration absorber, gives better vibration reduction compared to the resistor shunt. This device requires a large value of inductance in order to be tuned to a particular structural vibration mode. A large value inductor can be made by a using a gyrator type circuit however the circuit needs external power. A method of vibration control using a discrete time controller and piezoelectric devices is presented. That is, this paper describes the concept of a self-powered discrete time piezoelectric vibration damper which does not need tuning to the structural resonant frequency and is powered by piezoelectric elements, i.e. does not need an external power supply. This device is referred to as a strain amplitude minimization patch (STAMP) damper. A brief description of the theory used and of the scheme is presented. Also the operation of this device is compared with other 'passive' techniques, involving piezoelectric elements, such as the resistive passive damper and the parallel resonant passive damper cases. Experimental results presented, on a cantilevered beam, demonstrate the concept and show that the device, even in its current underdeveloped form, has better damping than the simple resistor damper. Measurements taken indicate that the maximum RMS tip accelerations, at resonance, are reduced by 17.3%, 62.7% and 39.5% for the resistor, parallel resonant and STAMP damper devices, respectively, when compared to the short circuit reference condition. The performance of each device is observed when the resonant frequency of the system changes when a mass is added to the tip of the cantilever. This paper also discusses areas where improvements in the performance of the STAMP damper can be achieved.
NASA Astrophysics Data System (ADS)
Kim, Gi-Woo; Kim, Jaehwan
2013-01-01
This paper presents a bio-inspired mechanism for the performance enhancement of piezoelectric power generation in vibration energy harvesting. A compliant bistable mechanism for vibration energy harvesting was explored based on the negative stiffness inspired by the auditory hair bundle structures. The proposed mechanism consists of a compliant, four-bar linkage system to mimic the hair bundle structure inside an inner ear. Our initial prototype energy harvester demonstrates that the compliant bistable mechanism featuring negative stiffness outperforms the conventional vibration energy harvester in the infra-low frequency range (1-10 Hz).
VIBRATING RF MEMS FOR LOW POWER WIRELESS COMMUNICATIONS
Nguyen, Clark T.-C.
VIBRATING RF MEMS FOR LOW POWER WIRELESS COMMUNICATIONS Clark T.-C. Nguyen Center for Integrated- nents. Recent advances in IC-compatible microelec- tromechanical system (MEMS) technologies that make Arbor, Michigan 48109-2122 ctnguyen@eecs.umich.edu ABSTRACT Micromechanical communication circuits fab
Resonant vibrational energy transfer in ice Ih
Shi, L.; Li, F.; Skinner, J. L.
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.
Production, Delivery and Application of Vibration Energy in Healthcare
NASA Astrophysics Data System (ADS)
Abundo, Paolo; Trombetta, Chiara; Foti, Calogero; Rosato, Nicola
2011-02-01
In Rehabilitation Medicine therapeutic application of vibration energy in specific clinical treatments and in sport rehabilitation is being affirmed more and more.Vibration exposure can have positive or negative effects on the human body depending on the features and time of the characterizing wave. The human body is constantly subjected to different kinds of vibrations, inducing bones and muscles to actively modify their structure and metabolism in order to fulfill the required functions. Like every other machine, the body supports only certain vibration energy levels over which long term impairments can be recognized. As shown in literature anyway, short periods of vibration exposure and specific frequency values can determine positive adjustments.
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.
Low-frequency meandering piezoelectric vibration energy harvester.
Berdy, David F; Srisungsitthisunti, Pornsak; Jung, Byunghoo; Xu, Xianfan; Rhoads, Jeffrey F; Peroulis, Dimitrios
2012-05-01
The design, fabrication, and characterization of a novel low-frequency meandering piezoelectric vibration energy harvester is presented. The energy harvester is designed for sensor node applications where the node targets a width-to-length aspect ratio close to 1:1 while simultaneously achieving a low resonant frequency. The measured power output and normalized power density are 118 ?W and 5.02 ?W/mm(3)/g(2), respectively, when excited by an acceleration magnitude of 0.2 g at 49.7 Hz. The energy harvester consists of a laser-machined meandering PZT bimorph. Two methods, strain-matched electrode (SME) and strain-matched polarization (SMP), are utilized to mitigate the voltage cancellation caused by having both positive and negative strains in the piezoelectric layer during operation at the meander's first resonant frequency. We have performed finite element analysis and experimentally demonstrated a prototype harvester with a footprint of 27 x 23 mm and a height of 6.5 mm including the tip mass. The device achieves a low resonant frequency while maintaining a form factor suitable for sensor node applications. The meandering design enables energy harvesters to harvest energy from vibration sources with frequencies less than 100 Hz within a compact footprint. PMID:22622969
Statistical energy analysis of nonlinear vibrating systems.
Spelman, G M; Langley, R S
2015-09-28
Nonlinearities in practical systems can arise in contacts between components, possibly from friction or impacts. However, it is also known that quadratic and cubic nonlinearity can occur in the stiffness of structural elements undergoing large amplitude vibration, without the need for local contacts. Nonlinearity due purely to large amplitude vibration can then result in significant energy being found in frequency bands other than those being driven by external forces. To analyse this phenomenon, a method is developed here in which the response of the structure in the frequency domain is divided into frequency bands, and the energy flow between the frequency bands is calculated. The frequency bands are assigned an energy variable to describe the mean response and the nonlinear coupling between bands is described in terms of weighted summations of the convolutions of linear modal transfer functions. This represents a nonlinear extension to an established linear theory known as statistical energy analysis (SEA). The nonlinear extension to SEA theory is presented for the case of a plate structure with quadratic and cubic nonlinearity. PMID:26303923
MEMS electrostatic vibration energy harvester without switches and inductive elements
NASA Astrophysics Data System (ADS)
Dorzhiev, V.; Karami, A.; Basset, P.; Dragunov, V.; Galayko, D.
2014-11-01
The paper is devoted to a novel study of monophase MEMS electrostatic Vibration Energy Harvester (e-VEH) with conditioning circuit based on Bennet's doubler. Unlike the majority of conditioning circuits that charge a power supply, the circuit based on Bennet's doubler is characterized by the absence of switches requiring additional control electronics, and is free from hardly compatible with batch fabrication process inductive elements. Our experiment with a 0.042 cm3 batch fabricated MEMS e-VEH shows that a pre-charged capacitor as a power supply causes a voltage increase, followed by a saturation which was not reported before. This saturation is due to the nonlinear dynamics of the system and the electromechanical damping that is typical for MEMS. It has been found that because of that coupled behavior there exists an optimal power supply voltage at which output power is maximum. At 187 Hz / 4 g external vibrations the system is shown to charge a 12 V supply with a output power of 1.8 ?W.
Vibration-to-electric energy conversion
Scott Meninger; Jose Oscar Mur-miranda; Rajeevan Amirtharajah; Anantha P. Chandrakasan; Jeffrey H. Lang
2001-01-01
Abstract: A system is proposed to convert ambient mechanicalvibration into electrical energy for use in powering autonomouslow power electronic systems. The energy is transduced throughthe use of a variable capacitor. Using microelectromechanical systems(MEMS) technology, such a device has been designed for thesystem. A low-power controller IC has been fabricated in a 0.6- mCMOS process and has been tested and measured
New nonlinear vibration energy harvesters based on PVDF hybrid fluid diaphragm
NASA Astrophysics Data System (ADS)
Huet, F.; Formosa, F.; Badel, A.
2014-11-01
A low resonance frequency piezoelectric energy harvesting using a hybrid fluid diaphragm (HFD) is presented. This paper describes the design, fabrication and measurement of such device for harvesting energy from environmental vibrations. The HFD consists in an incompressible fluid confined between two thin piezoelectric membranes. The output voltage and power of the PVDF HFD are studied based on experimental and simulation results. Compared with conventional vibration harvester, this proposed solution is very simple and suitable for miniaturization and integration.
Tuning energy transport using interacting vibrational modes
NASA Astrophysics Data System (ADS)
Guo, Chu; Mukherjee, Manas; Poletti, Dario
2015-08-01
We study energy transport in a chain of quantum harmonic and anharmonic oscillators where the anharmonicity is induced by interaction between local vibrational states of the chain. Using adiabatic elimination and numerical simulations with matrix product states, we show how strong interactions significantly slow down the relaxation dynamics (with the emergence of a different time scale) and can alter the properties of the steady state. We also show that steady-state properties are completely different depending on the order in which the limits of infinite time and infinite interaction are taken.
Membrane-type vibrational energy harvester based on a multi-layered piezoelectric membrane
NASA Astrophysics Data System (ADS)
Yoo, Seunghwan; Kim, Jonghun; Park, Suk-in; Jang, Cheol-Yong; Jeong, Hakgeun
2014-03-01
In this study, we fabricated a membrane-type vibrational energy harvester by using a conventional micro-electro-mechanical (MEMS) method. The membrane-type vibrational energy harvester consists of a multi-layered diaphragm for stable and flexible vibration, a piezoelectric ZnO film for responding to the vibrational energy and for generating electric power, and a vibrator connected to the bottom of multi-layered diaphragm for enhancing the vibrational displacement of the diaphragm. First, we characterized the quality of a ZnO film through scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD), which showed a preferred c-axis orientation, a hexagonal rod shape and a quite smooth surface. After the membrane-type vibrational energy harvester had been fabricated, we integrated it into a printing circuit board to realize piezoelectric generation and confirm its performance. Finally, under vibrational motion, we obtained a useful output voltage of 400 mV, and we estimated that the energy harvester generated an actual output voltage of about 200 uV.
Experimental study of a self-powered and sensing MR-damper-based vibration control system
NASA Astrophysics Data System (ADS)
Sapi?ski, Bogdan
2011-10-01
The paper deals with a semi-active vibration control system based on a magnetorheological (MR) damper. The study outlines the model and the structure of the system, and describes its experimental investigation. The conceptual design of this system involves harvesting energy from structural vibrations using an energy extractor based on an electromagnetic transduction mechanism (Faraday's law). The system consists of an electromagnetic induction device (EMI) prototype and an MR damper of RD-1005 series manufactured by Lord Corporation. The energy extracted is applied to control the damping characteristics of the MR damper. The model of the system was used to prove that the proposed vibration control system is feasible. The system was realized in the semi-active control strategy with energy recovery and examined through experiments in the cases where the control coil of the MR damper was voltage-supplied directly from the EMI or voltage-supplied via the rectifier, or supplied with a current control system with two feedback loops. The external loop used the sky-hook algorithm whilst the internal loop used the algorithm switching the photorelay, at the output from the rectifier. Experimental results of the proposed vibration control system were compared with those obtained for the passive system (MR damper is off-state) and for the system with an external power source (conventional system) when the control coil of the MR damper was supplied by a DC power supply and analogue voltage amplifier or a DC power supply and a photorelay. It was demonstrated that the system is able to power-supply the MR damper and can adjust itself to structural vibrations. It was also found that, since the signal of induced voltage from the EMI agrees well with that of the relative velocity signal across the damper, the device can act as a 'velocity-sign' sensor.
A Bistable Vibration Energy Harvester with Closed Magnetic Circuit
NASA Astrophysics Data System (ADS)
Sato, Takahiro; Sugisawa, Takeshi; Igarashi, Hajime
2014-11-01
In this work, to increase magnetic flux passing through the electric coil in a bistable vibration energy harvester, the magnetic circuit is made closed by introducing two coil systems which have magnetic core in their axis holes. The magnetic resistance of the magnetic circuit, composed of silicon steel and thin air gaps, is supressed to be small. The double well potential is realized from the spring force and nonlinear magnetic force between the magnets and the magnetic core. Two harvesters with opened and closed magnetic circuits are manufactured for comparison. It is also shown that the closed magnetic circuit can effectively improve the output power.
Improvement of force factor of magnetostrictive vibration power generator for high efficiency
NASA Astrophysics Data System (ADS)
Kita, Shota; Ueno, Toshiyuki; Yamada, Sotoshi
2015-05-01
We develop high power magnetostrictive vibration power generator for battery-free wireless electronics. The generator is based on a cantilever of parallel beam structure consisting of coil-wound Galfenol and stainless plates with permanent magnet for bias. Oscillating force exerted on the tip bends the cantilever in vibration yields stress variation of Galfenol plate, which causes flux variation and generates voltage on coil due to the law of induction. This generator has advantages over conventional, such as piezoelectric or moving magnet types, in the point of high efficiency, highly robust, and low electrical impedance. Our concern is the improvement of energy conversion efficiency dependent on the dimension. Especially, force factor, the conversion ratio of the electromotive force (voltage) on the tip velocity in vibration, has an important role in energy conversion process. First, the theoretical value of the force factor is formulated and then the validity was verified by experiments, where we compare four types of prototype with parameters of the dimension using 7.0 × 1.5 × 50 mm beams of Galfenol with 1606-turn wound coil. In addition, the energy conversion efficiency of the prototypes depending on load resistance was measured. The most efficient prototype exhibits the maximum instantaneous power of 0.73 W and energy of 4.7 mJ at a free vibration of frequency of 202 Hz in the case of applied force is 25 N. Further, it was found that energy conversion efficiency depends not only on the force factor but also on the damping (mechanical loss) of the vibration.
ABSORPTION OF ENERGY DURING WHOLE-BODY VIBRATION EXPOSURE
R. Lundstrom; P. Holmlund
1998-01-01
Absorbed power,PAbs, during exposure to vertical and horizontal whole-body vibration in sitting posture was measured using 15 male and 15 female subjects. Different experimental conditions were applied, such as vibration level (0·251·4 m\\/s2), frequency (1·1380 Hz), body weight (5493 kg), relaxed and erect upper body posture. Results show thatPAbswas strongly related to frequency of the vibration peaking, within the range
Absorption of energy during vertical whole-body vibration exposure
Ronnie Lundström; Patrik Holmlund; Lennart Lindberg
1998-01-01
Absorbed power (PAbs) during exposure to vertical whole-body vibration in a sitting posture was measured on 15 male and 15 female subjects. Different experimental conditions were applied, such as vibration level (0.51.4ms-2) and frequency (2100Hz), body weight (5493kg) and, relaxed and erected upper body positions. Results show that PAbs was strongly related to the frequency of the vibration, peaking within
Energy harvester array using piezoelectric circular diaphragm for broadband vibration
NASA Astrophysics Data System (ADS)
Xiao, Zhao; Yang, Tong qing; Dong, Ying; Wang, Xiu cai
2014-06-01
A piezoelectric generator fabricated by multiple circular diaphragm piezoelectric harvesters array is provided to harvest power over a broad range of frequencies. Four harvesters with varies tip masses are incorporated on a board with an area of 98 × 98 mm2. In this case, four strong output power peaks are obtained over frequencies from 120 Hz to 225 Hz. With an optimum load resistance of 15 k?, the value of four output power peaks is, respectively, 5.14, 6.65, 9.7, and 10 mW for the generator under an acceleration of 9.8 m/s2. By choosing an appropriate combination of tip masses with piezoelectric elements in array, the frequency range of energy harvesting can be obviously widened to meet the broadband vibration.
Vibration-based energy harvesting with stacked piezoelectrets
Pondrom, P., E-mail: ppondrom@nt.tu-darmstadt.de [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); Hillenbrand, J.; Sessler, G. M. [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); Bös, J.; Melz, T. [System Reliability and Machine Acoustics SzM, Technische Universität Darmstadt, Magdalenenstr. 4, 64289 Darmstadt (Germany)
2014-04-28
Vibration-based energy harvesters with multi-layer piezoelectrets (ferroelectrets) are presented. Using a simple setup with nine layers and a seismic mass of 8?g, it is possible to generate a power up to 1.3?µW at 140?Hz with an input acceleration of 1g. With better coupling between seismic mass and piezoelectret, and thus reduced damping, the power output of a single-layer system is increased to 5?µW at 700?Hz. Simulations indicate that for such improved setups with 10-layer stacks, utilizing seismic masses of 80?g, power levels of 0.1 to 1 mW can be expected below 100?Hz.
Resonance tracking and vibration stablilization for high power ultrasonic transducers.
Kuang, Y; Jin, Y; Cochran, S; Huang, Z
2014-01-01
Resonant frequency shift and electrical impedance variation are common phenomena in the application of high power ultrasonic transducers, e.g. in focused ultrasound surgery and in cutting. They result in low power efficiency and unstable vibration amplitude. To solve this problem, a driving and measurement system has been developed to track the resonance of high power transducers and to stabilise their vibration velocity. This has the ability to monitor the operating and performance parameters of the ultrasonic transducers in real time. The configuration of the system, with its control algorithm implemented in LabVIEW (National Instruments, Newbury, UK), ensures flexibility to suit different transducers and load conditions. In addition, with different programs, it can be utilised as a high power impedance analyser or an instantaneous electrical power measurement system for frequencies in the MHz range. The effectiveness of this system has been demonstrated in detailed studies. With it, high transducer performance at high power can be achieved and monitored in real time. PMID:23928264
A dimensionless analysis of a 2DOF piezoelectric vibration energy harvester
NASA Astrophysics Data System (ADS)
Xiao, Han; Wang, Xu; John, Sabu
2015-06-01
In this study, a dimensionless analysis method is proposed to predict the output voltage and harvested power for a 2DOF vibration energy harvesting system. This method allows us to compare the harvesting power and efficiency of the 2DOF vibration energy harvesting system and to evaluate the harvesting system performance regardless the sizes or scales. The analysis method is a hybrid of time domain simulation and frequency response analysis approaches, which would be a useful tool for parametric study, design and optimisation of a 2DOF piezoelectric vibration energy harvester. In a case study, a quarter car suspension model with a piezoelectric material insert is chosen to be studied. The 2DOF vibration energy harvesting system could potentially be applied in a vehicle to convert waste or harmful ambient vibration energy into electrical energy for charging the battery. Especially for its application in a hybrid vehicle or an electrical vehicle, the 2DOF vibration energy harvesting system could improve charge mileage, comfort and reliability.
Dark Energy Drives Vibrating Atoms, Chain reactions, Etc.:
NASA Astrophysics Data System (ADS)
Sven, Charles
2010-03-01
The 14 billion year old atom - destroyed Hiroshima, vibrates at a 100 trillion times/sec, emanates photons at the speed of light, contains atom sized proton force field that attracts electrons, all driven by ``Dark Energy.'' This ageless atom's superpowerful requirements, must be supplied from a huge, external, super high-frequency, super-cooled, ``Dark Energy field,'' undetected by current technology, existing for 14+ billion years without degradation. Demonstrating this age-old atom's ``dark energy'' power source requires the synthesis of a number of elements, forces, observations and experiments, many of which are combined in novel but only in replicable venues. Solution includes ``Dark Energy'' participation in celestial observations. Expanded excerpt from my presentation at: the American Physical Society's April meeting in Denver 2009 Section T8: Cosmology
A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.
Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei
2014-01-01
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%. PMID:24854054
Adaptive piezoelectric energy harvesting circuit for wireless remote power supply
Geffrey K. Ottman; Heath F. Hofmann; Archin C. Bhatt; George A. Lesieutre
2002-01-01
This paper describes an approach to harvesting electrical energy from a mechanically excited piezoelectric element. A vibrating piezoelectric device differs from a typical electrical power source in that it has a capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. An analytical expression for the optimal power flow from a rectified piezoelectric device
Nathan Killoran; Susana F. Huelga; Martin B. Plenio
2014-12-12
Recent evidence suggests that quantum effects may have functional importance in biological light-harvesting systems. Along with delocalized electronic excitations, it is now suspected that quantum coherent interactions with certain near-resonant vibrations contribute to light-harvesting performance. However, the actual quantum advantage offered by such coherent vibrational interactions has not yet been established. We investigate a quantum design principle, whereby coherent exchange of single energy quanta between electronic and vibrational degrees of freedom can enhance a light-harvesting system's power above what is possible by thermal mechanisms alone. We present a prototype quantum heat engine which cleanly illustrates this quantum design principle, and quantify its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle's applicability for realistic biological structures.
Killoran, Nathan; Plenio, Martin B
2014-01-01
Recent evidence suggests that quantum effects may have functional importance in biological light-harvesting systems. Along with delocalized electronic excitations, it is now suspected that quantum coherent interactions with certain near-resonant vibrations contribute to light-harvesting performance. However, the actual quantum advantage offered by such coherent vibrational interactions has not yet been established. We investigate a quantum design principle, whereby coherent exchange of single energy quanta between electronic and vibrational degrees of freedom can enhance a light-harvesting system's power above what is possible by thermal mechanisms alone. We present a prototype quantum heat engine which cleanly illustrates this quantum design principle, and quantify its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle's applicability for realistic biological structures.
NASA Astrophysics Data System (ADS)
Moss, Scott D.; Hart, Genevieve A.; Burke, Stephen K.; Carman, Gregory P.
2014-01-01
This paper reports on a hybrid rotary-translational vibration energy harvesting approach that exploits cycloidal motion to achieve a relatively high power density from an oscillatory kinetic energy harvester operating at frequencies below 10 Hz. The approach uses a rolling magnetic sphere. The rolling motion mechanically amplifies the velocity at which the magnetic pole of the sphere passes a nearby coil transducer, inducing a proportionally larger electro-motive force across the coil. A prototype cycloidal energy harvester is shown to produce a peak power of 201 mW from a host vibration of 500 mg rms at 5.4 Hz.
Development of a PMN-PT/PDMS vibrational energy harvester
NASA Astrophysics Data System (ADS)
Moon, Kee S.; Mathers, Alex; Yi, Jingang
2008-11-01
Improving the energy conversion efficiency is one critical factor for practical usage of vibrational energy harvesting devices. In this paper, we design and prototype a vibration-based energy harvester with a high output energy density. The proposed harvester is based on a composite cantilever beam-mass design. The cantilever beam is made of a high piezoelectric constant, lead magnesium niobate-lead titanate (PMN-PT) material. A polydimethylsiloxane (PDMS) coating is applied to the cantilevers to decrease stress concentration of the thin PMN-PT and therefore increase the strength of the cantilever. A PDMS proof mass is also added to decrease the natural frequency of the cantilever system and to increase displacement and the voltage output. It is found that a 7.4 mm PMN-PT cantilever with a PDMS coating and proof mass produces a sustained 0.7 mW of RMS power (16.8 V, 58 ?A) at an acceleration of 55 m/s2.
Accurate Measurement of Velocity and Acceleration of Seismic Vibrations near Nuclear Power Plants
NASA Astrophysics Data System (ADS)
Arif, Syed Javed; Imdadullah; Asghar, Mohammad Syed Jamil
In spite of all prerequisite geological study based precautions, the sites of nuclear power plants are also susceptible to seismic vibrations and their consequent effects. The effect of the ongoing nuclear tragedy in Japan caused by an earthquake and its consequent tsunami on March 11, 2011 is currently beyond contemplations. It has led to a rethinking on nuclear power stations by various governments around the world. Therefore, the prediction of location and time of large earthquakes has regained a great importance. The earth crust is made up of several wide, thin and rigid plates like blocks which are in constant motion with respect to each other. A series of vibrations on the earth surface are produced by the generation of elastic seismic waves due to sudden rupture within the plates during the release of accumulated strain energy. The range of frequency of seismic vibrations is from 0 to 10 Hz. However, there appears a large variation in magnitude, velocity and acceleration of these vibrations. The response of existing or conventional methods of measurement of seismic vibrations is very slow, which is of the order of tens of seconds. A systematic and high resolution measurement of velocity and acceleration of these vibrations are useful to interpret the pattern of waves and their anomalies more accurately, which are useful for the prediction of an earthquake. In the proposed work, a fast rotating magnetic field (RMF) is used to measure the velocity and acceleration of seismic vibrations in the millisecond range. The broad spectrum of pulses within one second range, measured by proposed method, gives all possible values of instantaneous velocity and instantaneous acceleration of the seismic vibrations. The spectrum of pulses in millisecond range becomes available which is useful to measure the pattern of fore shocks to predict the time and location of large earthquakes more accurately. Moreover, instead of average, the peak values of these quantities are helpful in proper design of earthquake resistant nuclear power plants, buildings and structures. The proposed measurement scheme is successfully tested with a microprocessor based rocking vibration arrangement and the overall performance is recorded at dynamic conditions.
A Review of Power Harvesting from Vibration Using Piezoelectric Materials
Henry A. Sodano; Daniel J. Inman
2004-01-01
The process of acquiring the energy surround- ing a system and converting it into usable electrical energy is termed power harvesting. In the last few years, there has been a surge of research in the area of power harvesting. This increase in research has been brought on by the mod- ern advances in wireless technology and low-power electron- ics such
A nanogenerator as a self-powered sensor for measuring the vibration spectrum of a drum membrane
NASA Astrophysics Data System (ADS)
Yu, Aifang; Zhao, Yong; Jiang, Peng; Wang, Zhong Lin
2013-02-01
A nanogenerator (NG) is a device that converts vibration energy into electricity. Here, a flexible, small size and lightweight NG is successfully demonstrated as an active sensor for detecting the vibration spectrum of a drum membrane without the use of an external power source. The output current/voltage signal of the NG is a direct measure of the strain of the local vibrating drum membrane that contains rich informational content, such as, notably, the vibration frequency, vibration speed and vibration amplitude. In comparison to the laser vibrometer, which is excessively complex and expensive, this kind of small and low cost sensor based on an NG is also capable of detecting the local vibration frequency of a drum membrane accurately. A spatial arrangement of the NGs on the membrane can provide position-dependent vibration information on the surface. The measured frequency spectrum can be understood on the basis of the theoretically calculated vibration modes. This work expands the application of NGs and reveals the potential for developing sound wave detection, environmental/infrastructure monitoring and many more applications.
A nanogenerator as a self-powered sensor for measuring the vibration spectrum of a drum membrane.
Yu, Aifang; Zhao, Yong; Jiang, Peng; Wang, Zhong Lin
2013-02-01
A nanogenerator (NG) is a device that converts vibration energy into electricity. Here, a flexible, small size and lightweight NG is successfully demonstrated as an active sensor for detecting the vibration spectrum of a drum membrane without the use of an external power source. The output current/voltage signal of the NG is a direct measure of the strain of the local vibrating drum membrane that contains rich informational content, such as, notably, the vibration frequency, vibration speed and vibration amplitude. In comparison to the laser vibrometer, which is excessively complex and expensive, this kind of small and low cost sensor based on an NG is also capable of detecting the local vibration frequency of a drum membrane accurately. A spatial arrangement of the NGs on the membrane can provide position-dependent vibration information on the surface. The measured frequency spectrum can be understood on the basis of the theoretically calculated vibration modes. This work expands the application of NGs and reveals the potential for developing sound wave detection, environmental/infrastructure monitoring and many more applications. PMID:23306794
A chaotic vibration energy harvester using magnetic material
NASA Astrophysics Data System (ADS)
Sato, Takahiro; Igarashi, Hajime
2015-02-01
This paper presents a new wideband electromagnetic vibration energy harvester (VEH) composed of a magnetic core embedded into the coil axis. The magnetic core generates a nonlinear magnetic force, which gives rise to the nonlinearity in the behavior of the VEH. Moreover, the magnetic core increases the flux linkage with the coil. These features improve the operational bandwidth and output power of the VEH. Numerical analysis and experimental measurements reveal that the operational bandwidth of the proposed VEH is over 30 Hz in which the output power is kept about 0.1 mW. Moreover, the proposed VEH operates by complicated oscillation due to nonlinear forces acting on the oscillator. Evaluation of the Lyapunov exponent for the measured oscillation suggests that the proposed VEH produces chaotic oscillation.
Saffar, Saber; Abdullah, Amir
2014-03-01
Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. PMID:24246149
NASA Astrophysics Data System (ADS)
Qiu, Jing; Wen, Yumei; Li, Ping; Chen, Hengjia; Yang, Jin
2015-05-01
In this research, a vibration energy harvester employing the FeCuNbSiB/Terfenol-D/PZT/Terfenol-D/FeCuNbSiB five-phase laminate composite transducer to convert mechanical vibration energy into electrical energy was presented. The electric output performance of the proposed vibration energy harvester has been investigated. It was found that appropriate FeCuNbSiB layer thickness was propitious to the electric output characteristics. Compared to traditional vibration energy harvester using Terfenol-D/PZT/Terfenol-D (MPM) transducer, the experimental results show that the proposed vibration energy harvester provides a remarkably enhanced output power performance. When the thickness of FeCuNbSiB layer was 30 ?m, the optimum output power of vibration energy harvester achieved 4.00 mW/g for an acceleration of 0.8 g at frequency of 34.5 Hz, which was 1.29 times as great as that of traditional MPM transducer. Remarkably, this power is a very encouraging power figure and the proposed vibration energy harvester has great potential as far as its application in wireless sensor network.
Note: Vibration energy harvesting based on a round acoustic fence.
Cui, Xiao-bin; Huang, Cheng-ping; Hu, Jun-hui
2015-07-01
An energy harvester based on a round acoustic fence (RAF) has been proposed and studied. The RAF is composed of cylindrical stubs stuck in a circular array on a thin metal plate, which can confine the acoustic energy efficiently. By removing one stub and thus opening a small gap in the RAF, acoustic leakage with larger intensity can be produced at the gap opening. With the vibration source surrounded by the RAF, the energy harvesting at the gap opening has a wide bandwidth and is insensitive to the position of the vibration source. The results may have potential applications in harvesting the energy of various vibration sources in solid structure. PMID:26233415
Note: Vibration energy harvesting based on a round acoustic fence
NASA Astrophysics Data System (ADS)
Cui, Xiao-bin; Huang, Cheng-ping; Hu, Jun-hui
2015-07-01
An energy harvester based on a round acoustic fence (RAF) has been proposed and studied. The RAF is composed of cylindrical stubs stuck in a circular array on a thin metal plate, which can confine the acoustic energy efficiently. By removing one stub and thus opening a small gap in the RAF, acoustic leakage with larger intensity can be produced at the gap opening. With the vibration source surrounded by the RAF, the energy harvesting at the gap opening has a wide bandwidth and is insensitive to the position of the vibration source. The results may have potential applications in harvesting the energy of various vibration sources in solid structure.
Heavy atom vibrational modes and low-energy vibrational autodetachment in nitromethane anions
NASA Astrophysics Data System (ADS)
Thompson, Michael C.; Baraban, Joshua H.; Matthews, Devin A.; Stanton, John F.; Weber, J. Mathias
2015-06-01
We report infrared spectra of nitromethane anion, CH3NO2-, 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.
Natural rubber for sustainable high-power electrical energy generation
Suo, Zhigang
Natural rubber for sustainable high-power electrical energy generation Rainer Kaltseis. Harvesting these sources of energy is highly desir- able. On a small scale, for example, the power generated energy, such as motions of people and vibrations of buildings and bridges, can potentially power portable
[Vibration-vibration energy transfer between highly vibrational excited RbH and H2, N2].
Zhang, Bin; Zhu, Dong-hui; Dai, Kang; Shen, Yi-fan
2012-03-01
Rb-H2 mixture was irradiated with pulses of 696.4 nm radiation from a OPO laser, populating 6D state by two-photon absorption. The vibrational levels of RbH(X1sigma+,v" = 0-2) generated in the reaction of Rb(6D) with H2. Vibrational-state-specific total-removal relaxation rate coefficients, k(v) (M), for RbH(X1sigma+, v" = 15-22) by M = H2 and N2 were investigated in a pump and probe configuration. By the overtone pumping with a cw diode laser, highly vibrational states v" = 15-22 of RbH in its ground electronic state were obtained. Another diode laser was used to probe the prepared vibrational state. The decay signal of laser induced time-resolved fluorescence from A 1sigma+ (v') --> X1sigma+ (v") transition was monitored. Based on the Stern-Volmer equation, the total relaxation rate coefficient k(v) (H2) were yielded. A plot of k(v) (H2 + N2) vs alpha (mole fraction H2) yields a line with a slope of k(v) (H2)-k(v) (N2) and an intercept of k(v) (N2). The values of k(v) (H2) obtained from the slope of the fitted lines compare well with determined values of the k(v) (H2) from the Sern-Volmer plots. At v" < 18, the rate coefficients k(v) (M) increases linearly with vibrational quantum number. This linear region is dominated by single quantum relaxation (deltav = 1) collisional propensity rules. The region (v" > or = 18) where the dependence is much stronger than linear shows significant contribution from multiquantum (deltav > or = 2) relaxation or resonant vibration-vibration energy transfer between highly vibrationally excited RbH and H2 or N2. For RbH(v") + N2 (0), we measured the time-profile of v" = 16 after preparation of v" = 21. A clear bimodal distribution was observed. The first peak is due to resonant vibration-vibration energy transfer: RbH (v" = 21) + N2 (0) --> RbH (v" = 16) + N2 (1). The much broader second peak, at longer time delays, is due to sequential single-quantum relaxation. Although the second process results in a distribution that is much more spread out in time, the peak height is in the same order of magnitude, indicating that the two processes are at least comparable in probability. PMID:22582611
Trimble, A. Zachary
2011-01-01
In general, vibration energy harvesting is the scavenging of ambient vibration by transduction of mechanical kinetic energy into electrical energy. Many mechanical or electro-mechanical systems produce mechanical vibrations. ...
NASA Astrophysics Data System (ADS)
Guggenberger, Johannes; Müller, Gerhard
Low frequent vibrations may cause from disturbing up to damaging effects. There is no precise distinction between structure-borne sound and vibrations. However - depending on the frequency range - measurements and predictions require different techniques. In a wide frequency range, the generation, transmission and propagation of vibrations can be investigated similar to structure-borne sound (see Chap. 9).
Hua, Kien A.
. The power conditioning circuit for a piezoelectric generator needs a maximum power point tracking (MPPT) to maximize the power transfer, while minimizing power consumption of the circuit. The presentation focuses on our research endeavors for power management circuits for vibration energy harvesting. Dong Ha received
Energy harvesting from vibration with cross-linked polypropylene piezoelectrets
NASA Astrophysics Data System (ADS)
Zhang, Xiaoqing; Wu, Liming; Sessler, Gerhard M.
2015-07-01
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 M? and a resonance frequency of 800 Hz, a maximum output power of 120 ?W, 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.
NASA Astrophysics Data System (ADS)
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 hundred milliwatts and are falling steadily as improvements are made, it is feasible to use energy harvesting to power WSNs. This research begins by presenting the results of a thorough survey of ambient vibrations in the machine room of a large campus building, which found that ambient vibrations are low frequency, low amplitude, time varying, and multi-frequency. The modeling and design of fixed-frequency micro scale energy harvesters are then presented. The model is able to take into account rotational inertia of the harvester's proof mass and it accepts arbitrary measured acceleration input, calculating the energy harvester's voltage as an output. The fabrication of the micro electromechanical system (MEMS) energy harvesters is discussed and results of the devices harvesting energy from ambient vibrations are presented. The harvesters had resonance frequencies ranging from 31 - 232 Hz, which was the lowest reported in literature for a MEMS device, and produced 24 pW/g2 - 10 nW/g2 of harvested power from ambient vibrations. A novel method for frequency modification of the released harvester devices using a dispenser printed mass is then presented, demonstrating a frequency shift of 20 Hz. Optimization of the MEMS energy harvester connected to a resistive load is then presented, finding that the harvested power output can be increased to several microwatts with the optimized design as long as the driving frequency matches the harvester's resonance frequency. A framework is then presented to allow a similar optimization to be conducted with the harvester connected to a synchronously switched pre-bias circuit. With the realization that the optimized energy harvester only produces usable amounts of power if the resonance frequency and driving frequency match, which is an unrealistic situation in the case of ambient vibrations which change over time and are not always known
A diamagnetically stabilized horizontally levitated electromagnetic vibration energy harvester
NASA Astrophysics Data System (ADS)
Palagummi, S.; Zou, J.; Yuan, F. G.
2015-04-01
This article investigates a horizontal diamagnetic levitation (HDL) system for vibration energy harvesting. In this configuration, two large magnets, alias lifting magnets, are arranged co-axially at a distance such that in between them a magnet, alias floating magnet, is passively levitated at a laterally offset equilibrium position. The levitation is stabilized in the horizontal direction by two diamagnetic plates made of pyrolytic graphite placed on each side of the floating magnet. This HDL configuration permits large amplitude vibration of the floating magnet and exploits the ability to tailor the geometry to meet specific applications due to its frequency tuning capability. Theoretical modeling techniques are discussed followed by an experimental setup to validate it. At an input root mean square (RMS) acceleration of 0.0434 m/s2 (0.0044 grms) and at a resonant frequency of 1.2 Hz, the prototype generated a RMS power of 3.6 ?W with an average system efficiency of 1.93%. Followed by the validation, parametric studies on the geometry of the components are undertaken to show that with the optimized parameters the efficiency can be further enhanced.
NASA Technical Reports Server (NTRS)
Hornick, R. J.
1973-01-01
Man's reactions to vibration are emphasized rather than his reactions to the vibrational characteristics of vehicles. Vibrational effects studies include: performance effects reflected in tracking proficiency, reaction time, visual impairment, and other measures related to man's ability to control a system; physiological reactions; biodynamic responses; subjective reactions; and human tolerance limits. Technological refinements in shaker systems and improved experimental designs are used to validate the data.
Vibrational energy relaxation of water in Aerosol OT reverse micelle
NASA Astrophysics Data System (ADS)
Pang, Yoonsoo; Deak, John; Dlott, Dana
2005-03-01
An IR-Raman technique with mid-IR pump and anti-Stokes Raman probe is used to investigate reverse micelle mixture of Aerosol OT, water, and carbon tetrachloride, where polar water phase and nonpolar oil phase is separated by a monolayer of surfactant molecules. Anti-Stokes Raman scattering is only dependent on the population of vibrationally excited states, thus time-dependent population changes of parent/daughter vibrations can be monitored with this technique. Vibrational energy from nanodroplet of water is transferred to the surfactant head group in 1.8 ps and then out to solvent in 10 ps. Vibrational energy directly pumped into the surfactant tail group results in a slower 20-40 ps energy transfer to solvent. This energy transfer cannot be explained by ordinary heat transfer, but the specific vibrational energy relaxation pathway such as sulfonate stretch of surfactant molecules should be used. We can change the water-to-solvent energy transfer rate by adopting different size of reverse micelles or changing pump frequency over the broad OH stretch mode of water due to hydrogen bond network. Water molecules confined in nanometer scale reverse micelles have very different properties from bulk water and we have found many differences between the vibrational dynamics of water in these reverse micelles and those of bulk water.
A resonant electromagnetic vibration energy harvester for intelligent wireless sensor systems
NASA Astrophysics Data System (ADS)
Qiu, Jing; Wen, Yumei; Li, Ping; Liu, Xin; Chen, Hengjia; Yang, Jin
2015-05-01
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.
NASA Astrophysics Data System (ADS)
Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R.
2015-05-01
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.
Dong, Hui; Lewis, Nicholas H C; Oliver, Thomas A A; Fleming, Graham R
2015-05-01
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. PMID:25956092
NASA Astrophysics Data System (ADS)
Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei
2014-04-01
Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.
Regular and chaotic vibration in a piezoelectric energy harvester with fractional damping
NASA Astrophysics Data System (ADS)
Cao, Junyi; Syta, Arkadiusz; Litak, Grzegorz; Zhou, Shengxi; Inman, Daniel J.; Chen, Yangquan
2015-06-01
We examine a vibrational energy harvester consisting of a mechanical resonator with a fractional damping and electrical circuit coupled by a piezoelectric converter. By comparing the bifurcation diagrams and the power output we show that the fractional order of damping changes the system response considerably and affects the power output. Various dynamic responses of the energy harvester are examined using phase trajectory, Fourier spectrum, Multi-scale entropy and 0-1 test. The numerical analysis shows that the fractionally damped energy harvesting system exhibits chaos, and periodic motion, as the fractional order changes. The observed bifurcations strongly influence the power output.
Energy harvesting from mechanical vibrations using piezoelectric cantilever beams
Thomas J. Johnson; David Charnegie; William W. Clark; Michael Buric; George Kusic
2006-01-01
In this paper, a design methodology for an energy harvesting device will be investigated and results will be presented to validate the design. The energy harvesting device in the study is 31- unimorph piezoelectric cantilever beam which was used to convert small amplitude mechanical vibration from a specific machine application into an electrical energy source that could be used for
NASA Astrophysics Data System (ADS)
Gruenbaum, S. M.; Skinner, J. L.
2013-11-01
Water clustering and connectivity around lipid bilayers strongly influences the properties of membranes and is important for functions such as proton and ion transport. Vibrational anisotropic pump-probe spectroscopy is a powerful tool for understanding such clustering, as the measured anisotropy depends upon the time-scale and degree of intra- and intermolecular vibrational energy transfer. In this article, we use molecular dynamics simulations and theoretical vibrational spectroscopy to help interpret recent experimental measurements of the anisotropy of water in lipid multi-bilayers as a function of both lipid hydration level and isotopic substitution. Our calculations are in satisfactory agreement with the experiments of Piatkowski, Heij, and Bakker, and from our simulations we can directly probe water clustering and connectivity. We find that at low hydration levels, many water molecules are in fact isolated, although up to 70% of hydration water forms small water clusters or chains. At intermediate hydration levels, water forms a wide range of cluster sizes, while at higher hydration levels, the majority of water molecules are part of a large, percolating water cluster. Therefore, the size, number, and nature of water clusters are strongly dependent on lipid hydration level, and the measured anisotropy reflects this through its dependence on intermolecular energy transfer.
NASA Astrophysics Data System (ADS)
Nawayseh, Naser; Griffin, Michael J.
2010-07-01
Previous studies have quantified the power absorbed in the seated human body during exposure to vibration but have not investigated the effects of body posture or the power absorbed at the back and the feet. This study investigated the effects of support for the feet and back and the magnitude of vibration on the power absorbed during whole-body vertical vibration. Twelve subjects were exposed to four magnitudes (0.125, 0.25, 0.625, and 1.25 m s -2 rms) of random vertical vibration (0.25-20 Hz) while sitting on a rigid seat in four postures (feet hanging, maximum thigh contact, average thigh contact, and minimum thigh contact) both with and without a rigid vertical backrest. Force and acceleration were measured at the seat, the feet, and the backrest to calculate the power absorbed at these three locations. At all three interfaces (seat, feet, and back) the absorbed power increased in proportion to the square of the magnitude of vibration, with most power absorbed from vibration at the seat. Supporting the back with the backrest decreased the power absorbed at the seat at low frequencies but increased the power absorbed at high frequencies. Supporting the feet with the footrest reduced the total absorbed power at the seat, with greater reductions with higher footrests. It is concluded that contact between the thighs and the seat increases the power absorbed at the seat whereas a backrest can either increase or decrease the power absorbed at the seat.
NASA Astrophysics Data System (ADS)
Pradhan, G. B.; Juanes-Marcos, J. C.; Balakrishnan, N.; Kendrick, Brian K.
2013-11-01
Quantum scattering calculations are reported for state-to-state vibrational relaxation and reactive scattering in O + OH(v = 2 - 3, j = 0) collisions on the electronically adiabatic ground state 2A'' potential energy surface of the HO2 molecule. The time-independent Schrödinger equation in hyperspherical coordinates is solved to determine energy dependent probabilities and cross sections over collision energies ranging from ultracold to 0.35 eV and for total angular momentum quantum number J = 0. A J-shifting approximation is then used to compute initial state selected reactive rate coefficients in the temperature range T = 1 - 400 K. Results are found to be in reasonable agreement with available quasiclassical trajectory calculations. Results indicate that rate coefficients for O2 formation increase with increasing the OH vibrational level except at low and ultralow temperatures where OH(v = 0) exhibits a slightly different trend. It is found that vibrational relaxation of OH in v = 2 and v = 3 vibrational levels is dominated by a multi-quantum process.
Demonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting
Uysal-Biyikoglu, Elif
Demonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting S-neutral operation of a wireless sensor network of MicaZ Motes through electromagnetic vibration energy harvesting harvested fully compensates for the energy used for the operation of the node. Keywords--Wireless sensor
Spectroscopic probes of vibrationally excited molecules at chemically significant energies
Rizzo, T.R.
1992-03-01
These experiments apply multiple-laser spectroscopic techniques to investigate the bond energies, potential surface topologies, and dissociation dynamics of highly vibrationally excited molecules. Infrared-optical double resonance pumping of light atom stretch vibrations in H{sub 2}O{sub 2} and HN{sub 3} prepares reactant molecules in single rovibrational states above the unimolecular dissociation threshold on the ground potential surface, and laser induced fluorescence detection of the OH or NH fragments monitors the partitioning of energy into individual product quantum states. Product energy partitioning data from H{sub 2}O{sub 2} dissociation provide a stringent test of statistical theories as well as potential energy surface calculations. Ongoing work on HN{sub 3} seeks to determine the height of the barrier to dissociation on the singlet potential energy surface. Our most recently developed spectroscopic scheme allows the measurement of high vibrational overtone spectra of jet-cooled molecules. This approach uses CO{sub 2} laser infrared multiphoton dissociation followed by laser induced fluorescence product detection to measure weak vibrational overtone transitions in low pressure environments. Application of this scheme to record the {Delta}V{sub OH}=4 and {Delta}V{sub OH}=5 transitions of CH{sub 3}OH cooled in a supersonic free-jet demonstrates both its feasibility and its utility for simplifying high vibrational overtone spectra.
NASA Astrophysics Data System (ADS)
Wickenheiser, Adam; Garcia, Ephrahim
2010-04-01
In much of the vibration-based energy harvesting literature, devices are modeled, designed, and tested for dissipating energy across a resistive load at a single base excitation frequency. This paper presents several practical scenarios germane to tracking, sensing, and wireless communication on humans and land vehicles. Measured vibrational data from these platforms are used to provide a time-varying, broadband input to the energy harvesting system. Optimal power considerations are given for several circuit topologies, including a passive rectifier circuit and active, switching methods. Under various size and mass constraints, the optimal design is presented for two scenarios: walking and idling a car. The frequency response functions are given alongside time histories of the power harvested using the experimental base accelerations recorded. The issues involved in designing an energy harvester for practical (i.e. timevarying, non-sinusoidal) applications are discussed.
Does acute side-alternating vibration exercise enhance ballistic upper-body power?
Cochrane, D J; Black, M J; Barnes, M J
2014-11-01
The aim of this study was to investigate the effects of acute vibration exercise, at 2 different frequencies, on upper body power output. Muscle activity (EMG) and upper-body peak power was measured in 12 healthy males during ballistic bench press throws at 30% of 1-repetition maximum on a Smith machine. Measures were made prior to, 30?s and 5?min after one of 3 conditions performed for 30?s in a press-up position: side-alternating vibration at 20?Hz, 26?Hz and no vibration. EMG was recorded in the anterior deltoid, triceps brachii and pectoralis major during ballistic bench press throws as well as during application of each condition. While peak power output was higher at 5?min post condition across all conditions, compared to baseline measures (P<0.05), only 20?Hz vibration resulted in a significant increase in peak power output (P<0.05) compared to no vibration. EMG was greater during both vibration conditions, compared to no vibration (P<0.001). However, this difference was not evident during bench press throws when no difference was seen in muscle activity between conditions. These findings suggest that 20?Hz vibration has an ergogenic effect on upper-body power that may be due to peripheral, rather than central, mediated mechanisms. PMID:24838267
K. Wollard; G. Zorpette
1988-01-01
The author reviews some key power and energy events that took place in 1987. He describes how Consumers Power Co. turned an 85% completed nuclear power plant into a natural-gas plant. Other utility companies are also joining forces to produce electricity. Meanwhile, the Nuclear Regulatory Commission changed a rule to allow nuclear plant owners to devise emergency plans of their
C. H. Hofmayer; J. R. Curreri; Y. J. Park; W. Y. Kato; J. F. Costello; H. T. Tang; S. Kawakami
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 tests involved increasing the excitation up to the limits of the vibration table in order to induce inelastic response in a reactor coolant system piping
A two-dimensional broadband vibration energy harvester using magnetoelectric transducer
Yang, Jin Wen, Yumei; Li, Ping; Yue, Xihai; Yu, Qiangmo; Bai, Xiaoling
2013-12-09
In this study, a magnetoelectric vibration energy harvester was demonstrated, which aims at addressing the limitations of the existing approaches in single dimensional operation with narrow working bandwidth. A circular cross-section cantilever rod, not a conventional thin cantilever beam, was adopted to extract vibration energy in arbitrary in-plane motion directions. The magnetic interaction not only resulted in a nonlinear motion of the rod with increased frequency bandwidth, but also contributed to a multi-mode motion to exhibit double power peaks. In energy harvesting with in-plane directions, it showed a maximum bandwidth of 4.4?Hz and power of 0.59?mW, with acceleration of 0.6?g (with g?=?9.8?m?s{sup ?2})
NASA Astrophysics Data System (ADS)
Qiu, Jing; Chen, Hengjia; Wen, Yumei; Li, Ping
2015-05-01
In this paper, a magnetoelectric (ME) and electromagnetic (EM) composite vibration energy harvester (VEH) employing a coil and a five-phase laminate ME transducer to convert low-frequency vibration energy into electrical energy are presented. The electric output performance of the proposed VEH has been investigated. Compared to a traditional single ME VEH or single EM VEH, the proposed ME/EM composite VEH can simultaneously obtain high voltage, large current, high power, and wide bandwidth. When the length of cantilever is 5 cm, the five-phase laminate composite ME transducer provides high voltage of 52 V and the coil provides large current of 97.8 mA. The optimum output power of the VEH achieves 16.47 mW for an acceleration of 0.5 g at a frequency of 27.5 Hz. Remarkably, the proposed ME/EM composite VEHs have great potential for its application in wireless sensor network.
NASA Astrophysics Data System (ADS)
Alamin Dow, Ali B.; Al-Rubaye, Hasan A.; Koo, David; Schneider, Michael; Bittner, Achim; Schmid, Ulrich; Kherani, Nazir P.
2011-06-01
Piezoelectric energy microgenerators are devices that continuously generate electricity when they are subjected to varying mechanical strain due to vibrations. They can generate electrical power up to 100 ?W which can be used to drive various sensing and actuating MEMS devices. Today, piezoelectric energy harvesters are considered autonomous and reliable energy sources to actuate low power microdevices such as wireless sensor networks, indoor-outdoor monitoring, facility management and biomedical applications. The advantages of piezoelectric energy harvesters including high power density, moderate output power and CMOS compatible fabrication in particular with aluminum nitride (AlN) have fuelled and motivated researchers to develop MEMS based energy harvesters. Recently, the use of AlN as a piezoelectric material has increased fabrication compatibility, enabling the realization of smart integrated systems on chip which include sensors, actuators and energy storage. Piezoelectric MEMS energy microgenerator is used to capture and transform the available ambient mechanical vibrations into usable electric energy via resonant coupling in the thin film piezoelectric material. Analysis and modeling of piezoelectric energy generators are very important aspects for improved performance. Aluminum nitride as the piezoelectric material is sandwiched between two electrodes. The device design includes a silicon cantilever on which the AlN film is deposited and which features a seismic mass at the end of the cantilever. Beam theory and lumped modeling with circuit elements are applied for modeling and analysis of the device operation at various acceleration values. The model shows good agreement with the experimental findings, thus giving confidence in the model.
Enhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n
Zuo, Lei
Enhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n Department-mass vibration energy harvester, where two masses are connected in series with the energy transducer and spring, is proposed and analyzed in this paper. The dual-mass vibration energy harvester is proved to be able
Jennie H. Dong; Ren G. Dong; Subhash Rakheja; Daniel E. Welcome; Thomas W. McDowell; John Z. Wu
2008-01-01
In this study it was hypothesized that the vibration-induced injuries or disorders in a substructure of human handarm system are primarily associated with the vibration power absorption distributed in that substructure. As the first step to test this hypothesis, the major objective of this study is to develop a method for analyzing the vibration power flow and the distribution of
NASA Technical Reports Server (NTRS)
Inoue, Katsumi; Krantz, Timothy L.
1995-01-01
While the vibration analysis of gear systems has been developed, a systematic approach to the reduction of gearbox vibration has been lacking. The technique of reducing vibration by shifting natural frequencies is proposed here for gearboxes and other thin-plate structures using the theories of finite elements, modal analysis, and optimization. A triangular shell element with 18 degrees of freedom is developed for structural and dynamic analysis. To optimize, the overall vibration energy is adopted as the objective function to be minimized at the excitation frequency by varying the design variable (element thickness) under the constraint of overall constant weight. Modal analysis is used to determine the sensitivity of the vibration energy as a function of the eigenvalues and eigenvectors. The optimum design is found by the gradient projection method and a unidimensional search procedure. By applying the computer code to design problems for beams and plates, it was verified that the proposed method is effective in reducing vibration energy. The computer code is also applied to redesign the NASA Lewis gear noise rig test gearbox housing. As one example, only the shape of the top plate is varied, and the vibration energy levels of all the surfaces are reduced, yielding an overall reduction of 1/5 compared to the initial design. As a second example, the shapes of the top and two side plates are varied to yield an overall reduction in vibration energy of 1/30.
NASA Astrophysics Data System (ADS)
Halim, Miah A.; Park, Jae Y.
2014-03-01
We present a non-resonant, frequency up-converted electromagnetic energy harvester that generates significant power from human-body-induced vibration, e.g., hand-shaking. Upon excitation, a freely movable non-magnetic ball within a cylinder periodically hits two magnets suspended on two helical compression springs located at either ends of the cylinder, allowing those to vibrate with higher frequencies. The device parameters have been designed based on the characteristics of human hand-shaking vibration. A prototype has been developed and tested both by vibration exciter (for non-resonance test) and by manual hand-shaking. The fabricated device generated 110 ?W average power with 15.4 ?W cm-3 average power density, while the energy harvester was mounted on a smart phone and was hand-shaken, indicating its ability in powering portable hand-held smart devices from low frequency (<5 Hz) vibrations.
NASA Astrophysics Data System (ADS)
Hsu, Chang-Hung; Liu, Jui-Jung; Fu, Chao-Ming; Huang, Yi-Mei; Chang, Chia-Wen; Cheng, Shan-Jen
2015-05-01
This study investigated the effect of magnetostriction-induced core magnetomechanical vibrations and noise on the magnetic properties of power transformers. The magnetostriction of grain-oriented Si steels was found to be extremely sensitive to compressive stress applied along the rolling direction and to tensile stress applied along the transverse direction. The compressive stress increased the variation in the magnitude of magnetostriction, which is correlated with core vibration and noise. A 2D model of the power transformer was used to simulate the noise and vibration variables through a finite element analysis.
DEAP-based energy harvesting using vortex-induced vibrations
NASA Astrophysics Data System (ADS)
Hoffstadt, Thorben; Heinze, Robert; Wahl, Tim; Kameier, Frank; Maas, Jürgen
2014-03-01
Generators based on dielectric electroactive polymers (DEAP) convert mechanical strain energy into electrical field energy. In order to harvest renewable energy from ambient sources adequate generator setups have to be developed. Thus, in this contribution a DEAP generator is presented which uses periodic vortex induced vibration of a circular cylinder as excitation mechanism, by which e.g. Flow energy of a wind or water current can be converted. For this purpose a novel generator design consisting of a cylinder that is elastically mounted on DEAP material is presented. Since the effect of vortex induced vibrations depends on the stiffness and damping of the utilized generator's eigenmode, a method to adapt both via the electrostatic pressure and energy conversion is proposed. After the validation of the general functionality of the novel generator design, analyses concerning the control of the overall harvester are carried out.
Energy Loss of Carbon Nanotube Cantilevers for Mechanical Vibration
NASA Astrophysics Data System (ADS)
Akita, Seiji; Sawaya, Shintaro; Nakayama, Yoshikazu
2007-09-01
We have investigated the mechanical vibrations of nanotube cantilevers in terms of energy loss. The quality factors, Q, for the resonant vibrations of nanotubes synthesized by arc discharge and chemical vapor deposition are related to Youngs modulus and diameters, which correspond to the defect density and the number of van der Waals (vdW) interlayer interactions. Molecular dynamics simulations reveal that pinhole defects on the wall of a nanotube significantly degrade the Q factor, whereas the strength in a small strain region remains high, which is similar to the case of a perfect nanotube. Furthermore, the Q factor is affected by the presence of the vdW interlayer interactions.
Vibration exposure for selected power hand tools used in automobile assembly.
Radwin, R G; Armstrong, T J; Vanbergeijk, E
1990-09-01
A practical method for assessing vibration exposure for workers operating vibrating hand tools on an automobile assembly line is presented. Vibration exposure is difficult to assess directly using many fast Fourier transform (FFT) spectral analyzers because of long task cycle times. Exposure time cannot be accurately estimated using time standards because of the high variability between operators and work methods. Furthermore, because workers frequently move about and get into inaccessible spaces, it is difficult to record vibration without interfering with the operation. A work sampling method was used for determining vibration exposure time by attaching accelerometers to the tools and suspending a battery-operated digital data logger from the air hose. Vibration acceleration and frequency spectra for each tool were obtained off-line replicating actual working conditions and analyzed together with exposure time data for determining individual worker vibration exposure. Eight pneumatic vibrating power hand tools, representing tools commonly used in an automobile assembly plant, were studied. Spectra for the rotary and reciprocating power tools and had large distinct dominant fundamental frequencies occurring in a narrow frequency range between 35 Hz and 150 Hz. These frequencies corresponded closely to tool free-running speeds, suggesting that major spectral component frequencies may be predicted on the basis of speed for some tools. PMID:2220569
Energy harvesting using vortex-induced vibrations of tensioned cables
Grouthier, Clement; de Langre, Emmanuel
2012-01-01
The development of energy harvesting systems based on fluid/structure interactions is part of the global search for innovative tools to produce renewable energy. In this paper, the possibility to harvest energy from a flow using vortex-induced vibrations (VIV) of a tensioned flexible cable is analyzed. The fluid loading on the vibrating solid and resulting dynamics are computed using an appropriate wake-oscillator model, allowing one to perform a systematic parametric study of the efficiency. The generic case of an elastically-mounted rigid cylinder is first investigated, before considering an infinite cable with two different types of energy harvesting : a uniformly spanwise distributed harvesting and then a periodic distribution of discrete harvesting devices. The maximum harvesting efficiency is of the same order for each configuration and is always reached when the solid body and its wake are in a frequency lock-in state.
Electron energy transfer rates for vibrational excitation of N2.
Campbell, L.; Cartwright, D. C.; Tuebner, P. J. O.; Brunger, M. J.
2003-01-01
The calculation of the electron density and electron temperature distribution in our ionosphere (from {approx} 150-600 km) requires a knowledge of the various heating, cooling and energy flow processes that occur. The energy transfer from electrons to neutral gases and ions is one of the dominant electron cooling processes in the ionosphere, and the role of vibrationally excited N2 in this is particularly significant.
THEORIES OF INTRAMOLECULAR VIBRATIONAL ENERGY TRANSFER
Miller, William H.
and classical mechanics of the 2.2. Criteria for IVR regimes 82 pendulum 105 2.3. Dephasing versus relaxation of energy sharing; approach nances 108 of radiationless transitions 86 5.3. Generalizing the pendulum 112 3-time experiments 90 energy transfer 116 3.4. Short-time experiments 91 6.1. Self-consistent description
A. L. Utz; J. D. Tobiason; M. D. Fritz; F. F. Crim
1992-01-01
Vibrational overtone excitation of acetylene molecules to energies between 6500 and 13 000 cm?1 followed by interrogation of the excited states during collisional relaxation determines both the mechanism and rates of energy transfer. A pulsed visible or near-infrared laser excites a single rotational state of C2H2 in the region of the first (2?CH), second (3?CH), or third (4?CH) overtone of
NASA Astrophysics Data System (ADS)
Ung, Chandarin; Moss, Scott D.; Chiu, Wing K.; Payne, Owen R.; Vandewater, Luke A.; Galea, Steve C.
2015-04-01
The dominant vibration frequencies exhibited by heavy haul railcars (operating in remote regions of Western Australia) are found to be 5.8 Hz and 14.6 Hz for loaded and unloaded trips respectively. This paper describes the in-service demonstration of two electromagnetic vibration energy harvesting technologies designed to generated power from these railcar vibrations: (i) a coupled two-degree of freedom (2-DoF) device capable of capturing both dominant frequencies of the railcar and (ii) a hybrid rotary-translational harvester device based on a magnetic sphere capable of harvesting from ? 6 Hz. The two devices were laboratory tested prior to mounting on a heavy railcar for in-service demonstration. Within the laboratory the coupled 2-DoF device was found to produce a maximum peak output power of 350 mW from 0.4 g root-mean-square (rms) acceleration at 15 Hz and 230 mW from 6 Hz. The hybrid rotary-translational device based on an oscillating magnetic sphere can produce ?138 mW from host vibration of 0.4 g rms at 5.4 Hz. This paper will discuss and compare the performance of the two prototypes, both within the laboratory and during the in-service demonstration on a heavy heal railcar.
Rakheja, Subhash; Mandapuram, Santosh; Dong, Ren G
2008-12-01
Absorbed power characteristics of seated human subjects under fore-aft (x-axis) and lateral (y-axis) vibration are investigated through measurements of dynamic interactions at the two driving-points formed by the body and the seat pan, and upper body and the backrest. The experiments involved: (i) three back support conditions (no back support, and back supported against a vertical and an inclined backrest); (ii) three seat pan heights (425, 390 and 350 mm); and three magnitudes (0.25, 0.5 and 1.0 m/s2 rms acceleration) of band limited random excitations in 0.5-10 Hz frequency range, applied independently along the x- and y- axes. The force responses, measured at the seat pan and the backrest are applied to characterize total energy transfer reflected on the seat pan and the backrest. The mean responses suggest strong contributions due to back support, and direction and magnitude of vibration. In the absence of a back support, the seat pan responses dominated in lower frequency bands centered at 0.63 and 1.25 Hz under both directions of motion. Most significant interactions of the upper body against the back support was observed under fore-aft vibration. The addition of back support caused the seat pan response to converge to a single primary peak near a higher frequency of 4 Hz under x- axis, with only little effect on the y-axis responses. The back support serves as an additional source of vibration to the occupant and an important constraint to limit the fore-aft movement of the upper body and thus relatively higher energy transfer under. The mean responses were further explored to examine the Wd frequency-weighting used for assessing exposure to horizontal vibration. The results show that the current weighting is suited for assessing the vibration exposure of human subjects seated only without a back support. PMID:19088407
Wollard, K.; Zorpette, G.
1988-01-01
The author reviews some key power and energy events that took place in 1987. He describes how Consumers Power Co. turned an 85% completed nuclear power plant into a natural-gas plant. Other utility companies are also joining forces to produce electricity. Meanwhile, the Nuclear Regulatory Commission changed a rule to allow nuclear plant owners to devise emergency plans of their own. As yet, the Shoreham and Seabrook plants still have not been licensed. The author says controversy over deregulation of the electric utility industry continued in 1987 with power engineers adding their voices. Meanwhile, two of the major suppliers of electrical equipment to the U.S. (ASEA AB and BBC Brown Boveir Ltd.) merged in Europe. Finally, the author says waste-to-energy plants are again being looked at to rid the country of garbage.
NASA Astrophysics Data System (ADS)
Hu, Mao-Bin; Kong, Xiang-Zhao; Wu, Qing-Song; Zhu, Zhen-Gang
The low frequency vibration energy absorption properties of granular materials have been investigated on an Invert Torsion Pendulum (ITP). The energy absorption rate of granular material changes nonlinearly with amplitude under low frequency vibration. The frequency of ITP system increases a little with granular materials in the holding cup. The vibration frequency of ITP system does not change with time.
White Noise Responsiveness of an AlN Piezoelectric MEMS Cantilever Vibration Energy Harvester
NASA Astrophysics Data System (ADS)
Jia, Y.; Seshia, A. A.
2014-11-01
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 ?m AlN on 10 ?m doped Si process. Cantilevers with 5 mm length and 2 mm width were tested at either unloaded condition (MC0: fn 577 Hz) or subjected to estimated end masses of 2 mg (MC2: fn 129 Hz) and 5 mg (MC5: fn 80 Hz). While MC0 was able to tolerate a higher drive acceleration prior to saturation (7 g with 0.7 ?W), MC5 exhibited higher peak power attainable at a lower input vibration (2.56 ?W 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 ?W 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.
Accurate ab initio vibrational energies of methyl chloride
NASA Astrophysics Data System (ADS)
Owens, Alec; Yurchenko, Sergei N.; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter
2015-06-01
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, CH335Cl and CH337Cl. 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 3Z. 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 CH3Cl without empirical refinement of the respective PESs.
Accurate ab initio vibrational energies of methyl chloride.
Owens, Alec; Yurchenko, Sergei N; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter
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, CH3 (35)Cl and CH3 (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 3Z. 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 CH3Cl without empirical refinement of the respective PESs. PMID:26133427
Acute Effects of Whole-Body Vibration on Muscle Activity, Strength, and Power
Prue Cormie; Russell S. Deane; N. Travis Triplett; Jeffrey M. McBride
2006-01-01
Cormie, P., R.S. Deane, N.T. Triplett, and J.M. McBride. Acute effects of whole-body vibration on muscle activ- ity, strength, and power. J. Strength Cond. Res. 20(2):257-261. 2006.The purpose of this study was to investigate the effects of a single bout of whole-body vibration on isometric squat (IS) and countermovement jump (CMJ) performance. Nine moder- ately resistance-trained men were tested for
Resonant vibrational excitation of CO by low-energy electrons
Poparic, G. B.; Belic, D. S.; Vicic, M. D. [Faculty of Physics, University of Belgrade, Studentski trg 12-16, P.O. Box 368, 11000 Belgrade (Serbia and Montenegro); Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110-1093 (United States)
2006-06-15
Electron impact vibrational excitation of the CO molecule, via the {sup 2}{pi} resonance, in the 0-4 eV energy region has been investigated. The energy dependence of the resonant excitation of the first ten vibrational levels, v=1 to v=10, has been measured by use of a crossed-beams double trochoidal electron spectrometer. Obtained relative differential cross sections are normalized to the absolute values. Integral cross sections are determined by using our recent results on scattered electrons angular distributions, which demonstrate clear p-partial wave character of this resonance. Substructures appear in the {sup 2}{pi} resonant excitation of the CO molecule which have not been previously observed.
EFFECT OF MAGNITUDE OF VERTICAL WHOLE-BODY VIBRATION ON ABSORBED POWER FOR THE SEATED HUMAN BODY
N. J. Mansfield; M. J. Griffin
1998-01-01
The power absorbed by 12 male subjects during exposure to vertical whole-body vibration at six magnitudes of random vibration (0·25, 0·5, 1·0, 1·5, 2·0 and 2·5 ms?2r.m.s.) has been measured in the laboratory. All subjects showed greatest absorbed power at about 5 Hz, but the frequency of this peak in the absorbed power reduced with increasing vibration magnitude. The total
Computation of acoustic power, vibration response and acoustic pressures of fluid-filled pipes
J. H. James
1982-01-01
Acoustic power radiated into the fluid around a pipe subjected to time harmonic excitation, the vibration response of the pipe wall, and the pressures in the exterior and interior fluids are computed. Pressure fields and pipe displacements are represented by Fourier transformations, and the acoustic power in the surrounding fluid is obtained from the stationary phase approximation to the far
Vibration energy harvesting using a spherical permanent magnet
NASA Astrophysics Data System (ADS)
Moss, Scott D.; Hart, Genevieve A.; Burke, Stephen K.; Galea, Steve C.; Carman, Gregory P.
2014-04-01
The authors recently reported on a hybrid rotary-translational vibration energy harvesting approach using a spherical permanent-magnet and employing cycloidal motion as a mechanical amplifier. The rotary-translational harvesting approach, which is resonant in nature, can yield approximately twice the e.m.f. compared with a similar translationalonly device. This paper explores the analytic and numerical modelling of the rotary-translational harvester with the goal of finding an efficient method for design optimisation.
Vibration energy absorption (VEA) in human fingers-hand-arm system
R. G. Dong; A. W. Schopper; T. W. McDowell; D. E. Welcome; J. Z. Wu; W. P. Smutz; C. Warren; S. Rakheja
2004-01-01
A methodology for measuring the vibration energy absorbed into the fingers and the palm exposed to vibration is proposed to study the distribution of the vibration energy absorption (VEA) in the fingers-hand-arm system and to explore its potential association with vibration-induced white finger (VWF). The study involved 12 adult male subjects, constant-velocity sinusoidal excitations at 10 different discrete frequencies in
Exploring the vibrational fingerprint of the electronic excitation energy via molecular dynamics
Deyne, Andy Van Yperen-De; Pauwels, Ewald; Ghysels, An; Waroquier, Michel; Van Speybroeck, Veronique; Hemelsoet, Karen, E-mail: karen.hemelsoet@ugent.be [Center for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium)] [Center for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium); De Meyer, Thierry [Center for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium) [Center for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium); Department of Textiles, Ghent University, Technologiepark 907, 9052 Zwijnaarde (Belgium); De Clerck, Karen [Department of Textiles, Ghent University, Technologiepark 907, 9052 Zwijnaarde (Belgium)] [Department of Textiles, Ghent University, Technologiepark 907, 9052 Zwijnaarde (Belgium)
2014-04-07
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.
Exploring the vibrational fingerprint of the electronic excitation energy via molecular dynamics
NASA Astrophysics Data System (ADS)
Deyne, Andy Van Yperen-De; De Meyer, Thierry; Pauwels, Ewald; Ghysels, An; De Clerck, Karen; Waroquier, Michel; Van Speybroeck, Veronique; Hemelsoet, Karen
2014-04-01
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.
Rotation-vibration energies for the HO 2 molecule
NASA Astrophysics Data System (ADS)
Bunker, P. R.; Hamilton, I. P.; Jensen, Per
1992-09-01
Walch and Duchovic [ J. Chem. Phys.94, 7068-7075 (1991)] recently carried out complete active space SCF and externally contracted configuration interaction (CASSCF-CCI) ab initio calculations to determine the potential energy surface of the X2A? electronic ground state of the HO 2 radical over a wide range of nuclear geometries. By fitting to 192 of their ab initio points, covering energies up to 12 000 cm -1 above the energy of the equilibrium geometry, we determine an analytical expression for the potential energy function in terms of the bond lengths and bond angle. The fitted potential gives R e(OH) = 0.971 Å (0.971 Å) , R e(OO) = 1.330 Å (1.331 Å) , and ?e = 104.3° (104.3°), where the experimental values are in parentheses. We use the analytical ab initio potential function with the Morse Oscillator Rigid Bender Internal Dynamics (MORBID) Hamiltonian [ J. Mol. Spectrosc.128, 478-501 (1988); J. Chem. Soc. Faraday Trans. 284, 1315-1340 (1988)] in a calculation of vibrational energies. We adjust four parameters in the potential in a fitting to experimental vibrational energies, and then calculate the energies of N = 0 and 1 levels up to 8000 cm -1 above the zero-point level using the MORBID approach. We have also used the Discrete Variable Representation and Distributed Gaussian Basis (DVR-DGB) approach to calculate the energies of the N = 0 levels for comparison. The aim of this work is to obtain a zeroth-order set of vibrational states (with their associated rotational constants) in the region between 7000 and 8000 cm -1 where there will be interaction with the low-lying Ć2A' state for which T0 = 7029 cm -1.
Bian, Hongtao; Chen, Hailong; Li, Jiebo; Wen, Xiewen; Zheng, Junrong
2011-10-27
The donor/acceptor energy mismatch and vibrational coupling strength dependences of interionic vibrational energy transfer kinetics in electrolyte aqueous solutions were investigated with ultrafast multiple-dimensional vibrational spectroscopy. An analytical equation derived from the Fermi's Golden rule that correlates molecular structural parameters and vibrational energy transfer kinetics was found to be able to describe the intermolecular mode specific vibrational energy transfer. Under the assumption of the dipole-dipole approximation, the distance between anions in the aqueous solutions was obtained from the vibrational energy transfer measurements, confirmed with measurements on the corresponding crystalline samples. The result demonstrates that the mode-specific vibrational energy transfer method holds promise as an angstrom molecular ruler. PMID:21916443
Nonlinear vibration analysis of the high-efficiency compressive-mode piezoelectric energy harvester
NASA Astrophysics Data System (ADS)
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.
Separation of time variant vibration sources by short time coherent output power
NASA Astrophysics Data System (ADS)
Trethewey, Martin W.
2011-02-01
This effort describes the use of time variant coherence causality based analysis to separate the effects of nonstationary time variant vibration excitation sources. A time variant coherence function using the Short Time Fourier Transform (STFT) is first discussed. The concept of a time variant coherent output power for source separation of systems with time variant transfer functions is developed. A parametric study is performed to examine the coherent output power separation capabilities with respect to the data processing parameters. The study guided the selection of the time-frequency processing parameters judged to provide a suitable compromise between the time event localization and output amplitude source separation. The time variant coherent output power is then applied to separate the effects of the two possible excitation sources on the prototype vibration isolation floor. The application was a subscale prototype isolation floor for a proposed vibration sensitive equipment site adjacent to a busy freight rail line. The moving train created time variant transmission paths. As there was a direct line of sight between the prototype floor and the rail line there was an airborne acoustic excitation path in addition to a ground path. The short time coherent output power was applied to separate prototype isolation floor vibration into respective components related to the two candidate sources. The analysis and discussion of the results focuses upon the interpretation and issues in such a complicated realistic environment. Ultimately the application was successful providing an explanation as to why the observed vibration isolation was degraded at higher frequencies.
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. PMID:22779465
Electron-vibration energy exchange models in nitrogen-containing plasma flows
Laporta, V. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 70125 Bari (Italy); Bruno, D. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 70125 Bari (Italy)
2013-03-14
The physics of vibrational kinetics in nitrogen-containing plasma produced by collisions with electrons is studied on the basis of recently derived cross sections and rate coefficients for the resonant vibrational-excitation by electron-impact. The temporal relaxation of the vibrational energy and of the vibrational distribution function is analyzed in a state-to-state approach. The electron and vibrational temperatures are varied in the range [0-50 000] K. Conclusions are drawn with respect to the derivation of reduced models and to the accuracy of a relaxation time formalism. An analytical fit of the vibrational relaxation time is given.
From MEMS to macro-world: a micro-milling machined wideband vibration piezoelectric energy harvester
NASA Astrophysics Data System (ADS)
Iannacci, J.; Sordo, G.
2015-05-01
In this work, we discuss a novel mechanical resonator design for the realization of vibration Energy Harvester (EH) capable to deliver power levels in the mW range. The device overcomes the typical constraint of frequency narrowband operability of standard cantilevered EHs, by exploiting a circular-shaped resonator with an increased number of mechanical Degrees Of Freedom (DOFs), leading to several resonant modes in the range of vibrations of interest (i.e. multi-modal wideband EH). The device, named Four-Leaf Clover (FLC), is simulated in Ansys Worbench, showing a significant number of resonant modes up to vibrations of around 2 kHz (modal eigenfrequencies analysis), and exhibiting levels of converted power up to a few mW at resonance (harmonic coupled-field analysis). The sole FLC mechanical structure is realized by micro-milling an Aluminum foil, while a cantilevered test structure also including PolyVinyliDene Fluoride (PVDF) film sheet is assembled in order to collect first experimental feedback on generated power levels. The first lab based tests show peak-to-peak voltages of several Volts when the cantilever is stimulated with a mechanical pulse. Further developments of this work will comprise the assembly of an FLC demonstrator with PVDF pads, and its experimental testing in order to validate the simulated results.
Tang, Qiaochu; Yang, Yongliang; Li, Xinxin
2014-04-01
An electromagnetic kinetic energy harvester has been developed, which can convert ultra-low-frequency motion and vibration energy into electrical power. This harvester employs a two-stage vibratory structure to collect low-frequency kinetic energy and effectively transfer it into electric power by using a pair of high-frequency resonant generators. Non-contact magnetic repulsive force is herein utilized for the 1st-stage sliding vibrator to drive the 2nd-stage resonators into frequency-up-conversion resonance. The non-contact actuation is helpful for durable and long-life working of the device. The prototyped device is fabricated and the design is well confirmed by experimental test. The harvester can be well operated at the frequency as low as 0.25 Hz. Under driving acceleration of 1 g at 0.5 Hz, the miniaturized harvester can generate a peak power of 4.42 mW and an average power of 158 ?W. PMID:24784650
Influence of vibration on mechanical power and electromyogram activity in human arm flexor muscles.
Bosco, C; Cardinale, M; Tsarpela, O
1999-03-01
The aim of this study was to evaluate the influence of vibration on the mechanical properties of arm flexors. A group of 12 international level boxers, all members of the Italian national team, voluntarily participated in the experiment: all were engaged in regular boxing training. At the beginning of the study they were tested whilst performing forearm flexion with an extra load equal to 5% of the subjects' body mass. Following this. one arm was given the experimental treatment (E; mechanical vibration) and the other was the control (no treatment). The E treatment consisted of five repetitions lasting 1-min each of mechanical vibration applied during arm flexion in isometric conditions with 1 min rest between them. Further tests were performed 5 min immediately after the treatment on both limbs. The results showed statistically significant enhancement of the average power in the arm treated with vibrations. The root mean square electromyogram (EMGrms) had not changed following the treatment but, when divided by mechanical power, (P) as an index of neural efficiency, it showed statistically significant increases. It was concluded that mechanical vibrations enhanced muscle P and decreased the related EMG/P relationship in elite athletes. Moreover, the analysis of EMGrms recorded before the treatment and during the treatment itself showed an enormous increase in neural activity during vibration up to more than twice the baseline values. This would indicate that this type of treatment is able to stimulate the neuromuscular system more than other treatments used to improve neuromuscular properties. PMID:10090628
Analysis of Energy Harvesting for Vibration-Motivated Wireless Sensor Networks
Lim, Sunho
Analysis of Energy Harvesting for Vibration-Motivated Wireless Sensor Networks Sunho Lim Dept.com Abstract-- Extracting an electrical energy from various environmental sources, called energy harvesting (or energy scavenging), has been attracting researchers' attention in energy replenishable networks
Field Telemetry of Blade-rotor Coupled Torsional Vibration at Matuura Power Station Number 1 Unit
NASA Technical Reports Server (NTRS)
Isii, Kuniyoshi; Murakami, Hideaki; Otawara, Yasuhiko; Okabe, Akira
1991-01-01
The quasi-modal reduction technique and finite element model (FEM) were used to construct an analytical model for the blade-rotor coupled torsional vibration of a steam turbine generator of the Matuura Power Station. A single rotor test was executed in order to evaluate umbrella vibration characteristics. Based on the single rotor test results and the quasi-modal procedure, the total rotor system was analyzed to predict coupled torsional frequencies. Finally, field measurement of the vibration of the last stage buckets was made, which confirmed that the double synchronous resonance was 124.2 Hz, meaning that the machine can be safely operated. The measured eigen values are very close to the predicted value. The single rotor test and this analytical procedure thus proved to be a valid technique to estimate coupled torsional vibration.
Modeling nonlinear random vibration: Implication of the energy conservation law
Xu Sun; Jinqiao Duan; Xiaofan Li
2012-06-18
Nonlinear random vibration under excitations of both Gaussian and Poisson white noises is considered. The model is based on stochastic differential equations, and the corresponding stochastic integrals are defined in such a way that the energy conservation law is satisfied. It is shown that Stratonovich integral and Di Paola-Falsone integral should be used for excitations of Gaussian and Poisson white noises, respectively, in order for the model to satisfy the underlining physical laws (e.g., energy conservation). Numerical examples are presented to illustrate the theoretical results.
Modeling and Tuning for Vibration Energy Harvesting using a Piezoelectric Bimorph
NASA Astrophysics Data System (ADS)
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 the modeling of piezoelectric generator, different methods are employed to modeling the coupled dynamics of a piezoelectric bimorph on a vibrating beam as well as a simple piezoelectric bimorph cantilever. The modeling of piezoelectric bimorph as an alternative current (AC) source with internal capacitance and resistance is used to analyze a piezoelectric bimorph cantilever and to calculate the optimal external load resistance for maximal power output. The couple dynamics method based on Hamilton's Principle is applied in the modeling of the piezoelectric bimorph on a vibrating beam. Impulse response experiment shows this method has a better estimation of the experimental results than the curvature model. The coupled dynamics model is also applied to piezoelectric bimorph cantilever and the external load resistance is also determined by this to maximize the power output. The finite element equations for the piezoelectric materials in the element domain are theoretically derived. The procedure of modeling a piezoelectric on a vibrating beam is demonstrated base on the package of ANSYS. The frequency response of ZnO nanowires with different dimensions is derived analytically for ambient mediums with different damping ratios. With help from nano research lab of Dr. Yong Zhu and the student Feng Xu, an experiment is conducted which indentifies the first modal frequency of ZnO nanowires with different dimensions. The experimental modal frequencies are compared with the numerical results. The influence of the thickness of deposit on the modal frequency is also investigated by finite element modeling.
Prediction of Flow-Induced Structural Vibration and Sound Radiation Using Energy Flow Analysis
NASA Astrophysics Data System (ADS)
Han, F.; Bernhard, R. J.; Mongeau, L. G.
1999-11-01
The energy flow analysis method used to predict the structural vibration response and the radiated sound power of a plate excited by wall pressure fluctuations under turbulent boundary layers, and separated-reattached flows. This method allows the spatially averages energy density and response to be calculated for non-uniform, distributed excitations while taking hydrodynamic flow/structural coupling effects into consideration. The power input was calculated using well known analytical models for the plate mechanical impedance and empirical models for the surface pressure cross-power spectral density and/or wave number-frequency spectral density. The Smol'yakov-Tkachenko model was used to estimate the fluctuation pressure field underneath turbulent boundary layer flows. The Corcos model was used to estimate the wall pressure field under non-uniform, separated-reattached flows. Experiments were performed in order to evaluate the energy flow model. A clamped plate installed in a quiet, low-speed wind tunnel was used. The wall pressure fluctuations, the plate vibration response, and the acoustic pressure radiated from the plate were measured. The energy flow analysis method was found to provide reasonably accurate predictions of the frequency-averaged transverse velocity response of the plate at high frequencies. The acoustic pressure radiated on the quiescent side of the plate was also predicted with comparable accuracy.
NASA Astrophysics Data System (ADS)
Tsampas, P.; Roditis, G.; Papadimitriou, V.; Chatzakos, P.; Gan, Tat-Hean
2013-05-01
Increasing demand in mobile, autonomous devices has made energy harvesting a particular point of interest. Systems that can be powered up by a few hundreds of microwatts could feature their own energy extraction module. Energy can be harvested from the environment close to the device. Particularly, the ambient mechanical vibrations conversion via piezoelectric transducers is one of the most investigated fields for energy harvesting. A technique for optimized energy harvesting using piezoelectric actuators called "Synchronized Switching Harvesting" is explored. Comparing to a typical full bridge rectifier, the proposed harvesting technique can highly improve harvesting efficiency, even in a significantly extended frequency window around the piezoelectric actuator's resonance. In this paper, the concept of design, theoretical analysis, modeling, implementation and experimental results using CEDRAT's APA 400M-MD piezoelectric actuator are presented in detail. Moreover, we suggest design guidelines for optimum selection of the storage unit in direct relation to the characteristics of the random vibrations. From a practical aspect, the harvesting unit is based on dedicated electronics that continuously sense the charge level of the actuator's piezoelectric element. When the charge is sensed, to come to a maximum, it is directed to speedily flow into a storage unit. Special care is taken so that electronics operate at low voltages consuming a very small amount of the energy stored. The final prototype developed includes the harvesting circuit implemented with miniaturized, low cost and low consumption electronics and a storage unit consisting of a super capacitors array, forming a truly self-powered system drawing energy from ambient random vibrations of a wide range of characteristics.
NASA Astrophysics Data System (ADS)
Jung, Joon O.; Gerber, R. Benny
1996-12-01
The vibrational ground state and the fundamental excited states of (Ar)13 were studied by vibrational self-consistent field (VSCF) calculations. These calculations treat the interaction between different modes through a mean potential approximation, and incorporate anharmonicity in full. The good accuracy of VSCF for such systems was demonstrated by test calculations for (Ar)3 and other clusters. The study of (Ar)13 focused on the properties of the wave functions and the excitation energies, on the role of the coupling between the modes and on the deviation from the harmonic approximation. It was found that SCF excitation energies for the fundamental transitions differ from the harmonic values by about 25% for the softest modes, and by about 10% for the stiffest modes. Coupling between the modes, treated by SCF, was found to be much more important than the intrinsic anharmonicity of the individual modes. For the ground state, the harmonic wave function compares well with VSCF, but for the fundamental excited states appreciable differences were found. The results for a potential field expanded to fourth-order polynomial in the normal mode displacements are found to be valid, almost indentical with those for a more elaborate sixth-order polynomial expansion. The fundamental excitation frequencies computed using the Aziz-Slaman Ar-Ar pair potential are very similar, with some quantitative deviations, to the values obtained with a Lennard-Jones potential. The differences are larger for certain specific modes, and very small for the others. These calculations demonstrate the computational power of VSCF as a tool for quantum-mechanical calculations for large clusters, at the level of specific wave functions.
Hu, Youfan; Yang, Jin; Jing, Qingshen; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin
2013-11-26
An unstable mechanical structure that can self-balance when perturbed is a superior choice for vibration energy harvesting and vibration detection. In this work, a suspended 3D spiral structure is integrated with a triboelectric nanogenerator (TENG) for energy harvesting and sensor applications. The newly designed vertical contact-separation mode TENG has a wide working bandwidth of 30 Hz in low-frequency range with a maximum output power density of 2.76 W/m(2) on a load of 6 M?. The position of an in-plane vibration source was identified by placing TENGs at multiple positions as multichannel, self-powered active sensors, and the location of the vibration source was determined with an error less than 6%. The magnitude of the vibration is also measured by the output voltage and current signal of the TENG. By integrating the TENG inside a buoy ball, wave energy harvesting at water surface has been demonstrated and used for lighting illumination light, which shows great potential applications in marine science and environmental/infrastructure monitoring. PMID:24168315
Active Vibration Control for Helicopter Interior Noise Reduction Using Power Minimization
NASA Technical Reports Server (NTRS)
Mendoza, J.; Chevva, K.; Sun, F.; Blanc, A.; Kim, S. B.
2014-01-01
This report describes work performed by United Technologies Research Center (UTRC) for NASA Langley Research Center (LaRC) under Contract NNL11AA06C. The objective of this program is to develop technology to reduce helicopter interior noise resulting from multiple gear meshing frequencies. A novel active vibration control approach called Minimum Actuation Power (MAP) is developed. MAP is an optimal control strategy that minimizes the total input power into a structure by monitoring and varying the input power of controlling sources. MAP control was implemented without explicit knowledge of the phasing and magnitude of the excitation sources by driving the real part of the input power from the controlling sources to zero. It is shown that this occurs when the total mechanical input power from the excitation and controlling sources is a minimum. MAP theory is developed for multiple excitation sources with arbitrary relative phasing for single or multiple discrete frequencies and controlled by a single or multiple controlling sources. Simulations and experimental results demonstrate the feasibility of MAP for structural vibration reduction of a realistic rotorcraft interior structure. MAP control resulted in significant average global vibration reduction of a single frequency and multiple frequency excitations with one controlling actuator. Simulations also demonstrate the potential effectiveness of the observed vibration reductions on interior radiated noise.
Novel optimized design of a piezoelectric energy harvester in a package for low amplitude vibrations
NASA Astrophysics Data System (ADS)
Murillo, G.; Campanella, H.; Esteve, J.; Abadal, G.
2013-12-01
This paper presents a novel piezoelectric energy harvesting device created with the flip-chip bonding of two different parts, one is a MEMS die which plays the role of inertial mass and the other is an associate CMOS chip anchored to the vibrating environment. The flip-chip bonding is performed between the MEMS die, which consists of four piezoelectric beams connected to four PADs or anchor points, and a test PCB, which is used to validate the feasibility of the whole assembled system. The resulting system in package is a proof of concept of a novel design concept that increases the extracted power from an ambient vibration. FEM simulations have been carried out to study the mechanical behaviour of the who le system. Moreover, the fabrication of the piezoelectric die and the test PCB has been successfully performed, as well as their flip-chip integration.
Energy Harvesting with Stochastic, Subharmonic and Ultraharmonic Vibrations
NASA Astrophysics Data System (ADS)
Lin, Ji-Tzuoh; Alphenaar, Bruce
2011-03-01
Non-linear bi-stable systems have been shown to provide improved efficiency for harvesting energy from random and broad band vibration sources. This paper explores the distinct frequency response in the broadened spectrum of a particular non-linear energy harvester, a piezoelectric cantilever with magnetic coupling. The cantilever response evolves dynamically with frequency around the main cantilever resonance. Both stochastic and multi-frequency vibration responses are observed, and account for some of the improved efficiency. In addition, sub-harmonics and ultra-harmonics of the main resonance, along with various combinations of these appear. Taken together, the sub-harmonic and ultra-harmonic response produces an average of four-fold increase in voltage production. For energy harvesting purposes, the mixtures of the stochastic and various harmonic features together with the un-damped resonant response enhances the performance well beyond that of a standard energy harvester. An analytical model of the bi-stable dynamics produces results consistent with those observed experimentally. The effort was funded by the U.S. Navy under Contract DAAB07-03-D-B010/TO-0198. Technical program oversight under Navy contract was provided by Naval Surface Warfare Center, Crane Division.
Dissociation energy and vibrational predissociation dynamics of the ammonia dimer
NASA Astrophysics Data System (ADS)
Case, Amanda S.; Heid, Cornelia G.; Kable, Scott H.; Crim, F. Fleming
2011-08-01
Experiments using infrared excitation of either the intramolecular symmetric N-H stretch (?NH,S) or the intramolecular antisymmetric N-H stretch (?NH,A) of the ammonia dimer ((NH3)2) in combination with velocity-map ion imaging provide new information on the dissociation energy of the dimer and on the energy disposal in its dissociation. Ion imaging using resonance enhanced multiphoton ionization to probe individual rovibrational states of one of the ammonia monomer fragments provides recoil speed distributions. Analyzing these distributions for different product states gives a dissociation energy of D0 = 660 ± 20 cm-1 for the dimer. Fitting the distributions shows that rotations are excited up to their energetic limit and determines the correlation of the fragment vibrations. The fragments NH3(v2 = 3+) and NH3(v2 = 2+) have a vibrational ground-state partner NH3(v = 0), but NH3(v2 = 1+) appears in partnership with another fragment in v2 = 1. This propensity is consistent with the idea of minimizing the momentum gap between the initial and final states by depositing a substantial fraction of the available energy into internal excitation.
NASA Technical Reports Server (NTRS)
Tessarzik, J. M.; Chiang, T.; Badgley, R. H.
1973-01-01
The vibration response of a gas-bearing rotor-support system was analyzed experimentally documented for sinusoidal and random vibration environments. The NASA Brayton Rotating Unit (BRU), 36,000 rpm; 10 KWe turbogenerator; was subjected in the laboratory to sinusoidal and random vibrations to evaluate the capability of the BRU to (1) survive the vibration levels expected to be encountered during periods of nonoperation and (2) operate satisfactorily (that is, without detrimental bearing surface contacts) at the vibration levels expected during normal BRU operation. Response power spectral density was calculated for specified input random excitation, with particular emphasis upon the dynamic motions of the thrust bearing runner and stator. A three-mass model with nonlinear representation of the engine isolator mounts was used to calculate axial rotor-bearing shock response.
Sassani, Farrokh
2014-01-01
The simulation results for electromagnetic energy harvesters (EMEHs) under broad band stationary Gaussian random excitations indicate the importance of both a high transformation factor and a high mechanical quality factor to achieve favourable mean power, mean square load voltage, and output spectral density. The optimum load is different for random vibrations and for sinusoidal vibration. Reducing the total damping ratio under band-limited random excitation yields a higher mean square load voltage. Reduced bandwidth resulting from decreased mechanical damping can be compensated by increasing the electrical damping (transformation factor) leading to a higher mean square load voltage and power. Nonlinear EMEHs with a Duffing spring and with linear plus cubic damping are modeled using the method of statistical linearization. These nonlinear EMEHs exhibit approximately linear behaviour under low levels of broadband stationary Gaussian random vibration; however, at higher levels of such excitation the central (resonant) frequency of the spectral density of the output voltage shifts due to the increased nonlinear stiffness and the bandwidth broadens slightly. Nonlinear EMEHs exhibit lower maximum output voltage and central frequency of the spectral density with nonlinear damping compared to linear damping. Stronger nonlinear damping yields broader bandwidths at stable resonant frequency. PMID:24605063
Vibrating RF MEMS for Low Power Communications Clark T.-C. Nguyen
Nguyen, Clark T.-C.
Vibrating RF MEMS for Low Power Communications Clark T.-C. Nguyen Center for Integrated Wireless, Michigan 48109-2122, U.S.A. ABSTRACT Micromechanical communication circuits fabricated via IC con- sumption. Technologies that integrate MEMS and transistor circuits into single-chip systems
Effect of Vibration Training on Anaerobic Power and Quardroceps Surface EMG in Long Jumpers
ERIC Educational Resources Information Center
Liu, Bin; Luo, Jiong
2015-01-01
Objective: To explore the anaerobic power and surface EMG (sEMG) of quardrocep muscle in lower extremities after single vibration training intervention. Methods: 8 excellent male long jumpers voluntarily participated in this study. Four intervention modes were devised, including high frequency high amplitude (HFHA,30Hz,6mm), low frequency low
Saffar, Saber; Abdullah, Amir
2014-01-01
The acoustic impedances of matching layers, their internal loss and vibration amplitude are the most important and influential parameters in the performance of high power airborne ultrasonic transducers. In this paper, the optimum acoustic impedances of the transducer matching layers were determined by using a genetic algorithm, the powerful tool for optimizating domain. The analytical results showed that the vibration amplitude increases significantly for low acoustic impedance matching layers. This enhancement is maximum and approximately 200 times higher for the last matching layer where it has the same interface with the air than the vibration amplitude of the source, lead zirconate titanate-pizo electric while transferring the 1 kW is desirable. This large amplitude increases both mechanical failure and temperature of the matching layers due to the internal loss of the matching layers. It has analytically shown that the temperature in last matching layer with having the maximum vibration amplitude is high enough to melt or burn the matching layers. To verify suggested approach, the effect of the amplitude of vibration on the induced temperature has been investigated experimentally. The experimental results displayed good agreement with the theoretical predictions. PMID:23664304
Low power energy harvesting and storage techniques from ambient human powered energy sources
NASA Astrophysics Data System (ADS)
Yildiz, Faruk
Conventional electrochemical batteries power most of the portable and wireless electronic devices that are operated by electric power. In the past few years, electrochemical batteries and energy storage devices have improved significantly. However, this progress has not been able to keep up with the development of microprocessors, memory storage, and sensors of electronic applications. Battery weight, lifespan and reliability often limit the abilities and the range of such applications of battery powered devices. These conventional devices were designed to be powered with batteries as required, but did not allow scavenging of ambient energy as a power source. In contrast, development in wireless technology and other electronic components are constantly reducing the power and energy needed by many applications. If energy requirements of electronic components decline reasonably, then ambient energy scavenging and conversion could become a viable source of power for many applications. Ambient energy sources can be then considered and used to replace batteries in some electronic applications, to minimize product maintenance and operating cost. The potential ability to satisfy overall power and energy requirements of an application using ambient energy can eliminate some constraints related to conventional power supplies. Also power scavenging may enable electronic devices to be completely self-sustaining so that battery maintenance can eventually be eliminated. Furthermore, ambient energy scavenging could extend the performance and the lifetime of the MEMS (Micro electromechanical systems) and portable electronic devices. These possibilities show that it is important to examine the effectiveness of ambient energy as a source of power. Until recently, only little use has been made of ambient energy resources, especially for wireless networks and portable power devices. Recently, researchers have performed several studies in alternative energy sources that could provide small amounts of electricity to low-power electronic devices. These studies were focused to investigate and obtain power from different energy sources, such as vibration, light, sound, airflow, heat, waste mechanical energy and temperature variations. This research studied forms of ambient energy sources such as waste mechanical (rotational) energy from hydraulic door closers, and fitness exercise bicycles, and its conversion and storage into usable electrical energy. In both of these examples of applications, hydraulic door closers and fitness exercise bicycles, human presence is required. A person has to open the door in order for the hydraulic door closer mechanism to function. Fitness exercise bicycles need somebody to cycle the pedals to generate electricity (while burning calories.) Also vibrations, body motions, and compressions from human interactions were studied using small piezoelectric fiber composites which are capable of recovering waste mechanical energy and converting it to useful electrical energy. Based on ambient energy sources, electrical energy conversion and storage circuits were designed and tested for low power electronic applications. These sources were characterized according to energy harvesting (scavenging) methods, and power and energy density. At the end of the study, the ambient energy sources were matched with possible electronic applications as a viable energy source.
Alternative Energy Technologies Solar Power
Scott, Christopher
#12;Alternative Energy Technologies Solar Power Photovoltaics Concentrating Solar Power (CSP) Power gauges, gas sensors. Light-emitting diodes (LED's) Power amplifiers for cell phones Indium Gallium #12;Concentrating Solar Power (CSP) Reflector material is Aluminum or Silver Tube material ..... Several possible
DSMC Modeling of Vibration-Vibration Energy Transfer Between Diatomic Molecules
Bondar, Ye. A.; Ivanov, M. S.
2008-12-31
Larsen-Borgnakke model, widely used in the DSMC method to simulate rotation-translation and vibration-translation exchanges in molecular collisions, is applied for the first time to resonant exchange between the vibrational modes of diatomic molecules (VV exchange). The validation of the model is performed through comparisons with experimental data on VV exchange in nitrogen.
Adhesion energy characterization of monolayer graphene by vibrational spectroscopy
NASA Astrophysics Data System (ADS)
Vahdat, Armin Saeedi; Cetinkaya, Cetin
2013-10-01
As at nano/micro-scale van der Waals forces often dominate various other types of forces, the accurate adhesion characterization of graphene (Gr) is essential to its processing, manipulation, and possible integration into integrated circuits and other nano/micro-scale devices. Since 2010, the reported (experimental) adhesion energy of monolayer Gr with silicon dioxide (SiO2) has increased from 151 ± 28 mJ/m2 to 450 ± 20 mJ/m2. Here, we report a set of adhesion energy values for Gr monolayers on a SiO2 substrate by adopting a unique vibrational spectroscopy approach based on the motion of adhesive microparticles on a vibrating substrate. The reported results indicate that the work-of-adhesion measurements of monolayer Gr on SiO2 could be highly scattered and its mean value is determined as WSiO2-Gr = 1160.26 mJ/m2, which is the highest value reported to date. Unlike the reported existing methods, the current non-contact and non-destructive spectral technique requires no knowledge of the mechanical properties of Gr. Based on the reported data, with the current approach, it is also demonstrated that the weak adhesive interactions between a polystyrene latex microparticle and SiO2 substrate across the monolayer Gr can be detected as well.
Determination of stepsize parameters for intermolecular vibrational energy transfer
Tardy, D.C.
1992-03-01
Intermolecular energy transfer of highly excited polyatomic molecules plays an important role in many complex chemical systems: combustion, high temperature and atmospheric chemistry. By monitoring the relaxation of internal energy we have observed trends in the collisional efficiency ({beta}) for energy transfer as a function of the substrate's excitation energy and the complexities of substrate and deactivator. For a given substrate {beta} increases as the deactivator's mass increase to {approximately}30 amu and then exhibits a nearly constant value; this is due to a mass mismatch between the atoms of the colliders. In a homologous series of substrate molecules (C{sub 3}{minus}C{sub 8}) {beta} decreases as the number of atoms in the substrate increases; replacing F with H increases {beta}. All substrates, except for CF{sub 2}Cl{sub 2} and CF{sub 2}HCl below 10,000 cm{sup {minus}1}, exhibited that {beta} is independent of energy, i.e. <{Delta}E>{sub all} is linear with energy. The results are interpreted with a simple model which considers that {beta} is a function of the ocillators energy and its vibrational frequency. Limitations of current approximations used in high temperature unimolecular reactions were evaluated and better approximations were developed. The importance of energy transfer in product yields was observed for the photoactivation of perfluorocyclopropene and the photoproduction of difluoroethyne. 3 refs., 18 figs., 4 tabs.
Straub, John E.
that the predominant channel for fast kinetic energy relaxation of the heme in native myoglobin is directed energy suggested the possibility that the vibrational energy could be transferred directly from the hemeVibrational Energy Relaxation of "Tailored" Hemes in Myoglobin Following Ligand Photolysis Supports
Note: A cubic electromagnetic harvester that convert vibration energy from all directions.
Han, Mengdi; Qiu, Guolin; Liu, Wen; Meng, Bo; Zhang, Xiao-Sheng; Zhang, Haixia
2014-07-01
We investigate the output performance of a cubic harvester which can scavenge low-frequency vibration energy from all directions. By adjusting the size and shape of the inside magnets, higher induced voltages and output power can be achieved. The optimal magnet is found to be cubic shape with the length of 6.35 mm (25.6% volume ratio), which can generate 4.27 mV root mean square voltage and 2.45 ?W average power at the frequency of 28.86 Hz and acceleration of 1.17 g. The device is also demonstrated as a self-powered tilt sensor by measuring induced voltages at different tilt angles. PMID:25085194
NASA Astrophysics Data System (ADS)
dos Santos, S. Fonseca; Balakrishnan, N.; Forrey, R. C.; Stancil, P. C.
2013-03-01
Quantum scattering calculations of vibration-vibration (VV) and vibration-translation (VT) energy transfer for non-reactive H2-H2 collisions on a full-dimensional potential energy surface are reported for energies ranging from the ultracold to the thermal regime. The efficiency of VV and VT transfer is known to strongly correlate with the energy gap between the initial and final states. In H2(v = 1, j = 0) + H2(v = 0, j = 1) collisions, the inelastic cross section at low energies is dominated by a VV process leading to H2(v = 0, j = 0) + H2(v = 1, j = 1) products. At energies above the opening of the v = 1, j = 2 rotational channel, pure rotational excitation of the para-H2 molecule leading to the formation of H2(v = 1, j = 2) + H2(v = 0, j = 1) dominates the inelastic cross section. For vibrationally excited H2 in the v = 2 vibrational level colliding with H2(v = 0), the efficiency of both VV and VT process is examined. It is found that the VV process leading to the formation of 2H2(v = 1) molecules dominates over the VT process leading to H2(v = 1) + H2(v = 0) products, consistent with available experimental data, but in contrast to earlier semiclassical results. Overall, VV processes are found to be more efficient than VT processes, for both distinguishable and indistinguishable H2-H2 collisions confirming room temperature measurements for v = 1 and v = 2.
Vibrating Beam With Spatially Periodic Stiffness
NASA Technical Reports Server (NTRS)
Townsend, John S.
1989-01-01
Report presents theoretical analysis of vibrations of simply supported beam, bending stiffness varying about steady value, sinusoidally with position along length. Problem of practical importance because related to vibrations of twisted-pair electric-power transmission lines. Twists promote nonuniform shedding of vortexes and prevents resonant accumulation of vibrational energy from wind.
Minimizing the Excitation of Parasitic Modes of Vibration in Slender Power Ultrasonic Devices
NASA Astrophysics Data System (ADS)
Mathieson, A.; Lucas, M.
The design of slender power ultrasonic devices can often be challenging due to the excitation of parasitic modes of vibration during operation. The excitation of these modes is known to manifest from behaviors such as modal coupling which if not controlled or designed out of the system can, under operational conditions, lead to poor device performance and device failure. However, a report published by the authors has indicted that the excitation of these modes of vibration could be minimized through device design, specifically careful location of the piezoceramic stack. This paper illustrates that it is possible, through piezoceramic stack position, to minimize modal coupling between a parasitic mode and the tuned longitudinal mode of vibration for slender ultrasonic devices.
A high-power linear ultrasonic motor using longitudinal vibration transducers with single foot.
Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun
2010-08-01
A high-power linear ultrasonic motor using longitudinal vibration transducers with single foot was proposed in this paper. The stator of proposed motor contains a horizontal transducer and a vertical transducer. Longitudinal vibrations are superimposed in the stator and generate an elliptical trajectory at the driving foot. The sensitivity analysis of structural parameters to the resonance frequencies of two working modes of the stator was performed using the finite element method. The resonance frequencies of two working modes were degenerated by adjusting the structural parameters. The vibration characteristics of stator were studied and discussed. A prototype motor was fabricated and measured. Typical output of the prototype is a no-load speed of 1160 mm/s and maximum thrust force of 20 N at a voltage of 200 V(rms). PMID:20679015
Ayazi, Farrokh
MULTI-AXIS ALN-ON-SILICON VIBRATION ENERGY HARVESTER WITH INTEGRATED FREQUENCY presents fully-integrated multi-axis piezoelectric-on-silicon kinetic energy harvesters (KEHs energy harvesters at such low frequencies. Piezoelectric cantilever harvesters generate
Bovenzi, M; Lindsell, C; Griffin, M
2001-01-01
OBJECTIVESTo investigate the acute response of finger circulation to vibration with different combinations of magnitude and duration but with the same "energy equivalent" acceleration magnitude according to current standards for hand transmitted vibration.?METHODSFinger skin temperature (FST) and finger blood flow (FBF) were measured in the middle fingers of both hands of 10 healthy men who had not used hand held vibrating tools regularly. With a static load of 10 N, the right hand was exposed to 125 Hz vibration with the following unweighted root mean square (rms) acceleration magnitudes and durations of exposure: 44 m/s2 for 30 minutes; 62 m/s2 for 15 minutes; 88 m/s2 for 7.5 minutes; 125 m/s2 for 3.75 minutes; and 176 m/s2 for 1.88 minutes. These vibration exposures produce the same 8 hour energy equivalent frequency weighted acceleration magnitude (~1.4 m/s2 rms) according to international standard ISO 5349 (1986). Finger circulation was measured in both the right (vibrated) and the left (non-vibrated) middle fingers before application of the vibration, and at fixed intervals during exposure to vibration and during a 45 minute recovery period.?RESULTSThe FST did not change during exposure to vibration, whereas vibration with any combination of acceleration magnitude and duration produced significant percentage reductions in the FBF of the vibrated finger compared with the FBF before exposure (from ?40.1% (95% confidence interval (95% CI) ?24.3% to ?57.2%) to ?61.4% (95% CI ?45.0% to ?77.8%). The reduction in FBF during vibration was stronger in the vibrated finger than in the non-vibrated finger. Across the five experimental conditions, the various vibration stimuli caused a similar degree of vasoconstriction in the vibrated finger during exposure to vibration. There was a progressive decrease in the FBF of both fingers after the end of exposure to vibration with acceleration magnitudes of 44 m/s2 for 30 minutes and 62 m/s2 for 15 minutes. Significant vasoconstrictor after effects were not found in either finger after exposure to any of the other vibration stimuli with greater acceleration magnitudes for shorter durations.?CONCLUSIONSFor the range of vibration magnitudes investigated (44 to 176 m/s2 rms unweighted; 5.5 to 22 m/s2 rms when frequency weighted according to ISO 5349), the vasoconstriction during exposure to 125 Hz vibration was independent of vibration magnitude. The after effect of vibration was different for stimuli with the same energy equivalent acceleration, with greater effects after longer durations of exposure. The energy equivalent acceleration therefore failed to predict the acute effects of vibration both during and after exposure to vibration. Both central and local vasoregulatory mechanisms are likely to be involved in the response of finger circulation to acute exposures to 125 Hz vibration.???Keywords: finger circulation; energy equivalent acceleration magnitude; vibration frequency; magnitude; and duration PMID:11171932
An investigation on vibration energy harvesting using nonlinear dynamic principles inspired by trees
NASA Astrophysics Data System (ADS)
Harne, R. L.; Sun, A.; Wang, K. W.
2015-04-01
Trees exploit intriguing mechanisms such as multimodal frequency distributions and nonlinearities to distribute and dampen the aerodynamically-induced vibration energies to which they are subjected. In dynamical systems, these mechanisms are comparable to the internal resonance phenomenon. In recent years, researchers have harnessed strong nonlinearities, including internal resonance, to induce energetic dynamics that enhance performance of vibration energy harvesting systems. For trees, the internal resonance-like dynamics are evidently useful damping mechanisms in spite of the high variation associated with excitation and structural parameters. Yet for dynamic systems, studies show narrow operating regimes which exhibit internal resonance-based behaviors, suggesting that the energetic dynamics may be deactivated if stochastic inputs corrupt ideal excitation properties. To address these issues, this research evaluates the opportunities enabled by exploiting nonlinear, multimodal motions in an L-shaped energy harvester platform. The system dynamics are probed analytically, numerically, and experimentally for comprehensive insights on the versatility of internal resonance-based behaviors for energy harvesting. It is found that although activating the high amplitude nonlinear dynamics to enhance power generation is robust to significant additive noise in the harmonic excitations, parameter sensitivities may pose practical challenges in application. Discussion is provided on means to address such concerns and on future strategies that may favorably exploit nonlinearity and multimodal dynamics for robust energy harvesting performance.
Chun, Inwoo; Lee, Hyun-Woo; Kwon, Kwang-Ho
2014-12-01
Limited energy sources of ubiquitous sensor networks (USNs) such as fuel cells and batteries have grave drawbacks such as the need for replacements and re-charging owing to their short durability and environmental pollution. Energy harvesting which is converting environmental mechanical vibration into electrical energy has been researched with some piezoelectric materials and various cantilever designs to increase the efficiency of energy-harvesting devices. In this study, we focused on an energy-harvesting cantilever with a broadband vibration frequency. We fabricated a lead zirconate titanate (PZT) cantilever array with various Si proof masses on small beams (5.5 mm x 0.5 mm x 0.5 mm). We obtained broadband resonant frequencies ranging between 127 Hz and 136 Hz using a micro electro-mechanical system (MEMS) process. In order to obtain broadband resonant characteristics, the cantilever array was comprised of six cantilevers with different resonant frequencies. We obtained an output power of about 2.461 ?W at an acceleration of 0.23 g and a resistance of 4 k?. The measured bandwidth of the resonant frequency was approximately 9 Hz (127-136 Hz), which is about six times wider than the bandwidth of a single cantilever. PMID:25971046
Power management for energy harvesting wireless sensors
NASA Astrophysics Data System (ADS)
Arms, S. W.; Townsend, C. P.; Churchill, D. L.; Galbreath, J. H.; Mundell, S. W.
2005-05-01
The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4 radio transceiver, and rechargeable battery. Extremely low power consumption sleep currents combined with periodic, timed wake-up was used to minimize the average power consumption. Furthermore, we deployed pulsed sensor excitation and microprocessor power control of the signal conditioning elements to minimize the sensors" average contribution to power draw. By sleeping in between samples, we were able to demonstrate extremely low average power consumption. At 10 Hz, current consumption was 300 microamps at 3 VDC (900 microwatts); at 5 Hz: 400 microwatts, at 1 Hz: 90 microwatts. When the RF stage was not used, but data were logged to memory, consumption was further reduced. Piezoelectric strain energy harvesting systems delivered ~2000 microwatts under low level vibration conditions. Output power levels were also measured from two miniature solar cells; which provided a wide range of output power (~100 to 1400 microwatts), depending on the light type & distance from the source. In summary, system power consumption may be reduced by: 1) removing the load from the energy harvesting & storage elements while charging, 2) by using sleep modes in between samples, 3) pulsing excitation to the sensing and signal conditioning elements in between samples, and 4) by recording and/or averaging, rather than frequently transmitting, sensor data.
A modal approach to modeling spatially distributed vibration energy dissipation.
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.
M. Ferrari; V. Ferrari; M. Guizzetti; D. Marioli
2010-01-01
Power harvesters from mechanical vibrations are commonly linear mechanical resonators that are most efficient when excited at resonance. Differently, under wideband vibrations, linear converters are suboptimal. A nonlinear converter is here proposed that implements nonlinearity and bistability by employing one external magnet, in order to improve conversion effectiveness while simplifying device fabrication. The converter is composed of a piezoelectric bimorph
Inversion vibration of PH3+(X~ 2A2'') studied by zero kinetic energy photoelectron spectroscopy
NASA Astrophysics Data System (ADS)
Yang, Jie; Li, Juan; Hao, Yusong; Zhou, Chang; Mo, Yuxiang
2006-08-01
We report the first rotationally resolved spectroscopic studies on PH3+(XA2?2) using zero kinetic energy photoelectron spectroscopy and coherent VUV radiation. The spectra about 8000cm-1 above the ground vibrational state of PH3+(XA2?2) have been recorded. We observed the vibrational energy level splittings of PH3+(XA2?2) due to the tunneling effect in the inversion (symmetric bending) vibration (?2+). The energy splitting for the first inversion vibrational state (0+/0-) is 5.8cm-1. The inversion vibrational energy levels, rotational constants, and adiabatic ionization energies (IEs) for ?2+=0-16 have been determined. The bond angles between the neighboring P-H bonds and the P-H bond lengths are also obtained using the experimentally determined rotational constants. With the increasing of the inversion vibrational excitations (?2+), the bond lengths (P-H) increase a little and the bond angles (H-P-H) decrease a lot. The inversion vibrational energy levels have also been calculated by using one dimensional potential model and the results are in good agreement with the experimental data for the first several vibrational levels. In addition to inversion vibration, we also observed firstly the other two vibrational modes: the symmetric P-H stretching vibration (?1+) and the degenerate bending vibration (?4+). The fundamental frequencies for ?1+ and ?4+ are 2461.6 (±2) and 1043.9 (±2)cm-1, respectively. The first IE for PH3 was determined as 79670.9 (±1)cm-1.
Yuksek, N. S.; Almasri, M. [Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211 (United States); Feng, Z. C. [Mechanical and Aerospace Engineering, University of Missouri, Columbia, Missouri 65211 (United States)
2014-09-15
In this paper, we propose an electromagnetic power harvester that uses a transformative multi-impact approach to achieve a wide bandwidth response from low frequency vibration sources through frequency-up conversion. The device consists of a pick-up coil, fixed at the free edge of a cantilever beam with high resonant frequency, and two cantilever beams with low excitation frequencies, each with an impact mass attached at its free edge. One of the two cantilevers is designed to resonate at 25?Hz, while the other resonates at 50?Hz within the range of ambient vibration frequency. When the device is subjected to a low frequency vibration, the two low-frequency cantilevers responded by vibrating at low frequencies, and thus their thick metallic masses made impacts with the high resonance frequency cantilever repeatedly at two locations. This has caused it along with the pick-up coil to oscillate, relative to the permanent magnet, with decaying amplitude at its resonance frequency, and results in a wide bandwidth response from 10 to 63?Hz at 2?g. A wide bandwidth response between 1051?Hz and 1058?Hz at acceleration values of 0.5?g and 2?g, respectively, were achieved by adjusting the impact cantilever frequencies closer to each other (25?Hz and 45?Hz). A maximum output power of 85??W was achieved at 5?g at 30?Hz across a load resistor, 2.68 ?.
Mercedes Alacid; Adolfo Bastida; Francisco J. Carvajal; Alberto Requena
1999-01-01
A potential energy surface for CO2is determined from experimental data using generalized internal vibrational coordinates. These coordinates are defined as two arbitrary distances and the angle between them and depend on two external parameters, which can be properly optimized. An optimal generalized internal coordinate system is obtained for CO2by minimizing unconverged vibrational energies with respect to the external parameters. The
NASA Astrophysics Data System (ADS)
Abdelkefi, A.; Najar, F.; Nayfeh, A. H.; Ben Ayed, S.
2011-11-01
Recently, piezoelectric cantilevered beams have received considerable attention for vibration-to-electric energy conversion. Generally, researchers have investigated a classical piezoelectric cantilever beam with or without a tip mass. In this paper, we propose the use of a unimorph cantilever beam undergoing bending-torsion vibrations as a new piezoelectric energy harvester. The proposed design consists of a single piezoelectric layer and a couple of asymmetric tip masses; the latter convert part of the base excitation force into a torsion moment. This structure can be tuned to be a broader band energy harvester by adjusting the first two global natural frequencies to be relatively close to each other. We develop a distributed-parameter model of the harvester by using the Euler-beam theory and Hamilton's principle, thereby obtaining the governing equations of motion and associated boundary conditions. Then, we calculate the exact eigenvalues and associated mode shapes and validate them with a finite element (FE) model. We use these mode shapes in a Galerkin procedure to develop a reduced-order model of the harvester, which we use in turn to obtain closed-form expressions for the displacement, twisting angle, voltage output, and harvested electrical power. These expressions are used to conduct a parametric study for the dynamics of the system to determine the appropriate set of geometric properties that maximizes the harvested electrical power. The results show that, as the asymmetry is increased, the harvester's performance improves. We found a 30% increase in the harvested power with this design compared to the case of beams undergoing bending only. We also show that the locations of the two masses can be chosen to bring the lowest two global natural frequencies closer to each other, thereby allowing the harvesting of electrical power from multi-frequency excitations.
Energy relaxation and vibrations in small 3D plasma clusters
NASA Astrophysics Data System (ADS)
Antonova, T.; Annaratone, B. M.; Thomas, H. M.; Morfill, G. E.
2008-04-01
The time evolution of three-dimensional (3D) plasma clusters containing 17 and 63 particles has been analyzed. Using a radiofrequency (rf) spot electrode, we were able to get almost un-stressed 3D clusters under gravity conditions on Earth. Fast 3D diagnostics of the particle positions allowed us to study the cluster structure and dynamics in detail. In particular, we were able to follow the evolution of the systems through rearrangement and particle evaporation to their final equilibrium state with minimum energy. The vibrations of the larger (63 particles) cluster were compatible with theoretical estimates for a liquid drop with surface tension. This indicates that macroscopic properties, normally associated with systems in the cooperative regime, provide an adequate description even for small (discrete) clusters.
[Vibrational energy transfer from vibrational levels of RbH(X 1sigma+, v = 0-2) to H2].
Shen, Xiao-Yan; Wang, Shu-Ying; Liu, Jing; Dai, Kang; Shen, Yi-Fan
2011-01-01
The vibrational energy transfer from vibrational levels of RbH(X 1sigma+, v = 0-2) by collision with H2 was determined using the integrated time-resolved laser induced fluorescence (LIF) in a five-arm crossed heat-pipe oven. Rb-H2 mixture was irradiated with pulses of 696.4 nm radiation from a OPO laser, populating 6D state by two-photon absorption. The vibrational levels of RbH(X 1sigma+) generated in the reaction of Rb(6D) and H2 were detected by LIF technique. The nascent quantum state distributions of RbH were obtained when the delay time between the pump and probe laser was 20 ns. The nascent RbH product molecules were found to populate the lowest three vibrational (v = 0, 1, 2) levels of the ground electronic state but could not be detected in any higher vibrational state. The integrated time-resolved LIF excited A 1sigma+ --> X 1sigma+ system in the presence of H2 was recorded with delay time from 0 to 10 micros. The RbH signal of v = 0, 1 levels first increased and then decreased on a larger time scale. RbH was created instantaneously then was quenched by collision and diffused. The rate equations for the population of the vibrational levels were given. The integrated profiles method permitted us to determine the rate coefficients for vibrational transfer of RbH(X 1sigma+, v = 0-2) by collision with H2. The rate coefficients for collisional transfer of RbH(X 1sigma+) by collisions with H2 are (in units of 10-(11) cm3 x s(-1)) 3.4 +/- 0.8 and 2.8 +/- 0.6 for v = 2 --> v = 1 and v = 1 --> v = 0 respectively. The diffusion rates of v = 0, 1, 2 are (in units of 10(5) s(-1)) 4.9 +/- 1.1, 1.0 +/- 0.3 and 0.6 +/- 10.2, respectively. The experiment showed that vibrational relaxation from RbH(X 1sigma+, v = 0-2) was more efficient compared to that of other vibrational levels studied here. PMID:21428051
A six-DOF vibration energy harvester based on the six-DOF parallel mechanism
NASA Astrophysics Data System (ADS)
Yuan, G.; Wang, D. H.
2015-04-01
The existing vibration energy harvesters can only harvest the vibration energy with single sensitive axial and narrow band, which lead to the problems of low efficiency and high level requirements for installation. This paper proposes a piezoelectric energy harvester for six-degree-of-freedom (six-DOF) vibration energy harvesting utilizing a six-DOF parallel mechanism with cubic configuration. It consists of a proof mass as the upper platform, six flexible legs with two spherical joints connected by a single-degree-of-freedom (single-DOF) harvester, and a foundation support. Compared to the conventional energy harvester, the proposed six-DOF vibration energy harvester has six sensitive axes and broader bandwidth for the proper designed six adjacent natural frequencies, so higher efficiency of energy harvesting can be expected. To investigate the characteristics of the proposed energy harvester, analytical developments and numerical simulations on its natural frequency and modes of vibration are carried out. These results show that the proposed six- DOF vibration energy harvester can harvest six-DOF vibration energy.
Mechanism of emergence of intense vibrations of turbines on the Sayano-Shushensk hydro power plant
V. B. Kurzin; V. S. Seleznev
2010-01-01
It is demonstrated that the level of vibrations of turbines on the Sayano-Shushensk hydro power plant is enhanced by the capability\\u000a of a compressible fluid to perform its own hydroacoustic oscillations (which can be unstable) in the turbine duct. Based on\\u000a the previously obtained results of solving the problem of natural hydroacoustic oscillations in the turbine duct and some\\u000a ideas
Vibration exercise as a warm-up modality for deadlift power output.
Cochrane, Darryl J; Coley, Karl W; Pritchard, Hayden J; Barnes, Matthew J
2015-04-01
Vibration exercise (VbX) has gained popularity as a warm-up modality to enhance performance in golf, baseball, and sprint cycling, but little is known about the efficacy of using VbX as a warm-up before resistance exercise, such as deadlifting. The aim of this study was to compare the effects of a deadlift (DL)-specific warm-up, VbX warm-up, and Control on DL power output (PO). The DL warm-up (DL-WU) included 10, 8, and 5 repetitions performed at 30, 40, and 50% 1-repetition maximum (1RM), respectively, where the number of repetitions was matched by body-weight squats performed with vibration and without vibration (Control). The warm-up conditions were randomized and performed at least 2 days apart. Peak power (PP), mean power, rate of force development (RFD), and electromyography (EMG) were measured during the concentric phase of 2 consecutive DLs (75% 1RM) at 30 seconds and 2:30 minutes after the warm-up conditions. There was no significant (p > 0.05) main effect or interaction effect between the DL-WU, VbX warm-up, and Control for PP, mean power, RFD, and EMG. Vibration exercise warm-up did not exhibit an ergogenic effect to potentiate muscle activity more than the specific DL-WU and Control. Therefore, DL PO is affected to a similar extent, irrespective of the type of stimuli, when the warm-up is not focused on raising muscle temperature. PMID:25353078
Energy 101: Concentrating Solar Power
None
2013-05-29
From towers to dishes to linear mirrors to troughs, concentrating solar power (CSP) technologies reflect and collect solar heat to generate electricity. A single CSP plant can generate enough power for about 90,000 homes. This video explains what CSP is, how it works, and how systems like parabolic troughs produce renewable power. For more information on the Office of Energy Efficiency and Renewable Energy's CSP research, see the Solar Energy Technology Program's Concentrating Solar Power Web page at http://www1.eere.energy.gov/solar/csp_program.html.
Influence of Förster-type energy transfer on the vibrational relaxation of anionic hydration shells
NASA Astrophysics Data System (ADS)
Lotze, Stephan; Bakker, Huib J.
2013-07-01
We study the influence of Förster energy transfer on the vibrational relaxation dynamics of anionic hydration shells by performing time-resolved mid-infrared spectroscopy on the OH-stretch vibration of water molecules in aqueous solutions of sodium iodide. We observe that the Förster energy transfer leads to a pronounced acceleration of the vibrational relaxation. We describe the observed dynamics with a model in which we include the Förster vibrational energy transfer between the different hydroxyl groups in solution. With this model we can quantitatively describe the experimental data over a wide range of isotopic compositions and salt concentrations. Our results show that resonant energy transfer is an efficient mechanism assisting in the vibrational relaxation of anionic hydration shells.
Vibration-to-electric energy conversion using a mechanically-varied capacitor
Yen, Bernard Chih-Hsun, 1981-
2005-01-01
Past research in vibration energy harvesting has focused on the use of variable capacitors, magnets, or piezoelectric materials as the basis of energy transduction. How- ever, few of these studies have explored the detailed ...
NASA Astrophysics Data System (ADS)
Jia, Yu; Yan, Jize; Soga, Kenichi; Seshia, Ashwin A.
2014-06-01
A vibration energy harvester designed to access parametric resonance can potentially outperform the conventional direct resonant approach in terms of power output achievable given the same drive acceleration. Although linear damping does not limit the resonant growth of parametric resonance, a damping dependent initiation threshold amplitude exists and limits its onset. Design approaches have been explored in this paper to passively overcome this limitation in order to practically realize and exploit the potential advantages. Two distinct design routes have been explored, namely an intrinsically lower threshold through a pendulum-lever configuration and amplification of base excitation fed into the parametric resonator through a cantilever-initial-spring configuration. Experimental results of the parametric resonant harvesters with these additional enabling designs demonstrated an initiation threshold up to an order of magnitude lower than otherwise, while attaining a much higher power peak than direct resonance.
Energy transfer of highly vibrationally excited naphthalene: collisions with CHF3, CF4, and Kr.
Chen Hsu, Hsu; Tsai, Ming-Tsang; Dyakov, Yuri A; Ni, Chi-Kung
2011-08-01
Energy transfer of highly vibrationally excited naphthalene in the triplet state in collisions with CHF(3), CF(4), and Kr was studied using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. Highly vibrationally excited naphthalene (2.0 eV vibrational energy) was formed via the rapid intersystem crossing of naphthalene initially excited to the S(2) state by 266 nm photons. The shapes of the collisional energy-transfer probability density functions were measured directly from the scattering results of highly vibrationally excited naphthalene. In comparison to Kr atoms, the energy transfer in collisions between CHF(3) and naphthalene shows more forward scatterings, larger cross section for vibrational to translational (V ? T) energy transfer, smaller cross section for translational to vibrational and rotational (T ? VR) energy transfer, and more energy transferred from vibration to translation, especially in the range -?E(d) = -100 to -800 cm(-1). On the other hand, the difference of energy transfer properties between collisional partners Kr and CF(4) is small. The enhancement of the V ? T energy transfer in collisions with CHF(3) is attributed to the large attractive interaction between naphthalene and CHF(3) (1-3 kcal/mol). PMID:21823704
NASA Astrophysics Data System (ADS)
Ye, Zhitong; Duan, Zhiyong; Takahata, Kenichi; Su, Yufeng
2014-08-01
In this paper, the force analysis and output performance of the micro-vibration energy harvester are elaborated. The force of the floating magnet in the magnetic field of the lifting magnet is firstly analyzed. Using COMSOL, the change of magnetic force exerted on the floating magnet versus the vertical distance and the horizontal eccentric distance is obtained for different lifting magnets of a cylinder, a ring and an inner cylinder plus an outer ring, respectively. When the distance between the lifting and floating magnets ranges from 7.3 to 8.1 mm, the change rate of the magnetic force versus the vertical distance for the inner cylinder plus outer ring structure is the smallest, whose value is 619 µN/mm. In other words, if the inner cylinder plus outer ring structure is used as the lifting magnet, the vibration space of the floating magnet is the largest, which is 8 and 7.6 % larger than the cylinder and ring lifting magnets, respectively. The horizontal restoring forces of the three structures are substantially equal to each other at the horizontal eccentric distance of 4 mm, which is around 860 µN. Then the equilibrium position change of the floating magnet is discussed when the energy harvester is in an inclined position. Finally, by the analysis of the vibration model, the output performances of the energy harvester are comparatively calculated under the vertical and inclined positions. At the natural frequency of 6.93 Hz, the maximum power of 66.7 µW is generated.
NASA Astrophysics Data System (ADS)
Halim, M. A.; Cho, H. O.; Park, J. Y.
2014-11-01
We have presented a frequency up-converted hybrid type (Piezoelectric and Electromagnetic) vibration energy harvester that can be used in powering portable and wearable smart devices by handy motion. A transverse impact mechanism has been employed for frequency up-conversion. Use of two transduction mechanisms increases the output power as well as power density. The proposed device consists of a non-magnetic spherical ball (freely movable at handy motion frequency) to impact periodically on the parabolic top of a piezoelectric (PZT) cantilevered mass by sliding over it, allowing it to vibrate at its higher resonant frequency and generates voltage by virtue of piezoelectric effect. A magnet attached to the cantilever vibrates along with it at the same frequency and a relative motion between the magnet and a coil placed below it, induces emf voltage across the coil terminals as well. A macro-scale prototype of the harvester has been fabricated and tested by handy motion. With an optimum magnet-coil overlap, a maximum 0.98mW and 0.64mW peak powers have been obtained from the piezoelectric and the electromagnetic transducers of the proposed device while shaken, respectively. It offers 84.4?Wcm?3 peak power density.
NASA Astrophysics Data System (ADS)
Wang, Peihong; Du, Hejun
2015-07-01
Zinc oxide (ZnO) thin film piezoelectric microelectromechanical systems (MEMS) based vibration energy harvesters with two different designs are presented. These harvesters consist of a silicon cantilever, a silicon proof mass, and a ZnO piezoelectric layer. Design I has a large ZnO piezoelectric element and Design II has two smaller and equally sized ZnO piezoelectric elements; however, the total area of ZnO thin film in two designs is equal. The ZnO thin film is deposited by means of radio-frequency magnetron sputtering method and is characterized by means of XRD and SEM techniques. These ZnO energy harvesters are fabricated by using MEMS micromachining. The natural frequencies of the fabricated ZnO energy harvesters are simulated and tested. The test results show that these two energy harvesters with different designs have almost the same natural frequency. Then, the output performance of different ZnO energy harvesters is tested in detail. The effects of series connection and parallel connection of two ZnO elements on the load voltage and power are also analyzed. The experimental results show that the energy harvester with two ZnO piezoelectric elements in parallel connection in Design II has higher load voltage and higher load power than the fabricated energy harvesters with other designs. Its load voltage is 2.06 V under load resistance of 1 M? and its maximal load power is 1.25 ?W under load resistance of 0.6 M?, when it is excited by an external vibration with frequency of 1300.1 Hz and acceleration of 10 m/s2. By contrast, the load voltage of the energy harvester of Design I is 1.77 V under 1 M? resistance and its maximal load power is 0.98 ?W under 0.38 M? load resistance when it is excited by the same vibration.
Wang, Peihong; Du, Hejun
2015-07-01
Zinc oxide (ZnO) thin film piezoelectric microelectromechanical systems (MEMS) based vibration energy harvesters with two different designs are presented. These harvesters consist of a silicon cantilever, a silicon proof mass, and a ZnO piezoelectric layer. Design I has a large ZnO piezoelectric element and Design II has two smaller and equally sized ZnO piezoelectric elements; however, the total area of ZnO thin film in two designs is equal. The ZnO thin film is deposited by means of radio-frequency magnetron sputtering method and is characterized by means of XRD and SEM techniques. These ZnO energy harvesters are fabricated by using MEMS micromachining. The natural frequencies of the fabricated ZnO energy harvesters are simulated and tested. The test results show that these two energy harvesters with different designs have almost the same natural frequency. Then, the output performance of different ZnO energy harvesters is tested in detail. The effects of series connection and parallel connection of two ZnO elements on the load voltage and power are also analyzed. The experimental results show that the energy harvester with two ZnO piezoelectric elements in parallel connection in Design II has higher load voltage and higher load power than the fabricated energy harvesters with other designs. Its load voltage is 2.06 V under load resistance of 1 M? and its maximal load power is 1.25 ?W under load resistance of 0.6 M?, when it is excited by an external vibration with frequency of 1300.1 Hz and acceleration of 10 m/s(2). By contrast, the load voltage of the energy harvester of Design I is 1.77 V under 1 M? resistance and its maximal load power is 0.98 ?W under 0.38 M? load resistance when it is excited by the same vibration. PMID:26233403
Reliability of vibration energy harvesters of metal-based PZT thin films
NASA Astrophysics Data System (ADS)
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 ?m) 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.
Modeling and design of a vibration energy harvester using the magnetic shape memory effect
NASA Astrophysics Data System (ADS)
Saren, A.; Musiienko, D.; Smith, A. R.; Tellinen, J.; Ullakko, K.
2015-09-01
In this study, a vibration energy harvester is investigated which uses a NiMnGa sample that is mechanically strained between 130 and 300 Hz while in a constant biasing magnetic field. The crystallographic reorientation of the sample during mechanical actuation changes its magnetic properties due to the magnetic shape memory (MSM) effect. This leads to an oscillation of the magnetic flux in the yoke which generates electrical energy by inducing an alternating current within the pick-up coils. A power of 69.5 mW (with a corresponding power density of 1.37 mW mm?3 compared to the active volume of the MSM element) at 195 Hz was obtained by optimizing the biasing magnetic field, electrical resistance and electrical resonance. The optimization of the electrical resonance increased the energy generated by nearly a factor of four when compared to a circuit with no resonance. These results are strongly supported by a theoretical model and simulation which gives corresponding values with an error of approximately 20% of the experimental data. This model will be used in the design of future MSM energy harvesters and their optimization for specific frequencies and power outputs.
NASA Astrophysics Data System (ADS)
Nawayseh, Naser; Griffin, Michael J.
2012-01-01
Although the discomfort or injury associated with whole-body vibration cannot be predicted directly from the power absorbed during exposure to vibration, the absorbed power may contribute to understanding of the biodynamics involved in such responses. From measurements of force and acceleration at the seat, the feet, and the backrest, the power absorbed at these three locations was calculated for subjects sitting in four postures (feet hanging, maximum thigh contact, average thigh contact, and minimum thigh contact) both with and without a rigid vertical backrest while exposed to four magnitudes (0.125, 0.25, 0.625, and 1.25 m s -2 rms) of random fore-and-aft vibration. The power absorbed by the body at the supporting seat surface when there was no backrest showed a peak around 1 Hz and another peak between 3 and 4 Hz. Supporting the back with the backrest decreased the power absorbed at the seat at low frequencies but increased the power absorbed at high frequencies. Foot support influenced both the magnitude and the frequency of the peaks in the absorbed power spectra as well as the total absorbed power. The measurements of absorbed power are consistent with backrests being beneficial during exposure to low frequency fore-and-aft vibration but detrimental with high frequency fore-and-aft vibration.
NASA Technical Reports Server (NTRS)
Tessarzik, J. M.; Chiang, T.; Badgley, R. H.
1973-01-01
The random vibration response of a gas bearing rotor support system has been experimentally and analytically investigated in the amplitude and frequency domains. The NASA Brayton Rotating Unit (BRU), a 36,000 rpm, 10 KWe turbogenerator had previously been subjected in the laboratory to external random vibrations, and the response data recorded on magnetic tape. This data has now been experimentally analyzed for amplitude distribution and magnetic tape. This data has now been experimentally analyzed for amplitude distribution and frequency content. The results of the power spectral density analysis indicate strong vibration responses for the major rotor-bearing system components at frequencies which correspond closely to their resonant frequencies obtained under periodic vibration testing. The results of amplitude analysis indicate an increasing shift towards non-Gaussian distributions as the input level of external vibrations is raised. Analysis of axial random vibration response of the BRU was performed by using a linear three-mass model. Power spectral densities, the root-mean-square value of the thrust bearing surface contact were calculated for specified input random excitation.
Underwater energy harvesting from vibrations of annular ionic polymer metal composites
NASA Astrophysics Data System (ADS)
Cha, Youngsu; Abdolhamidi, Shervin; Porfiri, Maurizio
2015-04-01
In this paper, we investigate the feasibility of energy harvesting from axisymmetric vibrations of annular ionic polymer metal composites (IPMCs). We consider an in-house fabricated IPMC that is clamped at its inner radius to a moving base and is free at its outer radius. We propose a physics-based model for energy harvesting from underwater vibrations, in which the IPMC is described as a thin annular plate undergoing axisymmetric vibrations with an added mass due to the encompassing fluid. Experiments are performed to elucidate the effect of the shunting resistance and the excitation frequency on energy harvesting.
Nakamura, Ryosuke; Hamada, Norio
2015-05-14
Vibrational energy flow in the electronic ground state of photoactive yellow protein (PYP) is studied by ultrafast infrared (IR) pump-visible probe spectroscopy. Vibrational modes of the chromophore and the surrounding protein are excited with a femtosecond IR pump pulse, and the subsequent vibrational dynamics in the chromophore are selectively probed with a visible probe pulse through changes in the absorption spectrum of the chromophore. We thus obtain the vibrational energy flow with four characteristic time constants. The vibrational excitation with an IR pulse at 1340, 1420, 1500, or 1670 cm(-1) results in ultrafast intramolecular vibrational redistribution (IVR) with a time constant of 0.2 ps. The vibrational modes excited through the IVR process relax to the initial ground state with a time constant of 6-8 ps in parallel with vibrational cooling with a time constant of 14 ps. In addition, upon excitation with an IR pulse at 1670 cm(-1), we observe the energy flow from the protein backbone to the chromophore that occurs with a time constant of 4.2 ps. PMID:25896223
Dynamical traps lead to the slowing down of intramolecular vibrational energy flow
Manikandan, Paranjothy; Keshavamurthy, Srihari
2014-01-01
The phenomenon of intramolecular vibrational energy redistribution (IVR) is at the heart of chemical reaction dynamics. Statistical rate theories, assuming instantaneous IVR, predict exponential decay of the population with the properties of the transition state essentially determining the mechanism. However, there is growing evidence that IVR competes with the reaction timescales, resulting in deviations from the exponential rate law. Dynamics cannot be ignored in such cases for understanding the reaction mechanisms. Significant insights in this context have come from the state space model of IVR, which predicts power law behavior for the rates with the power law exponent, an effective state space dimensionality, being a measure of the nature and extent of the IVR dynamics. However, whether the effective IVR dimensionality can vary with time and whether the mechanism for the variation is of purely quantum or classical origins are issues that remain unresolved. Such multiple power law scalings can lead to surprising mode specificity in the system, even above the threshold for facile IVR. In this work, choosing the well-studied thiophosgene molecule as an example, we establish the anisotropic and anomalous nature of the quantum IVR dynamics and show that multiple power law scalings do manifest in the system. More importantly, we show that the mechanism of the observed multiple power law scaling has classical origins due to a combination of trapping near resonance junctions in the network of classical nonlinear resonances at short to intermediate times and the influence of weak higher-order resonances at relatively longer times. PMID:25246538
Harvesting broadband kinetic impact energy from mechanical triggering/vibration and water waves.
Wen, Xiaonan; Yang, Weiqing; Jing, Qingshen; Wang, Zhong Lin
2014-07-22
We invented a triboelectric nanogenerator (TENG) that is based on a wavy-structured Cu-Kapton-Cu film sandwiched between two flat nanostructured PTFE films for harvesting energy due to mechanical vibration/impacting/compressing using the triboelectrification effect. This structure design allows the TENG to be self-restorable after impact without the use of extra springs and converts direct impact into lateral sliding, which is proved to be a much more efficient friction mode for energy harvesting. The working mechanism has been elaborated using the capacitor model and finite-element simulation. Vibrational energy from 5 to 500 Hz has been harvested, and the generator's resonance frequency was determined to be ?100 Hz at a broad full width at half-maximum of over 100 Hz, producing an open-circuit voltage of up to 72 V, a short-circuit current of up to 32 ?A, and a peak power density of 0.4 W/m(2). Most importantly, the wavy structure of the TENG can be easily packaged for harvesting the impact energy from water waves, clearly establishing the principle for ocean wave energy harvesting. Considering the advantages of TENGs, such as cost-effectiveness, light weight, and easy scalability, this approach might open the possibility for obtaining green and sustainable energy from the ocean using nanostructured materials. Lastly, different ways of agitating water were studied to trigger the packaged TENG. By analyzing the output signals and their corresponding fast Fourier transform spectra, three ways of agitation were evidently distinguished from each other, demonstrating the potential of the TENG for hydrological analysis. PMID:24964297
A global ab initio potential for HCN/HNC, exact vibrational energies, and comparison to experiment
NASA Technical Reports Server (NTRS)
Bentley, Joseph A.; Bowman, Joel M.; Gazdy, Bela; Lee, Timothy J.; Dateo, Christopher E.
1992-01-01
An ab initio (i.e., from first principles) calculation of vibrational energies of HCN and HNC is reported. The vibrational calculations were done with a new potential derived from a fit to 1124 ab initio electronic energies which were calculated using the highly accurate CCSD(T) coupled-cluster method in conjunction with a large atomic natural orbital basis set. The properties of this potential are presented, and the vibrational calculations are compared to experiment for 54 vibrational transitions, 39 of which are for zero total angular momentum, J = 0, and 15 of which are for J = 1. The level of agreement with experiment is unprecedented for a triatomic with two nonhydrogen atoms, and demonstrates the capability of the latest computational methods to give reliable predictions on a strongly bound triatomic molecule at very high levels of vibrational excitation.
A Study on Energy Harvesting Aware Routing for Vibration-Motivated Wireless Sensor Networks
Lim, Sunho
A Study on Energy Harvesting Aware Routing for Vibration-Motivated Wireless Sensor Networks TTU an electrical energy from various environmental sources, called energy harvesting (or energy scavenging), has been an issue and attracting researchers' attention in energy replenishable networks. In par- ticular
Straub, John E.
-specific vibrational energy relaxation in imidazole ligated ferrous iron porphine were studied using a non strongly through its overtone with the 7 porphine in-plane vibration. This suggests a possible mechanism
NASA Technical Reports Server (NTRS)
Mckenzie, R. L.
1975-01-01
A semiclassical model of the inelastic collision between a vibrationally excited anharmonic oscillator and a structureless atom was used to predict the variation of thermally averaged vibration-translation rate coefficients with temperature and initial-state quantum number. Multiple oscillator states were included in a numerical solution for collinear encounters. The results are compared with CO-He experimental values for both ground and excited initial states using several simplified forms of the interaction potential. The numerical model was also used as a basis for evaluating several less complete but analytic models. Two computationally simple analytic approximations were found that successfully reproduced the numerical rate coefficients for a wide range of molecular properties and collision partners. Their limitations were also identified. The relative rates of multiple-quantum transitions from excited states were evaluated for several molecular types.
Potential energy function and vibrational states of N2CO+
NASA Astrophysics Data System (ADS)
Hochlaf, M.; Léonard, C.; Ferguson, E. E.; Rosmus, P.; Reinsch, E.-A.; Carter, S.; Handy, N. C.
1999-09-01
A six-dimensional potential energy function (PEF) for the electronic ground state of N2CO++ (X 2AA') has been generated by electronic structure calculations using the restricted open shell coupled cluster RCCSD(T) approach. The ion has a planar trans equilibrium structure with: RNN=1.106 Å, RNC=1.905 Å, RCO=1.127Å, ?NNC=175.3°, and ?NCO=129.1°. Variational calculations of the vibrational states (J=0) have yielded the following anharmonic wavenumbers for the fundamentals: ?1 (NN stretch) 2287.2, ?2 (CO stretch) 2071.0, ?3 (CN stretch+NCO bend) 546.9, ?4 (CN stretch+NCO bend) 215.2, ?5 (in-plane NNC bend) 123.4, ?6 (out-of-plane NNC bend) 133.8 (all values are in cm-1). For fixed equilibrium coordinates except one, the barriers to linearity have been calculated to be 8 cm-1 for the NNC and 2260 cm-1 for the NCO moieties, the torsional barrier to be 35 cm-1. It has been found that the ?3 and ?4 modes are strongly coupled, the in-plane ?5 and out-of-plane ?6 bending modes possess an inverse anharmonicity and fall into clusters. Using complete active space self-consitent-field CASSCF approach on the collinear cuts of the PEF for low-lying excited states several conical intersections between the 2? and the 2?+ states have been located.
NASA Astrophysics Data System (ADS)
Colin, M.; Basrour, S.; Rufer, L.
2013-05-01
Current version of implantable cardioverter defibrillators (ICDs) and pacemakers consists of a battery-powered pulse generator connected onto the heart through electrical leads inserted through the veins. However, it is known that long-term lead failure may occur and cause a dysfunction of the device. When required, the removal of the failed leads is a complex procedure associated with a potential risk of mortality. As a consequence, the main players in the field of intracardiac implants prepare a next generation of devices: miniaturized and autonomous leadless implants, which could be directly placed inside the heart. In this paper, we discuss the frequency content of a heart vibration spectrum, and the dimensional restrictions in the case of a leadless pacemaker. In combination with the requirements in terms of useable energy, we will present a design study of a resonant piezoelectric scavenger aimed at powering such a device. In particular, we will show how the frequency-volume-energy requirement leads to new challenges in terms of power densities, which are to be addressed through implementation of innovative piezoelectric thick films fabrication processes. This paper also presents the simulation, fabrication and the testing of an ultralow frequency (15Hz) resonant piezoelectric energy harvester prototype. Using both harmonic (50mg) and real heart-induced vibrations, we obtained an output power of 60?W and 10?W respectively. Finally, we will place emphasis on the new constraint represented by the gravitational (orientation) sensitivity inherent to these ultra low frequency resonant energy harvesters.
Chung, Pao-Hung; Lin, Guan-Lun; Liu, Chiang; Chuang, Long-Ren; Shiang, Tzyy-Yuang
2013-01-01
The aim of this study was to determine whether performing Tai Chi Chuan on a customized vibration platform could enhance balance control and lower extremity muscle power more efficiently than Tai Chi Chuan alone in an untrained young population. Forty-eight healthy young adults were randomly assigned to the following three groups: a Tai Chi Chuan combined with vibration training group (TCV), a Tai Chi Chuan group (TCC) or a control group. The TCV group underwent 30 minutes of a reformed Tai Chi Chuan program on a customized vibration platform (32 Hz, 1 mm) three times a week for eight weeks, whereas the TCC group was trained without vibration stimuli. A force platform was used to measure the moving area of a static single leg stance and the heights of two consecutive countermovement jumps. The activation of the knee extensor and flexor was also measured synchronously by surface electromyography in all tests. The results showed that the moving area in the TCV group was significantly decreased by 15.3%. The second jump height in the TCV group was significantly increased by 8.14%, and the activation of the knee extensor/flexor was significantly decreased in the first jump. In conclusion, Tai Chi Chuan combined with vibration training can more efficiently improve balance control, and the positive training effect on the lower extremity muscle power induced by vibration stimuli still remains significant because there is no cross-interaction between the two different types of training methods. Key points Eight weeks of Tai Chi Chuan combined with vibration training can more efficiently improve balance control for an untrained young population. The positive training effect on the lower extremity muscle power induced by vibration stimuli during Tai Chi Chuan movements still remains significant because of SSC mechanism. Combining Tai Chi Chuan with vibration training is more efficient and does not decrease the overall training effects due to a cross-interaction of each other. PMID:24149721
A fail-safe magnetorheological energy absorber for shock and vibration isolation
Bai, Xian-Xu; Wereley, Norman M.
2014-05-07
Magnetorheological (MR) energy absorbers (EAs) are an effective adaptive EA technology with which to maximize shock and vibration isolation. However, to realize maximum performance of the semi-active control system, the off-state (i.e., field off) stroking load of the MREA must be minimized at all speeds, and the dynamic range of the MREA must be maximized at high speed. This study presents a fail-safe MREA (MREA-FS) concept that, can produce a greater dynamic range at all piston speeds. A bias damping force is generated in the MREA-FS using permanent magnetic fields, which enables fail-safe behavior in the case of power failure. To investigate the feasibility and capability of the MREA-FS in the context of the semi-active control systems, a single-degree-of-freedom base excited rigid payload is mathematically constructed and simulated with skyhook control.
Exact solution for low energy quantum anharmonic vibrations in a long polymer chain
Alexander L. Burin
2015-09-08
We propose the algorithm for determining vibrational quantum eigenstates of periodic linear chain of atoms coupled by harmonic and third order anharmonic interactions (Fermi-Ulam-Pasta $\\alpha$ problem) in the long wavelength limit within the resonant approach. Eigenstates can be encoded by the sequence of integer numbers determining their energies and wavefunctions. Using these eigenstates we described a single phonon state time evolution showing coherent oscillations. The applications of theory to vibrational energy transport and quantum informatics are discussed.
Utility-based Time and Power Allocation on an Energy Harvesting Downlink: The Optimal
Uysal-Biyikoglu, Elif
harvest energy through solar cells, vibration absorption devices, thermoelectric generators, wind power problem where the transmitter is aware of the energy arrival statistics of a frame before the frame starts advances in the areas of solar, piezoelectric and thermal energy har- vesting, enable systems
Renewable Energy Powers Renewable Energy Lab, Employees
. NREL is also using solar energy for auxiliary purposes such as powering streetlights, water pumps and the lab's new entrance sign. An experimental 12-kilowatt rooftop solar system also feeds electricity back
ERIC Educational Resources Information Center
Holdren, John; Herrera, Philip
The demand of Americans for more and more power, particularly electric power, contrasted by the deep and growing concern for the environment and a desire by private citizens to participate in the public decisions that affect the environment is the dilemma explored in this book. Part One by John Holdren, offers a scientist's overview of the energy
Review of power electronics for kinetic energy harvesting systems
NASA Astrophysics Data System (ADS)
Li, Peng; Zhang, Chongxiao; Zuo, Lei
2013-04-01
In the past decade, there has been a dramatic rise of research in the field of energy harvesting from ambient environment, such as mechanical vibrations and dissipated heat. As a key element connecting the harvester and energy storage element in energy harvesting systems, power electronic interface circuitry has drawn significant interests. Abundant research on the power electronic circuits with functions of voltage regulation, optimal power extraction and damping control for energy harvesting systems has been conducted and reported, together with control algorithms and implementations to achieve these functions. This paper reviews the reported concepts for power electronic interface circuits in kinetic energy harvesting systems, such as electromagnetic and piezoelectric harvesters. Power electronic interface circuit concepts included were grouped in the view of energy scale, power flow direction, functionality and complexity. An overview of the power electronic circuit topologies with various functions available for constructing the power electronic interface circuits and problems yet to be solved for kinetic energy harvesting systems is provided by this paper.
NASA Astrophysics Data System (ADS)
Soloviev, V.; Seleznev, V.; Emanov, A.; Sal`Nikov, A.; Kashun, V.; Glinsky, B.; Kovalevsky, V.; Zhemchugova, I.; Danilov, I.; Liseikin, A.
2004-12-01
There are presented the materials of deep vibroseism researches, carried out in seismic active regions of Siberia with use of stationary (100-tos power) and moveable vibration sources (40-60tons power) and mobile digital recording equipment. There are given some examples of unique, have no world analogues, correlograms from high-power vibrators on distances to 400km and more. Using new vibroseismic technology of deep seismic researches, there were got detail deep sections of the Earth's crust and upper mantle, including time-sections of CDP-DSS up to depth of 80km. Materials of vibroseismic investigations on 2500km of seismic profiles in hard-to-reach regions of the Altay-Sayan region, the Baikal rift zone and Okhotsko-Chukotski regions are evidence of high cost efficiency, ecological safety, possibility to be realized in hard-to-reach region and finally of availability of deep seismic investigations with use of high-power vibration sources.
Two-dimensional concentrated-stress low-frequency piezoelectric vibration energy harvesters
NASA Astrophysics Data System (ADS)
Sharpes, Nathan; Abdelkefi, Abdessattar; Priya, Shashank
2015-08-01
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 mm2 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.
Hofmayer, C.H.; Curreri, J.R.; Park, Y.J.; Kato, W.Y.; Costello, J.F.; Tang, H.T.; 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 tests involved increasing the excitation up to the limits of the vibration table in order to induce inelastic response in a reactor coolant system piping model. The model was subjected to a maximum acceleration well beyond what nuclear power plants are designed to withstand. The High Level Vibration Test (HLVT) 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. The upper and middle steam generator shell supports of the model, which simulated the actual plant condition, were removed and the steam generator shell was truncated. Furthermore, the four lower support columns for the steam generator were replaced by a pin-type support. A modified earthquake excitation was used to drive the structure to a condition of substantial strain. Since the piping was pressurized, and the high level input motion was repeated several times, it was possible to investigate the effects of ratchetting and fatigue as well. An isometric view of the test model and support frame is shown in Figure 1. Further details of the hot leg pipe are shown in Figure 2. The piping in the model is stainless steel, 14-15 inches in diameter and 1 to 1 1/4 inches thick. This paper describes the overall plan, the input motion development and pre-test analysis results. 4 refs., 8 figs., 1 tab.
NASA Astrophysics Data System (ADS)
Khbeis, Michael Tawfik
Scavenging energy from environmental sources is an active area of research to enable remote sensing and microsystems applications. Furthermore, as energy demands soar, there is a significant need to explore new sources and curb waste. Vibration energy scavenging is one environmental source for remote applications and a candidate for recouping energy wasted by mechanical sources that can be harnessed to monitor and optimize operation of critical infrastructure (e.g. Smart Grid). Current vibration scavengers are limited by volume and ancillary requirements for operation such as control circuitry overhead and battery sources. This dissertation, for the first time, reports a mass producible hybrid energy scavenger system that employs both piezoelectric and electrostatic transduction on a common MEMS device. The piezoelectric component provides an inherent feedback signal and pre-charge source that enables electrostatic scavenging operation while the electrostatic device provides the proof mass that enables low frequency operation. The piezoelectric beam forms the spring of the resonant mass-spring transducer for converting vibration excitation into an AC electrical output. A serially poled, composite shim, piezoelectric bimorph produces the highest output rectified voltage of over 3.3V and power output of 145muW using ¼ g vibration acceleration at 120Hz. Considering solely the volume of the piezoelectric beam and tungsten proof mass, the volume is 0.054cm3, resulting in a power density of 2.68mW/cm3. Incorporation of a simple parallel plate structure that provides the proof mass for low frequency resonant operation in addition to cogeneration via electrostatic energy scavenging provides a 19.82 to 35.29 percent increase in voltage beyond the piezoelectric generated DC rails. This corresponds to approximately 2.1nW additional power from the electrostatic scavenger component and demonstrates the first instance of hybrid energy scavenging using both piezoelectric and synchronous electrostatic transduction. Furthermore, it provides a complete system architecture and development platform for additional enhancements that will enable in excess of 100muW additional power from the electrostatic scavenger.
Vibrational energy on surfaces: Ultrafast flash-thermal conductance of molecular monolayers
NASA Astrophysics Data System (ADS)
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.
Rotation vibration energy level clustering in the XB1 ground electronic state of PH2
NASA Astrophysics Data System (ADS)
Yurchenko, S. N.; Thiel, W.; Jensen, Per; Bunker, P. R.
2006-10-01
We use previously determined potential energy surfaces for the Renner-coupled XB1 and AA1 electronic states of the phosphino (PH 2) free radical in a calculation of the energies and wavefunctions of highly excited rotational and vibrational energy levels of the X state. We show how spin-orbit coupling, the Renner effect, rotational excitation, and vibrational excitation affect the clustered energy level patterns that occur. We consider both 4-fold rotational energy level clustering caused by centrifugal distortion, and vibrational energy level pairing caused by local mode behaviour. We also calculate ab initio dipole moment surfaces for the X and A states, and the X-A transition moment surface, in order to obtain spectral intensities.
Statistics of power injection in a plate set into chaotic vibration
NASA Astrophysics Data System (ADS)
Cadot, O.; Boudaoud, A.; Touzé, C.
2008-12-01
A vibrating plate is set into a chaotic state of wave turbulence by either a periodic or a random local forcing. Correlations between the forcing and the local velocity response of the plate at the forcing point are studied. Statistical models with fairly good agreement with the experiments are proposed for each forcing. Both distributions of injected power have a logarithmic cusp for zero power, while the tails are Gaussian for the periodic driving and exponential for the random one. The distributions of injected work over long time intervals are investigated in the framework of the fluctuation theorem, also known as the Gallavotti-Cohen theorem. It appears that the conclusions of the theorem are verified only for the periodic, deterministic forcing. Using independent estimates of the phase space contraction, this result is discussed in the light of available theoretical framework.
Voltage tuning of vibrational mode energies in single-molecule junctions
Li, Yajing; Doak, Peter; Kronik, Leeor; Neaton, Jeffrey B.; Natelson, Douglas
2014-01-01
Vibrational modes of molecules are fundamental properties determined by intramolecular bonding, atomic masses, and molecular geometry, and often serve as important channels for dissipation in nanoscale processes. Although single-molecule junctions have been used to manipulate electronic structure and related functional properties of molecules, electrical control of vibrational mode energies has remained elusive. Here we use simultaneous transport and surface-enhanced Raman spectroscopy measurements to demonstrate large, reversible, voltage-driven shifts of vibrational mode energies of C60 molecules in gold junctions. C60 mode energies are found to vary approximately quadratically with bias, but in a manner inconsistent with a simple vibrational Stark effect. Our theoretical model instead suggests that the mode shifts are a signature of bias-driven addition of electronic charge to the molecule. These results imply that voltage-controlled tuning of vibrational modes is a general phenomenon at metalmolecule interfaces and is a means of achieving significant shifts in vibrational energies relative to a pure Stark effect. PMID:24474749
NASA Astrophysics Data System (ADS)
Soloviev, V. M.; Seleznev, V. S.; Emanov, A. F.; Kashun, V. N.; Elagin, S. A.; Romanenko, I.; Shenmayer, A. E.; Serezhnikov, N.
2013-05-01
The paper presents data of operating vibroseismic observations using high-power stationary 100-tons and moveable 40-tons vibration sources, which have been carried out in Russia for 30 years. It is shown that investigations using high-power vibration sources open new possibilities for study stressedly-deformed condition of the Earth`s crust and the upper mantle and tectonic process in them. Special attention is given to developing operating seismic translucences of the Earth`s crust and the upper mantle using high-power 40-tons vibration sources. As a result of experimental researches there was proved high stability and repeatability of vibration effects. There were carried out long period experiments of many days with vibration source sessions of every two hours with the purpose of monitoring accuracy estimation. It was determined, that repeatability of vibroseismic effects (there was researched time difference of repeated sessions of P- and S-waves from crystal rocks surface) could be estimated as 10-3 - 10-4 sec. It is ten times less than revealed here annual variations of kinematic parameters according to regime vibroseismic observations. It is shown, that on hard high-speed grounds radiation spectrum becomes narrowband and is dislocated to high frequency; at the same time quantity of multiple high-frequency harmonic is growing. At radiation on soft sedimentary grounds (sand, clay) spectrum of vibration source in near zone is more broadband, correlograms are more compact. there Correspondence of wave fields from 40-tons vibration sources and explosions by reference waves from boundaries in he Earth`s crust and the upper mantle at record distance of 400 km was proved by many experiments in various regions of Russia; there was carried out the technique of high-power vibration sources grouping for increase of effectiveness of emanation and increase of record distance. According to results of long-term vibroseismic monitoring near Novosibirsk (1997-2012) there are determined variations in velocities of longitudinal and transverse waves. Both from 100-tons and 40-tons vibration sources there are distinctly determined annual and semiannual variations, and also variations of 120 and 90 days. There is determined correlations of revealed variations of P- and S-wave velocities with drowning of the upper part of the Earth`s crust because of season changes of water volumes in the biggest Novosibirsk water reservoir. There were carried out experiments on aperture widening of operating vibroseismic observations in seismic active zones of the South of Altay. All these results prove possibility of using moveable collapsible 40-tons vibration sources for active monitoring of seismic dangerous zones, nuclear power plants, nuclear waste storage etc.
Energy fluctuation, diffusivity and mobility in a 2D vibrated granular packing
NASA Astrophysics Data System (ADS)
Clement, Eric; Harich, Rim; Vandewalle, Nicolas; Lumay, Geoffroy
2008-03-01
We present an experimental realization of a 2D vibrated granular packing. The new agitation method allows a spatially non synchronized influx of energy and the study of the vibrated packing at steady state. By image analysis of fast-camera movies, we obtain the velocity fluctuation spectra at different vertical levels and then, we separate the agitation velocities from the velocity fluctuations corresponding to the ``thermalized'' degrees of freedom. By measuring the corresponding particle diffusivities, we show that, in spite a large heterogeneity and anisotropy of the vibration, a relation between diffusivity and ``thermalized'' kinetic energy can be identified. We relate this type of fluctuation-dissipation relation to the mobility of macroscopic intruders of different sizes and weight moving in the vibrated granular packing.
Novel vibration-based electrical energy generators for low and variable speed turbo-machinery
NASA Astrophysics Data System (ADS)
Rastegar, J.; Murray, R.
2007-04-01
A novel class of vibration-based electrical energy generators is presented for applications in which the input rotary speed is relatively low and varies significantly over time such as wind mills, turbo-machinery used to harvest tidal flows, and the like. Current technology uses magnet and coil based rotary generators to generate electrical energy in such machinery. However, to make the generation cycle efficient, gearing or other similar mechanisms have to be used to increase the output speed. In addition, variable speed mechanisms are usually needed to achieve high mechanical to electrical energy conversion efficiency since speed variation is usually significant in the aforementioned applications. The objective of the present work is the development of electrical energy generators that do not require the aforementioned gearing and speed control mechanisms, thereby significantly reducing complexity and cost, particularly those related to maintenance and service. This novel class of electrical energy generators operates based on repeated vibration of multiple vibrating elements that are tuned to vibrate at a fixed prescribed frequency. The mechanical energy stored in the vibration elements is transformed into electrical energy using piezoelectric elements. The present generators are very simple, can efficiently operate over a very large range of input speeds, and should require minimal service and maintenance. The project is at the early stages of its development, but the analytical modeling and computer simulation studies using realistic system and component parameters indicate the potentials of this class of piezoelectric-based generators for the indicated applications.
Kumar, Ratnesh
harvesting, especially beneficial where alternatives such as light, wind, biomass and thermal energy by external factors such as thunder or agricultural work, is a viable option. Harvesting kinetic energy be either linear or nonlinear. In order to maximize the energy harvested from broadband ambient vibrations
NASA Astrophysics Data System (ADS)
Pavlyuchko, A. I.; Yurchenko, S. N.; Tennyson, Jonathan
2015-07-01
A procedure for calculation of rotation-vibration states of medium sized molecules is presented. It combines the advantages of variational calculations and perturbation theory. The vibrational problem is solved by diagonalizing a Hamiltonian matrix, which is partitioned into two sub-blocks. The first, smaller sub-block includes matrix elements with the largest contribution to the energy levels targeted in the calculations. The second, larger sub-block comprises those basis states which have little effect on these energy levels. Numerical perturbation theory, implemented as a Jacobi rotation, is used to compute the contributions from the matrix elements of the second sub-block. Only the first sub-block needs to be stored in memory and diagonalized. Calculations of the vibrational-rotational energy levels also employ a partitioning of the Hamiltonian matrix into sub-blocks, each of which corresponds either to a single vibrational state or a set of resonating vibrational states, with all associated rotational levels. Physically, this partitioning is efficient when the Coriolis coupling between different vibrational states is small. Numerical perturbation theory is used to include the cross-contributions from different vibrational states. Separate individual sub-blocks are then diagonalized, replacing the diagonalization of a large Hamiltonian matrix with a number of small matrix diagonalizations. Numerical examples show that the proposed hybrid variational-perturbation method greatly speeds up the variational procedure without significant loss of precision for both vibrational-rotational energy levels and transition intensities. The hybrid scheme can be used for accurate nuclear motion calculations on molecules with up to 15 atoms on currently available computers.
An analytical investigation of an energy flow divider to attenuate hand-transmitted vibration
T. Cherian; S. Rakheja; R. B. Bhat
1996-01-01
A five-degrees-of-freedom (DOF) bio-mechanical model of the hand-arm system is developed to study the vibration transmissibility characteristics of the human hand-arm. The model parameters are identified from the characteristics of vibration transmitted to the hand, forearm and upper arm, measured in the 10200 Hz frequency range under a constant 25.0 N grip force. A concept of an energy flow divider
NASA Astrophysics Data System (ADS)
Leng, Y. G.; Gao, Y. J.; Tan, D.; Fan, S. B.; Lai, Z. H.
2015-02-01
To overcome the defect of conventional nonlinear piezoelectric cantilever vibration energy harvesters, in this paper we conceive an elastic-support model to study the performance of energy converters under two types of variable-intensity excitation conditions: filtered Gaussian noises and pink noises. When excitation intensity is insufficient, thanks to the system's variable potential function, frequent bistable transition oscillations between two wells occur in elastic-support systems, while only weak oscillations in either well could be observed in rigid-support systems. In practical applications, the structural parameters of energy harvesters are not allowed to make real-time changes. If considered remaining the magnet interval and the spring's elastic stiffness unchanged while receiving stable maximum output voltage, elastic-support systems can be made full use toward variable-intensity filtered Gaussian noises. It has been proven that elastic-support systems are capable of adapting to random excitations with variable intensity, through which maximum power output and sufficient electromechanical energy conversion of the system can be accomplished.
Vibrational energy transfer kinetics in molecular disequilibrium. Status report
Rich, J.W.
1980-03-01
A c-w CO laser was used to excite the CO vibrational mode in mixtures of CO and various other gases (N/sub 2/, Ar, NO). Products are (CN)/sub 2/ and C/sub 2/. Two possible mechanisms for C/sub 2/ formation are discussed. 3 figures, 3 tables. (DLC)
Collision-induced state-to-state flow of vibrational energy in S1 toluene
NASA Astrophysics Data System (ADS)
Kincaid, Edward H.; Worah, V.; Schuh, Merlyn D.
1991-04-01
State-to-state flow of vibrational energy in the S1 state of toluene vapor under ``single collision'' conditions has been measured. The 6b1 level (?'6b=530 cm-1 ) was pumped by pulsed laser excitation, and resolved fluorescence spectra revealed which vibrational levels in the S1 state were produced by collisions with three added gases. Energy flow was found to be selective and occurred into four channels. Endergonic flow of energy to identified, accessible vibrational levels is not observed. Collision cross sections increased with increasing molecular complexity of the collision partners, but similar energy flow patterns were observed with all collision partners. Energy flow between 6a1 and 6b1 levels, which have a spacing of about 90 cm-1, was found to be very inefficient.
Detection of high-energy adsorbate vibrational modes by atom-surface scattering
Tang, Yarong; Manson, J. R.; Rieder, K.-H.
2000-12-15
It is suggested that high-frequency vibrational modes of surface adsorbates can produce very characteristic signature features in the observable inelastic intensity in experiments using atomic beams as scattering probes. These features consist of peaks in the inelastic background, due to multiquantum excitation of the high-energy vibrational modes, and these peaks are significantly broadened and shifted in the direction of energy loss by the multiphonon scattering arising from the substrate and other low-energy adsorbate modes. Calculations for the scattering of rare gases from several types of adsorbate indicate that, by selecting the probe projectile species and tuning the incident energy and incident beam angle, selected high-energy modes can be excited, and the method can be used to accurately measure the vibrational frequencies and polarizations of these modes.
Ostasevicius, Vytautas; Janusas, Giedrius; Milasauskaite, Ieva; Zilys, Mindaugas; Kizauskiene, Laura
2015-01-01
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. PMID:26029948
Ostasevicius, Vytautas; Janusas, Giedrius; Milasauskaite, Ieva; Zilys, Mindaugas; Kizauskiene, Laura
2015-01-01
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 3.44.8-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. PMID:26029948
NASA Astrophysics Data System (ADS)
Han, Peng; Bester, Gabriel
2015-02-01
The three-dimensional confinement characterizing a nanocrystal (NC) leads to the formation of discrete electronic states. The energy gap between these states in colloidal NCs can be up to an order of magnitude larger than the vibrational energy of the host material. This large energetic mismatch (not given in self-assembled quantum dots) leads to the expectation that an electron occupying an excited state would be unable to release its energy to vibrations and a "phonon bottleneck" should finally be observed. Using large-scale ab initio calculations and a time-dependent formalism, we show that on the contrary, a phonon bottleneck can be observed only in a narrow window of diameters for CdSe and InAs NCs and should not occur at all in Si NCs. Two relaxation pathways enable fast carrier relaxation. For smaller structures (below 20-Å radius), the coupling strength and energy detuning are such that quantum mechanics allows us to effectively bridge electronic gaps much larger than the vibronic energy. For larger structures, the coupling to passivant modes, although very weak, leads to an efficient picosecond carrier relaxation. This work provides insight into the nature of carrier relaxation in colloidal nanostructures and highlights that defects, of any kind, are not necessary to explain the observed fast carrier relaxation.
NASA Astrophysics Data System (ADS)
Emdadul Hoque, Md.; Mizuno, Takeshi; Ishino, Yuji; Takasaki, Masaya
2010-08-01
This paper presents a six-degree-of-freedom hybrid vibration isolation system integrated with an active negative suspension, an active-passive positive suspension and a passive weight support mechanism. The aim of the research consists in maximizing the system and control performances, and minimizing the system development and maintenance costs. The vibration isolation system is, fundamentally, developed by connecting an active negative suspension realized by zero-power control in series with an active-passive positive suspension. The system could effectively isolate ground vibrations in addition to suppress the effect of on-board generated direct disturbances of the six-axis motions, associated with vertical and horizontal directions. The system is further reinforced by introducing a passive weight support mechanism in parallel with the basic system. The modified system with zero-power control allows simplified design of the isolation table without power consumption. It also offers enhanced performance on direct disturbance suppression and large payload supporting capabilities, without degrading transmissibility characteristics. A mathematical model of the system is presented and, therefore, analyzed to demonstrate that zero-compliance to direct disturbance could be generated by the developed system. Experimental demonstrations validate the proposed concept that exhibits high stiffness of the isolation table to static and dynamic direct disturbances, and good transmissibility characteristics against ground vibration. Further improvements of the vibration isolation system and the control system are discussed as well.
Energy-Investment Schemes for Increasing Output Power in Piezoelectric Harvesters
Rincon-Mora, Gabriel A.
Energy-Investment Schemes for Increasing Output Power in Piezoelectric Harvesters Dongwon Kwon alone seldom dampen vibrations enough to fully harness what is available, which is why investing energy and evaluates three investment schemes and 0.35-µm CMOS switched-inductor circuits that increase this force
Power and energy for posterity
NASA Technical Reports Server (NTRS)
Barthelemy, R. F.; Cooper, R. F.
1972-01-01
The use of sophisticated space energy generation and storage systems to benefit the general public was examined. The utilization of these systems for pollution-free generation of energy to satisfy mankind's future electrical, thermal, and propulsion needs was of primary concern. Ground, air, and space transportation; commercial, peaking, and emergency electrical power; and metropolitan and unit thermal energy requirements were considered. Each type of energy system was first analyzed in terms of its utility in satisfying the requirement, and then its potential in reducing the air, noise, thermal, water, and nuclear pollution from future electrical and thermal systems was determined.
Do, T P T; Duque, H V; Lopes, M C A; Konovalov, D A; White, R D; Brunger, M J; Jones, D B
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. PMID:25833578
NASA Astrophysics Data System (ADS)
Do, T. P. T.; Duque, H. V.; Lopes, M. C. A.; Konovalov, D. A.; White, R. D.; Brunger, M. J.; Jones, D. B.
2015-03-01
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.
Aspects of the Eckart frame ro-vibrational kinetic energy operator
NASA Astrophysics Data System (ADS)
Szalay, Viktor
2015-08-01
A most decisive part of developing the Eckart frame ro-vibrational kinetic energy operator (KEO) in terms of curvilinear internal coordinates is the introduction of vibrational displacements obeying the Eckart conditions. It is examined here, how such displacements may be constructed by orthogonal and nonorthogonal transformations, and how they can be employed in developing the KEO. In particular, it is shown analytically, by term by term comparison, that the Eckart KEOs obtained by employing Pickett's method and the gateway Hamiltonian method are equivalent. That is, although it may appear in the form of very different expressions, the general, exact ro-vibrational Eckart frame KEO is unique. As side result, it has been shown that the simple formula of the pseudo-potential derived by Watson for the exact KEO given in normal coordinates applies to any Eckart frame KEO, irrespective of the choice of the vibrational coordinates.
Aspects of the Eckart frame ro-vibrational kinetic energy operator.
Szalay, Viktor
2015-08-14
A most decisive part of developing the Eckart frame ro-vibrational kinetic energy operator (KEO) in terms of curvilinear internal coordinates is the introduction of vibrational displacements obeying the Eckart conditions. It is examined here, how such displacements may be constructed by orthogonal and nonorthogonal transformations, and how they can be employed in developing the KEO. In particular, it is shown analytically, by term by term comparison, that the Eckart KEOs obtained by employing Pickett's method and the gateway Hamiltonian method are equivalent. That is, although it may appear in the form of very different expressions, the general, exact ro-vibrational Eckart frame KEO is unique. As side result, it has been shown that the simple formula of the pseudo-potential derived by Watson for the exact KEO given in normal coordinates applies to any Eckart frame KEO, irrespective of the choice of the vibrational coordinates. PMID:26277124
Spectroscopic probes of vibrationally excited molecules at chemically significant energies
Rizzo, T.R.
1993-04-01
Infrared-optical double resonance is being used to study the unimolecular dissociation dynamics of hydrazoic acid (HN[sub 3]). 6[nu][sub NH] vibrational overtone excitation spectra are given for HN[sub 3]. Work was begun to determine the feasibility of extending the infrared-optical double resonance photofragment spectroscopy to small free radicals, and to be able to monitor atomic dissociation fragments via laser induced fluorescence in the VUV spectrum. 1 fig.
Energy Industry Powers CTE Program
ERIC Educational Resources Information Center
Khokhar, Amy
2012-01-01
Michael Fields is a recent graduate of Buckeye Union High School in Buckeye, Arizona. Fields is enrolled in the Estrella Mountain Community College (EMCC) Get Into Energy program, which means he is well on his way to a promising career. Specializing in power plant technology, in two years he will earn a certificate that will all but guarantee a
Sheldon Green; Hans-Martin Keller; Reinhard Schinke; Hans-Joachim Werner
1996-01-01
Collision cross sections for rotational and vibrational excitation of CO by fast H atoms are calculated for two potential energy surfaces, the older BowmanBitmanHarding potential and the recently constructed surface of Werner, Keller, and Schinke. Both quantum mechanical and classical calculations are performed. The results obtained with the new potential energy surface are very similar to those obtained with the
The potential energy surface and the highly excited vibrational band origins of the water molecule
Daiqian Xie; Guosen Yan
1996-01-01
The potential energy surface for the electronic ground state of the water molecule is optimized by means of a variational procedure using the exact vibrational Hamiltonian in the bond length-bond angle coordinates. In the optimization, Jensen's potential energy function (J. Mol. Spectry. 133 (1989) 438) is taken as the starting point andthe recently observed band origins below 22000 cm?1 given
Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures
NASA Technical Reports Server (NTRS)
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.
Effect of collision energy and vibrational excitation on endothermic ion-molecule reactions
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/sub 2//sup +/ + He and HD/sup +/ + 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/sub 2//sup +/ or HD/sup +/ 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/sub 2/H/sub 2//sup +/ + H/sub 2/ ..-->.. C/sub 2/H/sub 3//sup +/ + H.
Intermediate energy electron impact excitation of composite vibrational modes in phenol
NASA Astrophysics Data System (ADS)
Neves, R. F. C.; Jones, D. B.; Lopes, M. C. A.; Nixon, K. L.; de Oliveira, E. M.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; da Silva, G. B.; Brunger, M. J.
2015-05-01
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 (C6H5OH). 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 C6H5OH molecule by electron impact.
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 bi-annular-gap magnetorheological energy absorber for shock and vibration mitigation
NASA Astrophysics Data System (ADS)
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.
Farantos, Stavros C.
The vibrational energies of ozone up to the dissociation threshold: Dynamics calculations present an ab initio potential energy surface for the ground electronic state of ozone. It is global, i. All bound states of nonrotating ozone up to more than 99% of the dissociation energy are calculated
NASA Astrophysics Data System (ADS)
Chen, Yuehua; Jin, Guoyong; Zhu, Minggang; Liu, Zhigang; Du, Jingtao; Li, Wen L.
2012-02-01
The vibration behaviors of a box-type built-up structure and energy transmission through the structure are investigated analytically. The modeling of the structure is developed by employing the improved Fourier series method and treating the structure as four elastically coupled rectangular plates. The general coupling and boundary conditions are accounted for using the artificial spring technique and can easily be obtained by assigning the springs with corresponding values. The exact double Fourier series solutions considering both the flexural and in-plane vibrations are obtained by using the Rayleigh-Ritz approach, which are validated by comparison with the Finite Element Method (FEM) results. Since the modification of any parameter in this analytical model from one case to another is as simple as modifying the material properties, and does not involve any change to the solution procedures, thus this will make a parametric study and further mechanism analysis easier compared to most existing procedures. Subsequently, special attention is focused on the energy transmission and mechanism of the box-type structure by structural intensity analysis. Numerical analyses cover several important parameters including symmetrical and non-symmetrical coupling conditions and the excitations, and three types of models, namely the rigidly, elastically and weakly coupled models are involved. The results of the power flow and structural intensity are presented to obtain a clear physical understanding of the physical mechanisms of energy transmission. It is shown that the energy transmission behaviors can be significantly influenced by the coupling conditions and location of the excitation as well as the excitation frequency. Some unexpected interesting phenomena on the energy transmission were revealed, especially for the non-symmetrical model, and the corresponding mechanisms were interpreted. This study provides new and interesting insights into the vibration behaviors and energy transmission of the class of built-up box-type structure.
Effect of whole-body vibration on delayed onset muscular soreness, flexibility, and power.
Wheeler, Amanda A; Jacobson, Bert H
2013-09-01
Delayed onset muscle soreness (DOMS) occurs after unaccustomed or intense bouts of exercise. The effects of DOMS peak at approximately 48 hours postexercise, and DOMS is treated, albeit not highly successfully, in a variety of ways including the use of medication and therapeutic modalities. The objective of this study was to determine the effects of whole-body vibration (WBV) on DOMS through Visual Analog Scale (VAS) measures of perceived pain/soreness and to assess the effect of WBV on flexibility and explosive power after induced DOMS. Twenty healthy college-aged participants (10 men and 10 women) volunteered for this study and were randomly assigned to the experimental or the control group. Participants completed baseline measures for VAS, hamstring and lower back flexibility, and explosive power before completing a DOMS-inducing exercise. Measures for VAS, hamstring and lower back flexibility, and explosive power were measured immediately postexercise and again immediately posttreatment. Participants reported back to the laboratory for 4 additional data collections sessions. Both the experimental and control groups yielded significant differences (p < 0.05) in pretest and posttest DOMS between baseline and pretest and posttest 1, pretest and posttest 2, and pretest and posttest 3. No significance (p > 0.05) was found within or between groups when comparing preassessments and postassessments of DOMS, flexibility, or explosive power. No differences (p > 0.05) between WBV and light exercise were found for DOMS, flexibility, and explosive power. These results suggest that WBV is equally as effective as light exercise in reducing the severity of DOMS. Thus, WBV may be used as a recovery option in addition to current treatments. PMID:23249818
A modified method of vibration surveillance by using the optimal control at energy performance index
NASA Astrophysics Data System (ADS)
Kali?ski, Krzysztof J.; Galewski, Marek A.
2015-06-01
A method of vibration surveillance by using the optimal control at energy performance index has been creatively modified. The suggested original modification depends on consideration of direct relationship between the measured acceleration signal and the optimal control command. The paper presents the results of experiments and Hardware-in-the-loop simulations of a new active vibration reduction algorithm based on the energy performance index idea modified in such a way, that it directly utilises the acceleration feedback signal. Promising prospects towards real application of the modified method in case of the high speed milling are predicted as well.
NASA Astrophysics Data System (ADS)
Blaevi?, D.; Zelenika, S.
2015-05-01
Scavenging of low-level ambient vibrations i.e. the conversion of kinetic into electric energy, is proven as effective means of powering low consumption electronic devices such as wireless sensor nodes. Cantilever based scavengers are characterised by several advantages and thus thoroughly investigated; analytical models based on a distributed parameter approach, Euler-Bernoulli beam theory and eigenvalue analysis have thus been developed and experimentally verified. Finite element models (FEM) have also been proposed employing different modelling approaches and commercial software packages with coupled analysis capabilities. An approach of using a FEM analysis of a piezoelectric cantilever bimorph under harmonic excitation is used in this work. Modal, harmonic and linear and nonlinear transient analyses are performed. Different complex dynamic effects are observed and compared to the results obtained by using a distributed parameter model. The influence of two types of finite elements and three mesh densities is also investigated. A complex bimorph cantilever, based on commercially available Midé Technology® Volture energy scavengers, is then considered. These scavengers are characterised by an intricate multilayer structure not investigated so far in literature. An experimental set-up is developed to evaluate the behaviour of the considered class of devices. The results of the modal and the harmonic FEM analyses of the behaviour of the multilayer scavengers are verified experimentally for three different tip masses and 12 different electrical load values. A satisfying agreement between numerical and experimental results is achieved.
Comparison of Five Topologies of Cantilever-based MEMS Piezoelectric Vibration Energy Harvesters
NASA Astrophysics Data System (ADS)
Jia, Y.; Seshia, A. A.
2014-11-01
In the realm of MEMS piezoelectric vibration energy harvesters, cantilever-based designs are by far the most popular. Despite being deceptively simple, the active piezoelectric area near the clamped end is able to accumulate maximum strain-generated-electrical-charge, while the free end is able to accommodate a proof mass without compromising the effective area of the piezoelectric generator since it experiences minimal strain anyway. While other contending designs do exist, this paper investigates five micro-cantilever (MC) topologies, namely: a plain MC, a tapered MC, a lined MC, a holed MC and a coupled MC, in order to assess their relative performance as an energy harvester. Although a classical straight and plain MC offers the largest active piezoelectric area, alternative MC designs can potentially offer higher average mechanical strain distribution for a given mechanical loading. Numerical simulation and experimental comparison of these 5 MCs (0.5 ? AlN on 10 ?m Si) with the same practical dimensions of 500 ?m and 2000 ?m, suggest a cantilever with a coupled subsidiary cantilever yield the best power performance, closely followed by the classical plain topology.
Origin of Low-Energy Quadrupole Collectivity in Vibrational Nuclei
Walz, C.; Krugmann, A.; Neumann-Cosel, P. von; Pietralla, N.; Ponomarev, V. Yu.; Scheikh-Obeid, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Fujita, H. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); iThemba LABS, Post Office Box 722, Somerset West 7129 (South Africa); Wambach, J. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)
2011-02-11
The coupling of the giant quadrupole resonance to valence-space configurations is shown to be the origin of the formation of low-lying quadrupole-collective structures in vibrational nuclei with symmetric and mixed-symmetric character with respect to the proton-neutron degree of freedom. For the first time experimental evidence for this picture is obtained from electron- and proton scattering experiments on the nucleus {sup 92}Zr that are sensitive to the relative phase of valence-space amplitudes by quantum interference.
Low power interface IC's for electrostatic energy harvesting applications
NASA Astrophysics Data System (ADS)
Kempitiya, Asantha
The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of interest where the storage capacitor can be optimized to produce almost 70% of the ideal power taken as the power harvested with synchronous converters when neglecting the power consumption associated with synchronizing control circuitry. Theoretical predictions are confirmed by measurements on an asynchronous EHC implemented with a macro-scale electrostatic converter prototype. Based on the preceding analysis, the design of a novel ultra low power electrostatic integrated energy harvesting circuit is proposed for efficient harvesting of mechanical energy. The fundamental challenges of designing reliable low power sensing circuits for charge constrained electrostatic energy harvesters with capacity to self power its controller and driver stages are addressed. Experimental results are presented for a controller design implemented in AMI 0.7muM high voltage CMOS process using a macro-scale electrostatic converter prototype. The EHC produces 1.126muW for a power investment of 417nW with combined conduction and controller losses of 450nW which is a 20-30% improvement compared to prior art on electrostatic EHCs operating under charge constrain. Inherently dual plate variable capacitors harvest energy only during half of the mechanical cycle with the other half unutilized for energy conversion. To harvest mechanical energy over the complete mechanical vibration cycle, a low power energy harvesting circuit (EHC) that performs charge constrained synchronous energy conversion on a tri-plate variable capacitor for maximizing energy conversion is proposed. The tri-plate macro electrostatic generator with capacitor variation of 405pF to 1.15nF and 405pF to 1.07nF on two complementary adjacent capacitors is fabricated and used in the characterization of the designed EHC. The integrated circuit fabricated in AMI 0.7muM high voltage CMOS process, produces a total output power of 497nW to a 10muF reservoir capacitor from a 98Hz vibration signal. In summary, the thesis lays out the theoretical and experimental foundation for overcoming the main challenges associated with the desi
NASA Astrophysics Data System (ADS)
Eltanany, Ali M.; Yoshimura, Takeshi; Fujimura, Norifumi; Elsayed, Nour Z.; Ebied, Mohamed R.; Ali, Mohamed G. S.
2015-10-01
The role of nonlinear stiffness in the performance of the piezoelectric vibrational energy harvester (pVEH) was discussed. Harmonic balance and numerical methods are applied to characterize the electromechanical response of pVEHs based on Duffing oscillator at a deterministic harmonic excitation of fundamental vibration characteristics (2 Hz, 1 m·s?2), which corresponds to human walking. Then, the response to a vibration with two harmonic waves, which has a fixed fundamental frequency (2 Hz, 1 m·s?2) and a frequency varied from 1.5 to 2.5 Hz. The numerical results obtained in this study indicate that nonlinearity does not have a significant advantage on the energy harvesting from human walking.
NASA Astrophysics Data System (ADS)
Dudka, A.; Basset, P.; Cottone, F.; Blokhina, E.; Galayko, D.
2013-12-01
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 ?W 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.
ENergy and Power Evaluation Program
1996-11-01
In the late 1970s, national and international attention began to focus on energy issues. Efforts were initiated to design and test analytical tools that could be used to assist energy planners in evaluating energy systems, particularly in developing countries. In 1984, the United States Department of Energy (DOE) commissioned Argonne National Laboratory`s Decision and Information Sciences Division (DIS) to incorporate a set of analytical tools into a personal computer-based package for distribution in developing countries. The package developed by DIS staff, the ENergy and Power Evaluation Program (ENPEP), covers the range of issues that energy planners must face: economic development, energy demand projections, supply-and-demand balancing, energy system expansion, and environmental impact analysis. Following the original DOE-supported development effort, the International Atomic Energy Agency (IAEA), with the assistance from the US Department of State (DOS) and the US Department of Energy (DOE), provided ENPEP training, distribution, and technical support to many countries. ENPEP is now in use in over 60 countries and is an international standard for energy planning tools. More than 500 energy experts have been trained in the use of the entire ENPEP package or some of its modules during the international training courses organized by the IAEA in collaboration with Argonne`s Decision and Information Sciences (DIS) Division and the Division of Educational Programs (DEP). This report contains the ENPEP program which can be download from the internet. Described in this report is the description of ENPEP Program, news, forums, online support and contacts.
A wind energy powered wireless temperature sensor node.
Zhang, Chuang; He, Xue-Feng; Li, Si-Yu; Cheng, Yao-Qing; Rao, Yang
2015-01-01
A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 k? at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally. PMID:25734649
Sun, Kyung Ho; Kim, Young-Cheol; Kim, Jae Eun
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.
NASA Technical Reports Server (NTRS)
Tessarzik, J. M.; Chiang, T.; Badgley, R. H.
1974-01-01
A bearing damper, operating on the support flexure of a pivoted pad in a tilting-pad type gas-lubricated journal bearing, has been designed, built, and tested under externally-applied random vibrations. The NASA Brayton Rotating Unit (BRU), a 36,000 rpm, 10-Kwe turbogenerator had previously been subjected in the MTI Vibration Test Laboratory to external random vibrations, and vibration response data had been recorded and analyzed for amplitude distribution and frequency content at a number of locations in the machine. Based on data from that evaluation, a piston-type damper was designed and developed for each of the two flexibly-supported journal bearing pads (one in each of the two three-pad bearings). A modified BRU, with dampers installed, has been re-tested under random vibration conditions. Root-mean-square vibration amplitudes were determined from the test data, and displacement power spectral density analyses have been performed. Results of these data reduction efforts have been compared with vibration tolerance limits. Results of the tests indicate significant reductions in vibration levels in the bearing gas-lubricant films, particularly in the rigidly-mounted pads. The utility of the gas-lubricated damper for limiting rotor-bearing system vibrations in high-speed turbomachinery has thus been demonstrated.
NASA Astrophysics Data System (ADS)
Wu, Dan; Guyomar, Daniel; Richard, Claude
2013-04-01
A new global approach for improved vibration damping of smart structure, based on global energy redistribution by means of a network of piezoelectric elements is proposed. It is basically using semi-active Synchronized Switch Damping technique. SSD technique relies on a cumulative build-up of the voltage resulting from the continuous switching and it was shown that the performance is strongly related to this voltage. The increase of the piezoelectric voltage results in improvement of the damping performance. External voltage sources or improved switching sequences were previously designed to increase this voltage in the case of single piezoelectric element structure configurations. This paper deals with extended structure with many embedded piezoelectric elements. The proposed strategy consist of using an electric network made with non-linear component and switches in order to set up and control a low-loss energy transfer from source piezoelements extracting the vibration energy of the structure and oriented toward a given piezoelement in order to increase its operative energy for improving a given mode damping. This paper presents simulation of a clamped plate with four piezoelectric elements implemented in the Matlab/SimulinkTM environment and SimscapeTM library. The various simulation cases show the relationship between the damping performance on a given targeted mode and the established power flow. SSDD and SSDT are two proposed original networks. Performances are compared to the SSDI baseline. A damping increase of 18dB can be obtained even with a weakly coupled piezoelectric element in the multi-sine excitation case. This result proves the importance of new global non-linear multi-actuator strategies for improved vibration damping of extended smart structure.
Eggshell Cutter Using Ultrasonic Vibration
NASA Astrophysics Data System (ADS)
Miura, Hikaru
2003-05-01
An eggshell cutting apparatus which utilizes ultrasonic vibration was developed, replacing the conventional apparatus which uses an air cutter, to cut eggshells at the blunt end of eggs. Two ultrasonic vibration sources were used: one with longitudinal vibration only and the other with torsional vibration plus longitudinal vibration. Eggshell cutting experiments using these vibration sources were conducted. The eggshell cutting time sharply decreased with increasing longitudinal vibration amplitude as well as increasing input power. When the source with torsional vibration plus longitudinal vibration was used and the amplitude of longitudinal vibration was 12 ?m or less, the torsional vibration was effective for cutting eggshells. Furthermore, at the same input power, the eggshell cutting time by the source with longitudinal vibration only was shorter than that by the source with torsional vibration plus longitudinal vibration. When an egg was cut using the apparatus, there was essentially no cutting noise and the cut surface was smooth.
Net energy analysis: Powerful tool for selecting electric power options
NASA Astrophysics Data System (ADS)
Baron, S.
A number of net energy analysis studies have been conducted in recent years for electric power production from coal, oil and uranium fuels; synthetic fuels from coal and oil shale; and heat and electric power from solar energy. This technique is an excellent indicator of investment costs, environmental impact and potential economic competitiveness of alternative electric power systems for energy planners from the Eastern European countries considering future options. Energy conservation is also important to energy planners and the net energy analysis technique is an excellent accounting system on the extent of energy resource conservation. The author proposes to discuss the technique and to present the results of his studies and others in the field. The information supplied to the attendees will serve as a powerful tool to the energy planners considering their electric power options in the future.
NASA Astrophysics Data System (ADS)
Colin, M.; Mortier, Q.; Basrour, S.; Bencheikh, N.
2013-12-01
This paper introduces an innovative architecture of a piezoelectric harvester, which enables harvesting vibration energy at low frequency using the {33}-transduction mode of a piezoelectric element. Unlike cantilevers integrating ferroelectric material combined with interdigitated electrodes, the concept that we propose is based on the elongation/compression excitation of a piezoelectric bar.
Rabani, Eran
interconversion of electronic-to-vibrational energy transfer (EVET) is discovered between the band-gap excitation for dipole-dipole long-range, resonance, radiation- less interconversion of core band-gap electronic, are investigated. The graded-shell structure creates an effective confinement potential minimizing non- radiative
Yang, Juan
2007-09-17
energy functions for several vibrational states in the S0 ground state were determined. The barrier was found to be 154 cm-1 and the puckering angles to be Ć?Ā± 25Ć?Ā°, in good agreement with the millimeter wave barrier of 152 cm-1 and puckering angles...
Röder, Beate
Although discussed for more than three decades the vision of molecular electronics never lost itsIV characteristics of molecular wires in the presence of intramolecular vibrational energy Various interaction mechanisms may contribute to the currentvoltage (IV) characteristics of a single
Theoretical studies of vibrationally-resolved electron capture in low-energy ion-molecule collisions
Stancil, Phillip C.
are presented for the O 3+ + H2 and H + + CO collision systems. PACS numbers: 34.50.-s, 34.20.Mq, 34,70.+e 1. This results in increases in complexity of the molecular structure (potential surfaces and couplingsTheoretical studies of vibrationally-resolved electron capture in low-energy ion
NASA Astrophysics Data System (ADS)
Gonzįlez Ureńa, A.; Telle, H. H.; Tornero, J.
2013-01-01
A simple, inelastic electron-scattering dynamical model is presented to account for vibrational excitation in molecular adsorbates. The basic two ingredients of the theoretical model are: (i) the conservation of the total angular momentum, and (ii) the requirement of a critical time to allow for the intra-molecular energy re-arrangement of the transient negative-ion complex. The model is applied to the vibrational excitation dynamics of molecules chemisorbed at sub-monolayer conditions on ordered metal surfaces. This was exemplified for Acrylonitrile adsorbed on Cu(1 0 0), whose vibrational excitation was studied via energy loss spectra of low-energy two-photon photoemission (2PPE) electrons, and for ammonia (NH3 and ND3) adsorbed on Cu(1 0 0), being probed in a STM experiment. Fits of the model to the data allowed for deducing the energy threshold of the vibrational excitation of the Cdbnd C and Ctbnd N bonds of the ACN adsorbate molecules, and the threshold for the symmetric ?1-stretch mode excitation of adsorbed NH3/ND3. Also, information about the temporal dynamics underlying the inelastic electron scattering was gained.
Optimized Structure and Vibrational Properties by Error Affected Potential Energy Surfaces
Zen, Andrea; Zhelyazov, Delyan; Guidoni, Leonardo
2013-01-01
The precise theoretical determination of the geometrical parameters of molecules at the minima of their potential energy surface and of the corresponding vibrational properties are of fundamental importance for the interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo techniques are correlated electronic structure methods promising for large molecules, which are intrinsically affected by stochastic errors on both energy and force calculations, making the mentioned calculations more challenging with respect to other more traditional quantum chemistry tools. To circumvent this drawback in the present work, we formulate the general problem of evaluating the molecular equilibrium structures, the harmonic frequencies, and the anharmonic coefficients of an error affected potential energy surface. The proposed approach, based on a multidimensional fitting procedure, is illustrated together with a critical evaluation of systematic and statistical errors. We observe that the use of forces instead of energies in the fitting procedure reduces the statistical uncertainty of the vibrational parameters by 1 order of magnitude. Preliminary results based on variational Monte Carlo calculations on the water molecule demonstrate the possibility to evaluate geometrical parameters and harmonic and anharmonic coefficients at this level of theory with an affordable computational cost and a small stochastic uncertainty (<0.07% for geometries and <0.7% for vibrational properties). PMID:24093004
Semi-Classical Methods for Vibrational Energy Levels of Triatomic Molecules
Miller, William H.
Semi-Classical Methods for Vibrational Energy Levels of Triatomic Molecules BY N. C. HANDY,S. M April, 1976 The method recently proposed by Chapman, Garrett and Miller for semi-classical eigenvalues turned to the problem of determining semi-classical eigenvalues for molecular systems. The goal
NASA Astrophysics Data System (ADS)
Kruglova, T. V.
2004-01-01
The detailed spectroscope information about highly excited molecules and radicals such us as H+3, H2, HI, H2O, CH2 is needed for a number of applications in the field of laser physics, astrophysics and chemistry. Studies of highly excited molecular vibration-rotation states face several problems connected with slowly convergence or even divergences of perturbation expansions. The physical reason for a perturbation expansion divergence is the large amplitude motion and strong vibration-rotation coupling. In this case one needs to use the special method of series summation. There were a number of papers devoted to this problem: papers 1-10 in the reference list are only example of studies on this topic. The present report is aimed at the application of GET method (Generalized Euler Transformation) to the diatomic molecule. Energy levels of a diatomic molecule is usually represented as Dunham series on rotational J(J+1) and vibrational (V+1/2) quantum numbers (within the perturbation approach). However, perturbation theory is not applicable for highly excited vibration-rotation states because the perturbation expansion in this case becomes divergent. As a consequence one need to use special method for the series summation. The Generalized Euler Transformation (GET) is known to be efficient method for summing of slowly convergent series, it was already used for solving of several quantum problems Refs.13 and 14. In this report the results of Euler transformation of diatomic molecule Dunham series are presented. It is shown that Dunham power series can be represented of functional series that is equivalent to its partial summation. It is also shown that transformed series has the butter convergent properties, than the initial series.
NASA Astrophysics Data System (ADS)
Moeser, Beate; Janoschka, Adam; Wolny, Juliusz A.; Filipov, Igor; Chumakov, Aleksandr I.; Walker, F. Ann; Schünemann, Volker
2012-03-01
The binding of the signal molecule nitric oxide (NO) to the NO transporter protein Nitrophorin 2 (NP2) from the bloodsucking insect Rhodnius prolixus has been characterized by Mössbauer spectroscopy as well as nuclear forward scattering (NFS) and nuclear inelastic scattering (NIS). A striking feature of the vibrational spectrum obtained from NP2-NO is a vibration at 594 cm - 1. This mode is assigned to a Fe-NO stretching mode via simulation of the NIS data by density functional theory (DFT) coupled with molecular mechanics (MM) methods. At frequencies below 100 cm - 1 collective motions like heme doming occur which could explain spectroscopic features observed by NIS at these low energies.
Meier, Patrick; Oschetzki, Dominik; Rauhut, Guntram; Berger, Robert
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.
Exploring Energy, Power, and Transportation Technology.
ERIC Educational Resources Information Center
Bowers, Donovan; Kellum, Mary
These teacher's materials for a seven-unit course were developed to help students develop technological literacy, career exploration, and problem-solving skills relative to the communication industries. The seven units include an overview of energy and power, principles of energy and power, power production and conversion, power transmission and
Power Spectra Tests of the Dark Energy
Hu, Wayne
Power Spectra Tests of the Dark Energy Wayne Hu NASA/Goddard Space Flight Center k (Mpc1) 0.05 2 4 6 8 0.1 Power Growth Distance #12;Outline Power spectrum tests of the dark energy in light · Marcos Lima #12;Dark Energy Sensitivity · Growth: G=(growth rate)/a; normalized to high z · Distances: D
Ramakrishnan, Raghunathan; Carrington, Tucker
2014-02-01
We have computed vibrational energy levels of difluorodioxirane (CF2O2). For the potential, a Taylor expansion in normal coordinates is used. The CCSD(T) and MP2 methods and correlation consistent basis sets of quadruple-zeta quality are used to determine the force constants. The vibrational Schrödinger equation was solved using both a variational method and second order perturbation theory. The Watson kinetic energy operator and a discrete variable representation were used with the DEWE (E. Mįtyus, G. Czakó, B.T. Sutcliffe and A.G. Csįszįr, J. Chem. Phys. 127 (2007) 084102) computer program to do the variational calculations. For the variational calculations, the average absolute deviation of fundamentals, with respect to experimental values, is less than 3 cm(-1). Perturbative results are almost as good. About 300 vibrational levels were computed. (16)O?(18)O isotopic shifts have also been calculated variationally for the lowest 75 vibrational energy levels and are compared to experimental results. PMID:23290829
Aeolian vibrations; Wind energy input evaluated from measurements on an energized transmission line
Kraus, M.; Hagedorn, P. )
1991-07-01
In this paper field tests carried out in Buren in a completely automated test station are described. From these measurements the wind power input in an actual transmission line is estimated. A comparison with results from wind tunnel data is carried out. It corroborates the method now being used for the calculation of aeolian vibrations in transmission lines, so that it can be used in the future with more confidence.
Blevins, R.D.
1990-01-01
This book reports on dimensional analysis; ideal fluid models; vortex-induced vibration; galloping and flutter; instability of tube and cylinder arrays; vibrations induced by oscillating flow; vibration induced by turbulence and sound; damping of structures; sound induced by vortex shedding; vibrations of a pipe containing a fluid flow; indices. It covers the analysis of the vibrations of structures exposed to fluid flows; explores applications for offshore platforms and piping; wind-induced vibration of buildings, bridges, and towers; and acoustic and mechanical vibration of heat exchangers, power lines, and process ducting.
Power and energy containers for multicore servers
Kai Shen; Arrvindh Shriraman; Sandhya Dwarkadas; Xiao Zhang
2012-01-01
Power capping and energy efficiency are critical concerns in server systems, particularly when serving dynamic workloads on resource-sharing multicores. We present a new operating system facility (power and energy containers) that accounts for and controls the power\\/energy usage of individual fine-grained server requests. This facility is enabled by novel techniques for multicore power attribution to concurrent tasks, measurement\\/modeling alignment to
Careers in Geothermal Energy: Power from below
ERIC Educational Resources Information Center
Liming, Drew
2013-01-01
In the search for new energy resources, scientists have discovered ways to use the Earth itself as a valuable source of power. Geothermal power plants use the Earth's natural underground heat to provide clean, renewable energy. The geothermal energy industry has expanded rapidly in recent years as interest in renewable energy has grown. In 2011,
ENERGY SERIES "Emerging High Power Conversion Technologies"
Bergman, Keren
of embedded renewable energy sources. Whatever the renewable source of the prime energy is (wind, solar, hydro in the broad field of electrical energy generation, conversion and storage. He has received his Dipl. IngSEMINAR: ENERGY SERIES "Emerging High Power Conversion Technologies" Dujic Drazen Professor, Power
Intramolecular vibrational energy redistribution and the time evolution of molecular fluorescence
NASA Astrophysics Data System (ADS)
Freed, Karl F.; Nitzan, Abraham
1980-11-01
We note the presence of contradictory estimates of intramolecular vibrational relaxation rates in the literature where large molecules in high energy states, corresponding to huge densities of vibrational levels, have been ascribed relaxation rates orders of magnitude smaller than those assigned to smaller molecules with much smaller densities of vibrational levels. This unphysical disparity is explained as arising from vague (or undefined) definitions of intramolecular vibrational relaxation and/or from a consideration of quantities which are not directly measured or measurable. A resolution of a portion of the problem is already well known for electronic relaxation, but the application of those results to a description of the time evolution of the molecular fluorescence, produced during the intramolecular vibrational relaxation of the electronically excited molecules, requires a generalization of the electronic relaxation theory to separate and describe the ''unrelaxed'' and ''relaxed'' emission spectra. We provide this general theory of the time variation of the emission spectrum for molecules conforming to both the intermediate and statistical limits of intramolecular vibrational relaxation with emphasis placed upon the distinguishability between these two cases. The intermediate case analysis utilizes egalitarian and random coupling type models with essentially identical conclusions from both. The time evolution and relative yields associated with the emission spectra are described for both continuous and short pulse excitation, and reasons are provided for the absence of observation of time varying emission spectra in the experiments of Smalley and co-workers. Quantum beats are possible in principle in the sparse intermediate case. Their observability depends, however, on the detection method. When the emission spectrum can be resolved, beats are expected only in the frequency integrated intensity.
NASA Astrophysics Data System (ADS)
Komuro, Atsushi; Takahashi, Kazunori; Ando, Akira
2015-10-01
Vibration-to-translation (VT) energy transfer in atmospheric-pressure streamer discharge is numerically simulated using a two-dimensional electro-hydrodynamic model. The model includes state-to-state vibrational kinetics in humid air and is coupled with the compressible flow equation of the gas fluid. The vibrational distribution of {{\\text{O}}2}(v) reaches equilibrium more quickly than that of {{\\text{N}}2}(v) , whereas the energy released from {{\\text{O}}2}(v) does not increase the gas temperature. In humid air, the decay rate of the vibrational energy of {{\\text{N}}2}(v) is accelerated by the VT energy transfer through water molecules and the energy heats the gas. However, the increase in gas temperature due to VT energy transfer is not always seen because it competes with thermal diffusion.
Potential energy surface and vibrational band origins of the triatomic lithium cation
NASA Astrophysics Data System (ADS)
Searles, Debra J.; Dunne, Simon J.; von Nagy-Felsobuki, Ellak I.
The 104 point CISD Li +3 potential energy surface and its analytical representation is reported. The calculations predict the minimum energy geometry to be an equilateral triangle of side RLi?Li = 3.0 Å and of energy - 22.20506 E h. A fifth-order MorseDunham type analytical force field is used in the CarneyPorter normal co-ordinate vibrational Hamiltonian, the corresponding eigenvalue problem being solved variationally using a 560 configurational finite-element basis set. The predicted assignment of the vibrational band origins is in accord with that reported for H +3. Moreover, for 6Li +3 and 7Li +3 the lowest i.r. accessible band origin is the overline?0,1,±1 predicted to be at 243.6 and 226.0 cm -1 respectively.
Performance Evaluation of Vibration-Based Piezoelectric Energy Scavengers
Shu, Yi-Chung
consumption in integrated circuits (IC) will continue to decrease as IC processing moves towards smaller of piezoelectric power harvesting systems using either the standard or the synchronized switch harvesting in existing ones are also pointed here. 3.1 Introduction The development of wireless sensor and communication
Watanabe, Shinji; Fujii, Hidekazu; Kohguchi, Hiroshi; Hatano, Takayuki; Tokue, Ikuo; Yamasaki, Katsuyoshi
2008-10-01
A wide range of vibrational levels of O2(X(3)Sigma(g)(-), v = 6-13) generated in the ultraviolet photolysis of O3 was selectively detected by the laser-induced fluorescence (LIF) technique. The time-resolved LIF-excited B(3)Sigma(u)(-)-X(3)Sigma(g)(-) system in the presence of CF4 has been recorded and analyzed by the integrated profiles method (IPM). The IPM permitted us to determine the rate coefficients k(v)(CF4) for vibrational relaxation of O2(X(3)Sigma(g)(-), v = 6-12) by collisions with CF4. Energy transfer from O2 (v = 6-12) to CF4 is surprisingly efficient compared to that of other polyatomic relaxation partners studied so far. The k(v)(CF4) increases with vibrational quantum number v from [1.5 +/- 0.2(2sigma)] x 10(-12) for v = 6 to [7.3 +/- 1.5(2sigma)] x 10(-11) for v = 12, indicating that the infrared-active nu3 vibrational mode of CF4 mainly governs the energy transfer with O2(X(3)Sigma(g)(-), v = 6-12). The correlation between the rate coefficients and fundamental infrared intensities has been discussed based on a comparison of the efficiency of energy transfer by several collision partners. PMID:18593107
Kinetic model for the vibrational energy exchange in flowing molecular gas mixtures. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
Offenhaeuser, F.
1987-01-01
The present study is concerned with the development of a computational model for the description of the vibrational energy exchange in flowing gas mixtures, taking into account a given number of energy levels for each vibrational degree of freedom. It is possible to select an arbitrary number of energy levels. The presented model uses values in the range from 10 to approximately 40. The distribution of energy with respect to these levels can differ from the equilibrium distribution. The kinetic model developed can be employed for arbitrary gaseous mixtures with an arbitrary number of vibrational degrees of freedom for each type of gas. The application of the model to CO2-H2ON2-O2-He mixtures is discussed. The obtained relations can be utilized in a study of the suitability of radiation-related transitional processes, involving the CO2 molecule, for laser applications. It is found that the computational results provided by the model agree very well with experimental data obtained for a CO2 laser. Possibilities for the activation of a 16-micron and 14-micron laser are considered.
The reduction of rotorcraft power and vibration using optimally controlled active gurney flap
NASA Astrophysics Data System (ADS)
Bae, Eui Sung
The main topic of the present study is the application of active control scheme for the reduction of rotorcraft main rotor power reduction and vibratory load. When the helicopter is operated near its flight boundary, the required power and vibratory loads rapidly increases which impose a limit on the helicopter operation. Various methods were proposed and studied in order to achieve performance improvement under such operating condition. The effect of active control scheme was examined for its impact on the performance improvement and vibration reduction in the present study. Numerical simulations are based on the UH-60A Blackhawk helicopter with an active Gurney flap spanning from 70%R to 80%R of the main rotor. For obtaining the aeroelastic response of the rotor blade, finite element method was used to represent elastic blade. The aerodynamic loads acting on the blade are provided by CFD based 2D lookup table. Prescribed wake model was used to resolve the induced inflow over the rotor disk. The unsteady aerodynamic behavior due to the higher harmonic actuation of active Gurney flap was resolved by the time-domain unsteady aerodynamic model. The first part of preliminary study covers parametric study using Gurney flap. Starting with simple rigid blade representation of the rotor blade, the effect of 1/rev Gurney flap actuation was examined on three different gross weights. The effect of active Gurney flap width, the chordwise location of active Gurney flap, the effect of unsteady aerodynamic model, and the effect of 2/rev actuation frequency were examined. The second part of preliminary study was conducted with the elastic blade model to include the effect of torsion dynamics. Performance improvement using active Gurney flap was examined for maximizing thrust capability at two flight speeds. 1/rev Gurney flap actuation increased the gross weight capability up to 1,000 lbs. Also, 1/rev actuation of Gurney flap increased maximum altitude limit of baseline rotor by 1,400 ft. Furthermore, it was predicted that the maximum level flight speed can be increased by 30 knots with respect to that of the baseline rotor. The effect of active Gurney flap on the vibration reduction was first examined at the stall condition. Using 1/rev actuation, in-plane vibratory force and moment can be reduced by 68% and 44%, respectively. The effects of higher harmonic frequencies were investigated at the high-speed cruise speed, and single frequency phase sweep was conducted to find the best phase angle that minimizes each vibratory components. 3/rev actuation yielded 36% reduction in in-plane vibratory moment. 74% reduction in vertical vibratory force was predicted with 4/rev actuation. With 5/rev actuation, 81% reduction in vertical vibratory load was observed. With the input-output information obtained from single frequency phase sweep, the plant model which correlates active control inputs to helicopter vibratory loads was constructed. Multicyclic controller was applied to the plant model, and 25% reduction in the cost function was reported. Vertical vibratory load was reduced by 51%, and inplane force and moment were reduced by 18%, 22%, respectively.
NASA Astrophysics Data System (ADS)
Kim, In-Ho; Jang, Seon-Jun; Jung, Hyung-Jo
2013-07-01
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.
Non-classicality of the molecular vibrations assisting exciton energy transfer at room temperature
OReilly, Edward J.; Olaya-Castro, Alexandra
2014-01-01
Advancing the debate on quantum effects in light-initiated reactions in biology requires clear identification of non-classical features that these processes can exhibit and utilize. Here we show that in prototype dimers present in a variety of photosynthetic antennae, efficient vibration-assisted energy transfer in the sub-picosecond timescale and at room temperature can manifest and benefit from non-classical fluctuations of collective pigment motions. Non-classicality of initially thermalized vibrations is induced via coherent excitonvibration interactions and is unambiguously indicated by negativities in the phasespace quasi-probability distribution of the effective collective mode coupled to the electronic dynamics. These quantum effects can be prompted upon incoherent input of excitation. Our results therefore suggest that investigation of the non-classical properties of vibrational motions assisting excitation and charge transport, photoreception and chemical sensing processes could be a touchstone for revealing a role for non-trivial quantum phenomena in biology. PMID:24402469
NASA Astrophysics Data System (ADS)
Wolfsteiner, Peter; Breuer, Werner
2013-10-01
The assessment of fatigue load under random vibrations is usually based on load spectra. Typically they are computed with counting methods (e.g. Rainflow) based on a time domain signal. Alternatively methods are available (e.g. Dirlik) enabling the estimation of load spectra directly from power spectral densities (PSDs) of the corresponding time signals; the knowledge of the time signal is then not necessary. These PSD based methods have the enormous advantage that if for example the signal to assess results from a finite element method based vibration analysis, the computation time of the simulation of PSDs in the frequency domain outmatches by far the simulation of time signals in the time domain. This is especially true for random vibrations with very long signals in the time domain. The disadvantage of the PSD based simulation of vibrations and also the PSD based load spectra estimation is their limitation to Gaussian distributed time signals. Deviations from this Gaussian distribution cause relevant deviations in the estimated load spectra. In these cases usually only computation time intensive time domain calculations produce accurate results. This paper presents a method dealing with non-Gaussian signals with real statistical properties that is still able to use the efficient PSD approach with its computation time advantages. Essentially it is based on a decomposition of the non-Gaussian signal in Gaussian distributed parts. The PSDs of these rearranged signals are then used to perform usual PSD analyses. In particular, detailed methods are described for the decomposition of time signals and the derivation of PSDs and cross power spectral densities (CPSDs) from multiple real measurements without using inaccurate standard procedures. Furthermore the basic intention is to design a general and integrated method that is not just able to analyse a certain single load case for a small time interval, but to generate representative PSD and CPSD spectra replacing extensive measured loads in time domain without losing the necessary accuracy for the fatigue load results. These long measurements may even represent the whole application range of the railway vehicle. The presented work demonstrates the application of this method to railway vehicle components subjected to random vibrations caused by the wheel rail contact. Extensive measurements of axle box accelerations have been used to verify the proposed procedure for this class of railway vehicle applications. The linearity is not a real limitation, because the structural vibrations caused by the random excitations are usually small for rail vehicle applications. The impact of nonlinearities is usually covered by separate nonlinear models and only needed for the deterministic part of the loads. Linear vibration systems subjected to Gaussian vibrations respond with vibrations having also a Gaussian distribution. A non-Gaussian distribution in the excitation signal produces also a non-Gaussian response with statistical properties different from these excitations. A drawback is the fact that there is no simple mathematical relation between excitation and response concerning these deviations from the Gaussian distribution (see e.g. Ito calculus [6], which is usually not part of commercial codes!). There are a couple of well-established procedures for the prediction of fatigue load spectra from PSDs designed for Gaussian loads (see [4]); the question of the impact of non-Gaussian distributions on the fatigue load prediction has been studied for decades (see e.g. [3,4,11-13]) and is still subject of the ongoing research; e.g. [13] proposed a procedure, capable of considering non-Gaussian broadbanded loads. It is based on the knowledge of the response PSD and some statistical data, defining the non-Gaussian character of the underlying time signal. As already described above, these statistical data are usually not available for a PSD vibration response that has been calculated in the frequency domain. Summarizing the above and considering the fact of having highly non-Gaussian exci
Delahaye, Thibault; Nikitin, Andrei; Rey, Michaėl; Szalay, Péter G; Tyuterev, Vladimir G
2014-09-14
In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82,542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm(-1) for fundamental bands centers and 5.9 cm(-1) for vibrational bands up to 7800 cm(-1). Large scale vibrational and rotational calculations for (12)C2H4, (13)C2H4, and (12)C2D4 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm(-1) are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of (13)C2H4 and (12)C2D4 and rovibrational levels of (12)C2H4. PMID:25217910
NASA Astrophysics Data System (ADS)
Delahaye, Thibault; Nikitin, Andrei; Rey, Michaėl; Szalay, Péter G.; Tyuterev, Vladimir G.
2014-09-01
In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82 542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm-1 for fundamental bands centers and 5.9 cm-1 for vibrational bands up to 7800 cm-1. Large scale vibrational and rotational calculations for 12C2H4, 13C2H4, and 12C2D4 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm-1 are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of 13C2H4 and 12C2D4 and rovibrational levels of 12C2H4.
Imaging bond breaking and vibrational energy transfer in small water containing clusters
NASA Astrophysics Data System (ADS)
Samanta, Amit K.; Ch'ng, Lee C.; Reisler, Hanna
2013-06-01
This letter presents a brief overview of our recent experimental studies of state-to-state vibrational predissociation (VP) dynamics of small hydrogen bonded (H-bonded) clusters following vibrational excitation. Velocity map imaging (VMI) and resonance-enhanced multiphoton ionization (REMPI) are used to determine accurate bond dissociation energies (D0) of (H2O)2, (H2O)3, HCl-H2O and NH3-H2O. Pair-correlated product energy distributions from the VP of these complexes are also presented and compared to theoretical models. Further insights into mechanisms are obtained from the recent quasi-classical trajectory (QCT) calculations of Bowman and coworkers. The D0 values for (H2O)2 and (H2O)3 are in very good agreement with recent calculated values, and the results are used to estimate the contributions of cooperative interactions to the H-bonding network.
Chakraborty, Arindam; Truhlar, Donald G; Bowman, Joel M; Carter, Stuart
2004-08-01
The rovibration partition function of CH4 was calculated in the temperature range of 100-1000 K using well-converged energy levels that were calculated by vibrational-rotational configuration interaction using the Watson Hamiltonian for total angular momenta J = 0-50 and the MULTIMODE computer program. The configuration state functions are products of ground-state occupied and virtual modals obtained using the vibrational self-consistent field method. The Gilbert and Jordan potential energy surface was used for the calculations. The resulting partition function was used to test the harmonic oscillator approximation and the separable-rotation approximation. The harmonic oscillator, rigid-rotator approximation is in error by a factor of 2.3 at 300 K, but we also propose a separable-rotation approximation that is accurate within 2% from 100 to 1000 K. PMID:15260761
Department of Energy Bonneville Power Administration
Department of Energy Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208 to the Northwest Governors on Expenditures of the Bonneville Power Administration to Implement the Columbia River
NASA Astrophysics Data System (ADS)
Wood, Mitchell; Strachan, Alejandro
2014-03-01
We use molecular dynamics with the reactive force field ReaxFF to study the decomposition and subsequent reactions of the nitramine HMX under induced by electric fields and temperature. We find that electric fields of appropriately chosen frequencies can trigger chemical decomposition for total energy input significantly smaller than thermally excited systems. In addition, the energy barriers associated with exothermic chemical reactions are also dependent on the character of the excitation for electric field driven samples. We are able to characterize the frequency-dependent energy input and subsequent equilibration using the power spectra of atomic velocities and we find that the non-equilibrium nature of the energy distribution obtained via electric field excitations is responsible for the dependence of energy threshold for decomposition on type of perturbation. Timescales and decay pathways for vibron energy are discussed for HMX and other energetic materials.
Energy harvesting to power embedded condition monitoring hardware
NASA Astrophysics Data System (ADS)
Farinholt, Kevin; Brown, Nathan; Siegel, Jake; McQuown, Justin; Humphris, Robert
2015-04-01
The shift toward condition-based monitoring is a key area of research for many military, industrial, and commercial customers who want to lower the overall operating costs of capital equipment and general facilities. Assessing the health of rotating systems such as gearboxes, bearings, pumps and other actuation systems often rely on the need for continuous monitoring to capture transient signals that are evidence of events that could cause (i.e. cavitation), or be the result of (i.e. spalling), damage within a system. In some applications this can be accomplished using line powered analyzers, however for wide-spread monitoring, the use of small-scale embedded electronic systems are more desirable. In such cases the method for powering the electronics becomes a significant design factor. This work presents a multi-source energy harvesting approach meant to provide a robust power source for embedded electronics, capturing energy from vibration, thermal and light sources to operate a low-power sensor node. This paper presents the general design philosophy behind the multi-source harvesting circuit, and how it can be extended from powering electronics developed for periodic monitoring to sensing equipment capable of providing continuous condition-based monitoring.
Power marketing and renewable energy
Fang, J.M.
1997-09-01
Power marketing refers to wholesale and retail transactions of electric power made by companies other than public power entities and the regulated utilities that own the generation and distribution lines. The growth in power marketing has been a major development in the electric power industry during the last few years, and power marketers are expected to realize even more market opportunities as electric industry deregulation proceeds from wholesale competition to retail competition. This Topical Issues Brief examines the nature of the power marketing business and its relationship with renewable power. The information presented is based on interviews conducted with nine power marketing companies, which accounted for almost 54% of total power sales by power marketers in 1995. These interviews provided information on various viewpoints of power marketers, their experience with renewables, and their respective outlooks for including renewables in their resource portfolios. Some basic differences exist between wholesale and retail competition that should be recognized when discussing power marketing and renewable power. At the wholesale level, the majority of power marketers stress the commodity nature of electricity. The primary criteria for developing resource portfolios are the same as those of their wholesale customers: the cost and reliability of power supplies. At the retail level, electricity may be viewed as a product that includes value-added characteristics or services determined by customer preferences.
Micromachined PZT cantilever based on SOI structure for low frequency vibration energy harvesting
Dongna Shen; Jung-Hyun Park; Joo Hyon Noh; Song-Yul Choe; Seung-Hyun Kim; Howard C. Wikle III; Dong-Joo Kim
2009-01-01
A PZT piezoelectric cantilever with a micromachined Si proof mass is designed and fabricated for a low frequency vibration energy harvesting application. The SiO2 layer in the SOI wafer promotes accurate control of the silicon thickness that is used as a supporting layer in the cantilever beam structure. The entire effective volume of the fabricated device is about 0.7690mm3. When
Vibrational Energy Relaxation of Choloroiodomethane in Cold Argon
NASA Astrophysics Data System (ADS)
Jain, Amber; Sibert, Edwin L. Sibert, Iii
2013-06-01
Electronically exciting the C-I stretch in the molecule chloroiodomethane CH_{2}ClI embedded in a matrix of argon at 12K can lead to an isomer, iso-chloroiodomethane CH_{2}Cl-I, that features a chlorine iodine bond. By temporally probing the isomer at two different frequencies of 435 nm and 485 nm, multiple timescales for isomerization are inferred. To gain further mechanistic insights into this process we have studied the isomerization theoretically using molecular dynamics. Two and three low frequency modes (C-Cl-I bend, Cl-I stretch and C-Cl stretch) are included in the model. The experiment is simulated by equilibrating the molecule in the parent configuration and providing an energy of 37,500 cm^{-1}, corresponding to the electronic excitation of the C-I stretch. Subsequent time evolution of the classical trajectories is monitored, and the decay rates of energy are compared to the experimental spectroscopy results. Varying different parameters related to the potential energy surface can lead to different results and their implications to the energy flow are discussed. The decay rates in the isomer well are also compared to the classical Landau Teller theory. T. J. Preston, M. Dutta, B. J. Esselman, A. Kalume, L. George, R. J. McMahon, S. A. Reid, and F. F. Crim, J. Chem. Phys. 135, 114503 (2011)
Vibrational Energy Relaxation of Choloroiodomethane in Cold Argon
NASA Astrophysics Data System (ADS)
Jain, A.; Sibert, E. L.
2012-06-01
Electronically exciting the C-I stretch in the molecule chloroiodomethane CH2ClI embedded in a matrix of argon at 20K can lead to an isomer, iso-chloroiodomethane CH2Cl-I, that features a chlorine iodine bond [T. J. Preston et al., J. Chem. Phys. {135}, 114503 (2011)]. By temporally probing the isomer at two different frequencies of 435 nm and 485 nm, three timescales for isomerization were inferred. The first and second timescales correspond to formation and initial relaxation of the isomer, with a decay rate of 0.45 ps-1. The third timescale is attributed to further energy loss as the molecule cools to its local minima, with a decay rate of 0.07 ps-1. To gain further mechanistic insights into this process, we studied the isomerization theoretically using molecular dynamics. Initial energy of 37,500 cm-1 (corresponding to electronic excitation of C-I stretch) is provided to the C-I bond. As in the experiment, three timescales are observed. First the molecule loses energy through collisions with a few argon atoms, which leads to a loss of about 10,000 cm-1 in 100 fs. Subsequent energy loss follows a bi-exponential decay, with decay rates of 1.16 ps-1 and 0.21 ps-1. The implications of our results to the interpretation of the spectroscopic results will be discussed.
Tuning of nonlinear vibration via topology variation and its application in energy harvesting
NASA Astrophysics Data System (ADS)
Dai, Xuhan; Miao, Xiaodan; Sui, Linghe; Zhou, Hailin; Zhao, Xiaolin; Ding, Guifu
2012-01-01
A topology variation method for the tuning of nonlinear vibration of planar spring was proposed and experimentally validated, which exhibited great potential for the application of energy harvesting by broadening the response bandwidth of the device. According to the numerical simulation and experimental results of all the three typical topological configurations, the topological scheme with inclined straight shape could provide the best nonlinearity. When this method was applied to the energy harvesting, the prototype device demonstrated a bandwidth of 28 Hz @180 Hz. It is concluded that the topological variation methodology could be efficient for the performance optimization of the energy harvester.
Communication: fast transport and relaxation of vibrational energy in polymer chains.
Kurnosov, Arkady A; Rubtsov, Igor V; Burin, Alexander L
2015-01-01
We investigate ballistic vibrational energy transport through optical phonon band in oligomeric chains in the presence of decoherence. An exact solution is obtained for the excitation density in the space-time representation in the continuous limit and this solution is used to characterize the energy transport time and intensity. Three transport mechanisms are identified such as ballistic, diffusive, and directed diffusive regimes, occurring at different distances and time scales. The crossover between the two diffusive regimes is continuous, while the switch between the ballistic and diffusive mechanisms occurs in a discontinuous manner in accord with the recent experimental results on energy transport in perfluoroalkanes. PMID:25573545
Communication maps of vibrational energy transport through Photoactive Yellow Protein.
Xu, Yao; Leitner, David M
2014-09-01
We calculate communication maps for Photoactive Yellow Protein (PYP) from the purple phototropic eubacterium Halorhodospira halophile and use them to elucidate energy transfer pathways from the chromophore through the rest of the protein in the ground and excited state. The calculations reveal that in PYP excess energy from the chromophore flows mainly to regions of the surrounding residues that hydrogen bond to the chromophore. In addition, quantum mechanics/molecular mechanics and molecular dynamics (MD) simulations of the dielectric response of the protein and solvent environment due to charge rearrangement on the chromophore following photoexcitation are also presented, with both approaches yielding similar time constants for the response. Results of MD simulations indicate that the residues hydrogen bonding to the chromophore make the largest contribution to the response. PMID:24552496
Intramolecular Vibrational Energy Redistribution in the Reaction H_{3}^{+} + CO ? H_2 + HCO^+/HOC^+
NASA Astrophysics Data System (ADS)
Hirano, Tsuneo; Li, Hui; Le Roy, Robert J.; Amano, Takayoshi
2009-06-01
Observations of the rotational lines of HCO^+ produced in an extended negative glow discharge revealed high vibrational temperatures for the stretching vibrational modes, and non-thermal population distributions among the different ? levels of excited bending vibrational states. These results provide critical tests of our understanding of the dynamics and intramolecular vibrational energy redistribution (IVR) in this reaction process. The IVR in the HNC leftrightarrow HCN isomerization reaction has been studied previously by ab initio direct dynamics and vibration-mapping methods. An extension of the method used for the HNC/HCN isomerization reaction yields a new procedure for studying ``IVR in reactions'' which is applied to HCO^{+}/HOC^{+} production in the H_{3}^{+} + CO reaction, as described by the five-dimensional potential energy surface and pathways for this reaction reported recently by Li et al. Dynamics calculations have been performed for "co-linear configuration" reactions in which H_3^+ approaches the C end of CO with a translational temperature of 20 K (a typical kinetic temperature of dark clouds) or 330 K (a typical translational temperature for ions in a glow discharge). As H_3^+ approaches CO with the lower-temperature translational energy, the hopping of H^{+} to the CO moiety to form HCO^{+} occurs over a period of about 100 fs, and the H-C stretching mode of the product HCO^+ is highly excited. This excitation can relax within the same vibrational ladder and/or be transferred to the bending mode through anharmonic coupling. Details of direct dynamics calculations for this process will be reported. T. Hirao, S. Yu, and T. Amano,J. Chem. Phys., 127,074301 (2007). T. Hirao, S. Yu, and T. Amano, J. Mol. Spectrosc., 248, 26 (2008). Y. Kumeda, Y. Minami, K. Takano, T. Taketsugu, and T. Hirano, J. Mol. Struct. (THEOCHEM), 458, 285 (1999) T. Hirano, T. Taketsugu, and Y. Kurita, J. Phys. Chem., 98, 6936 (1994). H. Li, T. Hirano, T. Amano, and R.J. Le Roy, J. Chem. Phys., 129, 244306 (2008).
NASA Astrophysics Data System (ADS)
Lajimi, S. A. M.; Friswell, M. I.
2015-04-01
For a nonlinear beam-mass system used to harvest vibratory energy, the two-mode approximation of the response is computed and compared to the single-mode approximation of the response. To this end, the discretized equations of generalized coordinates are developed and studied using a computational method. By obtaining phase-portraits and time-histories of the displacement and voltage, it is shown that the strong nonlinearity of the system affects the system dynamics considerably. By comparing the results of single- and two-mode approximations, it is shown that the number of mode shapes affects the dynamics of the response. Varying the tip-mass results in different structural configurations namely linear, pre-buckled nonlinear, and post-buckled nonlinear configurations. The nonlinear dynamics of the system response are investigated for vibrations about static equilibrium points arising from the buckling of the beam. Furthermore, it is demonstrated that the harvested power is affected by the system configuration.
Influence of temperature on thymine-to-solvent vibrational energy transfer
NASA Astrophysics Data System (ADS)
West, Brantley A.; Womick, Jordan M.; Moran, Andrew M.
2011-09-01
At the instant following the non-radiative deactivation of its ??* electronic state, the vibrational modes of thymine possess a highly non-equilibrium distribution of excitation quanta (i.e., >4 eV in excess energy). Equilibrium is re-established through rapid (5 ps) vibrational energy transfer to the surrounding solvent. The mechanisms behind such vibrational cooling (VC) processes are examined here using femtosecond transient grating and two-dimensional photon echo spectroscopies conducted at 100 K and 300 K in a mixture of methanol and water. Remarkably, we find that this variation in temperature has essentially no impact on the VC kinetics. Together the experiments and a theoretical model suggest three possible mechanisms consistent with this behavior: (i) vibrational energy transfer from the solute to solvent initiates (directly) in intramolecular modes of the solute with frequencies >300 cm-1; (ii) the relaxation induced increase in the temperature of the environment reduces the sensitivity of VC to the temperature of the equilibrium system; (iii) the time scale of solvent motion approaches 0.1 ps even at 100 K. Mechanism (i) deserves strong consideration because it is consistent with the conclusions drawn in earlier studies of isotope effects on VC in hydrogen bonding solvents. Our model calculations suggest that mechanism (ii) also plays a significant role under the present experimental conditions. Mechanism (iii) is ruled out on the basis of long-lived correlations evident in the photon echo line shapes at 100 K. These insights into photoinduced relaxation processes in thymine are made possible by our recent extension of interferometric transient grating and photon echo spectroscopies to the mid UV spectral region.
NASA Astrophysics Data System (ADS)
Yachmenev, Andrey; Yurchenko, Sergei N.
2015-07-01
We present a new numerical method to construct a rotational-vibrational Hamiltonian of a general polyatomic molecule in the Eckart frame as a power series expansion in terms of curvilinear internal coordinates. The expansion of the kinetic energy operator of an arbitrary order is obtained numerically using an automatic differentiation (AD) technique. The method is applicable to molecules of arbitrary size and structure and is flexible for choosing various types of internal coordinates. A new way of solving the Eckart-frame equations for curvilinear coordinates also based on the AD technique is presented. The resulting accuracy of the high-order expansion coefficients for the kinetic energy operator using our numerical technique is comparable to that obtained by symbolic differentiation, with the advantage of being faster and less demanding in memory. Examples for H2CO, NH3, PH3, and CH3Cl molecules demonstrate the advantages of the curvilinear internal coordinates and the Eckart molecular frame for accurate ro-vibrational calculations. Our results show that very high accuracy and quick convergence can be achieved even with moderate expansions if curvilinear coordinates are employed, which is important for applications involving large polyatomic molecules.
A single-DOF vibration energy harvester for integrating into the parallel mechanism
NASA Astrophysics Data System (ADS)
Yuan, G.; Wang, D. H.
2015-04-01
In order to realize a six-degree-of-freedom (six-DOF) piezoelectric energy harvester through integrating six single-degree-of-freedom (single-DOF) piezoelectric energy harvesters into a parallel mechanism, which has six sensitive axes and broader bandwidth, a single-DOF piezoelectric energy harvester utilizing a clamped beam configuration is proposed in this paper. It consists of a proof mass and a corrugated clamped beam covered by piezoelectric patches, where the proof mass is mounted at the center of the beam. Compared to the conventional energy harvester, the proposed single-DOF vibration energy harvester has two parallelism mounting planes at the support of the beam and the mass, separately, and can be easily integrated into the parallel mechanism. The stiffness equation of the single-DOF piezoelectric energy harvester is established and analyzed. On this basis, the natural frequency and stress distribution of the harvester are investigated through analytical developments and numerical simulations. These results show that the proposed single-DOF vibration energy harvester has output with the excitation along its axis, while no outputs with the excitation perpendicular to the axis, and the natural frequency and stress distribution can be accurate estimated by the established theoretical models.
Potential energy, relaxation, vibrational dynamics and the boson peak, of hyperquenched glasses
NASA Astrophysics Data System (ADS)
Angell, C. Austen; Yue, Yuanzheng; Wang, Li-Min; Copley, John R. D.; Borick, Steve; Mossa, Stefano
2003-03-01
We describe a combination of laboratory and simulation studies that give quantitative information on the energy landscape for glass-forming liquids. Both types of study focus on the idea of suddenly extracting the thermal energy, so that the system obtained for subsequent study has the structure, and hence potential energy, of a liquid at a much higher temperature than the normal glass temperature Tg. One type of study gives information on the energy that can be trapped in experimental glasses by hyperquenching, relative to the normal glass, and on the magnitude of barriers separating basins of attraction on the landscape. Stepwise annealing studies also give information on the matter of energy heterogeneity and the question of 'nanogranularity' in liquids near Tg. The other type of study gives information on the vibrational properties of a system confined to a given basin, and particularly on how that vibrational structure changes with the state of configurational excitation of the liquid. A feature in the low frequency ('boson peak') region of the density of vibrational states of the normal glass becomes much stronger in the hyperquenched glass. Qualitatively similar observations are made on heating fragile glass-formers into the supercooled and stable liquid states. The vibrational dynamics findings are supported and elucidated by constant pressure molecular dynamics/normal mode MD/NM simulations/analysis of the densities of states of different inherent structures of a model fragile liquid (orthoterphenyl (OTP) in the Lewis-Wahnstrom approximation). These show that, when the temperature is raised at constant pressure, the total density of states changes in a manner that can be well represented by a two-Gaussian 'excitation across the centroid', leaving a third and major Gaussian component unchanging. The low frequency Gaussian component, which grows with increasing temperature, has a constant peak frequency of 18 cm-1 and is identified with the Boson peak. It is suggested that the latter can serve as a signature for configurational excitations of the ideal glass structure, i.e. the topologically diverse defects of the glassy solid state. The excess vibrational heat capacity associated with this generation of low frequency modes with structural excitation is shown to be responsible for about 60% of the jump in heat capacity at Tg, most of the remainder coming from configurational excitation.
Mancini, John S; Bowman, Joel M
2014-09-01
The hydrogen bond has been studied by chemists for nearly a century. Interest in this ubiquitous bond has led to several prototypical systems emerging to studying its behavior. Hydrogen chloride clusters stand as one such example. We present here a new many-body potential energy surface for (HCl)n constructed from one-, two-, and three-body interactions. The surface is constructed from previous highly accurate, semiempirical monomer and dimer surfaces, and a new high-level ab initio permutationally invariant full-dimensional three-body potential. The new three-body potential is based on fitting roughly 52,000 three-body energies computed using coupled cluster with single, doubles, perturbative triples, and explicit correlation and the augmented correlation consistent double-? basis set. The first application, described here, is to the ring HCl trimer, for which the many-body representation is exact. The new potential describes all known stationary points of the trimer as well its dissociation to either three monomers or a monomer and a dimer. The anharmonic vibrational energies are computed for the three H-Cl stretches, using explicit three-mode coupling calculations and local-monomer calculations with Hückel-type coupling. Both methods produce frequencies within 5 cm(-1) of experiment. A wavepacket calculation based on the Hückel model and full-dimensional classical calculation are performed to study the monomer H-Cl stretch vibration-vibration transfer process in the ring HCl trimer. Somewhat surprisingly, the results of the quantum and classical calculations are virtually identical, both exhibiting coherent beating of the excitation between the three monomers. Finally, this representation of the potential is used to study properties of larger clusters, namely to compute optimized geometries of the tetramer, pentamer, and hexamer and to perform explicit four-mode coupling calculations of the tetramer's anharmonic stretch frequencies. The optimized geometries are found to be in agreement with those of previous ab initio studies and the tetramer's anharmonic frequencies are computed within 11 cm(-1) of experiment. PMID:24444294
J. Terasaki; J. Engel
2011-05-19
Although nuclear energy density functionals are determined primarily by fitting to ground state properties, they are often applied in nuclear astrophysics to excited states, usually through the quasiparticle random phase approximation (QRPA). Here we test the Skyrme functionals SkM* and SLy4 along with the self-consistent QRPA by calculating properties of low-lying vibrational states in a large number of well-deformed even-even rare-earth nuclei. We reproduce trends in energies and transition probabilities associated with gamma-vibrational states, but our results are not perfect and indicate the presences of multi-particle-hole correlations that are not included in the QRPA. The Skyrme functional SkM* performs noticeably better than SLy4. In a few nuclei, changes in the treatment of the pairing energy functional have a significant effect. The QRPA is less successful with "beta-vibrational" states than with the gamma-vibrational states.
Water Power for a Clean Energy Future
2013-04-12
This document describes some of the accomplishments of the Department of Energy Water Power Program, and how those accomplishments are supporting the advancement of renewable energy generated using hydropower technologies and marine and hydrokinetic technologies.
Renewable Energy Powered Water Treatment Systems
Richards, Bryce S.; Schäfer, Andrea
2009-01-01
There are many motivations for choosing renewable energy technologies to provide the necessary energy to power water treatment systems for reuse and desalination. These range from the lack of an existing electricity grid, ...
Extensivity of Energy and Electronic and Vibrational Structure Methods for Crystals
NASA Astrophysics Data System (ADS)
Hirata, So; Keēeli, Murat; Ohnishi, Yu-ya; Sode, Olaseni; Yagi, Kiyoshi
2012-05-01
A pedagogical proof is presented for the extensivity of energies of metallic and nonmetallic crystals that proceeds by elucidating the asymptotic distance dependence of the effective chemical interactions: kinetic, Coulomb, exchange, and correlation. On this basis, a guideline for the size-consistent design of electronic and vibrational methods is proposed. This guideline underscores the significance of the distinct use of the intermediate and standard normalization of wave functions for extensive and intensive quantities, includes the extensive and intensive diagram theorems as the unambiguous criteria for determining size consistency of a method for extensive and intensive quantities, and introduces the extensive-intensive consistency theorem, which stipulates the precise balance between the determinant spaces reached by extensive and intensive operators. Electronic and vibrational methods for crystals are reviewed that are inspired by these formal analyses or developed in accordance with the guideline.
A new deformed Schiöberg-type potential and ro-vibrational energies for some diatomic molecules
NASA Astrophysics Data System (ADS)
Mustafa, Omar
2015-06-01
We suggest a new deformed Schiöberg-type potential for diatomic molecules. We show that it is equivalent to TietzHua oscillator potential. We discuss how to relate our deformed Schiöberg potential to Morse, to DengFan, to the improved ManningRosen, and to the deformed modified RosenMorse potential models. We transform our potential into a proper form and use the supersymmetric quantization to find a closed form analytical solution for the ro-vibrational energy levels that are highly accurate over a wide range of vibrational and rotational quantum numbers. We discuss our results using four-diatomic molecules NO?ft( {{X}2}{{\\Pi }r} \\right), {{O}2}?ft( {{X}3}? g- \\right), O2+?ft( {{X}2}{{\\Pi }g} \\right), and {{N}2}?ft( {{X}1}? g+ \\right). Our results turn out to compare excellently with those from a generalized pseudospectral numerical method.
A new deformed Schioberg-type potential and ro-vibrational energies for some diatomic molecules
Omar Mustafa
2015-04-24
We suggest a new deformed Schioberg-type potential for diatomic molecules. We show that it is equivalent to Tietz-Hua oscillator potential. We discuss how to relate our deformed Schi\\"oberg potential to Morse, to Deng-Fan , to the improved Manning-Rosen, and to the deformed modified Rosen-Morse potential models. We transform our potential into a proper form and use the supersymmetric quantization to find a closed form analytical solution for the ro-vibrational energy levels that are highly accurate over a wide range of vibrational and rotational quantum numbers. We discuss our results using 4-diatomic molecules NO, O2, O2+, and N2. Our results turn out to compare excellently with those from a generalized pseudospectral numerical method.
Shock and vibration tests of uranium mononitride fuel pellets for a space power nuclear reactor
NASA Technical Reports Server (NTRS)
Adams, D. W.
1972-01-01
Shock and vibration tests were conducted on cylindrically shaped, depleted, uranium mononitride (UN) fuel pellets. The structural capabilities of the pellets were determined under exposure to shock and vibration loading which a nuclear reactor may encounter during launching into space. Various combinations of diametral and axial clearances between the pellets and their enclosing structures were tested. The results of these tests indicate that for present fabrication of UN pellets, a diametral clearance of 0.254 millimeter and an axial clearance of 0.025 millimeter are tolerable when subjected to launch-induced loads.
NASA Astrophysics Data System (ADS)
Smith, J. M.; Nikow, M.; Dai, J. Ma Andh. L.
2013-06-01
Can a molecule be activated with large amounts of energy transferred in a single collision between an atom and a molecule? If so, this type of collision will greatly affect molecular reactivity and equilibrium in systems including combustion where abundant hot atoms exist. Conventional expectation of translation to vibration (T-V) energy transfer is that probability decreases exponentially with energy transferred. We show, however, that in collisions between a pair of atom/molecule for which chemical reactions may occur, such as between a hyperthermal H atom and an ambient acetylene molecule, (T-V) energy transfer occurs with surprisingly high efficiency through chemical complex formation. Time-resolved infrared emission observations reveal that collisions between H atoms moving with 60 kcal/mole energy and acetylene molecules result in transfer of up to 70% of this energy into vibrational degrees of freedom. These experimental results are further supported by state of the art quasi-classical trajectory calculations performed by Bowman and coworkers.
NASA Astrophysics Data System (ADS)
Sun, Weiguo; Hou, Shilin
2002-05-01
An algebraic method (AM) is proposed to study the accurate vibrational constants and energies based on an accurate limited experimental/theoretical input data set, and a potential variational method (PVM) is suggested to generate reliable force constants, rotational spectrum constants and rovibrational energies for a diatomic molecular electronic state based on the second order perturbation theory. The vibrational force constants fn's used to evaluate the rotational spectrum constants are determined variationally. The AM generates accurate vibrational constants and energies using standard algebraic approach without any mathematical and/or physical approximations. The accuracy of the AM vibrational constants and energies is uniquely dependent on the quality of the input experimental/theoretical data. Both the AM and the PVM have been applied to study 10 diatomic electronic states of H2, N2, O2, and Br2 molecules. These example studies show that: 1.) the AM not only reproduce the input energies, but also generate the Ev's of high vibrational excited states which may be difficult to obtain experimentally or theoretically; 2.) the PVM vibrational force constants fn's may be used to measure the relative chemical bond strengths of different diatomic electronic states for a molecule quantitatively.
Exact solution for low energy quantum anharmonic vibrations in a long polymer chain
Alexander L. Burin
2015-08-31
The exact analytical solution is obtained for vibrational quantum states of periodic linear chain of atoms coupled by harmonic and third order anharmonic interactions (Fermi-Ulam-Pasta $\\alpha$ problem) in the long wavelength limit within the resonant approach. Each eigenstate of the problem can be encoded by the sequence of integer numbers determining its energy and wavefunction. Using these eigenstates we described a single phonon state time evolution which oscillates in a coherent manner. The applications of the results to the energy transport through molecular chains are discussed.
The variational method for the calculation of RO-vibrational energy levels
NASA Astrophysics Data System (ADS)
Carter, S.; Handy, N. C.
1986-12-01
In this paper the current status of the variational method for the determination of the rotational-vibrational energy levels of polyatomic systems is reviewed. Special attention is made for the derivation of the kinetic energy operator in various coordinate systems, and several forms are given. Similarly, analytic forms which are in current use for the potentials are given. The calculation of the Hamiltonian matrix elements (expansion functions, numerical integration grid points and weights) is described in detail, and a description of our programs for this problem is given in section 6.
Solar energy thermally powered electrical generating system
NASA Technical Reports Server (NTRS)
Owens, William R. (Inventor)
1989-01-01
A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.
Renewable Energy. The Power to Choose.
ERIC Educational Resources Information Center
Deudney, Daniel; Flavin, Christopher
This book, consisting of 13 chapters, charts the progress made in renewable energy in recent years and outlines renewable energy's prospects. Areas addressed include: energy at the crossroads (discussing oil, gas, coal, nuclear power, and the conservation revolution); solar building design; solar collection; sunlight to electricity; wood; energy
Osmotic power a new, renewable energy source
Stein Erik Skilhagen
2010-01-01
The mixing of freshwater and seawater where rivers flows into the salty ocean releases large amounts of energy. This energy can be harvested and made into electricity using pressure retarded osmosis (PRO). This is the concept of osmotic power, a new and yet unexploited source of renewable energy. The idea of exploiting the energy from mixing fresh water and sea
Industrial Arts 7-9. Power/Energy: Electricity/Electronics, Power Mechanics, Power/Energy.
ERIC Educational Resources Information Center
Manitoba Dept. of Education, Winnipeg.
This guide for industrial arts grades 7-9 provides teachers with a curriculum for the subject cluster of power/energy. An "Overview" section presents the rationale, discusses how the content of the program is related to the developmental stages of the adolescent, describes the structure of the industrial arts program, and lists program goals and
Vibrational vs. translational energy in promoting a prototype metalhydrocarbon insertion reaction
Proctor, David L.; Davis, H. Floyd
2008-01-01
The reaction Y + CH4 ? HYCH3 ? YCH2 + H2 is initiated by CH insertion involving a 20 ± 3 kcal/mol potential energy barrier. The reaction is studied in crossed molecular beams under two different conditions with nearly the same total energy. One experiment is carried out at a collision energy of 15.1 kcal/mol with one quantum of CH4 antisymmetric (?3) stretching vibrational excitation (8.63 kcal/mol), the other at a collision energy of 23.8 kcal/mol. The reaction cross-section for CH stretch excited methane (?s) is found to be at least a factor of 2.2 times larger than for ground-state methane (?g) at the same total energy. PMID:18678904
NASA Technical Reports Server (NTRS)
Vlahopoulos, Nickolas
2005-01-01
The Energy Finite Element Analysis (EFEA) is a finite element based computational method for high frequency vibration and acoustic analysis. The EFEA solves with finite elements governing differential equations for energy variables. These equations are developed from wave equations. Recently, an EFEA method for computing high frequency vibration of structures either in vacuum or in contact with a dense fluid has been presented. The presence of fluid loading has been considered through added mass and radiation damping. The EFEA developments were validated by comparing EFEA results to solutions obtained by very dense conventional finite element models and solutions from classical techniques such as statistical energy analysis (SEA) and the modal decomposition method for bodies of revolution. EFEA results have also been compared favorably with test data for the vibration and the radiated noise generated by a large scale submersible vehicle. The primary variable in EFEA is defined as the time averaged over a period and space averaged over a wavelength energy density. A joint matrix computed from the power transmission coefficients is utilized for coupling the energy density variables across any discontinuities, such as change of plate thickness, plate/stiffener junctions etc. When considering the high frequency vibration of a periodically stiffened plate or cylinder, the flexural wavelength is smaller than the interval length between two periodic stiffeners, therefore the stiffener stiffness can not be smeared by computing an equivalent rigidity for the plate or cylinder. The periodic stiffeners must be regarded as coupling components between periodic units. In this paper, Periodic Structure (PS) theory is utilized for computing the coupling joint matrix and for accounting for the periodicity characteristics.
Yasser ALDIEN; Pierre MARCOTTE; Subhash RAKHEJA; Paul-Émile BOILEAU
2005-01-01
The biodynamic responses of the hand-arm system under xh-axis vibration are investigated in terms of the driving point mechanical impedance (DPMI) and absorbed power in a laboratory study. For this purpose, seven healthy male subjects are exposed to two levels of random vibration in the 8-1,000 Hz frequency range, using three instrumented cylindrical handles of different diameters (30, 40 and
Topology optimization and fabrication of low frequency vibration energy harvesting microdevices
NASA Astrophysics Data System (ADS)
Deng, Jiadong; Rorschach, Katherine; Baker, Evan; Sun, Cheng; Chen, Wei
2015-02-01
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 in the experiment matches the trend of the simulation data.
Pulsed Power Driven Fusion Energy
SLUTZ,STEPHEN A.
1999-11-22
Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.
Compact inductive energy storage pulse power system.
K, Senthil; Mitra, S; Roy, Amitava; Sharma, Archana; Chakravarthy, D P
2012-05-01
An inductive energy storage pulse power system is being developed in BARC, India. Simple, compact, and robust opening switches, capable of generating hundreds of kV, are key elements in the development of inductive energy storage pulsed power sources. It employs an inductive energy storage and opening switch power conditioning techniques with high energy density capacitors as the primary energy store. The energy stored in the capacitor bank is transferred to an air cored storage inductor in 5.5 ?s through wire fuses. By optimizing the exploding wire parameters, a compact, robust, high voltage pulse power system, capable of generating reproducibly 240 kV, is developed. This paper presents the full details of the system along with the experimental data. PMID:22667637
NASA Astrophysics Data System (ADS)
Alemi, Mallory; Loring, Roger F.
2015-06-01
The optimized mean-trajectory (OMT) approximation is a semiclassical method for computing vibrational response functions from action-quantized classical trajectories connected by discrete transitions that represent radiation-matter interactions. Here, we extend the OMT to include additional vibrational coherence and energy transfer processes. This generalized approximation is applied to a pair of anharmonic chromophores coupled to a bath. The resulting 2D spectra are shown to reflect coherence transfer between normal modes.
Nicholas J. Wright; R. Benny Gerber
2000-01-01
Potential energy surface points computed from variants of density functional theory (DFT) are used to calculate directly the anharmonic vibrational frequencies of H2O,Cl?H2O, and (H2O)2. The method is an adaptation to DFT of a recent algorithm for direct calculations of anharmonic vibrational frequencies using ab initio electronic structure codes. The DFT calculations are performed using the BLYP and the B3LYP
Nicholas J. Wright; R. Benny Gerber
2000-01-01
Potential energy surface points computed from variants of density functional theory (DFT) are used to calculate directly the anharmonic vibrational frequencies of H2O, Cl-H2O, and (H2O)2. The method is an adaptation to DFT of a recent algorithm for direct calculations of anharmonic vibrational frequencies using ab initio electronic structure codes. The DFT calculations are performed using the BLYP and the
Sastry, Ann Marie
2006-01-01
Journal of Power Sources 159 (2006) 758780 POWER (power optimization for wireless energy 48105, USA b Department of Material Science Engineering, University of Michigan, Ann Arbor, MI 48105 December 2005 Abstract We have expanded and implemented an algorithm for selecting power supplies
Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine.
Jones, D B; Ellis-Gibbings, L; Garcķa, G; Nixon, K L; Lopes, M C A; Brunger, M J
2015-09-01
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. PMID:26342367
Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine
NASA Astrophysics Data System (ADS)
Jones, D. B.; Ellis-Gibbings, L.; Garcķa, G.; Nixon, K. L.; Lopes, M. C. A.; Brunger, M. J.
2015-09-01
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.
Instantaneous pair theory for high-frequency vibrational energy relaxation in fluids
NASA Astrophysics Data System (ADS)
Larsen, Ross E.; Stratt, Richard M.
1999-01-01
Notwithstanding the long and distinguished history of studies of vibrational energy relaxation, exactly how it is that high frequency vibrations manage to relax in a liquid remains somewhat of a mystery. Both experimental and theoretical approaches seem to say that there is a natural frequency range associated with intermolecular motion in liquids, typically spanning no more than a few hundred cm-1. Landau-Teller-type theories explain rather easily how a solvent can absorb any vibrational energy within this "band," but how is it that molecules can rid themselves of superfluous vibrational energies significantly in excess of these values? In this paper we develop a theory for such processes based on the idea that the crucial liquid motions are those that most rapidly modulate the force on the vibrating coordinate and that by far the most important of these motions are those involving what we have called the mutual nearest neighbors of the vibrating solute. Specifically, we suggest that whenever there is a single solvent molecule sufficiently close to the solute that the solvent and solute are each other's nearest neighbors, then the instantaneous scattering dynamics of the solute-solvent pair alone suffices to explain the high-frequency relaxation. This highly reduced version of the dynamics has implications for some of the previous theoretical formulations of this problem. Previous instantaneous-normal-mode theories allowed us to understand the origin of a band of liquid frequencies, and even had some success in predicting relaxation within this band, but lacking a sensible picture of the effects of liquid anharmonicity on dynamics, were completely unable to treat higher frequency relaxation. When instantaneous-normal-mode dynamics is used to evaluate the instantaneous pair theory, though, we end up with a multiphonon picture of the relaxation which is in excellent agreement with the exact high-frequency dynamics suggesting that the critical anharmonicity behind the relaxation is not in the complex, underlying liquid dynamics, but in the relatively easy-to-understand nonlinear solute-solvent coupling. There are implications, as well, for the independent binary collision (IBC) theory of vibrational relaxation in liquids. The success of the instantaneous-pair approach certainly provides a measure of justification for the IBC model's focus on few-body dynamics. However, the pair theory neither needs nor supports the basic IBC factoring of relaxation rates into many-body and few-body dynamical components into collision rates and relaxation rates per collision. Rather, our results favor taking an instantaneous perspective: the relaxation rate is indeed exercise in few-body dynamics, but a different exercise for each instantaneous liquid configuration. The many-body features therefore appear only in the guise of a purely equilibrium problem, that of finding the likelihood of particularly effective solvent arrangements around the solute. All of these results are tested numerically on model diatomic solutes dissolved in atomic fluids (including the experimentally and theoretically interesting case of I2 dissolved in Xe). The instantaneous pair theory leads to results in quantitative agreement with those obtained from far more laborious exact molecular dynamics simulations.
Vibrational energy flow in the villin headpiece subdomain: Master equation simulations
NASA Astrophysics Data System (ADS)
Leitner, David M.; Buchenberg, Sebastian; Brettel, Paul; Stock, Gerhard
2015-02-01
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.
A mechanical solution of self-powered SSHI interface for piezoelectric energy harvesting systems
NASA Astrophysics Data System (ADS)
Liu, Haili; Ge, Cong; Liang, Junrui
2015-04-01
The synchronized switch interface circuits, e.g., synchronized switch harvesting on inductor (SSHI), can significantly enhance the harvesting capability of piezoelectric energy harvesting (PEH) systems. In these power conditioning circuits, the piezoelectric voltage is flipped with respect to a bias voltage at the instants when the piezoelectric element is at maximum deforming positions. Voltage peak detection and in time switching action are required for implementing these functions. The state-of-the-art solutions are mostly realized by electronic methods, i.e., both functions are carried out by electronic comparators and electronic switches. However, the peak detectors usually introduce switching phase lag; while the electronic switches function only when the vibration magnitude is above a threshold level. When the vibration is lower than such threshold, the SSHI interface shows no improvement. In this paper, we propose a mechanical solution for constructing the self-powered SSHI interface for PEH systems. This technique is realized by installing a low cost vibration sensor switch (VSS) at the free end of a piezoelectric cantilever. It senses the maximum deflecting places of the cantilever and automatically carries out synchronized switching actions. Compared to the existing electronic solutions, this mechanical solution is compact and has relative low switching threshold. Therefore, with this self-powered solution, the advantage of SSHI interface circuit can be sufficiently released, in particular, at low level vibration. Experiment shows the feasibility of this mechanical solution. The advantages and limitations are also discussed in this paper.
Benoit, David M
2008-12-21
We introduce a new reduced-coupling technique to accelerate direct calculations of a selected number of vibrational frequencies in large molecular systems. Our method combines the advantages of the single-to-all correlation-corrected vibrational self-consistent field (STA-CC-VSCF) approach [D. M. Benoit, J. Chem. Phys. 125, 244110 (2006)] with those of the fast-CC-VSCF technique [D. M. Benoit, J. Chem. Phys. 120, 562 (2004)] and allows the ab initio calculation of only the relevant parts of the required potential energy surface (PES). We demonstrate, using a set of five aliphatic alcohol molecules, that the new fast-STA-CC-VSCF method is accurate and leads to very substantial time gains for the computations of the PES. We then use the fast-STA-CC-VSCF method to accelerate the computation of the OH-stretch and NH-stretch frequencies of the two lowest-energy conformers of noradrenaline, namely, AG1a and GG1a. Our new approach enables us to run the calculation 89 times faster than the standard CC-VSCF technique and makes it possible to use a high-level MP2/TZP description of the PES. We demonstrate that the influence of the strong mode-mode couplings is crucial for a realistic description of the particular OH-stretch vibrational signature of each conformer. Finally, of the two possible low-energy conformers, we identify AG1a as the one most likely to have been observed in the experiments of Snoek et al. [Mol. Phys. 101, 1239 (2003)]. PMID:19102529
NASA Astrophysics Data System (ADS)
Poulsen, Jens Aage; Rossky, Peter J.
2001-11-01
Within the framework of Feynman-Kleinert variational theory, simple equations for correlation functions of arbitrary nonlinear operators are derived. These correlation functions, meaningful only for short times, are extended to longer times by a well established ansatz. The approach is tested against exact results for the quantum force correlation function in a two-dimensional Helium cluster problem and is found to perform very well. The theory is also applied to calculate quantum force correlation functions for a diatomic in a larger Neon bath. The results indicate that the method is effective for vibrational energy relaxation processes in simple liquids when quantum effects are significant.
NASA Astrophysics Data System (ADS)
Brown, James; Carrington, Tucker
2015-07-01
Although phase-space localized Gaussians are themselves poor basis functions, they can be used to effectively contract a discrete variable representation basis [A. Shimshovitz and D. J. Tannor, Phys. Rev. Lett. 109, 070402 (2012)]. This works despite the fact that elements of the Hamiltonian and overlap matrices labelled by discarded Gaussians are not small. By formulating the matrix problem as a regular (i.e., not a generalized) matrix eigenvalue problem, we show that it is possible to use an iterative eigensolver to compute vibrational energy levels in the Gaussian basis.
NASA Astrophysics Data System (ADS)
Brooks, C. L., III; Balk, M. W.; Adelman, S. A.
1983-07-01
The dynamics of vibrational energy relaxation of highly excited molecular iodine in three monatomic solvents is studied via stochastic classical trajectory simulations based on the molecular timescale generalized Langevin equation (MTGLE) of motion for liquid state chemical reactions [S. A. Adelman, J. Chem. Phys. 73, 3145 (1980)]. Also presented for comparison purposes are parallel studies based on a matrix Langevin equation of motion characterized by friction coefficients which depend on the instantaneous I2 internuclear separation R. The qualitative features of the energy relaxation may be interpreted as effects arising from modifications of the solute dynamics due to molecular timescale correlations between its motion and that of its solvation shells. Such dynamical solvent effects are realistically described by the MTGLE equation of motion but not by the Langevin equation. Thus, for example, the marked slowdown of the rate of I2 energy relaxtion in simple solvents when the I2 vibrational quantum number drops below a solvent-dependent critical value, earlier predicted by Nesbitt and Hynes, is predicted by MTGLE dynamics but not by Langevin dynamics. Finally, practical algorithms for numerically constructing the MTGLE and Langevin equations for specific solute-solvent systems are presented.
Artificial piezoelectric grass for energy harvesting from turbulence-induced vibration
NASA Astrophysics Data System (ADS)
Hobeck, J. D.; Inman, D. J.
2012-10-01
The primary objective of this research is to develop a deploy-and-forget energy harvesting device for use in low-velocity, highly turbulent fluid flow environments i.e. streams or ventilation systems. The work presented here focuses on a novel, lightweight, highly robust, energy harvester design referred to as piezoelectric grass. This biologically inspired design consists of an array of cantilevers, each constructed with piezoelectric material. When exposed to proper turbulent flow conditions, these cantilevers experience vigorous vibrations. Preliminary results have shown that a small array of piezoelectric grass was able to produce up to 1.0 mW per cantilever in high-intensity turbulent flow having a mean velocity of 11.5 m s-1. According to the literature, this is among the highest output achieved using similar harvesting methods. A distributed parameter model for energy harvesting from turbulence-induced vibration will be introduced and experimentally validated. This model is generalized for the case of a single cantilever in turbulent cross-flow. Two high-sensitivity pressure probes were needed to perform spectral measurements within various turbulent flows. The design and performance of these probes along with calibration and measurement techniques will be discussed.
Energy Storage for the Power Grid
Imhoff, Carl; Vaishnav, Dave
2014-07-01
The iron vanadium redox flow battery was developed by researchers at Pacific Northwest National Laboratory as a solution to large-scale energy storage for the power grid. This technology provides the energy industry and the nation with a reliable, stable, safe, and low-cost storage alternative for a cleaner, efficient energy future.
Teachers Environmental Resource Unit: Energy and Power.
ERIC Educational Resources Information Center
Bemiss, Clair W.
Problems associated with energy production and power are studied in this teacher's guide to better understand the impact of man's energy production on the environment, how he consumes energy, and in what quantities. The resource unit is intended to provide the teacher with basic information that will aid classroom review of these problems. Topics
Yu, Hua-Gen; Ndengue, Steve; Li, Jun; Dawes, Richard; Guo, Hua
2015-08-28
Accurate vibrational energy levels of the simplest Criegee intermediate (CH2OO) were determined on a recently developed ab initio based nine-dimensional potential energy surface using three quantum mechanical methods. The first is the iterative Lanczos method using a conventional basis expansion with an exact Hamiltonian. The second and more efficient method is the multi-configurational time-dependent Hartree (MCTDH) method in which the potential energy surface is refit to conform to the sums-of-products requirement of MCTDH. Finally, the energy levels were computed with a vibrational self-consistent field/virtual configuration interaction method in MULTIMODE. The low-lying levels obtained from the three methods are found to be within a few wave numbers of each other, although some larger discrepancies exist at higher levels. The calculated vibrational levels are very well represented by an anharmonic effective Hamiltonian. PMID:26328847
Koput, Jacek
2015-06-30
The accurate ground-state potential energy function of imidogen, NH, has been determined from ab initio calculations using the multireference averaged coupled-pair functional (MR-ACPF) method in conjunction with the correlation-consistent core-valence basis sets up to octuple-zeta quality. The importance of several effects, including electron correlation beyond the MR-ACPF level of approximation, the scalar relativistic, adiabatic, and nonadiabatic corrections were discussed. Along with the large one-particle basis set, all of these effects were found to be crucial to attain "spectroscopic" accuracy of the theoretical predictions of vibration-rotation energy levels of NH. PMID:25920622
Rizzo, T.R.
1992-03-01
These experiments apply multiple-laser spectroscopic techniques to investigate the bond energies, potential surface topologies, and dissociation dynamics of highly vibrationally excited molecules. Infrared-optical double resonance pumping of light atom stretch vibrations in H{sub 2}O{sub 2} and HN{sub 3} prepares reactant molecules in single rovibrational states above the unimolecular dissociation threshold on the ground potential surface, and laser induced fluorescence detection of the OH or NH fragments monitors the partitioning of energy into individual product quantum states. Product energy partitioning data from H{sub 2}O{sub 2} dissociation provide a stringent test of statistical theories as well as potential energy surface calculations. Ongoing work on HN{sub 3} seeks to determine the height of the barrier to dissociation on the singlet potential energy surface. Our most recently developed spectroscopic scheme allows the measurement of high vibrational overtone spectra of jet-cooled molecules. This approach uses CO{sub 2} laser infrared multiphoton dissociation followed by laser induced fluorescence product detection to measure weak vibrational overtone transitions in low pressure environments. Application of this scheme to record the {Delta}V{sub OH}=4 and {Delta}V{sub OH}=5 transitions of CH{sub 3}OH cooled in a supersonic free-jet demonstrates both its feasibility and its utility for simplifying high vibrational overtone spectra.
Non-resonant vibration conversion
NASA Astrophysics Data System (ADS)
Spreemann, D.; Manoli, Y.; Folkmer, B.; Mintenbeck, D.
2006-09-01
The development of distributed wireless sensor systems for automotive, medical or industrial monitoring applications is one of the aims for MEMS technology. For applications where environmental vibrations are present, the harvesting of this kinetic energy is an opportunity to power remote sensor nodes. For the conversion, typically resonant spring-mass-damper systems are considered. In this paper, a novel non-resonant conversion mechanism is presented. Depending on the geometry of the harvester and the vibration, this conversion mechanism shows a few advantages: low frequencies can be converted, higher or lower modes of vibration will be converted instantaneously, the transducer has 2 DOF for energy conversion and the generation of energy is not limited to a small frequency band. Based on a vibration amplitude of 100 µm, the behavior of a fine-mechanical generator and a MEMS generator has been simulated. The results of the fine-mechanical generator were verified by measurements of a prototype with 1.5 cm3 volume. So far the transducer is capable of producing 0.4-3 mW for vibration frequencies ranging from 30 to 80 Hz.
The influence of translational and vibrational energy on the reaction of Cl with CH{sub 3}D
Berke, Andrew E.; Volpa, Ethan H.; Annesley, Christopher J.; Crim, F. Fleming
2013-06-14
The reaction of Cl atoms with CH{sub 3}D proceeds either by abstraction of hydrogen to produce HCl + CH{sub 2}D or by abstraction of deuterium to produce DCl + CH{sub 3}. Using Cl atoms with different amounts of translational energy, produced by photolysis of Cl{sub 2} with 309, 355, or 416 nm light, reveals the influence of translational energy on the relative reaction probability for the two channels. These measurements give an estimate of the energy barrier for the reaction for comparison to theory and indicate that tunneling is the dominant reaction mechanism at low collision energies. Adding two quanta of C-H stretching vibration causes the reaction to proceed readily at all collision energies. Detecting the vibrational state of the CH{sub 2}D product shows that vibrational energy initially in the surviving C-H bond appears as vibrational excitation of the product, an example of spectator behavior in the reaction. The reaction produces both stretch and stretch-bend excited products except at the lowest collision energy. A subtle variation in the reaction probability of the lowest energy rotational states with translational energy may reflect the presence of a van der Waals well in the entrance channel.
NASA Technical Reports Server (NTRS)
Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)
1995-01-01
A description is given of an algorithm for computing ro-vibrational energy levels for tetratomic molecules. The expressions required for evaluating transition intensities are also given. The variational principle is used to determine the energy levels and the kinetic energy operator is simple and evaluated exactly. The computational procedure is split up into the determination of one dimensional radial basis functions, the computation of a contracted rotational-bending basis, followed by a final variational step coupling all degrees of freedom. An angular basis is proposed whereby the rotational-bending contraction takes place in three steps. Angular matrix elements of the potential are evaluated by expansion in terms of a suitable basis and the angular integrals are given in a factorized form which simplifies their evaluation. The basis functions in the final variational step have the full permutation symmetries of the identical particles. Sample results are given for HCCH and BH3.
NASA Astrophysics Data System (ADS)
Duque, H. V.; Chiari, L.; Jones, D. B.; Pettifer, Z.; da Silva, G. B.; Limćo-Vieira, P.; Blanco, F.; Garcķa, G.; White, R. D.; Lopes, M. C. A.; Brunger, M. J.
2014-06-01
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 ?-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.
Duque, H V; Chiari, L; Jones, D B; Pettifer, Z; da Silva, G B; Limćo-Vieira, P; Blanco, F; Garcķa, G; White, R D; Lopes, M C A; Brunger, M J
2014-06-01
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 ?-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. PMID:24908007
Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Fķsica, 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 Garēas, Mato Grosso (Brazil); Limćo-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Fķsica, Faculdade de Ciźncias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, F. [Departamento de Fķsica Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); Garcķa, G. [Instituto de Fķsica 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 Fķsica, 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 2050 eV range, are reported for excitation of several composite vibrational modes in ?-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 analysis of the solar power satellite.
Herendeen, R A; Kary, T; Rebitzer, J
1979-08-01
The energy requirements to build and operate the proposed Solar Power Satellite are evaluated and compared with the energy it produces. Because the technology is so speculative, uncertainty is explicitly accounted for. For a proposed 10-gigawatt satellite system, the energy ratio, defined as the electrical energy produced divided by the primary nonrenewable energy required over the lifetime of the system, is of order 2, where a ratio of 1 indicates the energy breakeven point. This is significantly below the energy ratio of today's electricity technologies such as light-water nuclear or coal-fired electric plants. PMID:17758765
NASA Astrophysics Data System (ADS)
Jurado-Navarro, Į. A.; López-Puertas, M.; Funke, B.; Garcķa-Comas, M.; Gardini, A.; Stiller, G. P.; Clarmann, T. von
2015-08-01
We present a retrieval of several vibrational-vibrational (V V) and vibrational-thermal (V-T) collisional rate coefficients affecting the populations of the CO2 levels emitting at 10, 4.3 and 2.7 ?m from high-resolution limb atmospheric spectra taken by Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). This instrument has a high spectral resolution (0.0625 cm-1) and a wide spectral coverage (from 685 to 2410 cm-1) that allow measuring and discriminating among the many bands originating the atmospheric 4.3 ?m radiance. Also its high sensitivity allows measuring the atmospheric limb emission in a wide altitude range, from 20 to 170 km in its middle and upper atmosphere modes, and hence obtain information on the temperature dependence of the collisional rates. In particular, we retrieve the rate coefficients and their temperature dependence in the 130-250 K range of the following processes: CO2(vd,v3)+N2?CO2(vd,v3-1)+N2(1) with vd=2v1+v2=2,3, and 4; CO2(v1,v2,l,1,r)+M?CO2(v1',v2',l',1,r')+M with ?vd=vd'-vd=0 and ?l = 0; and with ?vd=0 and ?l ? 0. In addition we have also retrieved the thermal relaxation of CO2(v3) into the v1 and v2 modes, e.g., CO2(vd,v3)+M?CO2(vd',v3-1)+M with ?vd=2-4 and ?v3=-1 and the efficiency of the excitation of N2(1) by O(1D). All of them were retrieved with a much better accuracy than were known before. The new rates have very important effects on the atmospheric limb radiance in the 10, 4.3 and 2.7 ?m spectral regions (5-8% at 4.3 ?m) and allow a more accurate inversion of the CO2 volume mixing ratio in the mesosphere and lower thermosphere from measurements taken in those spectral regions.
Department of Energy Bonneville Power Administration
the RPA, and develop new projects designed to contribute to hydro, habitat, hatchery and predationDepartment of Energy Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208 Director Northwest Power & Conservation Council 851 S.W. Sixth Avenue, Suite 1100 Portland, OR 97204
Department of Energy Bonneville Power Administration
designed to contribute to hydro, habitat, hatchery and predation management activities required underDepartment of Energy Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208 Division Director Northwest Power & Conservation Council 851 S.W. Sixth Avenue, Suite 1100 Portland
Department of Energy Bonneville Power Administration
designed to contribute to hydro, habitat, hatchery and predation management activities required underDepartment of Energy Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208 Director Northwest Power & Conservation Council 851 S.W. Sixth Avenue, Suite 1100 Portland, OR 97204
Voltage, energy and power in electric circuits
Haase, Markus
Voltage, energy and power in electric circuits Science teaching unit #12;Disclaimer The Department and power in electric circuits Background This teaching sequence bridges Key Stage 3 to Key Stage 4' understanding of electric circuits. The teaching approaches set out here are planned to be interactive in nature
Energy, environment, and advances in power electronics
Bimal K. Bose
2000-01-01
The technology of power electronics has gone through rapid technological advancement during the last four decades, and recently, its applications are fast expanding in industrial, commercial, residential, military and utility environments. In the global industrial automation, energy conservation and environmental pollution control trends of the 21st Century, the widespread impact of power electronics is inevitable. The paper begins with a
Energy Decisions: Is Solar Power the Solution?
ERIC Educational Resources Information Center
Childress, Vincent W.
2011-01-01
People around the world are concerned about affordable energy. It is needed to power the global economy. Petroleum-based transportation and coal-fired power plants are economic prime movers fueling the global economy, but coal and gasoline are also the leading sources of air pollution. Both of these sources produce greenhouse gases and toxins.
Power Technologies Energy Data Book - Fourth Edition
Aabakken, J.
2006-08-01
This report, prepared by NREL's Strategic Energy Analysis Center, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, and conversion factors.
Apkarian, V. Ara
PATHWAYS IN CH,F UNDER WEAK AND STRONG EXCITATION CONDITIONS: A COMPARISON V.A. APKARIAN, J.M. LINDQUIST September 1984 Energy transfer processes in CH3F have been reinvestigated under high excitation conditions excitation conditions. 1. Introduction Studies of vibrational energy transfer in CH,F have been extensive
NASA Astrophysics Data System (ADS)
Mahmoudi, S.; Kacem, N.; Bouhaddi, N.
2014-07-01
A multiphysics model of a hybrid piezoelectric-electromagnetic vibration energy harvester (VEH), including the main sources of nonlinearities, is developed. The continuum problem is derived on the basis of the extended Hamilton principle, and the modal Galerkin decomposition method is used in order to obtain a reduced-order model consisting of a nonlinear Duffing equation of motion coupled with two transduction equations. The resulting system is solved analytically using the method of multiple time scales and numerically by means of the harmonic balance method coupled with the asymptotic numerical continuation technique. Closed-form expressions for the moving magnet critical amplitude and the critical load resistance are provided in order to allow evaluation of the linear dynamic range of the proposed device. Several numerical simulations have been performed to highlight the performance of the hybrid VEH. In particular, the power density and the frequency bandwidth can be boosted, by up to 60% and 29% respectively, compared to those for a VEH with pure magnetic levitation thanks to the nonlinear elastic guidance. Moreover, the hybrid transduction permits enhancement of the power density by up to 84%.
Self-powered Wireless Energy Meter
Davide Brunelli; Danilo Porcarelli; Domenico Balsamo; Maurizio Rossi
2013-01-01
We present the design of a Wireless Electrical Energy Metering node (WEM) for the integration in a wireless sensor network. The node has energy harvesting capability for long lasting monitoring, and measures the power consumption, of residential and industrial appliances, in the range 10W-10kW. Energy harvesting makes the monitoring activity completely energy autonomous by exploiting a single current transformer to
NASA Astrophysics Data System (ADS)
Miller, David W.; Adelman, Steven A.
2002-08-01
A molecular theory of liquid phase vibrational energy relaxation (VER) [S. A. Adelman [et al.], Adv. Chem. Phys. 84, 73 (1993)] is applied to study the temperature T and density rho dependencies of the VER rate constant k(T,rho)=T1-1, where T1 is the energy relaxation time, of model Lennard-Jones systems that roughly simulate solutions of high-mass, low-frequency dihalogen solutes in rare gas solvents; specifically the I2/Xe, I2/Ar, and ICI/Xe solutions. For selected states of these systems, the theory's assumptions are tested against molecular dynamics (MD) results. The theory is based on the expression T1=beta]-1([omegal), where omegal and beta]([omega) are, respectively, the solute's liquid phase vibrational frequency and vibrational coordinate friction kernel. The friction kernel is evaluated as a cosine transform of the fluctuating force autocorrelation function of the solute vibrational coordinate, conditional that this coordinate is fixed at equilibrium. Additionally, the early-time decay of the force autocorrelation function is approximated by a Gaussian function which is exact to order t2. This Gaussian approximation permits evaluation of T1 in terms of integrals over equilibrium solute-solvent pair correlation functions. The pair correlation function formulas yield T1's in semiquantitative agreement with those found by MD evaluations of the Gaussian approximation, but with three orders of magnitude less computational effort. For the isothermal rho dependencies of k(T,rho), the theory predicts for all systems that the Gaussian decay time tau is nearly independent of rho. This in turn implies that k(T,rho) factorizes into a liquid phase structural contribution and a gas phase dynamical contribution, yielding a first-principles form for k(T,rho) similar to that postulated by the isolated binary collision model. Also, the theory predicts both "classical" superlinear rate isotherms, and "nonclassical" sublinear isotherms similar to those recently observed by Troe and co-workers for azulene relaxation in supercritical fluids. The isochoric T dependencies of k(T,rho) are studied in the range 300 to 1000 K. For none of the solutions are the rate isochores found to accurately conform to either Arrhenius or Landau-Teller kinetics.
Galayko, Dimitri; Paracha, Ayyaz Mahmood
2008-01-01
Electrostatic transducers for vibration energy scavenging have been an object to numerous studies, but are still facing major issues relating to their conditioning circuit. One of the most popular ones uses a charge pump and a flyback circuit based on a Buck DC-DC converter (Fig. 1). A commutation between the energy accumulation in the charge pump and the recharge of the buffer capacitor Cres is assured by a switch which is the major bottleneck in the energy harvester circuit. The commutation timing of the switch determines the efficiency of the energy harvesting. In previous papers [1] the switch commutates periodically with some fixed duty ratio. However, this solution is not appropriate when the environment parameters, e.g. the vibration frequency, change. We found that the switching should be ordered by the internal state of the circuit, an not by some fixed timing scenario. We presents how to find the optimal operation mode of the harvester. To validate the study, the system was modeled using a mixed VHD...
Vibration Testing of an Operating Stirling Convertor
NASA Technical Reports Server (NTRS)
Hughes, William O.; McNelis, Mark E.; Goodnight, Thomas W.
2000-01-01
The NASA John H. Glenn Research Center and the U.S. Department of Energy are currently developing a Stirling convertor for use as an advanced spacecraft power system for future NASA deep-space missions. As part of this development, a Stirling Technology Demonstrator Convertor (TDC) was recently tested to verify its survivability and capability of withstanding its expected launch random vibration environment. The TDC was fully operational (producing power) during the random vibration testing. The output power of the convertor was measured during the testing, and these results are discussed in this paper. Numerous accelerometers and force gauges were also present which provided information on the dynamic characteristics of the TDC and an indication of any possible damage due to vibration. These measurements will also be discussed in this paper. The vibration testing of the Stirling TDC was extremely successful. The TDC survived all its vibration testing with no structural damage or functional performance degradation. As a result of this testing, the Stirling convertor's capability to withstand vibration has been demonstrated, enabling its usage in future spacecraft power systems.
NASA Astrophysics Data System (ADS)
Ashebo, Demeke Beyene; Tan, Chin An; Wang, Jun; Li, Gang
2008-03-01
In recent years, wireless sensors technologies are attracted many researchers in the field of structural health monitoring (SHM) of civil, mechanical and aerospace systems. Another potential application of wireless sensors is in the Vehicle-Infrastructure Integration (VII) which is an initiative by the U.S. Department of Transportation to improve road safety and reduce congestion, through as part of its Intelligent Transportation System program. However, fundamental issues remain unresolved before a broad application of the wireless SHM or VII sensor network concept is the question of sustainable power source for each independent sensor mounted on infrastructures. With a vast number of sensors nodes/networks in the infrastructure, connecting them to the grid power source is simply uneconomical in the era of wireless technology. The other option, which is providing power to each sensor from battery sources, has its own setbacks, as batteries can only provide power for a limited period, have to be replaced periodically (often difficult and costly), and their disposal creates environmental hazard. This study addresses the feasibility of energy harvesting from the ambient vibration of transportation infrastructures to power wireless sensors. Based on the vibration responses from simulation and field tests, vehicle induced vibrations on bridge and pavement were obtained and the theoretical power output from such vibration sources were computed. The expected results from this study will be demonstrated by avoiding complex wiring to the sensors by which the associated cost of wiring and batteries will be significantly reduced, and at the same time the technology can easily be deployed, meaning it is one step forward in improving the SHM and VII applications.
Coal and nuclear power: Illinois' energy future
Not Available
1982-01-01
This conference was sponsored by the Energy Resources Center, University of Illinois at Chicago; the US Department of Energy; the Illinois Energy Resources Commission; and the Illinois Department of Energy and Natural Resources. The theme for the conference, Coal and Nuclear Power: Illinois' Energy Future, was based on two major observations: (1) Illinois has the largest reserves of bituminous coal of any state and is surpassed in total reserves only by North Dakota, and Montana; and (2) Illinois has made a heavy commitment to the use of nuclear power as a source of electrical power generation. Currently, nuclear power represents 30% of the electrical energy produced in the State. The primary objective of the 1982 conference was to review these two energy sources in view of the current energy policy of the Reagan Administration, and to examine the impact these policies have on the Midwest energy scene. The conference dealt with issues unique to Illinois as well as those facing the entire nation. A separate abstract was prepared for each of the 30 individual presentations.
Fiscalini Farms Renewable Energy Power Generation Project
2009-02-01
Funded by the American Recovery and Reinvestment Act of 2009 Fiscalini Farms L.P., in collaboration with University of the Pacific, Biogas Energy, Inc., and the University of California at Berkeley will measure and analyze the efficiency and regulatory compliance of a renewable energy system for power generation. The system will utilize digester gas from an anaerobic digester located at the Fiscalini Farms dairy for power generation with a reciprocating engine. The project will provide power, efficiency, emissions, and cost/benefit analysis for the system and evaluate its compliance with federal and California emissions standards.
Space solar power - An energy alternative
NASA Technical Reports Server (NTRS)
Johnson, R. W.
1978-01-01
The space solar power concept is concerned with the use of a Space Power Satellite (SPS) which orbits the earth at geostationary altitude. Two large symmetrical solar collectors convert solar energy directly to electricity using photovoltaic cells woven into blankets. The dc electricity is directed to microwave generators incorporated in a transmitting antenna located between the solar collectors. The antenna directs the microwave beam to a receiving antenna on earth where the microwave energy is efficiently converted back to dc electricity. The SPS design promises 30-year and beyond lifetimes. The SPS is relatively pollution free as it promises earth-equivalence of 80-85% efficient ground-based thermal power plant.
Saving Energy Through Advanced Power Strips (Poster)
Christensen, D.
2013-10-01
Advanced Power Strips (APS) look just like ordinary power strips, except that they have built-in features that are designed to reduce the amount of energy used by many consumer electronics. There are several different types of APSs on the market, but they all operate on the same basic principle of shutting off the supply power to devices that are not in use. By replacing your standard power strip with an APS, you can signifcantly cut the amount of electricity used by your home office and entertainment center devices, and save money on your electric bill. This illustration summarizes the different options.
Reduction of Helicopter BVI Noise, Vibration, and Power Consumption Through Individual Blade Control
NASA Technical Reports Server (NTRS)
Jacklin, Stephen A.; Blaas, Achim; Teves, Dietrich; Kube, Roland; Warmbrodt, William (Technical Monitor)
1994-01-01
A wind tunnel test was conducted with a full-scale BO 105 helicopter rotor to evaluate the potential of open-loop individual blade control (IBC) to improve rotor performance, to reduce blade vortex interaction (BVI) noise, and to alleviate helicopter vibrations. The wind tunnel test was an international collaborative effort between NASA/U.S. Army AFDD, ZF Luftfahrttechnik, Eurocopter Deutschland, and the German Aerospace Laboratory (DLR) and was conducted under the auspices of the U.S./German MOU on Rotorcraft Aeromechanics. In this test the normal blade pitch links of the rotor were replaced by servo-actuators so that the pitch of each blade could be controlled independently of the other blades. The specially designed servoactuators and IBC control system were designed and manufactured by ZF Luftfahrttechnik, GmbH. The wind tunnel test was conducted in the 40- by 80-Foot Wind Tunnel at the NASA Ames Research Center. An extensive amount of measurement information was acquired for each IBC data point. These data include rotor performance, static and dynamic hub forces and moments, rotor loads, control loads, inboard and outboard blade pitch motion, and BVI noise data. The data indicated very significant (80 percent) simultaneous reductions in both BVI noise and hub vibrations could be obtained using multi-harmonic input at the critical descent (terminal approach) condition. The data also showed that performance improvements of up to 7 percent could be obtained using 2P input at high-speed forward flight conditions.
A strain energy-based vibrational NDE method applied to an aerospace structure
Osegueda, R. A.; Andre, G.; Ferregut, C. M.; Carrasco, C.; Pereyra, L. [FAST Center for Structural Integrity of Aerospace Systems, University of Texas at El Paso, El Paso, Texas 79968 (United States); James, G. III [University of Houston, Houston, Texas 77204 (United States); Grygier, M.; Rocha, R. [NASA Johnson Space Center, Mail Code ES4, Houston, Texas 77058 (United States)
1999-12-02
An early prototype of the Vertical Stabilizer Assembly (VSA) of the Shuttle Orbiter was modal tested at healthy and damaged states to study vibrational nondestructive damage evaluation in aerospace structures. Frequency Response and Coherence functions were collected with a Laser Vibrometer at 84 points when the healthy and damaged VSA was shaken with a continuous random force from 0 to 300 Hz. The measurements were used to extract the resonant frequencies and modal shapes for the healthy and damaged states. After pairing of the mode shapes between the healthy and damaged states through the Modal Assurance Criterion, the strain energy of the modes were determined through a finite element model of the VSA and normalized. The localization of the damage is achieved through an analysis of the differences between the modal strain energy in the healthy and damaged states and a fusion on the information obtained from several modes. This paper evaluates the detectability and performance of four different methods.
State and species selective energy flow in gas ensembles containing vibrationally excited O2.
McCaffery, Anthony J
2012-10-01
State-to-state, collision-induced, energy transfer is followed to equilibrium through sequences of collision cycles in gas ensembles containing vibrationally excited oxygen molecules (v = 8 and 1) in several different atomic and molecular bath gases. Quantum state distributions for each of the constituent species are available at each stage of the ensemble's evolution and enable the dominant energy exchange mechanisms to be identified. Equilibration is generally a complex process that evolves through several phases of inter- and intra-molecular events, each with their characteristic response rate to collisions. The results suggest that single quantum state population loss rate constants, however precisely determined, may miss key features of the overall equilibration process. PMID:23039593
NASA Astrophysics Data System (ADS)
Csįszįr, Attila G.; Handy, Nicholas C.
Forms for the exact non-relativistic quantum mechanical vibrational (J = 0) kinetic energy operators for sequentially bonded (A-B-C-D-E) and (A,B)-C-D-E-type penta-atomic molecules, expressed in valence internal coordinates, are presented. As advocated earlier (Handy, N. C., 1987, Molec. Phys., 61, 207), computer algebra has been employed during the derivation. The suggested use of these operators in calculations for vibrational energy levels of interesting penta-atomic molecules (e.g., C3O2, and H2CCO) is outlined.
Power conditioning system for energy sources
Mazumder, Sudip K. (Chicago, IL); Burra, Rajni K. (Chicago, IL); Acharya, Kaustuva (Chicago, IL)
2008-05-13
Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.
Breezy Power: From Wind to Energy
ERIC Educational Resources Information Center
Claymier, Bob
2009-01-01
This lesson combines the science concepts of renewable energy and producing electricity with the technology concepts of design, constraints, and technology's impact on the environment. Over five class periods, sixth-grade students "work" for a fictitious power company as they research wind as an alternative energy source and design and test a
Fluid Power Systems. Energy Technology Series.
ERIC Educational Resources Information Center
Center for Occupational Research and Development, Inc., Waco, TX.
This course in fluid power systems is one of 16 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in company-sponsored
Uranga-Pińa, L; Tremblay, J C
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 demontrates that most of the mode mixing during relaxation is due to the potential part of the Hamiltonian and not to the coupling among relaxation operators. PMID:25149802
NASA Astrophysics Data System (ADS)
Farley, Francis William, Jr.
The extent to which Intramolecular Vibration-Rotation Energy Transfer (IVRET) occurs in isolated polyatomic molecules is determined by measuring the deflection of a molecular beam by an inhomogeneous electric field. Regular or rigid body rotational motion is characterized by a broad deflection distribution arising from the interaction between the electric field and a distribution of time-averaged (space-fixed) molecular dipole moments. At the other extreme, in the limit of statistical IVRET, the time-averaged value of the molecular dipole moment is zero and the molecules experience no deflection. Molecular behavior is studied at various temperatures to search for a threshold for the onset of IVRET. Strong evidence that IVRET is a general phenomenon in isolated highly excited polyatomic molecules is provided. Fourteen compounds were successfully studied; extensive data were recorded for five: o-difluorobenzene, o-dichlorobenzene, p-chlorotoluene, POCl_3 , and CBrF_3. The physical properties of the molecules of the compounds investigated show a broad range of diversity. Molecules were typically studied over a temperature range of 300 to 1100 K. At densities of vibrational states >=10 ^5 states per cm^ {-1}, IVRET was extensive, as shown by a significant decrease in the deflection of the molecular beam. For the first three compounds above, for which the density of vibrational states at the highest temperature in the range was >10^8 states per cm^{-1}, IVRET approaching the statistical limit was observed. Here the deflection all but vanished. Data recorded for several compounds at high temperatures, particularly at high deflection voltages, showed a small but measurable deflection which is attributed to a field -induced polarization characteristic of a thermal ensemble. Depending upon the interaction of vibration and rotation, the reorientation of the molecules in response to the field produces this polarization in the absence of collisions, and provides further evidence of the occurrence of IVRET in such excited molecules. It is demonstrated that the decrease in deflection does not arise from thermal isomerization of ortho compounds, nor from a mechanism by which the electric field introduces the frequent occurrence of isolated avoided crossings of the potential curves of the molecules as they traverse the field.
Energy Servers Deliver Clean, Affordable Power
NASA Technical Reports Server (NTRS)
2010-01-01
K.R. Sridhar developed a fuel cell device for Ames Research Center, that could use solar power to split water into oxygen for breathing and hydrogen for fuel on Mars. Sridhar saw the potential of the technology, when reversed, to create clean energy on Earth. He founded Bloom Energy, of Sunnyvale, California, to advance the technology. Today, the Bloom Energy Server is providing cost-effective, environmentally friendly energy to a host of companies such as eBay, Google, and The Coca-Cola Company. Bloom's NASA-derived Energy Servers generate energy that is about 67-percent cleaner than a typical coal-fired power plant when using fossil fuels and 100-percent cleaner with renewable fuels.
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
2014-10-01
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. PMID:25297434
Shirhatti, Pranav R.; Werdecker, Jörn; Golibrzuch, Kai; Wodtke, Alec M.; Bartels, Christof
2014-09-28
We investigated the translational incidence energy (E{sub i}) and surface temperature (T{sub s}) dependence of CO vibrational excitation upon scattering from a clean Au(111) surface. We report absolute v = 0 ? 1 excitation probabilities for E{sub i} between 0.16 and 0.84 eV and T{sub s} between 473 and 973 K. This is now only the second collision system where such comprehensive measurements are available the first is NO on Au(111). For CO on Au(111), vibrational excitation occurs via direct inelastic scattering through electron hole pair mediated energy transfer it is enhanced by incidence translation and the electronically non-adiabatic coupling is about 5 times weaker than in NO scattering from Au(111). Vibrational excitation via the trapping desorption channel dominates at E{sub i} = 0.16 eV and quickly disappears at higher E{sub i}.
Czurlok, Denis; Gleim, Jeannine; Lindner, Jörg; Vöhringer, Peter
2014-10-01
The vibrational relaxation dynamics following an ultrafast nitrile stretching (?3) excitation of thiocyanate anions dissolved in light and heavy water have been studied over a wide temperature and density range corresponding to the aqueous liquid up to the supercritical phase. In both solvents, the relaxation of the ?3 = 1 state of the anion leads to a direct recovery of the vibrational ground state and involves the resonant transfer of the excess vibrational energy onto the solvent. In light water, the energy-accepting states are provided by the bending-librational combination band (?b + ?L), while in heavy water, the relaxation is thermally assisted by virtual acceptor states derived from the stretching-librational/restricted translational hot band (?S - ?L,T). The relaxation rate is found to strictly obey Fermi's Golden Rule when the density of resonant solvent states is estimated from the linear infrared spectra of the solute and the pure solvents. PMID:26278447
Energy storage options for space power
Hoffman, H.W.; Martin, J.F.; Olszewski, M.
1985-01-01
Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Review of storage options (superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels) suggests that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal energy storage densities of 1500 to 2000 kJ/kg at temperatures to 1675/sup 0/K. Innovative techniques allow these media to operate in direct contact with the heat engine working fluid. Enhancing thermal conductivity and/or modifying PCM crystallization habit provide other options. Flywheels of low-strain graphite and Kevlar fibers have achieved mechanical energy storage densities of 300 kJ/kg. With high-strain graphite fibers, storage densities appropriate to space power needs (approx. 550 kJ/kg) seem feasible. Coupling advanced flywheels with emerging high power density homopolar generators and compulsators could result in electric pulse-power storage modules of significantly higher energy density.
Role of energy exchange in vibrational dephasing processes in liquids and solids
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/sub 14/-durene (perdeutero-1,2,4,5-tetramethylbenzene) and compared to previous data obtained on pure h/sub 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.
NASA Astrophysics Data System (ADS)
Hanumantha Rao, T. V.; Srinivasa Rao, M. S. S.; Apparao, B. V.; Satyanarayana, K.
2014-04-01
The basic purpose of a damper is to reduce the vibration and to have a better ride comfort, road handling and safety to the rider. Recent developments show that an active vibration damper can effectively work much better than a passive damper. The effectiveness and reliability can be further enhanced by using hybrid dampers, which is a combination of active and passive dampers. But the need to have energy optimization in any field need not be stressed. Consequently, novel suspension concepts are required, not only to improve the vehicle's dynamic performance, but also to see that the energy generated during vibration can be harvested by utilizing regeneration functions. Hence if a hybrid damper with energy harvesting capability be designed, it would serve both purposes. In the hybrid damper a combination of hydraulic damper to act as a passive damper and an electromagnetic (EM) damper to act as an active damper is considered. The hydraulic system has more reliability and is time tested and the EM system acts as a dynamic vibration system as well as energy harvester. In this study a hybrid EM damper is modeled, analyzed and validity is shown for frequency response functions and energy balance for its active use. It is also shown how the effectiveness of the suspension system can be enhanced by using a hybrid damper.
NASA Technical Reports Server (NTRS)
Kachadourian, G. (compiler)
1977-01-01
Summary plots are presented for the time histories and power spectral density analyses of vibration and acceleration on the spacecraft from the Titan Centaur launchings carrying the Viking dynamic simulator and the two Viking spacecraft (TC-1, TC-3 and TC-4).
Alekseev, A. S.; Chichinin, I. S.; Korneev, V. A.; Komissarov, V. V.; Seleznev, V. S.; Emanov, A. F.
2004-06-11
In the past two decades, active seismology studies in Russia have made use of powerful (40- and 100-ton) low-frequency vibrators. These sources create a force amplitude of up to 100 tons and function in the 1.5-3, 3-6 and 5-10 Hz frequency bands. The mobile versions of the vibrator have a force amplitude of 40 tons and a 6-12 Hz frequency band. Registration distances for the 100 ton vibrator are as large as 350 km, enabling the refracted waves to penetrate down to 50 km depths. Vibrator operation sessions are highly repeatable, having distinct ''summer'' or ''winter'' spectral patterns. A long profile of seismic records allows estimating of fault zone depths using changes in recorded spectra. Other applications include deep seismic profiling, seismic hazard mapping, structural testing, stress induced anisotropy studies, seismic station calibration, and large-structure integrity testing. In more detail, these questions are discussed in reports of our colleagues from Novosibirsk. This report is devoted mainly to powerful low-frequency vibrators, their theoretical description and design. Besides, problems of vibroseismic monitoring of engineering constructions are briefly elucidated.
NASA Astrophysics Data System (ADS)
Zhou, Shengxi; Cao, Junyi; Wang, Wei; Liu, Shengsheng; Lin, Jing
2015-05-01
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.
NASA Astrophysics Data System (ADS)
Poulsen, Jens Aage; Rossky, Peter J.
2001-11-01
We present a method based on centroid molecular dynamics (CMD) to calculate nonlinear quantum force correlation functions important in the golden rule approach for studying vibrational energy relaxation (VER) in condensed phases. We consider a model of a diatomic molecule in a two-dimensional neon liquid and also a diatomic coupled to a small Helium cluster. The predictions of the theory for the neon bath are compared and found in close agreement with available theories for VER based on the Egelstaff correction factor and Feynman-Kleinert variational theory. For the Helium cluster, the force spectrum obtained from CMD is found to be in slightly better agreement with the exact result than a method based on a cumulant approach. The results support the use of CMD in condensed phase studies of VER when quantum effects are important.
Anharmonic Effects on the Electron-Energy Spectra of Surface Vibrations
NASA Astrophysics Data System (ADS)
Ariyasu, Janice Carol
First, we consider the effect of lateral interactions on double losses and overtones in electron-energy-loss studies of surface vibrations. We develop a theory of two-phonon losses in the dipole-dominated regime of small -angle scattering. Our calculation employs the simple model of an ordered overlayer of molecules adsorbed on a crystal surface. With this model, we can identify two features; one which corresponds to the double loss and another which corresponds the excitation of an overtone. We then study the role of lateral interactions in each. We find that the presence of lateral interactions affects the position of the overtone relative to the double loss, and influences both its width and shape. The implications of these results are discussed, particularly as they relate to estimates of dissociation energies by the Birge-Sponer procedure. Next, we consider the anharmonic damping of adsorbate vibrations, with specific applications to species (S, O, and CO) adsorbed on the Ni(100) and Ni(111) surfaces. Our attention is restricted to adsorbate modes that can decay by two-phonon processes to one substrate phonon and either another substrate mode phonon or to a phonon of a mode that is localized on the adsorbate. The magnitude and temperature variation of the linewidth of adsorbate modes by this mechanism is explored; we find that near room temperature the calculated linewidths vary linearly with temperature. We also simulate the inhomogeneous broadening produced by disorder by considering the eigenfrequencies of infrared -active modes. Finally, we consider the diffuse scattering of electrons from surfaces by long-wavelength, acoustic phonons. The mechanism that we explore is the modulation of the image potential from ripples induced in the surface profile by thermally-excited surface and bulk phonons. We compare our results with earlier studies, and with the scattering produced by the dynamic-dipole moment of the surface atoms.
Stancil, Phillip C.
-channel (QMOCC) approach, we investigate single electron capture in collisions of O3+ with various molecularTarget isotope effects for vibrationally-resolved electron capture in low-energy collisions of O3+ with molecular hydrogen P. C. Stancil Department of Physics and Astronomy and the Center for Simulational Physics
R. Schinke; G. H. F. Diercksen
1985-01-01
We present a fully quantal dynamical study of vibrational relaxation of CO in collisions with H2 treating H2 as a structureless projectile. The potential energy surface consists of a SCF part, including explicitly the variation with the CO bond distance, and a damped long range dispersion part. This potential model contains only two free parameters in the damping function which
Czakó, Gįbor; Braams, Bastiaan J; Bowman, Joel M
2008-08-14
Accurate equilibrium structure, dissociation energy, global potential energy surface (PES), dipole moment surface (DMS), and the infrared vibrational spectrum in the 0-3000 cm(-1) range of the F(-)-CH4 anion complex have been obtained. The equilibrium electronic structure calculations employed second-order Mųller-Plesset perturbation theory (MP2) and coupled-cluster (CC) method up to single, double, triple, and perturbative quadruple excitations using the aug-cc-p(C)VXZ [X = 2(D), 3(T), 4(Q), and 5] correlation-consistent basis sets. The best equilibrium geometry has been obtained at the all-electron CCSD(T)/aug-cc-pCVQZ level of theory. The dissociation energy has been determined based on basis set extrapolation techniques within the focal-point analysis (FPA) approach considering (a) electron correlation beyond the all-electron CCSD(T) level, (b) relativistic effects, (c) diagonal Born-Oppenheimer corrections (DBOC), and (d) variationally computed zero-point vibrational energies. The final D(e) and D0 values are 2398 +/- 12 and 2280 +/- 20 cm(-1), respectively. The global PES and DMS have been computed at the frozen-core CCSD(T)/aug-cc-pVTZ and MP2/aug-cc-pVTZ levels of theory, respectively. Variational vibrational calculations have been performed for CH4 and F(-)-CH4 employing the vibrational configuration interaction (VCI) method as implemented in Multimode. PMID:18651724
Quarks are vibrating possibly quantum mechanically
NASA Astrophysics Data System (ADS)
Brekke, Stewart
2003-04-01
Quarks are vibrating. All fundamental particles are vibrating or oscillating due to heat energy in the environment. Therefore, quarks, being fundamental should be vibrating also. Quarks forming a particle such as a proton may be vibrating independently in the whole particle as well as vibrating along with the total particle. As is known, quarks are spinning and may obey the pauli exclusion principle. Vibration is a common feature of electrons, nuclei, atoms and molecules and even neutrinos and are probably vibrating.
Karami, M Amin; Bilgen, Onur; Inman, Daniel J; Friswell, Michael I
2011-07-01
This research presents an experimental and theoretical energy harvesting characterization of beam-like, uniform cross-section, unimorph structures employing single-crystal piezoelectrics. Different piezoelectric materials, substrates, and configurations are examined to identify the best design configuration for lightweight energy harvesting devices for low-power applications. Three types of piezoelectrics (singlecrystal PMN-PZT, polycrystalline PZT-5A, and PZT-5H-type monolithic ceramics) are evaluated in a unimorph cantilevered beam configuration. The devices have been excited by harmonic base acceleration. All of the experimental characteristics have been used to validate an exact electromechanical model of the harvester. The study shows the optimum choice of substrate material for single-crystal piezoelectric energy harvesting. Comparison of energy scavengers with stainless steel substrates reveals that single-crystal harvesters produce superior power compared with polycrystalline devices. To further optimize the power harvesting, we study the relation between the thickness of the substrate and the power output for different substrate materials. The relation between power and substrate thickness profoundly varies among different substrate materials. The variation is understood by examining the change of mechanical transmissibility and the variations of the coupling figure of merit of the harvesters with thickness ratio. The investigation identifies the optimal thickness of the substrate for different substrate materials. The study also shows that the densities of the substrates and their mechanical damping coefficients have significant effects on the power output. PMID:21768034
Vibrational Energy Flows in Beam Networks with Compliant and Dissipative Joints
NASA Astrophysics Data System (ADS)
Beshara, M.; Keane, A. J.
1997-06-01
Many structures and machines are made up from components (rods, beams and plates) which are joined together by welds, bolts or rivets. The mechanical behaviour of such built-up systems is greatly affected by the properties of their joints which are usually compliant and dissipative.In this work, a general solution for the vibrational energy flows through a plane network of beams is sought, based on the receptance approach. The joints between any two elements are assumed to act at discrete points and are modelled by three sets of springs and dashpots, thus being compliant and non-conservative in all the three degrees of freedom relevant to this case. The beams are assumed to be slender and elastic, and the deflections at the joint are assumed to be small, so that conventional linear beam theory may be used in the analysis. The aim of this study is to give greater insight into the problem of non-conservative coupling, which has not been extensively discussed in the literature. Interest is focused on the effect of damping in the joints on the magnitudes of energy flows between, and energy levels in, each beam. Variations in the energy flows through a compliant joint between two beams with changes in their coupling angle are also discussed. Numerical examples which illustrate these various ideas are presented.
Energy management system functions in deregulated power systems
Magnago, Fernando Hugo
1997-01-01
The market structures for electric energy and power are changing. In the past interconnected electric utility systems dealt only with each other to buy and sell power and energy. In recent times, the electric power industry is facing...
Absolute cross sections for vibrational excitations of cytosine by low energy electron impact
Michaud, M.; Bazin, M.; Sanche, L.
2013-01-01
The absolute cross sections (CSs) for vibrational excitations of cytosine by electron impact between 0.5 and 18 eV were measured by electron-energy loss (EEL) spectroscopy of the molecule deposited at monolayer coverage on an inert Ar substrate. The vibrational energies compare to those that have been reported from IR spectroscopy of cytosine isolated in Ar matrix, IR and Raman spectra of poly-crystalline cytosine, and ab initio calculation. The CSs for the various H bending modes at 142 and 160 meV are both rising from their energy threshold up to 1.7 and 2.1 × 10?17 cm2 at about 4 eV, respectively, and then decrease moderately while maintaining some intensity at 18 eV. The latter trend is displayed as well for the CS assigned to the NH2 scissor along with bending of all H at 179 meV. This overall behavior in electron-molecule collision is attributed to direct processes such as the dipole, quadrupole, and polarization contributions, etc. of the interaction of the incident electron with a molecule. The CSs for the ring deformation at 61 meV, the ring deformation with N-H symmetric wag at 77 meV, and the ring deformations with symmetric bending of all H at 119 meV exhibit common enhancement maxima at 1.5, 3.5, and 5.5 eV followed by a broad hump at about 12 eV, which are superimposed on the contribution due to the direct processes. At 3.5 eV, the CS values for the 61-, 77-, and 119-meV modes reach 4.0, 3.0, and 4.5 × 10?17 cm2, respectively. The CS for the C-C and C-O stretches at 202 meV, which dominates in the intermediate EEL region, rises sharply until 1.5 eV, reaches its maximum of 5.7 × 10?17 cm2 at 3.5 eV and then decreases toward 18 eV. The present vibrational enhancements, correspond to the features found around 1.5 and 4.5 eV in electron transmission spectroscopy (ETS) and those lying within 1.52.1 eV, 5.26.8 eV, and 9.510.9 eV range in dissociative electron attachment (DEA) experiments with cytosine in gas phase. While the ETS features are ascribed to shape resonances associated with the electron occupation of the second and third antibonding ?-orbitals of the molecule in its ground state, the correspondence with DEA features suggests the existence of common precursor anion states decaying with certain probabilities into the vibrationally excited ground state. PMID:22998289
Miyata, Tomohiro; Fukuyama, Mao; Hibara, Akihide; Okunishi, Eiji; Mukai, Masaki; Mizoguchi, Teruyasu
2014-10-01
Investigations on the dynamic behavior of molecules in liquids at high spatial resolution are greatly desired because localized regions, such as solid-liquid interfaces or sites of reacting molecules, have assumed increasing importance with respect to improving material performance. In application to liquids, electron energy loss spectroscopy (EELS) observed with transmission electron microscopy (TEM) is a promising analytical technique with the appropriate resolutions. In this study, we obtained EELS spectra from an ionic liquid, 1-ethyl-3-methylimidazolium bis (trifluoromethyl-sulfonyl) imide (C2mim-TFSI), chosen as the sampled liquid, using monochromated scanning TEM (STEM). The molecular vibrational spectrum and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the liquid were investigated. The HOMO-LUMO gap measurement coincided with that obtained from the ultraviolet-visible spectrum. A shoulder in the spectrum observed ?0.4 eV is believed to originate from the molecular vibration. From a separately performed infrared observation and first-principles calculations, we found that this shoulder coincided with the vibrational peak attributed to the C-H stretching vibration of the [C2mim(+)] cation. This study demonstrates that a vibrational peak for a liquid can be observed using monochromated STEM-EELS, and leads one to expect observations of chemical reactions or aids in the analysis of the dynamic behavior of molecules in liquid. PMID:25015973
Energy Flux in the Cochlea: Evidence Against Power Amplification of the Traveling Wave.
van der Heijden, Marcel; Versteegh, Corstiaen P C
2015-10-01
Traveling waves in the inner ear exhibit an amplitude peak that shifts with frequency. The peaking is commonly believed to rely on motile processes that amplify the wave by inserting energy. We recorded the vibrations at adjacent positions on the basilar membrane in sensitive gerbil cochleae and tested the putative power amplification in two ways. First, we determined the energy flux of the traveling wave at its peak and compared it to the acoustic power entering the ear, thereby obtaining the net cochlear power gain. For soft sounds, the energy flux at the peak was 1?±?0.6 dB less than the middle ear input power. For more intense sounds, increasingly smaller fractions of the acoustic power actually reached the peak region. Thus, we found no net power amplification of soft sounds and a strong net attenuation of intense sounds. Second, we analyzed local wave propagation on the basilar membrane. We found that the waves slowed down abruptly when approaching their peak, causing an energy densification that quantitatively matched the amplitude peaking, similar to the growth of sea waves approaching the beach. Thus, we found no local power amplification of soft sounds and strong local attenuation of intense sounds. The most parsimonious interpretation of these findings is that cochlear sensitivity is not realized by amplifying acoustic energy, but by spatially focusing it, and that dynamic compression is realized by adjusting the amount of dissipation to sound intensity. PMID:26148491
Novel Nuclear Powered Photocatalytic Energy Conversion
White,John R.; Kinsmen,Douglas; Regan,Thomas M.; Bobek,Leo M.
2005-08-29
The University of Massachusetts Lowell Radiation Laboratory (UMLRL) is involved in a comprehensive project to investigate a unique radiation sensing and energy conversion technology with applications for in-situ monitoring of spent nuclear fuel (SNF) during cask transport and storage. The technology makes use of the gamma photons emitted from the SNF as an inherent power source for driving a GPS-class transceiver that has the ability to verify the position and contents of the SNF cask. The power conversion process, which converts the gamma photon energy into electrical power, is based on a variation of the successful dye-sensitized solar cell (DSSC) design developed by Konarka Technologies, Inc. (KTI). In particular, the focus of the current research is to make direct use of the high-energy gamma photons emitted from SNF, coupled with a scintillator material to convert some of the incident gamma photons into photons having wavelengths within the visible region of the electromagnetic spectrum. The high-energy gammas from the SNF will generate some power directly via Compton scattering and the photoelectric effect, and the generated visible photons output from the scintillator material can also be converted to electrical power in a manner similar to that of a standard solar cell. Upon successful implementation of an energy conversion device based on this new gammavoltaic principle, this inherent power source could then be utilized within SNF storage casks to drive a tamper-proof, low-power, electronic detection/security monitoring system for the spent fuel. The current project has addressed several aspects associated with this new energy conversion concept, including the development of a base conceptual design for an inherent gamma-induced power conversion unit for SNF monitoring, the characterization of the radiation environment that can be expected within a typical SNF storage system, the initial evaluation of Konarka's base solar cell design, the design and fabrication of a range of new cell materials and geometries at Konarka's manufacturing facilities, and the irradiation testing and evaluation of these new cell designs within the UML Radiation Laboratory. The primary focus of all this work was to establish the proof of concept of the basic gammavoltaic principle using a new class of dye-sensitized photon converter (DSPC) materials based on KTI's original DSSC design. In achieving this goal, this report clearly establishes the viability of the basic gammavoltaic energy conversion concept, yet it also identifies a set of challenges that must be met for practical implementation of this new technology.
NASA Astrophysics Data System (ADS)
Anton, S. R.; Taylor, S. G.; Raby, E. Y.; Farinholt, K. M.
2013-03-01
With a global interest in the development of clean, renewable energy, wind energy has seen steady growth over the past several years. Advances in wind turbine technology bring larger, more complex turbines and wind farms. An important issue in the development of these complex systems is the ability to monitor the state of each turbine in an effort to improve the efficiency and power generation. Wireless sensor nodes can be used to interrogate the current state and health of wind turbine structures; however, a drawback of most current wireless sensor technology is their reliance on batteries for power. Energy harvesting solutions present the ability to create autonomous power sources for small, low-power electronics through the scavenging of ambient energy; however, most conventional energy harvesting systems employ a single mode of energy conversion, and thus are highly susceptible to variations in the ambient energy. In this work, a multi-source energy harvesting system is developed to power embedded electronics for wind turbine applications in which energy can be scavenged simultaneously from several ambient energy sources. Field testing is performed on a full-size, residential scale wind turbine where both vibration and solar energy harvesting systems are utilized to power wireless sensing systems. Two wireless sensors are investigated, including the wireless impedance device (WID) sensor node, developed at Los Alamos National Laboratory (LANL), and an ultra-low power RF system-on-chip board that is the basis for an embedded wireless accelerometer node currently under development at LANL. Results indicate the ability of the multi-source harvester to successfully power both sensors.
Energy harvesting for self-powered nanosystems
Zhong Lin Wang
2008-01-01
In this article, an introduction is presented about the energy harvesting technologies that have potential for powering nanosystems.\\u000a Our discussion mainly focuses on the approaches other than the well-known solar cell and thermoelectrics. We mainly introduce\\u000a the piezoelectric nanogenerators developed using aligned ZnO nanowire arrays. This is a potential technology for converting\\u000a mechanical movement energy (such as body movement, muscle
Zhang, Zhedong; Wang, Jin
2015-04-01
Recently, the quantum nature in the energy transport in solar cells and light-harvesting complexes has attracted much attention as being triggered by the experimental observations. We model the light-harvesting complex (i.e., PEB50 dimer) as a quantum heat engine (QHE) and study the effect of the undamped intramolecule vibrational modes on the coherent energy-transfer process and quantum transport. We find that the exciton-vibration interaction has nontrivial contribution to the promotion of quantum yield as well as transport properties of the QHE at steady state by enhancing the quantum coherence quantified by entanglement entropy. The perfect quantum yield over 90% has been obtained, with the exciton-vibration coupling. We attribute these improvements to the renormalization of the electronic couplings effectively induced by exciton-vibration interaction and the subsequent delocalization of excitons. Finally, we demonstrate that the thermal relaxation and dephasing can help the excitation energy transfer in the PEB50 dimer. PMID:25776946
NASA Astrophysics Data System (ADS)
Zhang, Zhedong; Wang, Jin
2015-05-01
Recently the quantum nature in the energy transport in solar cell and light-harvesting complexes have attracted much attention, by being triggered by the experimental observations. We model the light-harvesting complex (i.e., PEB50 dimer) as a quantum heat engine and study the effect of the undamped intra-molecule vibrational modes on the coherent energy transfer and quantum transport. Possibly this system can be artificially simulated by atom-cavity setup. We find that the exciton-vibration interaction has non-trivial contribution to the promotion of quantum yield as well as transport properties of the quantum heat engine at steady state, by enhancing the quantum coherence quantified by entanglement entropy. The perfect quantum yield over 90% has been obtained, assisted by exciton-vibration coupling. We attribute these improvements to the renormalization of the electronic couplings effectively induced by exciton-vibration interaction and the subsequent delocalization of excitons. Finally we demonstrate that the thermal relaxation and dephasing can help the excitation energy transfer in PEB50 dimer.
NASA Astrophysics Data System (ADS)
Hopkins, John B.; Xu, Xiaobing; Lingle, Robert, Jr.; Zhu, Huiping; Yu, Soo-chang
1991-06-01
We have directly observed hot vibrations in photoexcited deoxyhemoglobin. The data quantitatively indicate a heme vibrational temperature of 20 K above room temperature within the time sampled by an 8ps laser pulse. The slow component of vibrational relaxation occurs with a rate constant of (2.5ps)1. Similar dynamics are observed in oxyhemoglobin. The initial stages of recombmation of 02 with the heme following photodissociation of oxyhemoglobin are observed in the transient vibrational spectrum. Contrary to previous work, we do not observe the influence of protein dynamics on 02 recombination.
NASA Astrophysics Data System (ADS)
Zhang, Yi; Sun, Weiguo; Fu, Jia; Fan, Qunchao; Ma, Jie; Xiao, Liantuan; Jia, Suotang; Feng, Hao; Li, Huidong
2014-01-01
The algebraic method (AM) proposed by Sun et al. is improved to be a variational AM (VAM) to offset the possible experimental errors and to adapt to the individual energy expansion nature of different molecular systems. The VAM is used to study the full vibrational spectra {E?} and the dissociation energies De of 4HeH+-X1?+, 7Li2-13?g, Na2-C1?u, NaK-71?, Cs2-B1?u and 79Br2-?1g(3P2) diatomic electronic states. The results not only precisely reproduce all known experimental vibrational energies, but also predict correct dissociation energies and all unknown high-lying levels that may not be given by the original AM or other numerical methods or experimental methods. The analyses and the skill suggested here might be useful for other numerical simulations and theoretical fittings using known data that may carry inevitable errors.
A theoretical study on the mechanism of electronic to vibrational energy transfer in Hg/3P/ + CO
NASA Technical Reports Server (NTRS)
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.
W. Wang; S. Rakheja; P.-É. Boileau
2006-01-01
The power absorption characteristics of 27 male and female seated subjects, exposed to vertical vibration in the 0.540Hz frequency range, are characterized under different sitting postures. The measurements are performed for a total of 36 different sitting postural configurations realized through variations in hands position (in lap and on steering wheel), seat heights (510, 460 and 410mm), and seat design
Mohanty, Saraju P.
Energy and Transient Power MinimizationEnergy and Transient Power Minimization using Multiple Clocking Saraju P. Mohanty Dept. of Computer Science and Engineering University of South Florida smohanty Architecture · Datapath Scheduling Schemes for Power Minimization · Image Watermarking Chip Design
Lattice vibrations in the Frenkel-Kontorova model. I. phonon dispersion, number density, and energy
Meng, Qingping; Wu, Lijun; Welch, David O.; Zhu, Yimei
2015-06-01
We studied the lattice vibrations of two inter-penetrating atomic sublattices via the Frenkel-Kontorova (FK) model of a linear chain of harmonically interacting atoms subjected to an on-site potential, using the technique of thermodynamic Green's functions based on quantum field-theoretical methods. General expressions were deduced for the phonon frequency-wave-vector dispersion relations, number density, and energy of the FK model system. As the application of the theory, we investigated in detail cases of linear chains with various periods of the on-site potential of the FK model. Some unusual but interesting features for different amplitudes of the on-site potential of the FK modelmore »are discussed. In the commensurate structure, the phonon spectrum always starts at a finite frequency, and the gaps of the spectrum are true ones with a zero density of modes. In the incommensurate structure, the phonon spectrum starts from zero frequency, but at a non-zero wave vector; there are some modes inside these gap regions, but their density is very low. In our approximation, the energy of a higher-order commensurate state of the one-dimensional system at a finite temperature may become indefinitely close to the energy of an incommensurate state. This finding implies that the higher-order incommensurate-commensurate transitions are continuous ones and that the phase transition may exhibit a devil's staircase behavior at a finite temperature.« less
Lattice vibrations in the Frenkel-Kontorova model. I. Phonon dispersion, number density, and energy
NASA Astrophysics Data System (ADS)
Meng, Qingping; Wu, Lijun; Welch, David O.; Zhu, Yimei
2015-06-01
We studied the lattice vibrations of two interpenetrating atomic sublattices via the Frenkel-Kontorova (FK) model of a linear chain of harmonically interacting atoms subjected to an on-site potential using the technique of thermodynamic Green's functions based on quantum field-theoretical methods. General expressions were deduced for the phonon frequency-wave-vector dispersion relations, number density, and energy of the FK model system. As the application of the theory, we investigated in detail cases of linear chains with various periods of the on-site potential of the FK model. Some unusual but interesting features for different amplitudes of the on-site potential of the FK model are discussed. In the commensurate structure, the phonon spectrum always starts at a finite frequency, and the gaps of the spectrum are true ones with a zero density of modes. In the incommensurate structure, the phonon spectrum starts from zero frequency, but at a nonzero wave vector; there are some modes inside these gap regions, but their density is very low. In our approximation, the energy of a higher-order commensurate state of the one-dimensional system at a finite temperature may become indefinitely close to the energy of an incommensurate state. This finding implies that the higher-order incommensurate-commensurate transitions are continuous ones and that the phase transition may exhibit a "devil's staircase" behavior at a finite temperature.
Power and Energy Engineering Workforce Collaborative
reliant on technology Convergence of communications, computing and energy systems Changing societal to the bulk power system reliability, exacerbated by the lack of new recruits entering the field. Recognition · Top three career path influencers: 1.Interesting career 2.Opportunity to solve significant societal
Science of NHL Hockey: Work, Energy & Power
NSDL National Science Digital Library
NBC Learn
2010-10-07
The slapshot is one of the fastest projectiles in team sports. In order to generate a 100 mile-per-hour (160 kph) slapper, NHL players depend on three important physics concepts: work, energy and power. "Science of NHL Hockey" is a 10-part video series funded by the National Science Foundation and produced in partnership with the National Hockey League.
ENERGY, POWER AND ENVIRONMENT (Environmental Analytical Chemistry)
Sherrill, David
-economic impact. In order to understand these issues, basics of nuclear physics, chemistry, radiochemistryENERGY, POWER AND ENVIRONMENT (Environmental Analytical Chemistry) CHEM 6284/CHEM 4803 Fall 2014 3 credit hours J. (Art) Janata jiri.janata@chemistry.gatech.edu; 404 894 4828 Since the dawn of history
Tower Power: Producing Fuels from Solar Energy
ERIC Educational Resources Information Center
Antal, M. J., Jr.
1976-01-01
This article examines the use of power tower technologies for the production of synthetic fuels. This process overcomes the limitations of other processes by using a solar furnace to drive endothermic fuel producing reactions and the resulting fuels serve as a medium for storing solar energy. (BT)
NASA Astrophysics Data System (ADS)
Shank, Alex; Wang, Yimin; Kaledin, Alexey; Braams, Bastiaan J.; Bowman, Joel M.
2009-04-01
We report three modifications to recent ab initio, full-dimensional potential energy surfaces (PESs) for the water dimer [X. Huang et al., J. Chem. Phys. 128, 034312 (2008)]. The first modification is a refit of ab initio electronic energies to produce an accurate dissociation energy De. The second modification adds replacing the water monomer component of the PES with a spectroscopically accurate one and the third modification produces a hybrid potential that goes smoothly in the asymptotic region to the flexible, Thole-type model potential, version 3 dimer potential (denoted TTM3-F) [G. S. Fanourgakis and S. S. Xantheas, J. Chem. Phys. 128, 074506 (2008)]. The rigorous D0 for these PESs, obtained using diffusion Monte Carlo calculations of the dimer zero-point energy, and an accurate zero-point energy of the monomer, range from 12.5 to 13.2 kJ/mol (2.99-3.15 kcal/mol), with the latter being the suggested benchmark value. For TTM3-F D0 equals 16.1 kJ/mol. Vibrational calculations of monomer fundamental energies using the code MULTIMODE are reported for these PESs and the TTM3-F PES and compared to experiment. A classical molecular dynamics simulation of the infrared spectra of the water dimer and deuterated water dimer at 300 K are also reported using the ab initio dipole moment surface reported previously [X. Huang, B. J. Braams, and J. M. Bowman, J. Phys. Chem. A 110, 445 (2006)].
NASA Technical Reports Server (NTRS)
Green, C.
1971-01-01
Guidelines of the methods and applications used in vibration technology at the MSFC are presented. The purpose of the guidelines is to provide a practical tool for coordination and understanding between industry and government groups concerned with vibration of systems and equipments. Topics covered include measuring, reducing, analyzing, and methods for obtaining simulated environments and formulating vibration specifications. Methods for vibration and shock testing, theoretical aspects of data processing, vibration response analysis, and techniques of designing for vibration are also presented.
Nuclear Power and the World's Energy Requirements
V. Castellano; R. F. Evans; J. Dunning-Davies
2004-06-10
The global requirements for energy are increasing rapidly as the global population increases and the under-developed nations become more advanced. The traditional fuels used in their traditional ways will become increasingly unable to meet the demand. The need for a review of the energy sources available is paramount, although the subsequent need to develop a realistic strategy to deal with all local and global energy requirements is almost as important. Here attention will be restricted to examining some of the claims and problems of using nuclear power to attempt to solve this major question.
Watanabe, Shinji; Usuda, Shin-Ya; Kohguchi, Hiroshi; Yamasaki, Katsuyoshi
2010-01-21
The vibrational levels of O2(X3Sigma(g)-) generated in the ultraviolet photolysis of O3 at 266 nm were detected via laser-induced fluorescence (LIF) of the B3Sigma(u)- - X3Sigma(g)- system. The nascent vibrational energy distributions of O2(X3Sigma(g)-, nu = 6-13) have been measured by two different methods. One is a kinetic analysis based on the originally developed integrated profiles method (IPM). The time-resolved LIF of a single vibrational level has been recorded in the presence of CF4 or O2 as a relaxation partner. The IPM analysis of the profiles gave the relative detectabilities of adjacent vibrational levels, and the initial relative populations of the vibrational levels have been determined from the intensities of LIF subsequent to the photolysis. The other is the analysis of the area intensities of the LIF of the vibrational levels of interest. The rotational levels with the identical quantum numbers of different vibrational levels in the X3Sigma(g)- state were excited to a common vibrational level nu' = 0 in the B3Sigma(u)- state. Correction for the LIF intensities with the Franck-Condon factors was made, and the initial relative populations have been obtained. The two different methods have given similar nascent vibrational energy distributions, and comparison to the previous reports has been made. PMID:19919074
SUPPORTING SOLAR ENERGY DEVELOPMENT THROUGH GREEN POWER MARKETS Blair Swezey
SUPPORTING SOLAR ENERGY DEVELOPMENT THROUGH GREEN POWER MARKETS Blair Swezey Lori Bird Christy or from a competitive green power supplier. Solar power from both utility-scale and small, distributed in part through green power marketing. This paper describes the use of solar energy in green power
Low-energy vibrational excitations in carbon nanotubes studied by heat capacity
NASA Astrophysics Data System (ADS)
Lasjaunias, J. C.; Biljakovic, K.; Monceau, P.; Sauvajol, J. L.
2003-09-01
We present low-temperature heat capacity measurements performed on two different kinds of single-walled carbon nanotube bundles which essentially differ in their mean number of tubes (NT) per bundle. For temperatures below a few kelvin, the vibrational heat capacity can be analysed as the sum of two contributions. The first one is a regular T3 phononic one, characteristic of the three-dimensional (3D) elastic character of the bundle for long-wavelength phonons. A crossover to a lower effective dimensionality appears at a few kelvin. From the 3D contribution, we estimate a mean sound velocity, and hence a mean shear modulus of the bundle. The difference in amplitude of the acoustic term and in the crossover temperature between the two samples is ascribed to the different bundle topology (i.e. NT). The second contribution, of similar amplitude in both kinds of samples, shows a peculiar power law Talpha variation (alpha < 1) indicative of localized excitations, very probably due to intrinsic structural defects of the nanotubes.
Unbundling of electric power and energy services
Keith, D.M. [Keith and Associates, Ltd., Stilwell, KS (United States); Lewis, B.R. [UtiliCorp United Inc., Kansas City, MO (United States)
1996-12-31
The world-wide movement to restructure the electric and power and energy industry is now well underway in the United States. The most recent thrust came this year, with the Federal Energy Regulatory Commission`s (FERC`s) issuance on April 24th of new regulations designed to open the interconnected transmission grid to all qualified wholesale users. Other movements have been in the many forms of earlier statutes and regulations promulgated in 1978 to make more efficient use of fuels burned; utility diversification efforts; utility creation of affiliate and subsidiary organizations and operations; introduction into the market of private non-utility power developers; utilities obtaining clearance from the Securities and Exchange Commission (SEC) to venture in international markets; massive mergers and acquisitions; bankruptcies; the entry into the market of nonutility power marketers and brokers, including entities from the gas and securities industries not previously involved in the electric power and energy industry; additional congressional consideration of outright repeal of Holding Company legislation dating back to 1935; some states entering into an era of abandoning the control past in favor of complete re-regulation of the industry on the basis of performance; the coming of Independent System Operators (ISO`s), Regional Transmission Groups (RTG`s), and the possible coming of Capacity Reservation Tariffs (CRT`s), to name a few.
NASA Astrophysics Data System (ADS)
Green, David; Hammond, Sarah; Keske, John; Pate, Brooks H.
1999-01-01
The asymmetric -CH2(F) stretch spectrum of 2-fluoroethanol near 2980 cm-1 has been rotationally assigned using microwave-infrared double-resonance spectroscopy methods in an electric-resonance optothermal molecular-beam spectrometer. The eigenstate-resolved infrared spectrum shows the effects of intramolecular vibrational energy redistribution (IVR) through the fragmentation of each rotational level of the vibrationally excited state into a set of transitions. From the spectrum we determine the IVR lifetime of the asymmetric -CH2(F) stretch to be 275 ps. The measured vibrational state density at 2980 cm-1 is 44 states/cm-1, and matches the value for the total state density obtained from a direct count. This agreement suggests that vibrational states of both the Gg' and Tt conformers are coupled by the intramolecular dynamics. From measurements of the c-type pure rotational transitions of the Gg' conformer we determine that the tunneling splitting for the Gg' ground state is less than 35 kHz. The infrared spectrum is characterized by a large number of closely spaced infrared transitions. The clustering of vibrational energy levels is attributed to the weak interaction between the degenerate Gg' and nondegenerate Tt vibrational states. This lifting of the effective Gg' parity degeneracy is quantitatively investigated through the shape of the nearest-neighbor level spacing distribution. From this analysis we estimate that the isomerization lifetime for the Gg' conformer of 2-fluoroethanol is 2 ns.
Homayoon, Zahra; Bowman, Joel M
2014-10-28
A semi-global, permutationally invariant potential energy surface for NO3 is constructed from a subset of roughly 5000 Multi-State CASPT2 calculations (MS-CAS(17e,13o)PT2/aug-cc-pVTZ) reported by Morokuma and co-workers [H. Xiao, S. Maeda, and K. Morokuma, J. Chem. Theory Comput. 8, 2600 (2012)]. The PES, with empirical adjustments to modify the energies of two fundamentals and a hot-band transition, is used in full-dimensional vibrational self-consistent field/virtual state configuration interaction calculations using the code MULTIMODE. Vibrational energies and assignments are given for the fundamentals and low-lying combination states, including two that have been the focus of some controversy. Energies of a number of overtone and combinations are shown to be in good agreement with experiment and previous calculations using a model vibronic Hamiltonian [C. S. Simmons, T. Ichino, and J. F. Stanton, J. Phys. Chem. Lett. 3, 1946 (2012)]. Notably, the fundamental v3 is calculated to be at 1099 cm(-1) in accord with the prediction from the vibronic analysis, although roughly 30 cm(-1) higher. The state at 1493 cm(-1) is assigned as v3 + v4, which is also in agreement with the vibronic analysis and some experiments. Vibrational energies for (15)NO3 are also presented and these are also in good agreement with experiment. PMID:25362265
Electromagnetic harvester for lateral vibration in rotating machines
NASA Astrophysics Data System (ADS)
de Araujo, Marcus Vinķcius Vitoratti; Nicoletti, Rodrigo
2015-02-01
Energy harvesters are devices that convert mechanical energy, usually vibration, into electrical energy that can be used to supply low power circuits (e.g. sensors). In this work, an energy harvester is designed for converting the mechanical energy of the lateral vibrations of shafts into electrical energy. For that, permanent magnets are mounted in the shaft and coils are mounted in a fixed structure. A configuration analysis is performed to find the appropriated polarization of the magnets and orientation of the coils in order to have electromagnetic induction without resisting torque on the shaft. Experimental tests are done for different electrical configurations of the coils: independent, in series and, in parallel. The results show that more electric power is induced when the coils are connected in series, and vibration reduction is more evident when the coils are connected independently.
Yuan, W.; Tosa, R.; Chao, K.-J.; Rabinovitch, B.S.
1981-10-20
The study of varying molecular structure on the efficiency of vibrational energy transfer between molecules and a hot surface has been extended to the pair, cyclopropane/cyclopropane-d6. The latter is less efficient in energy loss, as corresponds to the greater vibrational eigenstate density. Conversely, the probability of energy up-transitions is enhanced; in thermal low pressure unimolecular reactions this corresponds to the inverse statistical weight secondary isotope effect.
Energy Storage Applications in Power Systems with Renewable Energy Generation
NASA Astrophysics Data System (ADS)
Ghofrani, Mahmoud
In this dissertation, we propose new operational and planning methodologies for power systems with renewable energy sources. A probabilistic optimal power flow (POPF) is developed to model wind power variations and evaluate the power system operation with intermittent renewable energy generation. The methodology is used to calculate the operating and ramping reserves that are required to compensate for power system uncertainties. Distributed wind generation is introduced as an operational scheme to take advantage of the spatial diversity of renewable energy resources and reduce wind power fluctuations using low or uncorrelated wind farms. The POPF is demonstrated using the IEEE 24-bus system where the proposed operational scheme reduces the operating and ramping reserve requirements and operation and congestion cost of the system as compared to operational practices available in the literature. A stochastic operational-planning framework is also proposed to adequately size, optimally place and schedule storage units within power systems with high wind penetrations. The method is used for different applications of energy storage systems for renewable energy integration. These applications include market-based opportunities such as renewable energy time-shift, renewable capacity firming, and transmission and distribution upgrade deferral in the form of revenue or reduced cost and storage-related societal benefits such as integration of more renewables, reduced emissions and improved utilization of grid assets. A power-pool model which incorporates the one-sided auction market into POPF is developed. The model considers storage units as market participants submitting hourly price bids in the form of marginal costs. This provides an accurate market-clearing process as compared to the 'price-taker' analysis available in the literature where the effects of large-scale storage units on the market-clearing prices are neglected. Different case studies are provided to demonstrate our operational-planning framework and economic justification for different storage applications. A new reliability model is proposed for security and adequacy assessment of power networks containing renewable resources and energy storage systems. The proposed model is used in combination with the operational-planning framework to enhance the reliability and operability of wind integration. The proposed framework optimally utilizes the storage capacity for reliability applications of wind integration. This is essential for justification of storage deployment within regulated utilities where the absence of market opportunities limits the economic advantage of storage technologies over gas-fired generators. A control strategy is also proposed to achieve the maximum reliability using energy storage systems. A cost-benefit analysis compares storage technologies and conventional alternatives to reliably and efficiently integrate different wind penetrations and determines the most economical design. Our simulation results demonstrate the necessity of optimal storage placement for different wind applications. This dissertation also proposes a new stochastic framework to optimally charge and discharge electric vehicles (EVs) to mitigate the effects of wind power uncertainties. Vehicle-to-grid (V2G) service for hedging against wind power imbalances is introduced as a novel application for EVs. This application enhances the predictability of wind power and reduces the power imbalances between the scheduled output and actual power. An Auto Regressive Moving Average (ARMA) wind speed model is developed to forecast the wind power output. Driving patterns of EVs are stochastically modeled and the EVs are clustered in the fleets of similar daily driving patterns. Monte Carlo Simulation (MCS) simulates the system behavior by generating samples of system states using the wind ARMA model and EVs driving patterns. A Genetic Algorithm (GA) is used in combination with MCS to optimally coordinate the EV fleets for their V2G services and minimize the penalty cost associated wit
Blancafort, Lluis; Gatti, Fabien; Meyer, Hans-Dieter
2011-10-07
The double bond photoisomerization of fulvene has been studied with quantum dynamics calculations using the multi-configuration time-dependent Hartree method. Fulvene is a test case to develop optical control strategies based on the knowledge of the excited state decay mechanism. The decay takes place on a time scale of several hundred femtoseconds, and the potential energy surface is centered around a conical intersection seam between the ground and excited state. The competition between unreactive decay and photoisomerization depends on the region of the seam accessed during the decay. The dynamics are carried out on a four-dimensional model surface, parametrized from complete active space self-consistent field calculations, that captures the main features of the seam (energy and locus of the seam and associated branching space vectors). Wave packet propagations initiated by single laser pulses of 5-25 fs duration and 1.85-4 eV excitation energy show the principal characteristics of the first 150 fs of the photodynamics. Initially, the excitation energy is transferred to a bond stretching mode that leads the wave packet to the seam, inducing the regeneration of the reactant. The photoisomerization starts after the vibrational energy has flowed from the bond stretching to the torsional mode. In our propagations, intramolecular energy redistribution (IVR) is accelerated for higher excess energies along the bond stretch mode. Thus, the competition between unreactive decay and isomerization depends on the rate of IVR between the bond stretch and torsion coordinates, which in turn depends on the excitation energy. These results set the ground for the development of future optical control strategies.
NASA Astrophysics Data System (ADS)
Rastegar, J.; Murray, R.
2010-04-01
A novel class of piezoelectric-based energy-harvesting power sources has been developed for gun-fired munitions and similar high-G applications. The power sources are designed to harvest energy primarily from the firing acceleration, but from in-flight vibratory motions as well. During the firing, a spring-mass element reacts to the axial acceleration, deforming and storing mechanical potential energy. After the projectile has exited the muzzle, the spring-mass element is free to vibrate, and the energy of the vibration is harvested using piezoelectric materials. These piezoelectric-based devices have been shown to produce enough electrical energy for many applications such as fuzing, and are able to eliminate the need for chemical batteries in many applications. When employed in fuzing applications, the developed power sources have the added advantage of providing augmented safety, since the fuzing electronics are powered only after the projectile has exited the muzzle and traveled a safe distance from the weapon platform. An overview of the development of these novel power sources is provided, especially designing and packaging for the high-G environment. Extensive laboratory and field testing has been performed on various prototypes; the methods and results of these experiments are presented. In addition to presenting the development and validation of this technology, methods for integrating the generators into different classes of projectiles are discussed along with strategies for manufacturing. This technology is currently validated to the extent that prototype devices have been successfully fired on-board actual gun-fired projectiles, demonstrating survivability and indicating performance. Strategies for designing the devices for a particular round and transitioning to commercialization are also discussed.
Li, Peng; Jin, Feng; Yang, Jiashi
2013-10-01
We propose a new structure for piezoelectric energy harvesters. It consists of an elastic beam with two pairs of piezoelectric films operating with the fundamental flexural modes in perpendicular directions. A one-dimensional model is developed and used to analyze the proposed structure. The output power density is calculated and examined. Results show that, with simultaneous flexural motions in two perpendicular directions, the output power has two peaks close to each other resulting from the two fundamental flexural resonances. The distance between the two peaks can be adjusted through design to make the two peaks merge into one wide peak. Hence, the frequency bandwidth through which energy can be harvested is roughly doubled when compared with conventional beam bimorph energy harvesters operating with flexural motion in one direction and one resonance only. PMID:24081271
Designing and Managing Datacenters Powered by Renewable Energy
Designing and Managing Datacenters Powered by Renewable Energy “I~nigo Goiri, William Katsak, Kien,wkatsak,lekien,tdnguyen,ricardob}@cs.rutgers.edu Abstract On-site renewable energy has the potential to reduce data- centers' carbon footprint and power/energy" datacenters, i.e. datacenters partially or completely powered by renewables such as solar or wind energy
Power Supplies for High Energy Particle Accelerators
NASA Astrophysics Data System (ADS)
Dey, Pranab Kumar
2015-05-01
The on-going research and the development projects with Large Hadron Collider at CERN, Geneva, Switzerland has generated enormous enthusiasm and interest amongst all to know about the ultimate findings on `God's Particle'. This paper has made an attempt to unfold the power supply requirements and the methodology adopted to provide the stringent demand of such high energy particle accelerators during the initial stages of the search for the ultimate particles. An attempt has also been made to highlight the present status on the requirement of power supplies in some high energy accelerators with a view that, precautionary measures can be drawn during design and development from earlier experience which will be of help for the proposed third generation synchrotron to be installed in India at a huge cost.
NASA Astrophysics Data System (ADS)
Fréchette, Luc G.
2007-09-01
Energy is a sector of paramount importance over the coming decades if we are to ensure sustainable development that respects our environment. The research and development of novel approaches to convert available energy into usable forms using micro and nanotechnologies can contribute towards this goal and meet the growing need for power in small scale portable applications. The dominant power sources for handheld and other portable electronics are currently primary and rechargeable batteries. Their limited energy density and adverse effects on the environment upon disposal suggest that alternative approaches need to be explored. This special issue will showcase some of the leading work in this area, initially presented at PowerMEMS 2006, the 6th International Workshop on Micro and Nanotechnologies for Power Generation and Energy Conversion Applications. Power MEMS are defined as microsystems for electrical power generation and other energy conversion applications, including propulsion and cooling. The range of power MEMS technologies includes micro thermodynamic machines, such as microturbines, miniature internal combustion engines and micro-coolers; solid-state direct energy conversion, such as thermoelectric and photovoltaic microstructures; micro electrochemical devices, such as micro fuel cells and nanostructure batteries; vibration energy harvesting devices, such as piezoelectric, magnetic or electrostatic micro generators, as well as micro thrusters and rocket engines for propulsion. These can either be driven by scavenging thermal, mechanical or solar energy from the environment, or from a stored energy source, such as chemical fuel or radioactive material. The unique scope leads to unique challenges in the development of power MEMS, ranging from the integration of novel materials to the efficient small scale implementation of energy conversion principles. In this special issue, Mitcheson et al provide a comparative assessment of three inertial vibration energy harvesting approaches. Technologies and approaches for micro heat engines are shared, ranging from a complete microsystem for thermal energy harvesting (Cho et al) to core bearing and microturbomachinery technologies for rotating micro heat engines (Waits et al, Nakajima et al). Electrochemical microsystems are also presented, based on methanol as fuel (Morse et al), as well as novel micro and nanofabrication approaches (Chu et al). Fuel cell microsystems with integrated hydrogen generation approaches are also investigated by Peterson et al and Varady et al, illustrating the benefits and challenges of miniaturizing complete power sources. Finally, biological micro fuel cells that leverage the principles found in nature are presented, in contrast to chemical fuel cells (Chen et al, Morishima et al). We hope that this work will inspire others to pursue innovative research and development activities in the area of power MEMS, and consequently contribute to addressing our energy challenges for the 21st century.
Introducing The Captain Power and The Power Quiz. Energy Education Programs.
ERIC Educational Resources Information Center
Niedermeyer, F.; Roberson, E.
Two energy education programs are described in this informational brochure. Both "Captain Power" for second graders and "Power Quiz" for fifth graders are designed to teach energy concepts and to help students develop and use conservation skills. Program outcomes focus on energy concepts, types of energy, energy costs, energy needs, and
Electric Power From Ambient Energy Sources
DeSteese, John G.; Hammerstrom, Donald J.; Schienbein, Lawrence A.
2000-10-03
This report summarizes research on opportunities to produce electric power from ambient sources as an alternative to using portable battery packs or hydrocarbon-fueled systems in remote areas. The work was an activity in the Advanced Concepts Project conducted by Pacific Northwest National Laboratory (PNNL) for the Office of Research and Development in the U.S. Department of Energy Office of Nonproliferation and National Security.
A. J. C. Varandas; J. M. C. Marques
1994-01-01
A method for calculating quasiclassical trajectories on potential energy surfaces defined using a sequence of model quadratic surfaces (QCT\\/GH) is suggested, and tested for atomdiatom collisions against the traditional quasiclassical trajectory approach. A simple model is also suggested to constrain the classical energy of a bound vibrational mode to be greater than a specified amount, namely, its zero-point energy value.
Vogt, Jochen; Huck, Christian; Neubrech, Frank; Toma, Andrea; Gerbert, David; Pucci, Annemarie
2015-09-01
We report on the impact of the differing spectral near- and far-field properties of resonantly excited gold nanoantennas on the vibrational signal enhancement in surface-enhanced infrared absorption (SEIRA). The knowledge on both spectral characteristics is of considerable importance for the optimization of plasmonic nanostructures for surface-enhanced spectroscopy techniques. From infrared micro-spectroscopic measurements, we simultaneously obtain spectral information on the plasmonic far-field response and, via SEIRA spectroscopy of a test molecule, on the near-field enhancement. The molecular test layer of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) was deposited on the surface of gold nanoantennas with different lengths and thus different far-field resonance energies. We carefully studied the Fano-type vibrational lines in a broad spectral window, in particular, how the various vibrational signals are enhanced in relation to the ratio of the far-field plasmonic resonance and the molecular vibrational frequencies. As a detailed experimental proof of former simulation studies, we show the clearly red-shifted maximum SEIRA enhancement compared to the far-field resonance. PMID:25516198
Schmuttenmaer, C.A.; Cohen, R.C.; Loeser, J.G.; Saykally, R.J. (Department of Chemistry, University of California, and Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (USA))
1991-07-01
Two new intermolecular vibration--rotation-tunneling (VRT) bands of Ar--NH{sub 3} have been measured using tunable far infrared laser spectroscopy. We have unambiguously assigned these and a previously measured FIR band (Gwo {ital et} {ital al}., Mol. Phys. {bold 71}, 453 (1990)) as {Pi}(1{sub 0}, {ital n}=0){l arrow}{Sigma}(0{sub 0}, {ital n}=0), {Sigma}(1{sub 0}, {ital n}=0){l arrow}{Sigma}(0{sub 0}, {ital n}=0), and {Sigma}(0{sub 0}, {ital n}=1){l arrow}{Sigma}(0{sub 0}, {ital n}=0). The three upper states of these are found to be strongly mixed by anisotropy and Coriolis effects. A simultaneous least squares fit of all transitions has yielded vibrational frequencies, rotational and centrifugal distortion constants, and a Coriolis parameter as well as quadrupole hyperfine coupling constants for the upper states. An effective angular potential energy surface for Ar--NH{sub 3} in its lowest stretching state has been determined from these data, after explicitly accounting for the effects of bend stretch interactions. Features of the surface include a global minimum at the near T-shaped configuration ({theta}=90{degree}), a 30 cm{sup {minus}1} to 60 cm{sup {minus}1} barrier to rotation at {theta}=180{degree} (or 0{degree}), and a very low barrier or possibly a secondary minimum at {theta}=0{degree} (or 180{degree}). Both attractive and repulsive interactions are shown to contribute significantly to the anisotropic forces in the complex. Comparison with {ital ab} {ital initio} calculations are presented.
NASA Astrophysics Data System (ADS)
Sapozhnikov, B. G.; Gorbunova, A. M.; Zelenkova, Yu. O.; Sapozhnikov, G. B.; Shiryaeva, N. P.
2014-06-01
We present experimental data on the coefficients of heat and mass transfer for freely floating bodies simulating fragments of cladding and large conglomerates of fuel, as well as on the local coefficients of heat and mass transfer over the bed height, which point to high intensity of heat and mass transfer processes that take place in the elements of vibration apparatuses intended for subjecting spent fuel from nuclear power plants to oxidative recrystallization.
Y. Aldien; P. Marcotte; S. Rakheja; P.-É. Boileau
2006-01-01
The effect of handle size and hand forces, on the power absorbed by the handarm system, was investigated in a laboratory study using seven healthy male subjects exposed to two levels of broadband random vibration in the 81000Hz frequency range along the zh-axis. The measurements were performed with three instrumented cylindrical handles of different diameter (30, 40 and 50mm). The
Reliability of potassium ion electret in silicon oxide for vibrational energy harvester applications
NASA Astrophysics Data System (ADS)
Misawa, Kensuke; Sugiyama, Tatsuhiko; Hashiguchi, Gen; Toshiyoshi, Hiroshi
2015-06-01
In this paper, we report on the long-term reliability of potassium ion electret included in a thermally grown silicon oxide. The electret in this work is used in a microelectromechanical systems (MEMS) energy harvester to generate electrical current from mechanical vibration. A spring-mass system similar to a comb-drive electrostatic actuator is developed by silicon micromachining, and the surface is oxidized by wet-oxidation through a potassium hydroxide bubbler, thereby including potassium atoms at a high concentration. The potassium is then electrically polarized by an applied voltage of 150 V at 650 °C for 5 min. Degradation of the stored polarization potential is monitored in a vacuum of 1 × 10?3 Pa at elevated temperatures of 350, 400, and 450 °C. The time needed to cause a ?1 dB decay of the potential is used as the lifetime of the electret, and the Arrhenius extrapolation plot suggested a life time of more than 400 years at 25 °C.
NASA Astrophysics Data System (ADS)
Denny, R. Aldrin; Bagchi, Biman; Barbara, Paul F.
2001-10-01
The existing theoretical formulations of electron transfer reactions (ETR) neglect the effects of vibrational energy relaxation (VER) and do not include higher vibrational states in both the reactant and the product surfaces. Both of these aspects can be important for photo-induced electron transfer reactions, particularly for those which are in the Marcus inverted regime. In this article, a theoretical formulation is presented which describes the two aspects. The formalism requires an extension of the hybrid model introduced earlier by Barbara et al. [Science 256, 975 (1992)]. We model a general electron transfer as a two-surface reaction where overlap between the vibrational levels of the two surfaces create multiple, broad reaction windows. The strength and the accessibility of each window is determined by many factors. We find that when VER and reverse transfer are present, the time dependence of the survival probability of the reactant differs significantly (from the case when they are assumed to be absent) for a large range of values of the solvent reorganization energy (?X), quantum mode reorganization energy (?q), electronic coupling constant (Vel) and vibrational energy relaxation rate (kVER). Several interesting results, such as a transient rise in the population of the zeroth vibrational level of the reactant surface, a Kramers (or Grote-Hynes) type recrossing due to back reaction and a pronounced role of the initial Gaussian component of the solvation time correlation function in the dynamics of electron transfer reaction, are observed. Significant dependence of the electron transfer rate on the ultrafast Gaussian component of solvation dynamics is predicted for a range of values of Vel, although dependence on average solvation time can be weak. Another result is that, although VER alters relaxation dynamics in both the product and the reactant surfaces noticeably, the average rate of electron transfer is found to be weakly dependent on kVER for a range of values of Vel; this independence breaks down only at very small values of Vel. In addition, the hybrid model is employed to study the time resolved fluorescence line shape for the electron transfer reactions. It is found that VER can have a significant influence on the fluorescence spectrum. The possibility of vibrational state resolved spectra is investigated.
Straub, John E.
Mode-Specific Vibrational Energy Relaxation of Amide I and II Modes in N-Methylacetamide/Water. Straub* Department of Chemistry, Boston UniVersity, Boston, Massachusetts 02215 ReceiVed: December 13 reported for proteins with varying composition of R-helix and -sheet structures, suggesting that the amide
NASA Technical Reports Server (NTRS)
Lee, H.-W.; Lam, K. S.; Devries, P. L.; George, T. F.
1980-01-01
A new semiclassical decoupling scheme (the trajectory-based decoupling scheme) is introduced in a computational study of vibrational-to-electronic energy transfer for a simple model system that simulates collinear atom-diatom collisions. The probability of energy transfer (P) is calculated quasiclassically using the new scheme as well as quantum mechanically as a function of the atomic electronic-energy separation (lambda), with overall good agreement between the two sets of results. Classical mechanics with the new decoupling scheme is found to be capable of predicting resonance behavior whereas an earlier decoupling scheme (the coordinate-based decoupling scheme) failed. Interference effects are not exhibited in P vs lambda results.
Vibration Suppression and Flywheel Energy Storage in a Drillstring Bottom-Hole-Assembly
Saeed, Ahmed
2012-07-16
, and the geometric constraints. A five-axis magnetic levitation control system was implemented and tuned to maintain continuous suspension of the flywheel under the harsh lateral, axial and torsional drilling vibrations of the BHA. Thus, an integrated finite element...
Power processing and active protection for photovoltaic energy extraction
Chang, Arthur Hsu Chen
2015-01-01
Solar photovoltaic power generation is a promising clean and renewable energy technology that can draw upon the planet's most abundant power source - the sun. However, relatively high levelized cost of energy (LCOE), the ...
Static power conversion techniques for unique energy devices
Welch, Richard Andrew
1998-01-01
Solar power, fuel cells, and supercapacitors are some hics. of the new energy devices that are being used today in various power applications. The first two of these devices are exciting alternative sources of clean energy. The third device...
Power and Energy of Exploding Wires
NASA Astrophysics Data System (ADS)
Valancius, Cole
2015-06-01
Exploding wires are used in many high-energy applications, such as initiating explosives. Analysis of gold wire burst in detonator applications has shown Burst Current and Action metrics to be incapable of explaining burst phenomenon as the inductance of a firing circuit is changed. Energy Density better captures the correlation between different wire geometries, different electrical inputs, and explosive initiation. This idea has been expanded upon, to analyze the burst properties in Power-Energy space. Further inconsistencies in the understanding of wire burst and its relation to peak voltage have been found. An argument will be made for redefining the definition of burst. The result is a more broad understanding of rapid metal phase transition and the physical applications of the released shock wave.
NASA Astrophysics Data System (ADS)
Majumder, Moumita; Dawes, Richard; Wang, Xiao-Gang; Carrington, Tucker; Li, Jun; Guo, Hua; Manzhos, Sergei
2014-06-01
New potential energy surfaces for methane were constructed, represented as analytic fits to about 100,000 individual high-level ab initio data. Explicitly-correlated multireference data (MRCI-F12(AE)/CVQZ-F12) were computed using Molpro [1] and fit using multiple strategies. Fits with small to negligible errors were obtained using adaptations of the permutation-invariant-polynomials (PIP) approach [2,3] based on neural-networks (PIP-NN) [4,5] and the interpolative moving least squares (IMLS) fitting method [6] (PIP-IMLS). The PESs were used in full-dimensional vibrational calculations with an exact kinetic energy operator by representing the Hamiltonian in a basis of products of contracted bend and stretch functions and using a symmetry adapted Lanczos method to obtain eigenvalues and eigenvectors. Very close agreement with experiment was produced from the purely ab initio PESs. References 1- H.-J. Werner, P. J. Knowles, G. Knizia, 2012.1 ed. 2012, MOLPRO, a package of ab initio programs. see http://www.molpro.net. 2- Z. Xie and J. M. Bowman, J. Chem. Theory Comput 6, 26, 2010. 3- B. J. Braams and J. M. Bowman, Int. Rev. Phys. Chem. 28, 577, 2009. 4- J. Li, B. Jiang and Hua Guo, J. Chem. Phys. 139, 204103 (2013). 5- S Manzhos, X Wang, R Dawes and T Carrington, JPC A 110, 5295 (2006). 6- R. Dawes, X-G Wang, A.W. Jasper and T. Carrington Jr., J. Chem. Phys. 133, 134304 (2010).
Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power Plants
1 Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power Plants by Sarah Bashadi of the Requirements for the Degree of Master of Science in Technology and Policy at the Massachusetts Institute and Policy Program #12;2 #12;3 Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power
Piccardo, Matteo; Bloino, Julien; Barone, Vincenzo
2015-01-01
Models going beyond the rigid-rotor and the harmonic oscillator levels are mandatory for providing accurate theoretical predictions for several spectroscopic properties. Different strategies have been devised for this purpose. Among them, the treatment by perturbation theory of the molecular Hamiltonian after its expansion in power series of products of vibrational and rotational operators, also referred to as vibrational perturbation theory (VPT), is particularly appealing for its computational efficiency to treat medium-to-large systems. Moreover, generalized (GVPT) strategies combining the use of perturbative and variational formalisms can be adopted to further improve the accuracy of the results, with the first approach used for weakly coupled terms, and the second one to handle tightly coupled ones. In this context, the GVPT formulation for asymmetric, symmetric, and linear tops is revisited and fully generalized to both minima and first-order saddle points of the molecular potential energy surface. The computational strategies and approximations that can be adopted in dealing with GVPT computations are pointed out, with a particular attention devoted to the treatment of symmetry and degeneracies. A number of tests and applications are discussed, to show the possibilities of the developments, as regards both the variety of treatable systems and eligible methods. © 2015 Wiley Periodicals, Inc.
Marco Liserre; Thilo Sauter; John Hung
2010-01-01
This paper discusses about integrating renewable energy sources into the smart power grid through industrial electronics. This paper discusses photovoltaic power, wind energy conversion, hybrid energy systems, and tidal energy conversion.
Renewable Energy Penetration on the power Grid Fall / 2010
Stuart, Steven J.
ECE 420 Renewable Energy Penetration on the power Grid Fall / 2010 Instructor: Dr. E. B. Makram: TBA Text: Renewable Energy Systems M. Godoy Simoes and Felix A. Farret Attendance: Test attendance): Principles of Renewable Sources of Energy and Electric Power: basic definitions of electrical power