Sample records for vibration energy powered

  1. PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY

    E-print Network

    Ervin, Elizabeth K.

    with other smart materials for power harvesting #12;Piezoelectric MaterialsPiezoelectric MaterialsPIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING and magneticand magnetic field.field. Piezoelectric Materials as Smart Material- Among the all smart materials

  2. Vibration energy harvesting for low power and wireless applications

    NASA Astrophysics Data System (ADS)

    Challa, Vinod Reddy

    Vibration energy harvesting is an attractive technique for the potential powering of wireless sensors and low power devices. While the technique can be employed to harvest energy from ambient and mechanical vibrations, there are several generic requirements independent of the energy transfer mechanism that needs to be satisfied for efficient energy harvesting which are pursued here. For example, most energy harvesting devices developed are based on a single resonance frequency, and while recently efforts are being attempted to broaden the frequency range of the devices, lacking is a robust frequency tunable technique. In this work, a resonance frequency tunable mechanism employing magnetic force/stiffness technique is developed that allows the device frequency to increase or decrease based on the mode (attractive, repulsive) of the magnetic force applied. The developed technique provides the device to tune to approximately +/- 25% of its untuned resonance frequency allowing a wide frequency bandwidth. Further, this technique is developed into a self-tunable technique for autonomous device development. Another generic requirement is to match the electrical damping to the mechanical damping in the energy harvesting system for maximum efficiency. To satisfy this requirement, two independent energy harvesting techniques (piezoelectric and electromagnetic) are coupled through design, resulting in ˜30% and ˜65.5% increase in two different independent devices. Another key requirement is developing MEMS scale energy harvesting devices that will not only promises to enhance the power density but also allows potential integration with wireless sensors as an on-chip power source. Piezoelectric MEMS composite structures along with integrated silicon tip masses are fabricated using standard microfabrication techniques. Spray coating and spin coating techniques were explored to deposit zinc oxide as the piezoelectric material. Commercially available magnets were employed to demonstrate the frequency tuning/calibration of these structures resulting in ˜50% bandwidth. These approaches set the stage for a MEMS scale frequency tuning mechanism to be developed that would allow the integration of a self-tunability methodology for a completely autonomous MEMS scale energy harvesting devices for wide applications.

  3. A micropower programmable DSP powered using a MEMS-based vibration-to-electric energy converter

    Microsoft Academic Search

    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

  4. A MEMS-Based Piezoelectric Power Generator for Low Frequency Vibration Energy Harvesting

    Microsoft Academic Search

    Hua-Bin Fang; Jing-Quan Liu; Zheng-Yi Xu; Lu Dong; Di Chen; Bing-Chu Cai; Yue Liu

    2006-01-01

    A novel power generator has been achieved to convert vibration to electrical energy via the piezoelectric effect. The generator obtained by micro fabrication process mainly consists of silicon based frame and composite cantilever. The prototype tested at resonant vibration generates 1.15 muW of effective power to a 20.4-kOmega resistance load. The potential of this work is to offer miniaturization solutions

  5. High output power AlN vibration-driven energy harvesters

    NASA Astrophysics Data System (ADS)

    Cao, Z.; He, J.; Wang, Q.; Hara, M.; Oguchi, H.; Kuwano, H.

    2013-12-01

    This paper presents miniature AlN harvesters for harvesting low-frequency and two-dimensional vibration energy. A high fracture toughness and high yield strength stainless steel substrate was used to enhance output power and reduce resonate frequency of vibration energy harvesters. The thickness of 1.89 ?m AlN films were deposited on 50 ?m thick stainless steel (SUS) substrates for fabricating the harvesters. The Al/AlN/SUS multi-layer sheet was made into long and thin plate-like cantilevers with heavy proof masses attached at their free ends. The devices can collect vibration energy efficiently not only under perpendicular direction to the plate surface of cantilevers but also under the parallel direction. When vibration acceleration was 1.0 g, output power was 28.114 ?W for perpendicular vibration and 51.735 ?W for parallel vibration. When the acceleration of parallel vibration was 1.6 g, output power was 89.339 ?W.

  6. Self-powered autonomous wireless sensor node using vibration energy harvesting

    Microsoft Academic Search

    R. Torah; P. Glynne-Jones; M. Tudor; T. O'Donnell; S. Roy; S. Beeby

    2008-01-01

    This paper reports the development and implementation of an energy aware autonomous wireless condition monitoring sensor system (ACMS) powered by ambient vibrations. An electromagnetic (EM) generator has been designed to harvest sufficient energy to power a radio-frequency (RF) linked accelerometer-based sensor system. The ACMS is energy aware and will adjust the measurement\\/transmit duty cycle according to the available energy; this

  7. 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.

  8. Electromagnetic vibration energy harvesting with high power density using a magnet array

    NASA Astrophysics Data System (ADS)

    Tang, Xiudong; Lin, Teng; Zuo, Lei

    2012-04-01

    Electromagnetic vibration energy harvesters have been widely used to convert the vibration energy into electricity. However, one of the main challenges of using electromagnetic vibration energy harvesters is that they are usually in very large size with low power density. In this paper, a new type of electromagnetic vibration energy harvester with remarkably high power density is developed. By putting the strong rare-earth magnets in alternating directions and using high-magnetic-conductive casing, magnetic flux density up to 0.9T are obtained. This configuration also has a small current loop with less electrical reluctance, which further increases the high power density when the coil is designed to follow the current loop. The prototype, the size of which is 142x140x86 mm3, can provided up to 727Ns/m damping coefficient, which means 428 kNs/m4 damping density when it is shunt with 70? external resistive load which is set to the same as the internal resistor of the harvester to achieve maximum power. The corresponding power density is 725 ?W/cm3 at 15HZ harmonic force excitation of 2.54mm peak-to-peak amplitude. When shot-circuited, 1091Ns/m damping coefficient and 638 kNs/m4 damping density is achieved. The effectiveness of this novel vibration energy harvester is shown both by FEA and experiments. The eddy current damper is also discussed in this paper for comparison. The proposed configuration of the magnet array can also be extended for both micro-scale and large-scale energy harvesting applications, such as vibration energy harvesting from tall buildings, long bridges and railways.

  9. Scaling and power density metrics of electromagnetic vibration energy harvesting devices

    NASA Astrophysics Data System (ADS)

    Moss, Scott D.; Payne, Owen R.; Hart, Genevieve A.; Ung, Chandarin

    2015-02-01

    A review of the vibration energy harvesting literature has been undertaken with the goal of establishing scaling laws for experimentally demonstrated harvesting devices based on electromagnetic transduction. Power density metrics are examined with respect to scaling length, mass, frequency and drive acceleration. Continuous improvements in demonstrated power density of harvesting devices over the past decade are noted. Scaling laws are developed from observations that appear to suggest an upper limit to the power density achievable with current harvesting techniques.

  10. Fabrication and performance of MEMS-based piezoelectric power generator for vibration energy harvesting

    Microsoft Academic Search

    Hua-bin Fang; Jing-quan Liu; Zheng-yi Xu; Lu Dong; Li Wang; Di Chen; Bing-chu Cai; Yue Liu

    2006-01-01

    A MEMS-based energy harvesting device, micro piezoelectric power generator, is designed to convert ambient vibration energy to electrical power via piezoelectric effect. In this work, the generator structure of composite cantilever with nickel metal mass is devised. Micro-electronic-mechanical systems (MEMS) related techniques such as sol–gel, RIE dry etching, wet chemical etching, UV-LIGA are developed to fabricate the device and then

  11. Vibration energy harvesting is an attractive technique for the potential powering of wireless sensors and low power devices. While the technique can be employed to

    E-print Network

    Fisher, Frank

    ABSTRACT Vibration energy harvesting is an attractive technique for the potential powering of wireless sensors and low power devices. While the technique can be employed to harvest energy from ambient transfer mechanism is that the vibration energy harvesting device operate in resonance at the excitation

  12. Vibration energy harvester with sustainable power based on a single-crystal piezoelectric cantilever array.

    PubMed

    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

  13. A MEMS-based piezoelectric power generator array for vibration energy harvesting

    Microsoft Academic Search

    Jing-Quan Liu; Hua-Bin Fang; Zheng-Yi Xu; Xin-Hui Mao; Xiu-Cheng Shen; Di Chen; Hang Liao; Bing-Chu Cai

    2008-01-01

    Piezoelectric power generator made by microelectromechanical system (MEMS) technology can scavenge power from low-level ambient vibration sources. The developed MEMS power generators are featured with fixed\\/narrow operation frequency and power output in microwatt level, whereas, the frequency of ambient vibration is floating in some range, and power output is insufficient. In this paper, a power generator array based on thick-film

  14. Electromagnetic Energy Harvesting Circuit With Feedforward and Feedback DC–DC PWM Boost Converter for Vibration Power Generator System

    Microsoft Academic Search

    Xinping Cao; Wen-Jen Chiang; Ya-Chin King; Yi-Kuen Lee

    2007-01-01

    This paper presents an integrated vibration power generator system. The system consists of a mini electromagnetic vibration power generator and a highly efficient energy harvesting circuit implemented on a minute printed circuit board and a 0.35-mum CMOS integrated chip. By introducing a feedback control into the dc-dc pulsewidth modulation (PWM) boost converter with feedforward control, the energy harvesting circuit can

  15. The role of damping on energy and power in vibrating systems

    NASA Astrophysics Data System (ADS)

    Pavic, G.

    2005-03-01

    The role of damping with respect to energy and energy flow in vibrating mechanical systems was examined with the aim of establishing some general relationships. The link between the energy flow and the system energy is considered from both the local and global points of view. Locally, the mean intensity divergence is shown to be strictly proportional to the product of internal damping and potential energy density at a given point, while the imaginary value of complex divergence is proportional to the mean Lagrangian energy density. Globally, the mean value of the total vibratory power input to a structure is proportional to the volume integral of the product between the loss factor and the potential energy density. If the damping is uniformly distributed within a structure, this integral reduces to the product between the (constant) loss factor and the total potential energy. The global potential and kinetic energies can be obtained from the known complex input power to the structure and the known loss factor. In the case of non-uniform damping, the simple power-energy relationships are shown to hold fairly well where potential energy is involved, but could break down if kinetic energy is used instead. Several examples are given to illustrate the theoretical findings.

  16. Downhole vibration sensing by vibration energy harvesting

    E-print Network

    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 ...

  17. Enhancement of piezoelectric vibration energy harvester output power level for powering of wireless sensor node in large rotary machine diagnostic system

    Microsoft Academic Search

    B. Pekoslawski; Piotr Pietrzak; Maciej Makowski; Andrzej Napieralski

    2009-01-01

    The paper presents results of experimental and theoretical studies on small-size piezoelectric generators, in which energy of machine mechanical vibrations is harvested and converted to electric energy. These piezoelectric generators were proposed, as an alternative to a battery-based solution, for powering of sensor nodes in condition monitoring systems of large rotary machines such as turbogenerators in power plants. Initial studies

  18. A vibration energy harvesting device with bidirectional resonance frequency tunability

    Microsoft Academic Search

    Vinod R Challa; M G Prasad; Yong Shi; Frank T Fisher

    2008-01-01

    Vibration energy harvesting is an attractive technique for potential powering of wireless sensors and low power devices. While the technique can be employed to harvest energy from vibrations and vibrating structures, a general requirement independent of the energy transfer mechanism is that the vibration energy harvesting device operate in resonance at the excitation frequency. Most energy harvesting devices developed to

  19. Harvesting energy from non-ideal vibrations

    E-print Network

    Chang, Samuel C

    2013-01-01

    Energy harvesting has drawn significant interest for its potential to power autonomous low-power applications. Vibration energy harvesting is particularly well suited to industrial condition sensing, environmental monitoring ...

  20. Design and fabrication of vibration based energy harvester using microelectromechanical system piezoelectric cantilever for low power applications.

    PubMed

    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

  1. On energy harvesting from ambient vibration

    Microsoft Academic Search

    N. G. Stephen

    2006-01-01

    Future MEMS devices will harvest energy from their environment. One can envisage an autonomous condition monitoring vibration sensor being powered by that same vibration, and transmitting data over a wireless link; inaccessible or hostile environments are obvious areas of application. The base excitation of an elastically mounted magnetic seismic mass moving past a coil, considered previously by several authors, is

  2. Vibration shape effects on the power output in piezoelectric vibro-impact energy harvesters

    NASA Astrophysics Data System (ADS)

    Twiefel, Jens

    2013-04-01

    Vibro-Impcact harvesting devices are one concept to increase the bandwidth of resonant operated piezoelectric vibration generators. The fundamental setup is a piezoelectric bending element, where the deflection is limited by two stoppers. After starting the system in resonance operation the bandwidth increases towards higher frequencies as soon the deflection reach the stopper. If the stoppers are rigid, the frequency response gives constant amplitude for increasing frequencies, as long the system is treated as ideal one-DOF system with symmetric stoppers. In consequence, the bandwidth is theoretically unlimited large. However, such a system also has two major drawbacks, firstly the complicated startup mechanism and secondly the tendency to drop from the high constant branch in the frequency response on the much smaller linear branch if the system is disturbed. Nevertheless, the system has its application wherever the startup problem can be solved. Most modeling approaches utilize modal one-DOF models to describe the systems behavior and do not tread the higher harmonics of the beam. This work investigates the effects of the stoppers on the vibration shape of the piezoelectric beam, wherefore a finite element model is used. The used elements are one-dimensional two node elements based on the Timoshenko-beam theory. The finite element code is implemented in Matlab. The model is calculated utilizing time step integration for simulation, to reduce the computation time an auto-resonant calculation method is implemented. A control loop including positive feedback and saturation is used to create a self-excited system. Therefore, the system is always operated in resonance (on the backbone curve) and the frequency is a direct result of the computation. In this case tip velocity is used as feedback. This technique allows effective parametric studies. Investigated parameters include gap, excitation amplitude, tip mass as well as the stiffness of the stopper. The stress and strain distribution as well as the generated electrical power is analyzed with respect to the proper operation range.

  3. Energy harvesting vibration sources for microsystems applications

    Microsoft Academic Search

    S P Beeby; M J Tudor; N M White

    2006-01-01

    This paper reviews the state-of-the art in vibration energy harvesting for wireless, self-powered microsystems. Vibration-powered generators are typically, although not exclusively, inertial spring and mass systems. The characteristic equations for inertial-based generators are presented, along with the specific damping equations that relate to the three main transduction mechanisms employed to extract energy from the system. These transduction mechanisms are: piezoelectric,

  4. Piezoelectric energy harvesting from broadband random vibrations

    Microsoft Academic Search

    S. Adhikari; M. I. Friswell; D. J. Inman

    2009-01-01

    Energy harvesting for the purpose of powering low power electronic sensor systems has received explosive attention in the last few years. Most works using deterministic approaches focusing on using the piezoelectric effect to harvest ambient vibration energy have concentrated on cantilever beams at resonance using harmonic excitation. Here, using a stochastic approach, we focus on using a stack configuration and

  5. 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.

  6. Adjustable Nonlinear Springs to Improve Efficiency of Vibration Energy Harvesters

    E-print Network

    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%).

  7. 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.

  8. Intramolecular Vibration-to-Vibration Energy Transfer in Carbon Dioxide

    Microsoft Academic Search

    James T. Yardley; C. Bradley Moore

    1967-01-01

    We have used a vibrational fluorescence technique to study the deactivation of the asymmetric stretching vibration (00°1) of CO2 by intramolecular vibration-to-vibration energy transfer during CO2—rare-gas collisions. The efficiency for deactivation has only a slight dependence on mass, with a peak corresponding to resonance between the duration of the collision and the frequency difference between the vibrational levels involved. We

  9. Vibration based energy harvesting using piezoelectric material

    Microsoft Academic Search

    M. N Fakhzan; Asan G. A. Muthalif

    2011-01-01

    Energy harvesting has been around for centuries in the form of windmills, watermills and passive solar power systems. It is not only restricted to the natural resources but it has widen the tapping source to utilise the vibration which happen all around us. In the last decade, beam with piezoceramic patches have been used as a method to harverst energy.

  10. A low-frequency vibration-to-electrical energy harvester

    Microsoft Academic Search

    Min Zhang; Daniel Brignac; Pratul Ajmera; Kun Lian

    2008-01-01

    As the power consumption of modern electronics and wireless circuits decreases to a few hundred microwatts, it becomes possible to power these electronic devices by using ambient energy harvested from the environment. Mechanical vibration is among the more pervasive ambient available energy forms. Recent works in vibration-to-electrical energy harvesters have been centered on high frequency vibration applications. Although high-frequency mechanical

  11. Self-powered signal processing using vibration-based power generation

    Microsoft Academic Search

    Rajeevan Amirtharajah; Anantha P. Chandrakasan

    1998-01-01

    Low power design trends raise the possibility of using ambient energy to power future digital systems. A chip has been designed and tested to demonstrate the feasibility of operating a digital system from power generated by vibrations in its environment. A moving coil electromagnetic transducer was used as a power generator. Calculations show that power on the order of 400

  12. PERFORMANCE OF MICROFABRICATED PIEZOELECTRIC VIBRATION ENERGY HARVESTERS

    Microsoft Academic Search

    NOËL DUTOIT; BRIAN WARDLE

    2006-01-01

    Model verification and design of MEMS piezoelectric vibration energy harvesters (MPVEH) are presented, motivated by lowering power requirements of wireless sensor nodes. Applications include structural health monitoring. Coupled electromechanical harvester models are presented and verified (through comparison with experimental data). Harvester material selection is discussed. The model is used to concurrently design a prototype MPVEH and a microfabrication scheme. Targeting

  13. Vibrational power flow analysis of rods and beams. Thesis

    NASA Technical Reports Server (NTRS)

    Wohlever, James Christopher; Bernhard, R. J.

    1988-01-01

    A new method to model vibrational power flow and predict the resulting energy density levels in uniform rods and beams is investigated. This method models the flow of vibrational power in a manner analogous to the flow of thermal power in a heat conduction problem. The classical displacement solutions for harmonically excited, hysteretically damped rods and beams are used to derive expressions for the vibrational power flow and energy density in the rod and beam. Under certain conditions, the power flow in these two structural elements will be shown to be proportional to the energy density gradient. Using the relationship between power flow and energy density, an energy balance on differential control volumes in the rod and beam leads to a Poisson's equation which models the energy density distribution in the rod and beam. Coupling the energy density and power flow solutions for rods and beams is also discussed. It is shown that the resonant behavior of finite structures complicates the coupling of solutions, especially when the excitations are single frequency inputs. Two coupling formulations are discussed, the first based on the receptance method, and the second on the travelling wave approach used in Statistical Energy Analysis. The receptance method is the more computationally intensive but is capable of analyzing single frequency excitation cases. The traveling wave approach gives a good approximation of the frequency average of energy density and power flow in coupled systems, and thus, is an efficient technique for use with broadband frequency excitation.

  14. Vibration Energy Harvesting by Carbon Nanotube Network\\/Polydimethylsiloxane Composite

    Microsoft Academic Search

    Qiang Lv; Mingxiang Chen; Keling Wu; Sheng Liu

    2010-01-01

    There are many vibration energy in nature, vibration energy harvesting is an attractive technique for low-power devices. In this paper, a new vibration energy harvesting by carbon nanotube network(NTN)\\/polydimethylsiloxane(PDMS) composite was investigated. The composite of NTN embedded in PDMS matrix has been fabricated by using filtration, standard integrated circuits processes and transfer process. The NTN\\/PDMS composite can be used to

  15. Harvesting Vibrational Energy Using Material Work Functions

    PubMed Central

    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

  16. Harvesting vibrational energy using material work functions.

    PubMed

    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

  17. Energy harvesting from wind-induced vibration of suspension bridges

    E-print Network

    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 ...

  18. Vibration characteristic of high power CO2 laser

    NASA Astrophysics Data System (ADS)

    Zhang, Kuo

    2015-02-01

    High power CO2 laser is widely used in various scientific, industrial and military applications. Vibration is a common phenomenon during laser working process, it will affect the working performance of high power CO2 laser, vibration must be strictly controlled in the condition where the laser pointing is required. This paper proposed a method to investigate the vibration characteristic of high power CO2 laser. An experiment device with vibration acceleration sensor was established to measure vibration signal of CO2 laser, the measured vibration signal was mathematically treated using space-frequency conversion, and then the vibration characteristic of high power CO2 laser can be obtained.

  19. Energy Harvesting from Vibration Using Polymer Electret

    Microsoft Academic Search

    Yuji Suzuki

    2008-01-01

    A vibration-driven electret generator has been developed for energy harvesting applications. Perfluorinated polymer electret with extremely-high surface charge density is employed for large power output. By using parylene as the spring material, a low-resonant-frequency MEMS generator is realized. Large in-plane amplitude of 0.8 mm at the resonant frequency as low as 37 Hz has been achieved. With our early prototype,

  20. A MEMS vibration energy harvester for automotive applications

    NASA Astrophysics Data System (ADS)

    van Schaijk, R.; Elfrink, R.; Oudenhoven, J.; Pop, V.; Wang, Z.; Renaud, M.

    2013-05-01

    The objective of this work is to develop MEMS vibration energy harvesters for tire pressure monitoring systems (TPMS), they can be located on the rim or on the inner-liner of the car tire. Nowadays TPMS modules are powered by batteries with a limited lifetime. A large effort is ongoing to replace batteries with small and long lasting power sources like energy harvesters [1]. The operation principle of vibration harvesters is mechanical resonance of a seismic mass, where mechanical energy is converted into electrical energy. In general, vibration energy harvesters are of specific interest for machine environments where random noise or repetitive shock vibrations are present. In this work we present the results for MEMS based vibration energy harvesting for applying on the rim or inner-liner. The vibrations on the rim correspond to random noise. A vibration energy harvester can be described as an under damped mass-spring system acting like a mechanical band-pass filter, and will resonate at its natural frequency [2]. At 0.01 g2/Hz noise amplitude the average power can reach the level that is required to power a simple wireless sensor node, approximately 10 ?W [3]. The dominant vibrations on the inner-liner consist mainly of repetitive high amplitude shocks. With a shock, the seismic mass is displaced, after which the mass will "ring-down" at its natural resonance frequency. During the ring-down period, part of the mechanical energy is harvested. On the inner-liner of the tire repetitive (one per rotation) high amplitude (few hundred g) shocks occur. The harvester enables an average power of a few tens of ?W [4], sufficient to power a more sophisticated wireless sensor node that can measure additional tire-parameters besides pressure. In this work we characterized MEMS vibration energy harvesters for noise and shock excitation. We validated their potential for TPMS modules by measurements and simulation.

  1. Modeling and design of a MEMS piezoelectric vibration energy harvester

    E-print Network

    Du Toit, Noël 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 ...

  2. Electrostatic vibration-to-electric energy conversion

    E-print Network

    Mur Miranda, José Oscar, 1972-

    2004-01-01

    Ultra-Low-Power electronics can perform useful functions with power levels as low as 170 nW. This makes them amenable to powering from ambient sources such as vibration. In this case, they can become autonomous. Motivated ...

  3. Vibrational energy transfer in fluids

    NASA Astrophysics Data System (ADS)

    Miller, David W.; Adelman, Steven A.

    A review of several of the available theories of vibrational energy transfer (VET) in the gas and liquid phases is presented. First the classical theory of gas phase VET mainly due to Landau and Teller, to Jackson and Mott and to Zener is developed in some detail. Next the Schwartz-Slawsky-Herzfeld theory, a framework for analysing VET data based on the classical theory, is outlined. Experimental tests of the classical theory and theoretical critiques of its assumptions are then described. Next a brief review of the modern ab-initio quantum approach to gas phase VET rates, taking as an example the work of Banks, Clary and Werner, is given. Theories of VET at elevated densities are then discussed. The isolated binary collision model is reviewed and a new molecular approach to the density, temperature and isotope dependences of vibrational energy relaxation rates, due to Adelman and co-workers, is outlined.

  4. Vibration energy harvesting for unmanned aerial vehicles

    NASA Astrophysics Data System (ADS)

    Anton, Steven R.; Inman, Daniel J.

    2008-03-01

    Unmanned aerial vehicles (UAVs) are a critical component of many military operations. Over the last few decades, the evolution of UAVs has given rise to increasingly smaller aircraft. Along with the development of smaller UAVs, termed mini UAVs, has come issues involving the endurance of the aircraft. Endurance in mini UAVs is problematic because of the limited size of the fuel systems that can be incorporated into the aircraft. A large portion of the total mass of many electric powered mini UAVs, for example, is the rechargeable battery power source. Energy harvesting is an attractive technology for mini UAVs because it offers the potential to increase their endurance without adding significant mass or the need to increase the size of the fuel system. This paper investigates the possibility of harvesting vibration and solar energy in a mini UAV. Experimentation has been carried out on a remote controlled (RC) glider aircraft with a 1.8 m wing span. This aircraft was chosen to replicate the current electric mini UAVs used by the military today. The RC glider was modified to include two piezoelectric patches placed at the roots of the wings and a cantilevered piezoelectric beam installed in the fuselage to harvest energy from wing vibrations and rigid body motions of the aircraft, as well as two thin film photovoltaic panels attached to the top of the wings to harvest energy from sunlight. Flight testing has been performed and the power output of the piezoelectric and photovoltaic devices has been examined.

  5. A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources

    E-print Network

    Paris-Sud XI, Université de

    A low-power circuit for piezoelectric vibration control by synchronized switching on voltage Accepted 18 April 2010 Available online 6 May 2010 Keywords: Piezoelectric Control Structural damping Semi-passive damping Energy harvesting a b s t r a c t In the paper, a vibration damping system powered by harvested

  6. 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.

  7. Multiple cell configuration electromagnetic vibration energy harvester

    NASA Astrophysics Data System (ADS)

    Marin, Anthony; Bressers, Scott; Priya, Shashank

    2011-07-01

    This paper reports the design of an electromagnetic vibration energy harvester that doubles the magnitude of output power generated by the prior four-bar magnet configuration. This enhancement was achieved with minor increase in volume by 23% and mass by 30%. The new 'double cell' design utilizes an additional pair of magnets to create a secondary air gap, or cell, for a second coil to vibrate within. To further reduce the dimensions of the device, two coils were attached to one common cantilever beam. These unique features lead to improvements of 66% in output power per unit volume (power density) and 27% increase in output power per unit volume and mass (specific power density), from 0.1 to 0.17 mW cm-3 and 0.41 to 0.51 mW cm-3 kg-1 respectively. Using the ANSYS multiphysics analysis, it was determined that for the double cell harvester, adding one additional pair of magnets created a small magnetic gradient between air gaps of 0.001 T which is insignificant in terms of electromagnetic damping. An analytical model was developed to optimize the magnitude of transformation factor and magnetic field gradient within the gap.

  8. Adaptive Vibration Reduction System Shown to Effectively Eliminate Vibrations for the Stirling Radioisotope Power System

    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.

  9. Parametric energy conversion of thermoacoustic vibrations

    NASA Astrophysics Data System (ADS)

    Guthy, C.; Van Neste, C. W.; Mitra, S.; Bhattacharjee, S.; Thundat, T.

    2012-05-01

    We demonstrate a parametric energy conversion method of thermoacoustic (TA) vibrations into electrical oscillations of a LC circuit. The inductance modulation necessary to excite the parametric oscillations is achieved by varying the air gap between two halves of a ferrite E-core coil. As a proof-of-concept, the parametric converter was attached to a Sondhauss tube that converts the heat into acoustic vibrations. The maximum total acoustic power output of this thermoacoustic engine was ˜5.3 mW. A flexible metallic membrane capping the Sondhauss tube connected to the moving half E-core served as a mechanical oscillator. The resonance frequency of the membrane was matched with the operating frequency (130 Hz) of the Sondhauss tube for resonant energy extraction. We have characterized the power output of the complete system as a function of electrical load. The maximum electrical power of 2.3 mW produced by the system corresponds to an acoustic-to-electric conversion efficiency of 44%.

  10. Vibration energy harvesting using macro-fiber composites

    Microsoft Academic Search

    Yaowen Yang; Lihua Tang; Hongyun Li

    2009-01-01

    The decreasing energy consumption of today's portable electronics has invoked the possibility of energy harvesting from the ambient environment for self-power supply. One common and simple method for vibration energy harvesting is to utilize the direct piezoelectric effect. Compared to traditional piezoelectric materials such as lead zirconate titanate (PZT), macro-fiber composites (MFC) are characterized by their flexibility on large deformation.

  11. Vibrational Energies of the CO2 Molecule

    Microsoft Academic Search

    V. Robert Stull; Philip J. Wyatt; Gilbert N. Plass

    1962-01-01

    The vibrational energy levels of the eight most abundant isotopic species of carbon dioxide have been calculated. Over 1800 energy levels are given for each isotope. The calculations included terms to the third order in the vibrational quantum numbers and took account of the Fermi resonance. The matrices were diagonalized by an eigenvalue routine of great accuracy.

  12. Vibration Monitoring of Power Distribution Poles

    SciTech Connect

    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 nation’s 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.

  13. A micro electromagnetic generator for vibration energy harvesting

    Microsoft Academic Search

    S P Beeby; R N Torah; M J Tudor; P Glynne-Jones; T O'Donnell; C R Saha; S Roy

    2007-01-01

    Vibration energy harvesting is receiving a considerable amount of interest as a means for powering wireless sensor nodes. This paper presents a small (component volume 0.1 cm3, practical volume 0.15 cm3) electromagnetic generator utilizing discrete components and optimized for a low ambient vibration level based upon real application data. The generator uses four magnets arranged on an etched cantilever with

  14. The Search for High-Impact Diagnostic and Management Tools for Low- and Middle-Income Countries: A Self-Powered Low-Cost Blood Pressure Measurement Device Powered by a Solid-State Vibration Energy Harvester.

    PubMed

    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

  15. Piezoelectric MEMS energy harvesting systems driven by harmonic and random vibrations

    Microsoft Academic Search

    Lars-Cyril Blystad; Einar Halvorsen; Svein Husa

    2010-01-01

    Switching power conditioning techniques are known to greatly enhance the performance of linear piezoelectric energy harvesters subject to harmonic vibrations. With such circuits, little is known about the effect of mechanical stoppers that limit the motion or about waveforms other than harmonic vibrations. This work presents SPICE simulations of piezoelectric micro energy harvester systems that differ in choice of power

  16. A low-power circuit for piezoelectric vibration control by synchronized switching on voltage sources

    E-print Network

    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.

  17. Power hand tool vibration effects on grip exertions

    Microsoft Academic Search

    ROBERT G. RADWIN; THOMAS J. ARMSTRONG; DON B. CHAFFIN

    1987-01-01

    Operation of vibrating power hand tools can result in excessive grip force, which may increase the risk of cumulative trauma disorders in the upper extremities. An experiment was performed to study grip force exerted by 14 subjects operating a simulated hand tool vibrating at 9.8 m\\/s and 49 m\\/s acceleration magnitudes, at 40 Hz and 160 Hz frequencies, with vibration

  18. Performance Evaluation of Vibration-Based Piezoelectric Energy Scavengers

    E-print Network

    Shu, Yi-Chung

    of piezoelectric power harvesting systems using either the standard or the synchronized switch harvestingChapter 3 Performance Evaluation of Vibration-Based Piezoelectric Energy Scavengers Yi-Chung Shu Abstract This chapter summarizes several recent activities for fundamental under- standing of piezoelectric

  19. A review of vibration-based MEMS piezoelectric energy harvesters

    Microsoft Academic Search

    Salem Saadon; Othman Sidek

    2011-01-01

    The simplicity associated with the piezoelectric micro-generators makes it very attractive for MEMS applications, especially for remote systems. In this paper we reviewed the work carried out by researchers during the last three years. The improvements in experimental results obtained in the vibration-based MEMS piezoelectric energy harvesters show very good scope for MEMS piezoelectric harvesters in the field of power

  20. Vibration power generator for a linear MR damper

    NASA Astrophysics Data System (ADS)

    Sapi?ski, Bogdan

    2010-10-01

    The paper describes the structure and the results of numerical calculations and experimental tests of a newly developed vibration power generator for a linear magnetorheological (MR) damper. The generator consists of permanent magnets and coil with foil winding. The device produces electrical energy according to Faraday's law of electromagnetic induction. This energy is applied to vary the damping characteristics of the MR damper attached to the generator by the input current produced by the device. The objective of the numerical calculations was to determine the magnetic field distribution in the generator as well as the electric potential and current density in the generator's coil during the idle run and under the load applied to the MR damper control coil. The results of the calculations were used during the design and manufacturing stages of the device. The objective of the experimental tests carried out on a dynamic testing machine was to evaluate the generator's efficiency and to compare the experimental and predicted data. The experimental results demonstrate that the engineered device enables a change in the kinetic energy of the reciprocal motion of the MR damper which leads to variations in the damping characteristics. That is why the generator may be used to build up MR damper based vibration control systems which require no external power.

  1. Piezoelectric MEMS Energy Harvester for Low-Frequency Vibrations With Wideband Operation Range and Steadily Increased Output Power

    Microsoft Academic Search

    Huicong Liu; Cho Jui Tay; Chenggen Quan; Takeshi Kobayashi; Chengkuo Lee

    2011-01-01

    A piezoelectric MEMS energy harvester (EH) with low resonant frequency and wide operation bandwidth was de- signed, microfabricated, and characterized. The MEMS piezo- electric energy harvesting cantilever consists of a silicon beam integrated with piezoelectric thin film (PZT) elements parallel- arranged on top and a silicon proof mass resulting in a low resonant frequency of 36 Hz. The whole chip

  2. Abstract--This paper presents ambient mechanical vibrations as an alternative source for energy harvesting, especially

    E-print Network

    Kumar, Ratnesh

    Abstract--This paper presents ambient mechanical vibrations as an alternative source for energy harvesting, especially beneficial where alternatives such as light, wind, biomass and thermal energy are limited, e.g., powering underground sensors. Transduction of ambient kinetic energy, e.g., the vibrations

  3. Department of Mechanical Engineering Fall 2011 Flowserve Vibration Energy Harvesting

    E-print Network

    Demirel, Melik C.

    PENNSTATE Department of Mechanical Engineering Fall 2011 Flowserve Vibration Energy Harvesting of these vibrations, Flowseve is looking at using vibration absorbers coupled with energy harvesting technology to deacrease vibration while also creating usable energy that would otherwise be wasted. Objectives The team

  4. 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.

  5. Vibration energy harvesting using Galfenol-based transducer

    NASA Astrophysics Data System (ADS)

    Berbyuk, Viktor

    2013-04-01

    In this paper the novel design of Galfenol based vibration energy harvester is presented. The device uses Galfenol rod diameter 6.35 mm and length 50mm, polycrystalline, production grade, manufactured by FSZM process by ETREMA Product Inc. For experimental study of the harvester, the test rig was developed. It was found by experiment that for given frequency of external excitation there exist optimal values of bias and pre-stress which maximize generated voltage and harvested power. Under optimized operational conditions and external excitations with frequency 50Hz the designed transducer generates about 10 V and harvests about 0,45 W power. Within the running conditions, the Galfenol rod power density was estimated to 340mW/cm3. The obtained results show high practical potential of Galfenol based sensors for vibration-to-electrical energy conversion, structural health monitoring, etc.

  6. Self-powered wireless vibration-sensing system for machining monitoring

    NASA Astrophysics Data System (ADS)

    Chung, Tien-Kan; Lee, Hao; Tseng, Chia-Yung; Lo, Wen-Tuan; Wang, Chieh-Min; Wang, Wen-Chin; Tu, Chi-Jen; Tasi, Pei-Yuan; Chang, Jui-Wen

    2013-04-01

    In this paper, we demonstrate an attachable energy-harvester-powered wireless vibration-sensing module for milling-process monitoring. The system consists of an electromagnetic energy harvester, MEMS accelerometer, and wireless module. The harvester consisting of an inductance and magnets utilizes the electromagnetic-induction approach to harvest the mechanical energy from the milling process and subsequently convert the mechanical energy to an electrical energy. Furthermore, through an energy-storage/rectification circuit, the harvested energy is capable of steadily powering both the accelerometer and wireless module. Through integrating the harvester, accelerometer, and wireless module, a self-powered wireless vibration-sensing system is achieved. The test result of the system monitoring the milling process shows the system successfully senses the vibration produced from the milling and subsequently transmits the vibration signals to the terminal computer. Through analyzing the vibration data received by the terminal computer, we establish a criterion for reconstructing the status, condition, and operating-sequence of the milling process. The reconstructed status precisely matches the real status of the milling process. That is, the system is capable of demonstrating a real-time monitoring of the milling process.

  7. Piezoelectric MEMS energy harvesting systems driven by harmonic and random vibrations.

    PubMed

    Blystad, Lars-Cyril; Halvorsen, Einar; Husa, Svein

    2010-04-01

    Switching power conditioning techniques are known to greatly enhance the performance of linear piezoelectric energy harvesters subject to harmonic vibrations. With such circuits, little is known about the effect of mechanical stoppers that limit the motion or about waveforms other than harmonic vibrations. This work presents SPICE simulations of piezoelectric micro energy harvester systems that differ in choice of power conditioning circuits and stopper models. We consider in detail both harmonic and random vibrations. The nonlinear switching conversion circuitry performs better than simple passive circuitry, especially when mechanical stoppers are in effect. Stopper loss is important under broadband vibrations. Stoppers limit the output power for sinusoidal excitations, but result in the same output power whether the stoppers are lossy or not. When the mechanical stoppers are hit by the proof mass during high-amplitude vibrations, nonlinear effects such as saturation and jumps are present. PMID:20378453

  8. Vibration energy harvesting by magnetostrictive material

    Microsoft Academic Search

    Lei Wang; F. G. Yuan

    2008-01-01

    A new class of vibration energy harvester based on magnetostrictive material (MsM), Metglas 2605SC, is designed, developed and tested. It contains two submodules: an MsM harvesting device and an energy harvesting circuit. Compared to piezoelectric materials, the Metglas 2605SC offers advantages including higher energy conversion efficiency, longer life cycles, lack of depolarization and higher flexibility to survive in strong ambient

  9. Electrical contact behaviour of power connector during fretting vibration

    Microsoft Academic Search

    N. Ben Jemaa; E. Carvou

    2006-01-01

    It is well known that vibration of contact interfaces is the main cause of contact degradation by the so called fretting corrosion phenomena. In fact the process of generated particles by mechanical wear produce the increase of contact voltage frequently assimilated as high contact resistance in low power and signal connector. In high power connector, this degradation is expected to

  10. Vibration energy absorption in the whole-body system of a tractor operator.

    PubMed

    Szczepaniak, Jan; Tana?, Wojciech; Kromulski, Jacek

    2014-01-01

    Many people are exposed to whole-body vibration (WBV) in their occupational lives, especially drivers of vehicles such as tractor and trucks. The main categories of effects from WBV are perception degraded comfort interference with activities-impaired health and occurrence of motion sickness. Absorbed power is defined as the power dissipated in a mechanical system as a result of an applied force. The vibration-induced injuries or disorders in a substructure of the human system are primarily associated with the vibration power absorption distributed in that substructure. The vibration power absorbed by the exposed body is a measure that combines both the vibration hazard and the biodynamic response of the body. The article presents measurement method for determining vibration power dissipated in the human whole body system called Vibration Energy Absorption (VEA). The vibration power is calculated from the real part of the force-velocity cross-spectrum. The absorbed power in the frequency domain can be obtained from the cross-spectrum of the force and velocity. In the context of the vibration energy transferred to a seated human body, the real component reflects the energy dissipated in the biological structure per unit of time, whereas the imaginary component reflects the energy stored/released by the system. The seated human is modeled as a series/parallel 4-DOF dynamic models. After introduction of the excitation, the response in particular segments of the model can be analyzed. As an example, the vibration power dissipated in an operator has been determined as a function of the agricultural combination operating speed 1.39 - 4.16 ms(-1). PMID:24959797

  11. Model reduction in stochastic vibration energy harvesting using compressive sampling

    NASA Astrophysics Data System (ADS)

    Wickenheiser, A. M.

    2013-09-01

    Vibration energy harvesters are designed to gather parasitic energy from the motion of their host structures. In many germane scenarios, this motion is broadband; however, the preponderance of design criteria appearing in the literature for vibration energy harvesters considers sinusoidal base excitation at a single frequency. While this analysis often leads to analytical formulas for estimating power harvested, they fail to account for the contribution of multiple frequency components of the host motion and the excitation of higher vibration modes of the transducer. In this paper, an attempt is made to provide brief, analytical approximation of these additional factors. To wit, the single-mode, single-frequency power formula is extended to multi-frequency inputs and multiple modal excitations by matching each base acceleration frequency component to at most one mode of vibration whose half-power bandwidth that frequency falls within. Then, due to orthogonality, the expected power can be written as the sum of the contributions of the individual frequency components. To demonstrate the accuracy of this approximation, recorded acceleration signals from a car idling and a person walking are used as inputs, and predictions from the approximation are compared to results from full simulations. Approximations using only three frequency components are shown to be more than 80% accurate, with increased accuracy as the base acceleration signal becomes narrower in bandwidth. The effects of charge cancellation in the higher modes are also considered using simulations and the aforementioned approximations. These studies show that rectifying the strain in the higher modes is only beneficial if these modes contribute significantly to the power harvested. The approximate formulas derived in this paper are useful for making this determination.

  12. Efficiency enhancement of a cantilever-based vibration energy harvester.

    PubMed

    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

  13. Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester

    PubMed Central

    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

  14. DESIGN CONSIDERATIONS FOR MEMS-SCALE PIEZOELECTRIC MECHANICAL VIBRATION ENERGY HARVESTERS

    Microsoft Academic Search

    NOËL E. DUTOIT; BRIAN L. WARDLE; SANG-GOOK KIM

    2005-01-01

    Design considerations for piezoelectric-based energy harvesters for MEMS-scale sensors are presented, including a review of past work. Harvested ambient vibration energy can satisfy power needs of advanced MEMS-scale autonomous sensors for numerous applications, e.g., structural health monitoring. Coupled 1-D and modal (beam structure) electromechanical models are presented to predict performance, especially power, from measured low-level ambient vibration sources. Models are

  15. Magnetostrictive Vibration Damper and Energy Harvester for Rotating Machinery

    NASA Technical Reports Server (NTRS)

    Deng, Zhangxian; Asnani, Vivake M.; Dapino, Marcelo J.

    2015-01-01

    Vibrations generated by machine driveline components can cause excessive noise and structural damage. 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 average 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.

  16. 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.

  17. 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.

  18. Electret transducer for vibration-based energy harvesting

    NASA Astrophysics Data System (ADS)

    Hillenbrand, J.; Pondrom, P.; Sessler, G. M.

    2015-05-01

    Vibration-based electret energy harvesters with soft cellular spacer rings are presented. These harvesters are closely related to recently introduced electret accelerometers; however, their development targets are partially differing. Various harvesters with seismic masses from 8 to 23 g and surface potentials in the 500 V regime were built and characterized and powers of up to 8 ?W at about 2 kHz and an acceleration of 1 g were measured. An analytical model is presented which, for instance, allows the calculation of the frequency response of the power output into a given load resistance. Finally, experimental and calculated results are compared.

  19. A Vibration Based Condition Monitoring System for Power Transformers

    Microsoft Academic Search

    He Ting-Ting; Wang Jing-Di; Guo Jie; Huang Hai; Chen Xiang-Xian; Pan Jie

    2009-01-01

    This paper is concerned with the design and development of an on-line condition monitoring system for large power transformers utilizing signals such as transformer vibration, voltages, currents, temperature and state of switches. The system consists of two parts which communicate each other via Ethernet or series port. The formal is a front-end computer subsystem used for data acquisition and processing,

  20. A study of electromagnetic vibration energy harvesters with different interface circuits

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Liang, Xingyu; Wei, Haiqiao

    2015-06-01

    A dimensionless analysis of piezoelectric vibration energy harvester was conducted in the previous work where the harvested power and energy harvesting efficiency were normalised and determined from two non-dimensional variables of resistance and force factor. This paper has developed a dimensionless analysis of an electromagnetic vibration energy harvester where the harvested power and energy harvesting efficiency are normalised and determined from two similar non-dimensional variables of resistance and equivalent force factor. The harvested power and efficiency are compared for the electromagnetic harvester with different interface circuits. The aim is to disclose some similarity and limitations of the piezoelectric and electromagnetic harvesters in a dimensionless scale.

  1. Powerful Low-Frequency Vibrators for Active Seismology

    SciTech Connect

    Alekseev, A.S.; Chichinin, I.S.; Korneev, V.A.

    2003-12-01

    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. Recording 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 estimation 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. The theoretical description of the low-frequency vibrator is given in the appendices, which contain numerical examples.

  2. Resonant vibrational energy transfer in ice Ih

    SciTech Connect

    Shi, L.; Li, F.; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2014-06-28

    Fascinating anisotropy decay experiments have recently been performed on H{sub 2}O ice Ih by Timmer and Bakker [R. L. A. Timmer, and H. J. Bakker, J. Phys. Chem. A 114, 4148 (2010)]. The very fast decay (on the order of 100 fs) is indicative of resonant energy transfer between OH stretches on different molecules. Isotope dilution experiments with deuterium show a dramatic dependence on the hydrogen mole fraction, which confirms the energy transfer picture. Timmer and Bakker have interpreted the experiments with a Förster incoherent hopping model, finding that energy transfer within the first solvation shell dominates the relaxation process. We have developed a microscopic theory of vibrational spectroscopy of water and ice, and herein we use this theory to calculate the anisotropy decay in ice as a function of hydrogen mole fraction. We obtain very good agreement with experiment. Interpretation of our results shows that four nearest-neighbor acceptors dominate the energy transfer, and that while the incoherent hopping picture is qualitatively correct, vibrational energy transport is partially coherent on the relevant timescale.

  3. Resonant vibrational energy transfer in ice Ih

    NASA Astrophysics Data System (ADS)

    Shi, L.; Li, F.; Skinner, J. L.

    2014-06-01

    Fascinating anisotropy decay experiments have recently been performed on H2O 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.

  4. Resonant vibrational energy transfer in ice Ih.

    PubMed

    Shi, L; Li, F; Skinner, J L

    2014-06-28

    Fascinating anisotropy decay experiments have recently been performed on H2O 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. PMID:24985650

  5. Kinetics of vibrational energy transfer in carbon dioxide and its mixtures with other gases

    Microsoft Academic Search

    S. A. Losev

    1976-01-01

    The paper reviews various types of vibrational energy transfer in carbon dioxide and mixtures which contain it, with emphasis on experimental results. Techniques for measuring vibrational energy transfer are discussed: ultrasonic, laser-fluorescence and gasdynamic methods. The following types of vibrational energy transfer are considered: (1) transfer between symmetric vibrations; (2) vibrational-translational transfer; (3) transfer between asymmetric and symmetric vibrations, and

  6. Low-frequency meandering piezoelectric vibration energy harvester.

    PubMed

    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

  7. Vibration energy harvesting using a piezoelectric circular diaphragm array.

    PubMed

    Wang, Wei; Yang, Tongqing; Chen, Xurui; Yao, Xi

    2012-09-01

    This paper presents a method for harvesting electric energy from mechanical vibration using a mechanically excited piezoelectric circular membrane array. The piezoelectric circular diaphragm array consists of four plates with series and parallel connection, and the electrical characteristics of the array are examined under dynamic conditions. With an optimal load resistor of 160 k?, an output power of 28 mW was generated from the array in series connection at 150 Hz under a prestress of 0.8 N and a vibration acceleration of 9.8 m/s(2), whereas a maximal output power of 27 mW can be obtained from the array in parallel connection through a resistive load of 11 k? under the same frequency, prestress, and acceleration conditions. The results show that using a piezoelectric circular diaphragm array can significantly increase the output of energy compared with the use of a single plate. By choosing an appropriate connection pattern (series or parallel connections) among the plates, the equivalent impedance of the energy harvesting devices can be tailored to meet the matched load of different applications for maximal power output. PMID:23007776

  8. Temperature dependence of vibrational energy transfer between vibrationally excited polyatomic molecules and bath gases

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Yakovlev, D. L.; Sambor, E. G.

    2000-08-01

    Efficiency of vibrational energy transfer (VET) in vibrational quasicontinuum of triplet states was estimated from the dependence of time-resolved delayed fluorescence of benzophenone and anthraquinone on bath gas pressure. The negative temperature dependence for vibration-vibration (V-V) and positive for vibration-translation (V-T) energy transfers from benzophenone and anthraquinone to bath gases (C 2H 4, SF 6, CCl 4, C 5H 12) were obtained between 373 and 553 K. Polarizability and dipole moment of colliding molecules seem to affect the efficiency of V-V relaxation. These data reflect the dominance of long-range attractive interactions in V-V energy transfer and short-range repulsive interactions in V-T energy transfer.

  9. Power extraction using flow-induced vibration of a circular cylinder placed near another fixed cylinder

    NASA Astrophysics Data System (ADS)

    Nishi, Yoshiki; Ueno, Yuta; Nishio, Masachika; Quadrante, Luis Antonio Rodrigues; Kokubun, Kentaroh

    2014-05-01

    We conducted an experiment in a towing tank to investigate the performance of an energy extraction system using the flow-induced vibration of a circular cylinder. This experiment tested three different cases involving the following arrangements of cylinder(s) of identical diameter: the upstream fixed-downstream movable arrangement (case F); the upstream movable-downstream fixed arrangement (case R); and a movable isolated cylinder (case I). In cases F and R, the separation distance (ratio of the distance between the centers of the two cylinders to their diameters) is fixed at 1.30. Measurement results show that while cases F and I generate vortex-induced vibration (VIV) resonance responses, case R yields wake-induced vibration (WIV) at reduced velocity over 9.0, which is significantly larger than that of the VIV response, leading to the induction of higher electronic power in a generator. Accordingly, primary energy conversion efficiency is higher in the case involving WIV.

  10. 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.

  11. 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.

  12. Smart nanocoated structure for energy harvesting at low frequency vibration

    NASA Astrophysics Data System (ADS)

    Sharma, Sudhanshu

    Increasing demands of energy which is cleaner and has an unlimited supply has led development in the field of energy harvesting. Piezoelectric materials can be used as a means of transforming ambient vibrations into electrical energy that can be stored and used to power other devices. With the recent surge of micro scale devices, piezoelectric power generation can provide a convenient alternative to traditional power sources. In this research, a piezoelectric power generator composite prototype was developed to maximize the power output of the system. A lead zirconate titanate (PZT) composite structure was formed and mounted on a cantilever bar and was studied to convert vibration energy of the low range vibrations at 30 Hz--1000 Hz. To improve the performance of the PZT, different coatings were made using different percentage of Ferrofluid (FNP) and Zinc Oxide nanoparticles (ZnO) and binder resin. The optimal coating mixture constituent percentage was based on the performance of the composite structure formed by applying the coating on the PZT. The fabricated PZT power generator composite with an effective volume of 0.062 cm3 produced a maximum of 44.5 ?W, or 0.717mW/cm3 at its resonant frequency of 90 Hz. The optimal coating mixture had the composition of 59.9%FNP + 40% ZnO + 1% Resin Binder. The coating utilizes the opto-magneto-electrical properties of ZnO and Magnetic properties of FNP. To further enhance the output, the magneto-electric (ME) effect was increased by subjecting the composite to magnetic field where coating acts as a magnetostrictive material. For the effective volume of 0.0062 cm 3, the composite produced a maximum of 68.5 ?W, or 1.11mW/cm 3 at its resonant frequency of 90 Hz at 160 gauss. The optimal coating mixture had the composition of 59.9% FNP + 40% ZnO + 1% Resin Binder. This research also focused on improving the efficiency of solar cells by utilizing the magnetic effect along with gas plasma etching to improve the internal reflection. Preliminary results showed an improvement in solar cell efficiency from 14.6% to 17.1%.

  13. A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.

    PubMed

    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

  14. Extension of vibrational power flow techniques to two-dimensional structures

    NASA Technical Reports Server (NTRS)

    Cuschieri, Joseph M.

    1988-01-01

    In the analysis of the vibration response and structure-borne vibration transmission between elements of a complex structure, statistical energy analysis (SEA) or finite element analysis (FEA) are generally used. However, an alternative method is using vibrational power flow techniques which can be especially useful in the mid frequencies between the optimum frequency regimes for SEA and FEA. Power flow analysis has in general been used on 1-D beam-like structures or between structures with point joints. In this paper, the power flow technique is extended to 2-D plate-like structures joined along a common edge without frequency or spatial averaging the results, such that the resonant response of the structure is determined. The power flow results are compared to results obtained using FEA results at low frequencies and SEA at high frequencies. The agreement with FEA results is good but the power flow technique has an improved computational efficiency. Compared to the SEA results the power flow results show a closer representation of the actual response of the structure.

  15. Extension of vibrational power flow techniques to two-dimensional structures

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1987-01-01

    In the analysis of the vibration response and structure-borne vibration transmission between elements of a complex structure, statistical energy analysis (SEA) or Finite Element Analysis (FEA) are generally used. However, an alternative method is using vibrational power flow techniques which can be especially useful in the mid- frequencies between the optimum frequency regimes for FEA and SEA. Power flow analysis has in general been used on one-dimensional beam-like structures or between structures with point joints. In this paper, the power flow technique is extended to two-dimensional plate like structures joined along a common edge without frequency or spatial averaging the results, such that the resonant response of the structure is determined. The power flow results are compared to results obtained using FEA at low frequencies and SEA at high frequencies. The agreement with FEA results is good but the power flow technique has an improved computational efficiency. Compared to the SEA results the power flow results show a closer representation of the actual response of the structure.

  16. Adaptive piezoelectric energy harvesting circuit for wireless remote power supply

    Microsoft Academic Search

    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

  17. 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.

  18. Ab initio nonadiabatic vibrational energies of the hydrogen molecule ion

    Microsoft Academic Search

    L. Wolniewicz; J. D. Poll

    1978-01-01

    Nonadiabatic corrections to the four lowest vibrational energy levels of H2+ and HD+ are computed by a variational-perturbational method. The results increase the disagreement with experiment of the theoretical 2-1 and 3-2 vibrational transitions and improve the theoretical energy of the 1-0 transition.

  19. On the Effectiveness of Vibration-based Energy Harvesting

    Microsoft Academic Search

    Shad Roundy

    2005-01-01

    There has been a significant increase in the research on vibration-based energy harvesting in recent years. Most research is focused on a particular technology, and it is often difficult to compare widely differing designs and approaches to vibration-based energy harvesting. The aim of this study is to provide a general theory that can be used to compare different approaches and

  20. Experimental Vibrational Zero-Point Energies: Diatomic Molecules Karl K. Irikuraa...

    E-print Network

    Magee, Joseph W.

    Experimental Vibrational Zero-Point Energies: Diatomic Molecules Karl K. Irikuraa... Physical online 18 April 2007 Vibrational zero-point energies ZPEs , as determined from published spectroscopic: molecular energetics; uncertainty; vibrational spectroscopy; zero-point energy. CONTENTS 1. Introduction

  1. A nanogenerator as a self-powered sensor for measuring the vibration spectrum of a drum membrane.

    PubMed

    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

  2. [The influence of posture on transmission and absorption of vibration energy in whole body vibration exercise].

    PubMed

    Berschin, G; Sommer, H-M

    2010-03-01

    Muscle exercise using whole body vibration platforms is well known as an alternative physical exercise in therapy as well as in high performance sports. Various studies could show an effectiveness in particular to improve maximal strength and springiness. Using these platforms there is no consideration to posture although the damage potential of vibration stress i. e. on intervertebral discs is well-known. Therefore the effect of posture on the transmission and absorption of vibration loads in bipedal standing was examined in a study with 20 sport students. They were exposed to a whole body vibration load in bipedal standing at a vibration frequency of 25 Hz. The transmission of energy was measured at the head in different postural positions. An average transmission of 9 % was measured in spontaneous bipedal standing. It significantly decreased with gradual changes of posture. After 6 weeks posture conditioning exercise this effect was significantly improved. In conclusion different posture in bipedal standing implies not only different energy absorption but also different effects on muscle performance which can explain the partly inconsistent results after vibration exercise. In addition whole body vibration exercise in a prone or sitting position may increase the risk of overload and should be avoided because of reduced energy absorption capacity. PMID:20229446

  3. A variable-capacitance vibration-to-electric energy harvester

    Microsoft Academic Search

    Bernard C. Yen; Jeffrey H. Lang

    2006-01-01

    Past research on vibration energy harvesting has focused primarily on the use of magnets or piezoelectric materials as the basis of energy transduction, with few experimental studies implementing variable-capacitance-based scavenging. In contrast, this paper presents the design and demonstration of a variable-capacitance vibration energy harvester that combines an asynchronous diode-based charge pump with an inductive energy flyback circuit to deliver

  4. Powerful Low-Frequency Vibrators and Outlooks of their Application at Monitoring of

    E-print Network

    Korneev, Valeri A.

    Powerful Low-Frequency Vibrators and Outlooks of their Application at Monitoring of Engineering are briefly elucidated. Key words: active monitoring, seismology, vibrators Figure 1. Seismograms recorded-frequency vibrators. These sources create a force amplitude of up to 100 tons and function in the 1.5-3, 3-6 and 5

  5. Vibrational energy transfer in shocked molecular crystals.

    PubMed

    Hooper, Joe

    2010-01-01

    We consider the process of establishing thermal equilibrium behind an ideal shock front in molecular crystals and its possible role in initiating chemical reaction at high shock pressures. A new theory of equilibration via multiphonon energy transfer is developed to treat the scattering of shock-induced phonons into internal molecular vibrations. Simple analytic forms are derived for the change in this energy transfer at different Hugoniot end states following shock compression. The total time required for thermal equilibration is found to be an order of magnitude or faster than proposed in previous work; in materials representative of explosive molecular crystals, equilibration is predicted to occur within a few picoseconds following the passage of an ideal shock wave. Recent molecular dynamics calculations are consistent with these time scales. The possibility of defect-induced temperature localization due purely to nonequilibrium phonon processes is studied by means of a simple model of the strain field around an inhomogeneity. The specific case of immobile straight dislocations is studied, and a region of enhanced energy transfer on the order of 5 nm is found. Due to the rapid establishment of thermal equilibrium, these regions are unrelated to the shock sensitivity of a material but may allow temperature localization at high shock pressures. Results also suggest that if any decomposition due to molecular collisions is occurring within the shock front itself, these collisions are not enhanced by any nonequilibrium thermal state. PMID:20078172

  6. Vibrational energy redistribution across a heavy atom

    NASA Astrophysics Data System (ADS)

    Lederman, Steven M.; López, Vicente; Fairén, Victor; Voth, Gregory A.; Marcus, R. A.

    1989-12-01

    Vibrational energy relaxation is studied for a model system with two different ligands separated by a heavy atom, there being initially an excess energy in one metal-ligand subsystem. The model has eleven coordinates to achieve a high density of states (two coordinates for one metal-ligand subsystem and nine for the other). The behavior was studied using classical and quantum mechanical methods, and the results compared. Artificial intelligence searching was used in the quantum treatment, because of the large number of potentially contributing quantum states. For the present system the adiabatic separation of motion of the local group modes, previously characterized for a C-C-Sn ligand in a smaller system, still holds when the other ligand has this high density of states. Further, the agreement between the classical and quantum results is much improved over that obtained earlier for a four-coordinate symmetric system. In the latter case isolated intrinsic resonances were responsible for the "energy transfer" which was facilitated sometimes by tunneling. The present agreement of the classical and quantum calculations is generally quantitative at shorter times and at least qualitative for longer times for most states studied. This agreement is encouraging since the former can be less computationally intensive.

  7. The dynamic characteristics of harvesting energy from mechanical vibration via piezoelectric conversion

    NASA Astrophysics Data System (ADS)

    Fan, Kang-Qi; Ming, Zheng-Feng; Xu, Chun-Hui; Chao, Feng-Bo

    2013-10-01

    As an alternative power solution for low-power devices, harvesting energy from the ambient mechanical vibration has received increasing research interest in recent years. In this paper we study the transient dynamic characteristics of a piezoelectric energy harvesting system including a piezoelectric energy harvester, a bridge rectifier, and a storage capacitor. To accomplish this, this energy harvesting system is modeled, and the charging process of the storage capacitor is investigated by employing the in-phase assumption. The results indicate that the charging voltage across the storage capacitor and the gathered power increase gradually as the charging process proceeds, whereas the charging rate slows down over time as the charging voltage approaches to the peak value of the piezoelectric voltage across the piezoelectric materials. In addition, due to the added electrical damping and the change of the system natural frequency when the charging process is initiated, a sudden drop in the vibration amplitude is observed, which in turn affects the charging rate. However, the vibration amplitude begins to increase as the charging process continues, which is caused by the decrease in the electrical damping (i.e., the decrease in the energy removed from the mechanical vibration). This electromechanical coupling characteristic is also revealed by the variation of the vibration amplitude with the charging voltage.

  8. Nonlinear vibration control and energy harvesting of a beam using a nonlinear energy sink and a piezoelectric device

    NASA Astrophysics Data System (ADS)

    Nili Ahmadabadi, Z.; Khadem, S. E.

    2014-09-01

    This paper presents an optimal design for a system comprising a nonlinear energy sink (NES) and a piezoelectric-based vibration energy harvester attached to a free-free beam under shock excitation. The energy harvester is used for scavenging vibration energy dissipated by the NES. Grounded and ungrounded configurations are examined and the systems parameters are optimized globally to both maximize the dissipated energy by the NES and increase the harvested energy by piezoelectric element. A satisfactory amount of energy has been harvested as electric power in both configurations. The realization of nonlinear vibration control through one-way irreversible nonlinear energy pumping and optimizing the system parameters result in acquiring up to 78 percent dissipation of the grounded system energy.

  9. Energy harvesting of random wide-band vibrations with applications to an electro-magnetic rotational energy harvester

    E-print Network

    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. ...

  10. Characterization of Direct Piezoelectric Properties for Vibration Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Yoshimura, Takeshi; Miyabuchi, Hiroki; Murakami, Syuichi; Ashida, Atsushi; Fujimura, Norifumi

    2011-10-01

    Direct piezoelectric effect of Pb(Zr,Ti)O3 (PZT) thin films was investigated to discuss the application of ferroelectric films to vibration energy harvesting. From the model of the piezoelectric vibration energy harvester, it was found that the figure of merit (FOM) is proportional of the square of the effective transverse piezoelectric coefficient e31,f. The e31,f coefficient of PZT films were measured by substrate bending method. Furthermore, it was found that the e31,f coefficient increases with increasing strain, which is favourable for the vibration energy harvesting.

  11. Micro-scale piezoelectric vibration energy harvesting: From fixed-frequency to adaptable-frequency devices

    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 priori, an adaptable-frequency energy harvester was designed. The adaptable-frequency harvester works by taking advantage of the coupling between

  12. Direct measurements of state-to-state rotational and vibrational energy transfer in highly vibrational excited acetylene: vibrational overtone excitation--LIF detection

    Microsoft Academic Search

    Joseph D. Tobiason; A. L. Utz; Fleming F. Crim

    1993-01-01

    Vibrational overtone excitation of single rovibrational eigenstates followed by laser-induced fluorescence (LIF) detection of the collisionally populated quantum states in single collision conditions provides a method for directly measuring state-to-state rotational and vibrational energy transfer rates in highly vibrationally excited acetylene. There are several advantages in collecting the data in vibrational overtone excitation spectra with LIF detection (scanning excitation laser

  13. Piezoelectric energy harvesting from flow-induced vibration

    Microsoft Academic Search

    D.-A. Wang; H.-H. Ko

    2010-01-01

    A new piezoelectric energy harvester for harnessing energy from flow-induced vibration is developed. It converts flow energy into electrical energy by piezoelectric conversion with oscillation of a piezoelectric film. A finite element model is developed in order to estimate the generated voltage of the piezoelectric laminate subjected to a distributed load. Prototypes of the energy harvester are fabricated and tested.

  14. 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.

  15. Measurement of Aerodynamic Power Associated with Vortex-Induced Vibration of Electrical Transmission Lines

    Microsoft Academic Search

    J. M. Simmons; P. M. G. Cleary

    1980-01-01

    Prediction of the amplitude of vortex -induced vibration (aeolian vibration) of electrical transmission lines is based on knowledge of the aerodynamic power transferred to a circular cylinder oscilating in a cross flow. Methods for the measurement of aerodynamic power and the available data are reviewed. The paper reports new data obtained by direct measurement of the unsteady pressure distribution on

  16. Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

    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.

  17. Vibration-translation energy transfer in vibrationally excited diatomic molecules. Ph.D. Thesis - York Univ., Toronto

    NASA Technical Reports Server (NTRS)

    Mckenzie, R. L.

    1976-01-01

    A semiclassical collision model is applied to the study of energy transfer rates between a vibrationally excited diatomic molecule and a structureless atom. The molecule is modeled as an anharmonic oscillator with a multitude of dynamically coupled vibrational states. Three main aspects in the prediction of vibrational energy transfer rates are considered. The applicability of the semiclassical model to an anharmonic oscillator is first evaluated for collinear encounters. Second, the collinear semiclassical model is applied to obtain numerical predictions of the vibrational energy transfer rate dependence on the initial vibrational state quantum number. Thermally averaged vibration-translation rate coefficients are predicted and compared with CO-He experimental values for both ground and excited initial states. The numerical model is also used as a basis for evaluating several less complete but analytic models. Third, the role of rational motion in the dynamics of vibrational energy transfer is examined. A three-dimensional semiclassical collision model is constructed with coupled rotational motion included. Energy transfer within the molecule is shown to be dominated by vibration-rotation transitions with small changes in angular momentum. The rates of vibrational energy transfer in molecules with rational frequencies that are very small in comparison to their vibrational frequency are shown to be adequately treated by the preceding collinear models.

  18. 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.

  19. Optical manipulation of intrinsic localized vibrational energy in cantilever arrays

    E-print Network

    M. Sato; B. E. Hubbard; A. J. Sievers; B. Ilic; H. G. Craighead

    2004-03-16

    Optically-induced real-time impurity modes are used to shepherd intrinsic localized vibrational modes (discrete breathers) along micromechanical arrays via either attractive or replulsive interactions. Adding an electrode to the cantilever array provides control of the sign of lattice anharmonicity, hence allowing both hard and soft nonlinearities to be studied. A number of dynamical effects are demonstrated and explained, including the optical tweezing of localized vibrational energy in a nonlinear lattice.

  20. Vibrational spectroscopy of water in hydrated lipid multi-bilayers. III. Water clustering and vibrational energy transfer.

    PubMed

    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. PMID:24206336

  1. Chemical reaction versus vibrational quenching in low energy collisions of vibrationally excited OH with O.

    PubMed

    Pradhan, G B; Juanes-Marcos, J C; Balakrishnan, N; Kendrick, Brian K

    2013-11-21

    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 (2)A'' potential energy surface of the HO2 molecule. The time-independent Schro?dinger 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. PMID:24320324

  2. Analytical and experimental comparisons of electromechanical vibration response of a piezoelectric bimorph beam for power harvesting

    NASA Astrophysics Data System (ADS)

    Lumentut, M. F.; Howard, I. M.

    2013-03-01

    Power harvesters that extract energy from vibrating systems via piezoelectric transduction show strong potential for powering smart wireless sensor devices in applications of health condition monitoring of rotating machinery and structures. This paper presents an analytical method for modelling an electromechanical piezoelectric bimorph beam with tip mass under two input base transverse and longitudinal excitations. The Euler-Bernoulli beam equations were used to model the piezoelectric bimorph beam. The polarity-electric field of the piezoelectric element is excited by the strain field caused by base input excitation, resulting in electrical charge. The governing electromechanical dynamic equations were derived analytically using the weak form of the Hamiltonian principle to obtain the constitutive equations. Three constitutive electromechanical dynamic equations based on independent coefficients of virtual displacement vectors were formulated and then further modelled using the normalised Ritz eigenfunction series. The electromechanical formulations include both the series and parallel connections of the piezoelectric bimorph. The multi-mode frequency response functions (FRFs) under varying electrical load resistance were formulated using Laplace transformation for the multi-input mechanical vibrations to provide the multi-output dynamic displacement, velocity, voltage, current and power. The experimental and theoretical validations reduced for the single mode system were shown to provide reasonable predictions. The model results from polar base excitation for off-axis input motions were validated with experimental results showing the change to the electrical power frequency response amplitude as a function of excitation angle, with relevance for practical implementation.

  3. Direct measurements of rotation-specific, state-to-state vibrational energy transfer in highly vibrationally excited acetylene

    Microsoft Academic Search

    J. D. Tobiason; A. L. Utz; F. F. Crim

    1994-01-01

    Vibrational overtone excitation followed by laser-induced fluorescence detection allows the direct measurement of rotationally resolved vibrational energy transfer rates in highly vibrationally excited acetylene molecules. We detect transfer from the initial, even rotational states Ji=0–22 of 3?3 (?˜0=9640 cm?1) to the nearly isoenergetic final state Jf=4 of ?1+?2+?3+2?4, l=0 (?˜0=9668 cm?1). For these pathways, we observe changes in energy of

  4. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    SciTech Connect

    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.

  5. Demonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting

    E-print Network

    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

  6. Low-frequency vibration energy harvester using a spherical permanent magnet with controlled mass distribution

    NASA Astrophysics Data System (ADS)

    Choi, Yunhee; Ju, Suna; Chae, Song Hee; Jun, Sangbeom; Ji, Chang-Hyeon

    2015-06-01

    This paper presents a vibration energy harvester using a springless spherical permanent magnet with a non-uniform mass distribution as a proof mass. The magnet has been designed to have the center of mass below the geometrical center, which generates a roly-poly-like motion in response to external vibrations and maintains the upright position. Utilizing this roly-poly-like magnet, proof-of-concept electromagnetic energy harvesters have been fabricated, tested and analyzed. An analytical model which explains the motion of the magnet assembly and resulting output voltage has been developed by finite element analysis of the magnetic field distribution and motion analysis of the magnet assembly. With the fabricated device, a maximum open-circuit voltage of 48.85 mVrms and an output power of 9.03 ?W have been obtained in response to a 20 Hz sinusoidal vibration at 3 g acceleration.

  7. Switched-mode impedance synthesis for electrical tuning of a vibration energy harvester

    NASA Astrophysics Data System (ADS)

    Bowden, J. A.; Burrow, S. G.; Clare, L. R.

    2013-12-01

    Switched-mode power circuits are able to efficiently synthesise a variable complex load impedance that can tune a vibration energy harvester, whilst also providing rectification and feeding the harvested energy into a DC store. The electrical tuning system presented in this paper is based upon a boost rectifier configured as a variable power factor converter. Its performance is benchmarked against a more basic resistance emulator where it is demonstrated that electrical tuning provides an increase in power bandwidth of over three times. The paper describes the experimental results of electrical tuning in some detail and elucidates the design challenges for these systems.

  8. Development of a Cantilever Beam Generator Employing Vibration Energy Harvesting

    Microsoft Academic Search

    R. N. Torah; S. P. Beeby; M. J. Tudor; T. O'Donnell; S. Roy

    This paper details the development of a generator based upon a cantilever beam inertial mass system which harvests energy from ambient environmental vibrations. The paper compares the predicted results from Finite Element Analysis (FEA) of the mechanical behaviour and magnetic field simulations and experimental results from a generator. Several design changes were implemented to maximise the conversion of magnetic energy

  9. Low Head, Vortex Induced Vibrations River Energy Converter

    SciTech Connect

    Bernitsas, Michael B.; Dritz, Tad

    2006-06-30

    Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) is a novel, demonstrated approach to extracting energy from water currents. This invention is based on a phenomenon called Vortex Induced Vibrations (VIV), which was first observed by Leonardo da Vinci in 1504AD. He called it ‘Aeolian Tones.’ For decades, engineers have attempted to prevent this type of vibration from damaging structures, such as offshore platforms, nuclear fuel rods, cables, buildings, and bridges. The underlying concept of the VIVACE Converter is the following: Strengthen rather than spoil vortex shedding; enhance rather than suppress VIV; harness rather than mitigate VIV energy. By maximizing and utilizing this unique phenomenon, VIVACE takes this “problem” and successfully transforms it into a valuable resource for mankind.

  10. Connected Vibrating Piezoelectric Bimorph Beams as a Wide-band Piezoelectric Power Harvester

    Microsoft Academic Search

    Zengtao Yang; Jiashi Yang

    2009-01-01

    We analyze coupled flexural vibration of two elastically and electrically connected piezoelectric beams near resonance for converting mechanical vibration energy to electrical energy. Each beam is a so-called piezoelectric bimorph with two layers of piezoelectrics. The 1D equations for bending of piezoelectric beams are used for a theoretical analysis. An exact analytical solution to the beam equations is obtained. Numerical

  11. A two-dimensional broadband vibration energy harvester using magnetoelectric transducer

    SciTech Connect

    Yang, Jin, E-mail: yangjin@cqu.edu.cn; Wen, Yumei; Li, Ping; Yue, Xihai; Yu, Qiangmo; Bai, Xiaoling [Department of Optoelectronic Engineering, Research Center of Sensors and Instruments, Chongqing University, Chongqing 400044 (China)] [Department of Optoelectronic Engineering, Research Center of Sensors and Instruments, Chongqing University, Chongqing 400044 (China)

    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})

  12. IEEE Power and Energy

    NSDL National Science Digital Library

    2003-01-01

    IIEEE presents Power and Energy magazine online. The latest issue as well as several previous issues are available online for free use. Columns of Power and Energy highlight history, industry news, standards, and opinion articles. The archives currently go back to 2009.

  13. Enhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n

    E-print Network

    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

  14. Harvested power and sensitivity analysis of vibrating shoe-mounted piezoelectric cantilevers

    NASA Astrophysics Data System (ADS)

    Moro, L.; Benasciutti, D.

    2010-11-01

    This paper presents a preliminary investigation on energy harvesting from human walking via piezoelectric vibrating cantilevers. Heel accelerations during human gait are established by correlating data gathered from the literature with direct experimental measurements. All the observed relevant features are synthesized in a typical (standard) acceleration signal, used in subsequent numerical simulations. The transient electromechanical response and the harvested power of a shoe-mounted bimorph cantilever excited by the standard acceleration signal is computed by numerical simulations and compared with measurements on a real prototype. A sensitivity analysis is finally developed to estimate the mean harvested power for a wide range of scavenger configurations. Acceptability criteria based on imposed geometrical constraints and resistance strength limits (e.g. fatigue limit) are also established. This analysis allows a quick preliminary screening of harvesting performance of different scavenger configurations.

  15. Minimization of the Vibration Energy of Thin-Plate Structures and the Application to the Reduction of Gearbox Vibration

    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.

  16. Experimental Vibrational Zero-Point Energies: Diatomic Molecules

    Microsoft Academic Search

    Karl K. Irikura

    2007-01-01

    Vibrational zero-point energies (ZPEs), as determined from published spectroscopic constants, are derived for 85 diatomic molecules. Standard uncertainties are also provided, including estimated contributions from bias as well as the statistical uncertainties propagated from those reported in the spectroscopy literature. This compilation will be helpful for validating theoretical procedures for predicting ZPEs, which is a necessary step in the ab

  17. Piezoelectric energy harvesting from traffic-induced bridge vibrations

    E-print Network

    Paris-Sud XI, Université de

    Piezoelectric energy harvesting from traffic-induced bridge vibrations Micha¨el Peigney1 of cantilever piezoelectric harvester was designed, tested, and modeled. Even though the considered bridge for piezoelectric harvesters to be used on bridges. hal-00859131,version1-11Sep2013 Author manuscript, published

  18. On Mechanical Modeling of Cantilevered Piezoelectric Vibration Energy Harvesters

    Microsoft Academic Search

    A. Erturk; D. J. Inman

    2008-01-01

    Cantilevered beams with piezoceramic (PZT) layers are the most commonly investigated type of vibration energy harvesters. A frequently used modeling approach is the single-degree-of-freedom (SDOF) modeling of the harvester beam as it allows simple expressions for the electrical outputs. In the literature, since the base excitation on the harvester beam is assumed to be harmonic, the well known SDOF relation

  19. Vibration exposure for selected power hand tools used in automobile assembly.

    PubMed

    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

  20. Improved mechanical reliability of MEMS electret based vibration energy harvesters for automotive applications

    NASA Astrophysics Data System (ADS)

    Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.

    2014-11-01

    Current commercial wireless tire pressure monitoring systems (TPMS) require a battery as electrical power source. The battery limits the lifetime of the TPMS. This limit can be circumvented by replacing the battery by a vibration energy harvester. Autonomous wireless TPMS powered by MEMS electret based vibration energy harvester have been demonstrated. A remaining technical challenge to attain the grade of commercial product with these autonomous TPMS is the mechanical reliability of the MEMS harvester. It should survive the harsh conditions imposed by the tire environment, particularly in terms of mechanical shocks. As shown in this article, our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, several types of shock absorbing structures are investigated. With the best proposed solution, the shock resilience of the harvesters is brought above 2500 g.

  1. Minimization of the vibration energy of thin-plate structure

    NASA Technical Reports Server (NTRS)

    Inoue, Katsumi; Townsend, Dennis P.; Coy, John J.

    1992-01-01

    An optimization method is proposed to reduce the vibration of thin plate structures. The method is based on a finite element shell analysis, a modal analysis, and a structural optimization method. In the finite element analysis, a triangular shell element with 18 dof is used. In the optimization, the overall vibration energy of the structure is adopted as the objective function, and it is minimized at the given exciting frequency by varying the thickness of the elements. The technique of modal analysis is used to derive the sensitivity of the vibration energy with respect to the design variables. The sensitivity is represented by the sensitivities of both eigenvalues and eigenvectors. The optimum value is computed by the gradient projection method and a unidimensional search procedure under the constraint condition of constant weight. A computer code, based on the proposed method, is developed and is applied to design problems using a beam and a plate as test cases. It is confirmed that the vibration energy is reduced at the given exciting frequency. For the beam excited by a frequency slightly less than the fundamental natural frequency, the optimized shape is close to the beam of uniform strength.

  2. A Vibration-Based PMN-PT Energy Harvester

    Microsoft Academic Search

    Alex Mathers; Kee S. Moon; Jingang Yi

    2009-01-01

    We report design, modeling, analysis, and experimental study of a vibration-based piezoelectric energy harvester. The energy harvester is made of a composite cantilever of a single crystal relaxor ferroelectric material, (1- x)Pb(Mg1\\/3Nb2\\/3)O3-xPbTiO3 (PMN-PT), and a polydimethylsiloxane (PDMS) base layer. A PDMS proof mass is constructed at the tip of the composite cantilever beam and is used as a means to

  3. Frequency Up-Converted Low Frequency Vibration Energy Harvester Using Trampoline Effect

    NASA Astrophysics Data System (ADS)

    Ju, S.; Chae, S. H.; Choi, Y.; Jun, S.; Park, S. M.; Lee, S.; Lee, H. W.; Ji, C.-H.

    2013-12-01

    This paper presents a non-resonant vibration energy harvester based on magnetoelectric transduction mechanism and mechanical frequency up-conversion using trampoline effect. The harvester utilizes a freely movable spherical permanent magnet which bounces off the aluminum springs integrated at both ends of the cavity, achieving frequency up-conversion from low frequency input vibration. Moreover, bonding method of magnetoelectric laminate composite has been optimized to provide higher strain to piezoelectric material and thus obtain a higher output voltage. A proof-of-concept energy harvesting device has been fabricated and tested. Maximum open-circuit voltage of 11.2V has been obtained and output power of 0.57?W has been achieved for a 50k? load, when the fabricated energy harvester was hand-shaken.

  4. Energy Harvesting Devices Utilizing Resonance Vibration of Piezoelectric Buzzer

    NASA Astrophysics Data System (ADS)

    Ogawa, Toshio; Sugisawa, Ryosuke; Sakurada, Yuta; Aoshima, Hiroshi; Hikida, Masahito; Akaishi, Hiroshi

    2013-09-01

    A piezoelectric buzzer for energy harvesting was investigated. Although an external force was added to a buzzer, a lead zirconate titanate (PZT) unimorph in the buzzer, the ceramic disc diameter, thickness, and capacitance of which were respectively 14 mm, 0.2 mm, and 10 nF, generated resonance vibration. As a result, alternating voltages of around 30 V and a frequency of 5 kHz were observed. When the generated voltages were applied to a LED lamp, new devices such as a “night-view footwear” and a “piezo-walker” were developed. It was confirmed that the piezo-buzzer for energy harvesting utilizing resonance vibration is an effective tool for obtaining clean energy.

  5. Intermolecular vibrational energy transfers in liquids and solids.

    PubMed

    Chen, Hailong; Wen, Xiewen; Guo, Xunmin; Zheng, Junrong

    2014-07-21

    Resonant and nonresonant intermolecular vibrational energy transfers in KSCN/KSC(13)N/KS(13)C(15)N aqueous and DMF solutions and crystals are studied. Both energy-gap and temperature dependent measurements reveal some surprising results, e.g. inverted energy-gap dependent energy transfer rates and opposite temperature dependences of resonant and nonresonant energy transfer rates. Two competing mechanisms are proposed to be responsible for the experimental observations. The first one is the dephasing mechanism in which the measured energy transfer rate originates from the dephasing of the energy donor-acceptor coherence, and the second one is the phonon-compensation mechanism derived from the second order perturbation. It is found that both the nonresonant energy transfers in the liquids and resonant energy transfers in both liquids and solids can be well described by the first mechanism. The second mechanism explains the nonresonant energy transfers in one series of the solid samples very well. PMID:24899537

  6. Energy transfer in highly vibrationally excited acetylene: Relaxation for vibrational energies from 6500 to 13 000 cm?1

    Microsoft Academic Search

    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

  7. An Active Micro Vibration Isolator with Zero-Power Controlled Magnetic Suspension Technology

    Microsoft Academic Search

    Masaya Takasaki; Yuji Ishino; Hirohisa Suzuki; Takeshi Mizuno

    2006-01-01

    In this paper, a three-degree-of-freedom vibration isolation system using active zero-power controlled magnetic suspension is presented in order to isolate vibrations transmitted from the ground and to attenuate the effect of direct disturbances on the table. The zero-compliance of the isolator for direct disturbances was realized by connecting a conventional mechanical spring in series with a negative spring produced by

  8. A review of vibration problems in power station boiler feed pumps

    NASA Technical Reports Server (NTRS)

    France, David

    1994-01-01

    Boiler feed pump reliability and availability is recognized as important to the overall efficiency of power generation. Vibration monitoring is often used as a part of planned maintenance. This paper reviews a number of different types of boiler feed pump vibration problems describing some methods of solution in the process. It is hoped that this review may assist both designers and users faced with similar problems.

  9. A Study on Energy Harvesting Aware Routing for Vibration-Motivated Wireless Sensor Networks

    E-print Network

    Lim, Sunho

    , a piezoelectric device based energy harvesting from ambient vibrations is a promising technique for easy harvesting, Piezoelectric transducer, Routing, Vibration, Wireless sensor networks. This researchA Study on Energy Harvesting Aware Routing for Vibration-Motivated Wireless Sensor Networks TTU

  10. Vibrational and collisional energy effects in the reaction of ammonia ions with methylamine

    E-print Network

    Zare, Richard N.

    Vibrational and collisional energy effects in the reaction of ammonia ions with methylamine investigated the reactions of vibrationally state-selected ammonia ions with d3-methylamine over the center-of-mass collisional energy range of 0.5 to 10.0 eV and for ammonia ion vibrational states ranging from 2 1­9. Under

  11. Experimental Study of the Vibration-Induced Fretting of Silver-Plated High Power Automotive Connectors

    Microsoft Academic Search

    Rujian Fu; Song-Yul Choe; Robert L. Jackson; G. T. Flowers; Michael J. Bozack; Liang Zhong; Daegee Kim

    2010-01-01

    Relatively little is known about the fretting mechanism of high power connectors used in hybrid vehicles, even though the vehicles are widely being introduced to the market. This work experimentally investigates the fretting mechanisms of silver-plated high power connectors caused by vibrations. In order to emulate operational and environmental effects, a test stand was designed that is capable of measuring

  12. Statistical Study of Voltage Fluctuations in Power Connectors During Fretting Vibration

    Microsoft Academic Search

    Erwann Carvou; Noureddine Ben Jemaa

    2009-01-01

    It is well known that vibration of contact interfaces is the main cause of contact degradation by the so called fretting corrosion phenomenon. In fact the process of generating particles by mechanical wear produces an increase of contact voltage, frequently manifested by a high contact resistance in low power and signal connectors. In high power connectors, this degradation is expected

  13. Vibration-Induced Changes in the Contact Resistance of High Power Electrical Connectors for Hybrid Vehicles

    Microsoft Academic Search

    Rujian Fu; Song-Yul Ben Choe; Robert L. Jackson; George T. Flowers; Michael J. Bozack; Liang Zhong; Daegee Kim

    2012-01-01

    Relatively little is known about the fretting mechanism of high power connectors used in hybrid vehicles, even though the vehicles are widely being introduced to the market. This paper experimentally investigates the fretting mechanisms of silver-plated high power connectors caused by vibrations. In order to emulate operational and environmental effects, a test stand was designed that is capable of measuring

  14. 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.

  15. Vibration signal classification by wavelet packet energy flow manifold learning

    NASA Astrophysics Data System (ADS)

    He, Qingbo

    2013-04-01

    This paper proposes a new study to explore the wavelet packet energy (WPE) flow characteristics of vibration signals by using the manifold learning technique. This study intends to discover the nonlinear manifold information from the WPE flow map of vibration signals to characterize and discriminate different classes. A new feature, called WPE manifold feature, is achieved by three main steps: first, the wavelet packet transform (WPT) is conducted to decompose multi-class signals into a library of time-frequency subspaces; second, the WPE is calculated in each subspace to produce a feature vector for each signal; and finally, low-dimensional manifold features carrying class information are extracted from the WPE library for either training or testing samples by using the manifold learning algorithm. The new feature reveals the nonlinear WPE flow structure among various redundant time-frequency subspaces. It combines the benefits of time-frequency characteristics and nonlinear information, and hence exhibits valuable properties for vibration signal classification. The effectiveness and the merits of the proposed method are confirmed by case studies on vibration analysis-based machine fault classification.

  16. Structure-vibration Analysis of a Power Transformer (154kV\\/60MVA\\/Single Phase)

    Microsoft Academic Search

    Young-Dal Kim; Jae-Myung Shim; Woo-Yong Park; Sung-joong Kim; Dong Seok Hyun; Dae-Dong Lee

    The most common cause of power transformer failures is mechanical defect brought about by excessive vibration, which is formed by the combination of multiples of a frequency of 120 Hz. In this paper, the types of mechanical exciting forces applied to the power transformer were classified, and the mechanical damage mechanism of the power transformer was identified using the vibration

  17. A capacitive vibration-to-electricity energy converter with integrated mechanical switches

    NASA Astrophysics Data System (ADS)

    Chiu, Y.; Tseng, V. F. G.

    2008-10-01

    Due to recent advances in low-power VLSI design technology, it has become feasible to power portable or remote electronic devices by scavenging the ambient energy. The design, fabrication and measurement of a capacitive vibration-to-electricity energy converter are presented in this paper. With a device area constraint of 1 cm2 and an auxiliary battery supply of 3.6 V, the device was designed to generate an output power of 31 µW with an output saturation voltage of 40 V. An external mass of 4 g was needed to adjust the device resonance to match the input vibration of 2.25 m s-2 at 120 Hz. Mechanical contact switches were integrated onto the device to provide accurate charge-discharge energy conversion timing. The device was fabricated in SOI (silicon-on-insulator) wafers by deep silicon etching technology. Parasitic capacitance was minimized by partial back side substrate removal. Resonant frequencies of the fabricated device with and without the external mass agreed with the expected values. Without the external mass, the measured ac output power was 1.2 µW with a load of 5 M? at 1870 Hz. Detailed circuit modeling and ac output power measurement of the devices with the external mass attached are in progress.

  18. Ion clustering in aqueous solutions probed with vibrational energy transfer

    PubMed Central

    Bian, Hongtao; Wen, Xiewen; Li, Jiebo; Chen, Hailong; Han, Suzee; Sun, Xiuquan; Song, Jian; Zhuang, Wei; Zheng, Junrong

    2011-01-01

    Despite prolonged scientific efforts to unravel the hydration structures of ions in water, many open questions remain, in particular concerning the existences and structures of ion clusters in 1?1 strong electrolyte aqueous solutions. A combined ultrafast 2D IR and pump/probe study through vibrational energy transfers directly observes ion clustering in aqueous solutions of LiSCN, NaSCN, KSCN and CsSCN. In a near saturated KSCN aqueous solution (water/KSCN molar ratio = 2.4/1), 95% of the anions form ion clusters. Diluting the solution results in fewer, smaller, and tighter clusters. Cations have significant effects on cluster formation. A small cation results in smaller and fewer clusters. The vibrational energy transfer method holds promise for studying a wide variety of other fast short-range molecular interactions.

  19. Vibration–Translational Energy Transfer According to the Morse Potential

    Microsoft Academic Search

    Samuel L. Thompson

    1968-01-01

    A quantum-mechanical analysis of molecular vibration–translational motion energy transfer is obtained using the Morse potential, a one-dimensional model, and the method of distorted waves. All wavefunctions and transition matrix elements are obtained in closed form. In the limit of high temperatures, the results are identical to the Landau–Teller expression. At low temperatures, resonances are found to result from the attractive

  20. Exploring the vibrational fingerprint of the electronic excitation energy via molecular dynamics

    SciTech Connect

    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.

  1. Calculation of vibrational zero-point energy

    Microsoft Academic Search

    M. Rahal; M. Hilali; A. El Hammadi; M. El Mouhtadi; A. El Hajbi

    2001-01-01

    We have established an empirical formula for calculating the zero-point energy (ZPE) of organic compounds. We applied this formula to 80 molecular systems, and compared it to the AM1 semi-empirical method, in both cases with satisfactory results. We also observed that the sum ZPE+H(T)?H(0) and the empirically derived ZPE(empirical) are related by a quasi-linear relation.

  2. Electron-vibration energy exchange models in nitrogen-containing plasma flows

    SciTech Connect

    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.

  3. Research on new automobile power hydraulic braking system by vibratory energy

    Microsoft Academic Search

    Ding Zhi-hua; Lei Zheng-bao; Lei Mu-xi

    2011-01-01

    A new automobile power hydraulic braking system by vibratory energy is introduced which includes four vibration dampers, four energy accumulators, hydraulic booster, one storage tank, four wheel cylinders, four electromagnetic one-way valves, brake master cylinder, vacuum booster, brake pedal and loading sensing pressure proportioning valve(LSPV). Vibration damper is composed of nitrogen cavity, piston, piston rod, shell, rebound valve, compression valve,

  4. Theoretical investigations of energy harvesting efficiency from structural vibrations using piezoelectric and electromagnetic oscillators.

    PubMed

    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

  5. 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.

  6. Vibrational Energy Relaxation of Isotopically Labeled Amide I Modes in Cytochrome c: Theoretical Investigation of Vibrational Energy Relaxation Rates and Pathways

    E-print Network

    Straub, John E.

    Vibrational Energy Relaxation of Isotopically Labeled Amide I Modes in Cytochrome c: Theoretical theory, vibrational energy relaxation (VER) of isotopically labeled amide I modes in cytochrome c studied were isotopically labeled according to IR experiment.30,31 We decompose the VER rate into two

  7. Tracking energy transfer from excited to accepting modes: application to water bend vibrational relaxation.

    PubMed

    Rey, Rossend; Hynes, James T

    2012-05-14

    We extend, via a reformulation in terms of Poisson brackets, the method developed previously (Rey et al., J. Phys. Chem. A, 2009, 113, 8949) allowing analysis of the pathways of an excited molecule's ultrafast vibrational relaxation in terms of intramolecular and intermolecular contributions. In particular we show how to ascertain, through the computation of power and work, which portion of an initial excess molecular energy (e.g. vibrational) is transferred to various degrees of freedom (e.g. rotational, translational) of the excited molecule itself and its neighbors. The particular case of bend excess energy relaxation in pure water is treated in detail, completing the picture reported in the work cited above. It is shown explicitly, within a classical description, that almost all of the initial water bend excitation energy is transferred-either indirectly, via Fermi resonance centrifugal coupling to the bend-excited water's rotation, or directly via intermolecular coupling- to local water librations, only involving molecules in the first two hydration shells of the vibrationally excited water molecule. Finally, it is pointed out that the Poisson bracket formulation can also be applied to elucidate the microscopic character of solvation and rotational dynamics, and should prove useful in developing a quantum treatment for energy flow in condensed phases. PMID:22402668

  8. Modeling nonlinear random vibration: Implication of the energy conservation law

    E-print Network

    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.

  9. Vibration interaction in a multiple flywheel system

    NASA Astrophysics Data System (ADS)

    Firth, Jordan; Black, Jonathan

    2012-03-01

    This paper investigates vibration interaction in a multiple flywheel system. Flywheels can be used for kinetic energy storage in a satellite Integrated Power and Attitude Control System (IPACS). One hitherto unstudied problem with IPACS is vibration interaction between multiple unbalanced wheels. This paper uses a linear state-space dynamics model to study the impact of vibration interaction. Specifically, imbalance-induced vibration inputs in one flywheel rotor are used to cause a resonant whirling vibration in another rotor. Extra-synchronous resonant vibrations are shown to exist, but with damping modeled the effect is minimal. Vibration is most severe when both rotors are spinning in the same direction.

  10. Optimized energy harvesting from mechanical vibrations through piezoelectric actuators, based on a synchronized switching technique

    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.

  11. 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.

  12. Triboelectric nanogenerator built on suspended 3D spiral structure as vibration and positioning sensor and wave energy harvester.

    PubMed

    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

  13. Effects of vibration and shock on the performance of gas-bearing space-power Brayton cycle turbomachinery. 2: Sinusoidal and random vibration

    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.

  14. Optimal piezoelectric beam shape for single and broadband vibration energy harvesting: Modeling, simulation and experimental results

    NASA Astrophysics Data System (ADS)

    Muthalif, Asan G. A.; Nordin, N. H. Diyana

    2015-03-01

    Harvesting energy from the surroundings has become a new trend in saving our environment. Among the established ones are solar panels, wind turbines and hydroelectric generators which have successfully grown in meeting the world's energy demand. However, for low powered electronic devices; especially when being placed in a remote area, micro scale energy harvesting is preferable. One of the popular methods is via vibration energy scavenging which converts mechanical energy (from vibration) to electrical energy by the effect of coupling between mechanical variables and electric or magnetic fields. As the voltage generated greatly depends on the geometry and size of the piezoelectric material, there is a need to define an optimum shape and configuration of the piezoelectric energy scavenger. In this research, mathematical derivations for unimorph piezoelectric energy harvester are presented. Simulation is done using MATLAB and COMSOL Multiphysics software to study the effect of varying the length and shape of the beam to the generated voltage. Experimental results comparing triangular and rectangular shaped piezoelectric beam are also presented.

  15. Power dissipation and fluidization in a vibrated/stirred granular flow

    NASA Astrophysics Data System (ADS)

    Gilchrist, James; Ford, Kenneth; Caram, Hugo

    2006-11-01

    We investigate flow of powders within a model high shear granulation process. High shear granulators typically produce flow by sweeping a pitched bladed under a granular bed at high rotation rates, providing both fluidization from upward lift from fast moving blades and flow in a circular motion. In our experimental setup, we partially decouple the fluidization and circulation by independently vibrating and stirring a deep granular bed. Without stirring, vibration begins to fluidize the bed when the Froude number, Fr > 1. By attaching an accelerometer to the vessel, we measure the resulting time of flight. The deep granular bed primarily behaves as a solid mass at moderate Fr, and we compare the accelerometer data to a simple model of a bouncing mass on a spring. The stirring mechanism allows measurement of the power required to maintain a constant rotation rate. Without vibration, the power draw is linearly related to the rotation rate. At high Fr, the power requirements for stirring the fluidized bed decrease dramatically. At intermediate Fr, we observe a transition between dense granular flow and fluidized granular behavior with increased vibration and stirring by monitoring the power requirements for stirring. This transition marks the boundary between dense granular flow and fluidized granular flow, and suggests the degree to which stirring influences bulk fluidization.

  16. Using powerful vibrators for calibration of seismic traces in nuclear explosion monitoring problems.

    NASA Astrophysics Data System (ADS)

    Glinsky, B.; Kovalevsky, V.; Seleznev, V.; Emanov, A.; Soloviev, V.

    2009-04-01

    The efficiency of functioning of the International Seismic Monitoring System (ISMS) is connected with the accuracy of the location and identification of a source of seismic waves which can be nuclear explosion. The errors in the determination of the location are caused by local and regional variations of wave hodographs. Empirical approach to solving these problems is to use events for which the locations and times are known, in order to determine a set of corrections to the regional model of wave propagation. The using of powerful vibrators for calibration of seismic traces is a new way in nuclear explosion monitoring problems. Now the 60-100 tons force vibrator can radiate the signals which can be recorded at the distances up to 500 km and can be used for regional calibration of seismic traces. The comparison of the seismic wave fields of powerful vibrators and 100-ton chemical explosion "Omega-3" at the 630-km profile, quarry explosions of the Kuznetsk basin with power from 50 to 700 tons at the distances up to 355 km showed their equivalence in the main types of waves. The paper presents the results of experiments of long-distance recording of seismic signals of powerful vibrators and detailed investigation of the velocity characteristics of the Earth's crust in West Siberia and Altay-Sayan region.

  17. Using powerful vibrators for calibration of seismic traces in nuclear explosion monitoring problems

    NASA Astrophysics Data System (ADS)

    Glinsky, B.; Kovalevsky, V.; Seleznev, V.; Emanov, A.; Soloviev, V.

    2009-04-01

    The efficiency of functioning of the International Seismic Monitoring System (ISMS) is connected with the accuracy of the location and identification of a source of seismic waves which can be nuclear explosion. The errors in the determination of the location are caused by local and regional variations of wave hodographs. Empirical approach to solving these problems is to use events for which the locations and times are known, in order to determine a set of corrections to the regional model of wave propagation. The using of powerful vibrators for calibration of seismic traces is a new way in nuclear explosion monitoring problems. Now the 60-100 tons force vibrator can radiate the signals which can be recorded at the distances up to 500 km and can be used for regional calibration of seismic traces. The comparison of the seismic wave fields of powerful vibrators and 100-ton chemical explosion "Omega-3" at the 630-km profile, quarry explosions of the Kuznetsk basin with power from 50 to 700 tons at the distances up to 355 km showed their equivalence in the main types of waves. The paper presents the results of experiments of long-distance recording of seismic signals of powerful vibrators and detailed investigation of the velocity characteristics of the Earth's crust in West Siberia and Altay-Sayan region.

  18. Modeling and Simulation of Linear and Nonlinear MEMS Scale Electromagnetic Energy Harvesters for Random Vibration Environments

    PubMed Central

    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

  19. Piezoelectric energy harvesting devices for low frequency vibration applications

    Microsoft Academic Search

    Dongna Shen

    2009-01-01

    Energy harvesting, a process of capturing ambient waste energy and converting it into usable electricity, has been attracting more and more researchers' interest because of the limitations of traditional power sources, the increasing demands upon mobile devices such as wireless sensor networks, and the recent advent of the extremely low power electrical and mechanical devices such as microelectromechanical systems (MEMS).

  20. Vibrational energy relaxation rates in the S 2 state of azulene in nitrogen and carbon dioxide

    Microsoft Academic Search

    Y. Kimura; T. Yamaguchi; N. Hirota

    1999-01-01

    The solvent density dependence of the vibrational energy relaxation rates in the S2 state of azulene has been measured in nitrogen and carbon dioxide at 323.2 and 341 K. The vibrational energy relaxation rate is determined by measuring the time-dependent fluorescence spectra after photo-excitation at 283 nm. The density dependence of the vibrational energy relaxation rate is almost similar to

  1. An auto-parametrically excited vibration energy harvester

    E-print Network

    Jia, Yu; Seshia, Ashwin A.

    2014-01-01

    An auto-parametrically excited vibration energy harvester Yu Jia and Ashwin A. Seshia Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK E-mail: yj252@cam.ac.uk, aas41@cam.ac.uk Draft: September 11, 2014 Abstract — Parametric... designs to minimise this thresh- old, through non-resonant direct amplification of the base excitation that is subsequently fed into the parametric resonator. This paper explores the integration of auto-parametric resonance, as a form of resonant...

  2. Winding deformations detection in power transformers by tank vibrations monitoring

    Microsoft Academic Search

    Belén García; Juan Carlos Burgos; Ángel Alonso

    2005-01-01

    There is an increasing interest in applying monitoring systems and on line diagnosis techniques to power transformers, as these are one of the most expensive and critical components of a power system. Detecting failures in an incipient stage can avoid major transformer damages, allowing important savings in investing, and giving time enough to plan transformer outages. In recent years, a

  3. Efficiency improvement in a vibration power generator for a linear MR damper: numerical study

    NASA Astrophysics Data System (ADS)

    Sapi?ski, Bogdan; Krupa, Stanis?aw

    2013-04-01

    This paper summarizes a numerical analysis of the electromagnetic field, voltage and circuit properties and the cogging force in a vibration power generator comprising permanent magnets and a coil with a foil winding. The device converts the energy harvested from vibrations into electrical energy which is next used to vary the damping characteristics of a linear MR damper attached to the generator. The objective of the study is to propose a sufficiently efficient generator whose finally developed (target) version could be integrated with a small-scale MR damper to build a single device. Two design options for the device are numerically studied, the previously engineered generator 1 and the newly devised generator 2. Generator 1 incorporates two magnet systems having four magnets each and a single-section coil, while generator 2 comprises three magnet systems with four magnets each and a two-section coil. Calculations were performed to determine the electromagnetic field, voltage and current properties and the cogging force in the generators. The electromagnetic field parameters include the distribution of the magnetic field, the electrical potential field and the current density in the open turn and closed turn of the generators’ coils. The voltage and current properties include electromotive force (emf) in the generators and the voltage, current, instantaneous power and energy of the magnetic field in the MR damper control coil which is represented by resistance parameter R and inductance parameter L. The cogging force expresses the magnetic interactions between the permanent magnet systems and ferromagnetic structural components of the generators. The occurrence of this force is very unfavourable and attempts should be made to reduce it through control of the parameters of the magnetic circuit components. On one hand, comparison of the numerical results for the electromagnetic field parameters and voltage and current properties revealed that for the predetermined RL parameters of the MR damper control coil, generator 2 seems to be more efficient than generator 1 and hence is more suitable for supplying the MR damper. On the other hand, comparison of the calculated cogging force levels revealed that its value tends to be lower in generator 1. It is reasonable to suppose that development of a final version of the generator with the defined structure and enhanced efficiency would have to involve some trade-off between the emf and the cogging force.

  4. Vibrational spectroscopy and intramolecular energy transfer in isocyanic acid (HNCO)

    NASA Astrophysics Data System (ADS)

    Coffey, M. J.; Berghout, H. L.; Woods, E.; Crim, F. F.

    1999-06-01

    Room temperature photoacoustic spectra in the region of the first through the fourth overtones (2?1 to 5?1) and free-jet action spectra of the second through the fourth overtones (3?1 to 5?1) of the N-H stretching vibration permit analysis of the vibrational and rotational structure of HNCO. The analysis identifies the strong intramolecular couplings that control the early stages of intramolecular vibrational energy redistribution (IVR) and gives the interaction matrix elements between the zero-order N-H stretching states and the other zero-order states with which they interact. The experimentally determined couplings and zero-order state separations are consistent with ab initio calculations of East, Johnson, and Allen [J. Chem. Phys. 98, 1299 (1993)], and comparison with the calculation identifies the coupled states and likely interactions. The states most strongly coupled to the pure N-H stretching zero-order states are ones with a quantum of N-H stretching excitation (?1) replaced by different combinations of N-C-O asymmetric or symmetric stretching excitation (?2 or ?3) and trans-bending excitation (?4). The two strongest couplings of the n?1 state are to the states (n-1)?1+?2+?4 and (n-1)?1+?3+2?4, and sequential couplings through a series of low order resonances potentially play a role. The analysis shows that if the pure N-H stretch zero-order state were excited, energy would initially flow out of that mode into the strongly coupled mode in 100 fs to 700 fs, depending on the level of initial excitation.

  5. A donor-acceptor pair for the real time study of vibrational energy transfer in proteins.

    PubMed

    Müller-Werkmeister, Henrike M; Bredenbeck, Jens

    2014-02-21

    Vibrational energy transfer (VET) is believed to play an important role in protein function. Theoretical studies predict highly directional, anisotropic VET in proteins. Distinct energy transfer pathways which connect distant functional sites in proteins have been proposed by simulations, indicating a function in allosteric communication. Experimental evidence for such pathways, however, is lacking. In small molecules, ultrafast vibrational pump-probe spectroscopy has been used to investigate VET between different parts of a molecule in great detail. Here, we address the requirements for extending this powerful approach to proteins and present a protein-compatible donor-acceptor pair for the real time investigation of VET. This VET pair consists of two non-native amino acids, ?-(1-azulenyl)-alanine and azidohomoalanine, which can be positioned site-specifically and are found to be very well suited for spectroscopic studies of VET. Important for the study of proteins, co-translational incorporation of each of the amino acids has been demonstrated before using mutually independent approaches of protein engineering. We investigated the performance of the proposed VET pair in a model peptide which is designed to contain additional characteristic vibrational modes frequently used in infrared spectroscopy of proteins. Despite a larger inter-residue distance, we find that our VET acceptor generates a major signal that is easily observed compared to the other vibrational modes in the congested parts of the spectrum. We find sufficient signal size at concentrations compatible with proteins and over distances that will allow tracking of energy flow along predicted transfer pathways. PMID:24413252

  6. Analysis of Energy Harvesting for Vibration-Motivated Wireless Sensor Networks

    E-print Network

    Lim, Sunho

    . In particular, a piezoelectric device based energy harvesting from ambient vibrations is a promising technique for analyzing vibration-motivated WSNs. Index Terms--Energy harvesting, Piezoelectric transducer, Vi- bration available, it has been found that piezoelectric-based energy harvesting is the most promising technique [4

  7. A broadband vibrational energy harvester Louis Van Blarigan, Per Danzl, and Jeff Moehlisa)

    E-print Network

    Bigelow, Stephen

    . This harvester uses two flexi- ble ceramic piezoelectric elements from Advanced Cerame- trics, Inc., as shownA broadband vibrational energy harvester Louis Van Blarigan, Per Danzl, and Jeff Moehlisa for an energy harvester which has the potential to harvest vibrational energy over a broad range of ambient

  8. Multi-link Piezoelectric Structure for Vibration Energy Harvesting Rameen M. Aryanpur and Robert D. White

    E-print Network

    White, Robert D.

    Multi-link Piezoelectric Structure for Vibration Energy Harvesting Rameen M. Aryanpur and Robert D ABSTRACT Work in piezoelectric vibration energy harvesting has typically focused on single member Harvesting, Energy Scavenging, Multi-link, Wide bandwidth, PZT 1. INTRODUCTION The use of piezoelectric

  9. Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator

    E-print Network

    Wang, Zhong L.

    Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator Weiqing Yang1), a unique technology for harvesting ambient mechanical energy based on triboelectric effect, have been a rationally designed triple-cantilever based TENG for harvesting vibration energy. With the assistance

  10. 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.

  11. Operation Assist by Vibration Suppression Control Using Impulse Shaped Signals for Power Assist Type Conveyance System

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yuichi; Uchida, Masaki; Morita, Yoshifumi; Hara, Susumu

    This paper presents an assist control method for flexible parts conveyance task using power assist type conveyance system. The assist control method should be designed so as to not only suppress the vibration but also reduce degradation of operating feel. For this purpose, multiple impulse shaped signals are used as feedforward signals in order to reduce the vibration of flexible parts during conveyance. In addition, adjustment time is introduced to adjust input timing of impulse shaped signal and to suppress vibration. Moreover, in order to improve the degradation of operating feel, the smaller amplitudes of the three impulse shaped signals are used and input repeatedly. The effectiveness of the proposed system was verified experimentally.

  12. 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.

  13. Dynamical correlation between quantum entanglement and intramolecular energy in molecular vibrations: An algebraic approach

    NASA Astrophysics Data System (ADS)

    Feng, Hai-Ran; Meng, Xiang-Jia; Li, Peng; Zheng, Yu-Jun

    2014-07-01

    The dynamical correlation between quantum entanglement and intramolecular energy in realistic molecular vibrations is explored using the Lie algebraic approach. The explicit expression of entanglement measurement can be achieved using algebraic operations. The common and different characteristics of dynamical entanglement in different molecular vibrations are also provided. The dynamical study of quantum entanglement and intramolecular energy in small molecular vibrations can be helpful for controlling the entanglement and further understanding the intramolecular dynamics.

  14. Determination of stepsize parameters for intermolecular vibrational energy transfer

    SciTech Connect

    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.

  15. Response of finger circulation to energy equivalent combinations of magnitude and duration of vibration

    PubMed Central

    Bovenzi, M; Lindsell, C; Griffin, M

    2001-01-01

    OBJECTIVES—To 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.?METHODS—Finger 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.?RESULTS—The 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.?CONCLUSIONS—For 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

  16. MULTI-AXIS ALN-ON-SILICON VIBRATION ENERGY HARVESTER WITH INTEGRATED FREQUENCY-UPCONVERTING TRANSDUCERS

    E-print Network

    Ayazi, Farrokh

    presents fully-integrated multi-axis piezoelectric-on-silicon kinetic energy harvesters (KEHs energy harvesters at such low frequencies. Piezoelectric cantilever harvesters generateMULTI-AXIS ALN-ON-SILICON VIBRATION ENERGY HARVESTER WITH INTEGRATED FREQUENCY

  17. Partial discharge measurement and vibration monitoring on power transformer case study on power transformer with high level noise (75.22 dB)

    Microsoft Academic Search

    I. K. Solin; O. Yolanda; R. Siregar

    2009-01-01

    This paper is a study and share information of partial discharge measurement and vibration monitoring on power transformer. Power transformer is one of the critical components in power plant and transmission power system. Therefore, an appropriate maintenance program should be applied to the transformer in order to make power system more reliable and to prevent transformer failure at early stage.

  18. Micro electro-mechanical system piezoelectric cantilever array for a broadband vibration energy harvester.

    PubMed

    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

  19. Design considerations for small-scale wind energy harvesters driven by broadband vortex-induced vibrations

    NASA Astrophysics Data System (ADS)

    Paxson, Benjamin; Wickenheiser, Adam M.

    2014-04-01

    In recent years, an increasing number of breakthroughs have been made in the field of small-scale wind energy harvesting, where specialized materials are utilized to convert flow energy into electric power. Several studies on this power extraction rely on a common energy harvester setup in which a stiff cantilever beam is attached to the trailing edge of a miniature bluff body. At these small scales where boundary layer effects are appreciable in the laminar flow regime, periodic vortex shedding can be used to drive transverse vibrations in the beam. Interestingly, the fluid dynamics involved in this unsteady process have been studied for decades not to exploit their characteristics, but instead to eliminate potentially destructive effects. As a result, there is still much room for improvement and expansion on recent design studies. A study of how subtle changes in bluff body trailing edge geometry effect power output of a model will be presented in this paper. The model under consideration consists of a miniature bluff body on the order of tens of millimeters in diameter, to which a piezoelectric cantilever is attached at the trailing edge. This model is specifically designed for laminar to transitional Reynolds Number flows (500-2800) where the periodicity of vortex shedding approaches the natural frequency of the beam. As the flow speed is further increased, the effect of lock-in occurs where the resonant beam motion resists a change in vortex shedding frequency. Vibration amplitudes of the beam reach a maximum under this condition, thus maximizing power generation efficiency of the system and providing an optimal condition to operate the harvester. In an effort to meaningfully compare the results, a number of dimensionless parameters are employed. The influence of parameters such as beam length and natural frequency, fluid flow speed, and trailing edge geometry are studied utilizing COMSOL Multiphysics laminar, fluid-structure interaction simulations in order to create design guidelines for an improved energy harvester.

  20. Broadband electromagnetic power harvester from vibrations via frequency conversion by impact oscillations

    SciTech Connect

    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 10–51?Hz and 10–58?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 ?.

  1. A modal approach to modeling spatially distributed vibration energy dissipation.

    SciTech Connect

    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.

  2. Measurements of mechanical vibrations at magnetic cores of power transformers with fiber-optic interferometric intrinsic sensor

    Microsoft Academic Search

    Horatio Lamela Rivera; Jose A. García-Souto; J. Sanz

    2000-01-01

    A fiber-optic interferometric sensor with intrinsic transducer along a length of the fiber is presented for vibration measurements of the magnetic core inside an oil-filled power transformer. The sensor is designed for high sensitivity measurements into the harsh environment of electromagnetic fields, wide temperature change, and in oil immersing. This sensor allows enough sensitivity for the application, for which vibrations

  3. A coupled piezoelectric–electromagnetic energy harvesting technique for achieving increased power output through damping matching

    Microsoft Academic Search

    Vinod R Challa; M G Prasad; Frank T Fisher

    2009-01-01

    Vibration energy harvesting is being pursued as a means to power wireless sensors and ultra-low power autonomous devices. From a design standpoint, matching the electrical damping induced by the energy harvesting mechanism to the mechanical damping in the system is necessary for maximum efficiency. In this work two independent energy harvesting techniques are coupled to provide higher electrical damping within

  4. Mode-specific energy analysis for rotating-vibrating triatomic molecules in classical trajectory simulation

    E-print Network

    Kim, Myung Soo

    Mode-specific energy analysis for rotating-vibrating triatomic molecules in classical trajectory A method for the mode-specific energy analysis in a classical trajectory calculation is developed. The pure normal mode, the vibrational velocity is divided into two parts, the angular motion part and the angular

  5. 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.

  6. Dimensionless optimization of piezoelectric vibration energy harvesters with different interface This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Lin, Liwei

    Dimensionless optimization of piezoelectric vibration energy harvesters with different interface optimization of piezoelectric vibration energy harvesters with different interface circuits Xu Wang1 and Liwei piezoelectric vibration energy harvester and normalized in a dimensionless form. Performance optimizations have

  7. The Energy Aspect of the Reciprocal Interactions of Pairs of Two Different Vibration Modes of a Clamped Annular Plate

    NASA Astrophysics Data System (ADS)

    RDZANEK, W. P.

    2002-01-01

    The standardized mutual active and reactive sound power of a clamped plate, representing the energy aspect of the reciprocal interactions of two different in vacuo modes, has been computed. It was assumed that the vibrations are axisymmetric, elastic and time harmonic, the plate's transverse deflection is small as compared with the plate's size, and that the vibration velocity is small as compared with the acoustic wavenumber generated. The Kirchhoff-Love theory of a perfectly elastic plate was used. The integral formulae for the mutual sound power were transformed into their Hankel representations which made possible their subsequent computation. A closed path integral was used to express the integral in its Hankel representation to compute the mutual active sound power. The asymptotic stationary phase method was used to compute the two magnitudes, i.e., the mutual active and reactive sound power. The results obtained are the asymptotic formulae valid for the acoustically fast waves. The oscillating as well as the non-oscillating terms have been identified in the formulae to make possible their further separate analysis. The availability of the asymptotic formulae makes possible some fast numerical computations of the mutual sound power. Moreover, the formulae presented herein, together with those for the individual modes known from the literature, make a complete basis for further computations of the total sound power of the plate's damped and forced vibrations in fluid.

  8. [Vibrational energy transfer from vibrational levels of RbH(X 1sigma+, v = 0-2) to H2].

    PubMed

    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

  9. Energy-harvesting power sources for very-high-G gun-fired munitions

    Microsoft Academic Search

    J. Rastegar; R. Murray; C. Pereira; H.-L. Nguyen

    2010-01-01

    Several novel classes of piezoelectric-based energy-harvesting power sources are presented for very high-G gun-fired munitions (40,000 - 240,000 Gs). The power sources are designed to harvest energy from the firing acceleration and in certain applications also from in-flight vibrations. The harvested energy is converted to electrical energy for powering onboard electronics, and can provide enough energy to eliminate the need

  10. Field Investigation of Cavitation and Flow Induced Vibrations in Submerged Vertical Pumps in a Power Plant

    Microsoft Academic Search

    Tan Chek Zin; M. Salman Leong; Lee Yuk Choi

    Pumping sets are common but often critical operating assets in the industry. Such pumps often do not have adequate pressure\\u000a and flow instrumentation that could detect abnormal hydraulic operating conditions. This paper presents field investigations\\u000a of two submerged vertical pumps with suspected cavitation and flow induced vibrations in a power plant. These pumps had a\\u000a history of catastrophic impeller failures.

  11. Correct Prediction of the Vibration Behavior of the High Power Ultrasonic Transducers by Fem Simulation

    Microsoft Academic Search

    Abbas Pak; Amir Abdullah

    High power ultrasound is nowadays used in a wide variety of applications ranging from medical devices, ultrasonic cleaning,\\u000a ultrasonic welding and machining to sonochemistry [1]. Since Prof. Langevin developed the first sandwich ultrasonic transducer by embedding piezoelectric rings between two metals\\u000a and employed it for high intensity vibration, there have been great efforts in modeling and formulating such transducers [2–5].

  12. Reactivity-promoting criterion based on internal vibrational energy redistribution.

    PubMed

    Mitri?, Roland; Bürgel, Christian; Bonaci?-Koutecký, Vlasta

    2007-06-19

    We propose to introduce intrinsic dynamical properties as a criterion for promoting reactivity of small size noble metal reactive centers relevant for heterogeneous catalysis. To illustrate the concept, collisions between Ag6- or Au6- clusters and molecular oxygen have been investigated with direct ab initio molecular dynamics by using DFT. We show that different nature and efficiency of internal vibrational energy redistribution (IVR) during reaction dynamics is responsible for significantly different sticking probabilities of O2 to gold and to silver clusters. In the case of Au6- and O2 collisions, resonant IVR occurs between two subunits activating O2 and promoting subsequent oxidation reactions. In contrast, a dissipative IVR in Ag6- and O2 molecule prevents O2 to react with other adsorbates. These findings allow us to introduce the nature of IVR as a criterion for promoting the reactivity of noble metal clusters: Resonant IVR between reactants promotes reactivity toward adsorbates. PMID:17566104

  13. 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.

  14. Vibration-to-electric energy conversion using a mechanically-varied capacitor

    E-print Network

    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 ...

  15. 696 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 18, NO. 2, MARCH 2003 Optimized Piezoelectric Energy Harvesting Circuit

    E-print Network

    Hofmann, Heath F.

    of harvesting vibrational energy with a piezoelectric element using a step-down dc­dc converter is presented--DC­DC, discontinuous conduction mode, energy harvesting, piezoelectric devices. I. INTRODUCTION THE need for a remote and their noninvasive harvesting method. A vibrating piezoelectric device differs from a typical elec- trical power

  16. Power absorbed during whole-body fore-and-aft vibration: Effects of sitting posture, backrest, and footrest

    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.

  17. Relaxation of the bending mode of carbon dioxide by vibration to rotation and vibration to vibration energy transfer

    Microsoft Academic Search

    P. M. Walsh

    1977-01-01

    The V-T relaxation times of CH3F and mixtures of CO2 with CH4, CD4 and CH3F were measured over the temperature range 400-1000K in a shock tube using the laser Schlieren technique for measuring density gradients behind the incident shocks. A 2.7 micron m pulsed HF laser was used to excite vibrational levels of CO2 in CO2-Ar, CS2-CO2-Ar and OCS-CO1-Ar mixtures

  18. 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.

  19. Effects of vibration and shock on the performance of gas-bearing space-power Brayton cycle turbomachinery. Part 3: Sinusoidal and random vibration data reduction and evaluation, and random vibration probability analysis

    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.

  20. Energy 101: Concentrating Solar Power

    ScienceCinema

    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.

  1. State-resolved collisional energy transfer in highly vibrationally excited polyatomic molecules

    Microsoft Academic Search

    F. F. Crim

    1992-01-01

    The transfer of energy in isolated or colliding molecules is a fundamental process with practical consequences for complex phenomena occurring in atmospheric chemistry, combustion, molecular lasers, plasmas, and a host of other environments containing energetic species. We have developed a technique that combines vibrational overtone excitation, to prepare highly vibrationally excited initial states, and time-resolved spectroscopic detection, to probe the

  2. Uncertainties in scaling factors for ab initio vibrational zero-point energies

    Microsoft Academic Search

    Karl K. Irikura; Russell D. Johnson; Raghu N. Kacker; Rüdiger Kessel

    2009-01-01

    Vibrational zero-point energies (ZPEs) determined from ab initio calculations are often scaled by empirical factors. An empirical scaling factor partially compensates for the effects arising from vibrational anharmonicity and incomplete treatment of electron correlation. These effects are not random but are systematic. We report scaling factors for 32 combinations of theory and basis set, intended for predicting ZPEs from computed

  3. Higher-Order Rotation-Vibration Energies of Polyatomic Molecules. VI

    Microsoft Academic Search

    Marie-Louise Grenier-Besson; Gilbert Amat; Harald H. Nielsen

    1962-01-01

    When resonance between vibration frequencies of polyatomic molecules sets in, the contact-transformation method proposed by Shaffer, Nielsen, and Thomas is not directly applicable. It has been shown by Nielsen that a contact transformation method may still be used to advantage when computing rotation-vibration energies to a second order of approximation, the transformation function being, however, a modified one. This problem

  4. Energy harvesting and vibration control using piezoelectric elements and a nonlinear approach

    Microsoft Academic Search

    J. H. Qiu; H. L. Ji; H. Shen

    2009-01-01

    The piezoelectric materials, as the most widely used functional materials in smart structures, have many outstanding advantages for sensors and actuators, especially in vibration control and energy harvesting, because of their excellent mechanical-electrical coupling characteristics and frequency response characteristics. Semi-active vibration control based on state switching and pulse switching, have been receiving much attention over the past decade because of

  5. Non-adiabatic vibrational-electronic resonance in a model dimer - Implications for Photosynthetic Energy Transfer

    NASA Astrophysics Data System (ADS)

    Tiwari, Vivek; Jonas, David

    2014-03-01

    Recently Tiwari et al. [PNAS (2013)] have shown that for a model donor-acceptor system resonance between a vibrational quantum of energy of a weakly coupled Franck-Condon vibration and the excited state excitonic energy gap leads to an unavoidable nested energy funnel on the excited state of photosynthetic antennas. Anti-correlated nuclear motions on the two pigments are responsible for such non-adiabatic effects. Here we show that several vibrational modes lying close to an excitonic energy gap in the FMO antenna complex, and a finite width of vibrational-electronic resonance lead to an even stronger non-adiabatic vibrational-electronic mixing along a generalized energy tuning coordinate. Such a generalized tuning coordinate is similar to the ``tuning coordinate'' in a conical intersection. The 2D spectroscopic signatures of the resulting non-adiabatic effects are additive and lead to more than 2x enhancement of ground state anti-correlated vibrational wavepackets which are expected to dominate the long-lived 2D signatures. Thus, several near-resonant vibrations and a finite width of non-adiabatic coupling render the nested energy funnel in the FMO antenna as a robust and promising design principle for artificial energy and charge transport. This work was supported by the NSF. This work used the Janus Supercomputer which is supported by the NSF and CU Boulder.

  6. Reemitted-Positron Energy-Loss Spectroscopy: A Novel Probe of Adsorbate Vibrational Levels

    Microsoft Academic Search

    D. A. Fischer; K. G. Lynn; W. E. Frieze

    1983-01-01

    Vibrational excitations of carbon monoxide on Ni(100) have been observed for the first time in the energy-loss spectrum of reemitted positrons. For Ni(100)c(2×2)CO at room temperature, energy-loss peaks are found at ~ 57 and ~ 248 meV, corresponding to Ni-C and C-O stretching vibrations, respectively. These peak positions are in good agreement with previously reported results for electron energy-loss spectroscopy.

  7. Reemitted-positron energy-loss spectroscopy: A novel probe of adsorbate vibrational levels

    Microsoft Academic Search

    D. A. Fischer; K. G. Lynn; W. E. Frieze

    1983-01-01

    Vibrational excitations of carbon monoxide on Ni(100) have been observed for the first time in the energy-loss spectrum of reemitted positrons. For Ni(100)c(2 x 2)CO at room temperature energy-loss peaks are found at approx.57 and approx.248 meV, corresponding to Ni-C and C-O stretching vibrations, respectively. These peak positions are in good agreement with previously reported results for electron energy-loss spectroscopy.

  8. A global ab initio potential for HCN/HNC, exact vibrational energies, and comparison to experiment

    NASA Astrophysics Data System (ADS)

    Bentley, Joseph A.; Bowman, Joel M.; Gazdy, Bela; Lee, Timothy J.; Dateo, Christopher E.

    1992-10-01

    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.

  9. Power harvesting and management from vibrations: a multi-source strategy simulation for aircraft structure health monitoring

    NASA Astrophysics Data System (ADS)

    Durou, Hugo; Rossi, Carole; Brunet, Magali; Vanhecke, Claude; Bailly, Nicolas; Ardila, Gustavo; Ourak, Lamine; Ramond, Adrien; Simon, Patrice; Taberna, Pierre-Louis

    2008-12-01

    Vibration harvesting has been intensively developed recently and systems have been simulated and realized, but real-life situations (including aircraft Structure Health Monitoring (SHM)involve uneven, low amplitude, low frequency vibrations. In such an unfavorable case, it is very likely that no power can be harvested for a long time. To overcome this, multi-source harvesting is a relevant solution, and in our application both solar and thermal gradient sources are available. We propose in this paper a complete Microsystem including a piezoelectric vibration harvesting module, thermoelectric conversion module, signal processing electronics and supercapacitor. A model is proposed for these elements and a VHDL-AMS simulation of the whole system is presented, showing that the vibration harvesting device alone cannot supply properly a SHM wireless node. Its role is nevertheless important since it is a more reliable source than thermoelectric (which depends on climatic conditions). Moreover, synergies between vibration harvesting and thermoelectric scavenging circuits are presented.

  10. A fail-safe magnetorheological energy absorber for shock and vibration isolation

    SciTech Connect

    Bai, Xian-Xu, E-mail: bai@hfut.edu.cn [Department of Vehicle Engineering, Hefei University of Technology, Hefei 230009 (China); Wereley, Norman M. [Department of Aerospace Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    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.

  11. Ab initio potential energy and dipole moment surfaces for CS2: determination of molecular vibrational energies.

    PubMed

    Pradhan, Ekadashi; Carreón-Macedo, José-Luis; Cuervo, Javier E; Schröder, Markus; Brown, Alex

    2013-08-15

    The ground state potential energy and dipole moment surfaces for CS2 have been determined at the CASPT2/C:cc-pVTZ,S:aug-cc-pV(T+d)Z level of theory. The potential energy surface has been fit to a sum-of-products form using the neural network method with exponential neurons. A generic interface between neural network potential energy surface fitting and the Heidelberg MCTDH software package is demonstrated. The potential energy surface has also been fit using the potfit procedure in MCTDH. For fits to the low-energy regions of the potential, the neural network method requires fewer parameters than potfit to achieve high accuracy; global fits are comparable between the two methods. Using these potential energy surfaces, the vibrational energies have been computed for the four most abundant CS2 isotopomers. These results are compared to experimental and previous theoretical data. The current potential energy surfaces are shown to accurately reproduce the low-lying vibrational energies within a few wavenumbers. Hence, the potential energy and dipole moments surfaces will be useful for future study on the control of quantum dynamics in CS2. PMID:23199237

  12. The Power of Energy Storage

    E-print Network

    Sadoulet, Elisabeth

    the efficiency of the grid and the value of renewable energy. Finally, energy storage can eliminate someThe Power of Energy Storage How to Increase Deployment in California to Reduce Greenhouse Gas Emissions July 2010 #12;About this Report This policy paper is the sixth in a series of reports on how

  13. Renewable Energy Powers Renewable Energy Lab, Employees

    E-print Network

    . NREL is also using solar energy for auxiliary purposes such as powering streetlights, water pumps, they may cost more. But as more people try renewable energy, prices will come down. Just look at computers. This has steadily lowered costs to the point where wind energy is within reach of many consumers. The price

  14. Reactive Power from Distributed Energy

    SciTech Connect

    Kueck, John; Kirby, Brendan; Rizy, Tom; Li, Fangxing; Fall, Ndeye

    2006-12-15

    Distributed energy is an attractive option for solving reactive power and distribution system voltage problems because of its proximity to load. But the cost of retrofitting DE devices to absorb or produce reactive power needs to be reduced. There also needs to be a market mechanism in place for ISOs, RTOs, and transmission operators to procure reactive power from the customer side of the meter where DE usually resides. (author)

  15. Electric-energy generation using variable-capacitive resonator for power-free LSI: efficiency analysis and fundamental experiment

    Microsoft Academic Search

    Masayuki Miyazaki; Hidetoshi Tanaka; Goichi Ono; Tomohiro Nagano; Norio Ohkubo; Takayuki Kawahara; Kazuo Yano

    2003-01-01

    A power generator based on a vibration-to-electric energy converter using a variable-resonating capacitor is experimentally demonstrated. The generator consists of a complete system with a mechanical-variable capacitor, a charge-transporting LC tank circuit and an externally powered timing-capture controller. A practical design methodology to maximize the efficiency of the vibration-to-electric energy generation system is also described. The efficiency of the generator

  16. The Power of Energy

    NSDL National Science Digital Library

    Diana Congden

    2012-06-14

    Have you ever wondered how energy changes from one form to another? How you can put food in microwave, and seconds later it is hot? What happens between the time you plug in a TV and you see a picture? Students will take a deeper look into energy. What are all of the kinds of energy that help an object work? This lesson is a fun way to involve kids in their learning and include technology to present.

  17. Energy, A Crisis in Power.

    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…

  18. Ultrasonic vibration-assisted pelleting of wheat straw: a predictive model for energy consumption using response surface methodology.

    PubMed

    Song, Xiaoxu; Zhang, Meng; Pei, Z J; Wang, Donghai

    2014-01-01

    Cellulosic biomass can be used as a feedstock for biofuel manufacturing. Pelleting of cellulosic biomass can increase its bulk density and thus improve its storability and reduce the feedstock transportation costs. Ultrasonic vibration-assisted (UV-A) pelleting can produce biomass pellets whose density is comparable to that processed by traditional pelleting methods (e.g. extruding, briquetting, and rolling). This study applied response surface methodology to the development of a predictive model for the energy consumption in UV-A pelleting of wheat straw. Effects of pelleting pressure, ultrasonic power, sieve size, and pellet weight were investigated. This study also optimized the process parameters to minimize the energy consumption in UV-A pelleting using response surface methodology. Optimal conditions to minimize the energy consumption were the following: ultrasonic power at 20%, sieve size at 4 mm, and pellet weight at 1g, and the minimum energy consumption was 2.54 Wh. PMID:23859359

  19. Molecular dynamics simulation of vibrational energy relaxation of highly excited molecules in fluids. III. Equilibrium simulations of vibrational energy relaxation of azulene in carbon dioxide

    Microsoft Academic Search

    C. Heidelbach; V. S. Vikhrenko; D. Schwarzer; I. I. Fedchenia; J. Schroeder

    1999-01-01

    The expressions for vibrational energy relaxation (VER) rates of polyatomic molecules in terms of equilibrium capacity time correlation functions (TCFs) derived in the first paper of this series [J. Chem. Phys. 110, 5273 (1999)] are used for the investigation of VER of azulene in carbon dioxide at low (3.2 MPa) and high (270 MPa) pressure. It is shown that for

  20. Wind power and other energy options

    Microsoft Academic Search

    Inglis

    1979-01-01

    Past experience with wind power is considered along with the mechanics of wind energy conversion, small wind-power installations, large wind-power machines and installations, other solar-related energy sources, geophysical energy sources, nuclear power from fission, nuclear power from fusion, a comparison of dollar costs of wind power and nuclear power, social costs of wind power and nuclear power, and the choice

  1. Wind power and other energy options

    Microsoft Academic Search

    D. R. Inglis

    1978-01-01

    Past experience with wind power is considered along with the mechanics of wind energy conversion, small wind-power installations, large wind-power machines and installations, other solar-related energy sources, geophysical energy sources, nuclear power from fission, nuclear power from fusion, a comparison of dollar costs of wind power and nuclear power, social costs of wind power and nuclear power, and the choice

  2. Mechanism of vibrational energy dissipation of free OH groups at the air–water interface

    PubMed Central

    Hsieh, Cho-Shuen; Campen, R. Kramer; Okuno, Masanari; Backus, Ellen H. G.; Nagata, Yuki; Bonn, Mischa

    2013-01-01

    Interfaces of liquid water play a critical role in a wide variety of processes that occur in biology, a variety of technologies, and the environment. Many macroscopic observations clarify that the properties of liquid water interfaces significantly differ from those of the bulk liquid. In addition to interfacial molecular structure, knowledge of the rates and mechanisms of the relaxation of excess vibrational energy is indispensable to fully understand physical and chemical processes of water and aqueous solutions, such as chemical reaction rates and pathways, proton transfer, and hydrogen bond dynamics. Here we elucidate the rate and mechanism of vibrational energy dissipation of water molecules at the air–water interface using femtosecond two-color IR-pump/vibrational sum-frequency probe spectroscopy. Vibrational relaxation of nonhydrogen-bonded OH groups occurs at a subpicosecond timescale in a manner fundamentally different from hydrogen-bonded OH groups in bulk, through two competing mechanisms: intramolecular energy transfer and ultrafast reorientational motion that leads to free OH groups becoming hydrogen bonded. Both pathways effectively lead to the transfer of the excited vibrational modes from free to hydrogen-bonded OH groups, from which relaxation readily occurs. Of the overall relaxation rate of interfacial free OH groups at the air–H2O interface, two-thirds are accounted for by intramolecular energy transfer, whereas the remaining one-third is dominated by the reorientational motion. These findings not only shed light on vibrational energy dynamics of interfacial water, but also contribute to our understanding of the impact of structural and vibrational dynamics on the vibrational sum-frequency line shapes of aqueous interfaces. PMID:24191016

  3. Mechanism of vibrational energy dissipation of free OH groups at the air-water interface.

    PubMed

    Hsieh, Cho-Shuen; Campen, R Kramer; Okuno, Masanari; Backus, Ellen H G; Nagata, Yuki; Bonn, Mischa

    2013-11-19

    Interfaces of liquid water play a critical role in a wide variety of processes that occur in biology, a variety of technologies, and the environment. Many macroscopic observations clarify that the properties of liquid water interfaces significantly differ from those of the bulk liquid. In addition to interfacial molecular structure, knowledge of the rates and mechanisms of the relaxation of excess vibrational energy is indispensable to fully understand physical and chemical processes of water and aqueous solutions, such as chemical reaction rates and pathways, proton transfer, and hydrogen bond dynamics. Here we elucidate the rate and mechanism of vibrational energy dissipation of water molecules at the air-water interface using femtosecond two-color IR-pump/vibrational sum-frequency probe spectroscopy. Vibrational relaxation of nonhydrogen-bonded OH groups occurs at a subpicosecond timescale in a manner fundamentally different from hydrogen-bonded OH groups in bulk, through two competing mechanisms: intramolecular energy transfer and ultrafast reorientational motion that leads to free OH groups becoming hydrogen bonded. Both pathways effectively lead to the transfer of the excited vibrational modes from free to hydrogen-bonded OH groups, from which relaxation readily occurs. Of the overall relaxation rate of interfacial free OH groups at the air-H2O interface, two-thirds are accounted for by intramolecular energy transfer, whereas the remaining one-third is dominated by the reorientational motion. These findings not only shed light on vibrational energy dynamics of interfacial water, but also contribute to our understanding of the impact of structural and vibrational dynamics on the vibrational sum-frequency line shapes of aqueous interfaces. PMID:24191016

  4. Electron energy distribution functions in He--CO vibrationally excited post discharges

    SciTech Connect

    Gorse, C.; Paniccia, F.; Ricard, A.; Capitelli, M.

    1986-04-15

    Electron energy distribution functions (edf) and related parameters have been calculated in the post-discharge regime of vibrationally excited He--CO mixtures by solving the Boltzmann equation including superelastic vibrational collisions. The calculations point out to the importance of small concentration of CO molecules in affecting both edf 's and related quantities in the post-discharge reigme. In particular, the mixture closely follows the behavior of pure CO for molar fractions of CO (X/sub CO/) approximately equal to 20%. Helium affects edf 's by increasing elastic losses in the post discharge, for X/sub CO/<20%, leading to average electron temperatures, T/sub e/, lower than the corresponding vibrational temperatures, theta/sub 1/. The results obtained by using Treanor's and Boltzmann distributions emphasize the role of excited vibrational levels (v>2) in affecting edf and the average electron energy.

  5. Definitions of non-stationary vibration power for time-frequency analysis and computational algorithms based upon harmonic wavelet transform

    NASA Astrophysics Data System (ADS)

    Heo, YongHwa; Kim, Kwang-joon

    2015-02-01

    While the vibration power for a set of harmonic force and velocity signals is well defined and known, it is not as popular yet for a set of stationary random force and velocity processes, although it can be found in some literatures. In this paper, the definition of the vibration power for a set of non-stationary random force and velocity signals will be derived for the purpose of a time-frequency analysis based on the definitions of the vibration power for the harmonic and stationary random signals. The non-stationary vibration power, defined as the short-time average of the product of the force and velocity over a given frequency range of interest, can be calculated by three methods: the Wigner-Ville distribution, the short-time Fourier transform, and the harmonic wavelet transform. The latter method is selected in this paper because band-pass filtering can be done without phase distortions, and the frequency ranges can be chosen very flexibly for the time-frequency analysis. Three algorithms for the time-frequency analysis of the non-stationary vibration power using the harmonic wavelet transform are discussed. The first is an algorithm for computation according to the full definition, while the others are approximate. Noting that the force and velocity decomposed into frequency ranges of interest by the harmonic wavelet transform are constructed with coefficients and basis functions, for the second algorithm, it is suggested to prepare a table of time integrals of the product of the basis functions in advance, which are independent of the signals under analysis. How to prepare and utilize the integral table are presented. The third algorithm is based on an evolutionary spectrum. Applications of the algorithms to the time-frequency analysis of the vibration power transmitted from an excitation source to a receiver structure in a simple mechanical system consisting of a cantilever beam and a reaction wheel are presented for illustration.

  6. State-To Rotational and Vibrational Energy Transfers Following Vibrational Excitation of (1010000) and (0112000) in the Ground Electronic State of Acetylene

    Microsoft Academic Search

    Jiande Han; Keith Freel; Michael C. Heaven

    2011-01-01

    We have examined state-to-state rotational and vibrational energy transfers for the vibrational levels (1010000) and (0112000) of C2H2 in the ground electronic state at ambient temperature. Measurements were made using a pulsed IR - UV double resonance technique. Total removal rate constants and state-to-state rotational energy transfer rate constants have been characterized for certain even-numbered rotational levels from J =

  7. Accurate potential energy, dipole moment curves, and lifetimes of vibrational states of heteronuclear alkali dimers

    NASA Astrophysics Data System (ADS)

    Fedorov, Dmitry A.; Derevianko, Andrei; Varganov, Sergey A.

    2014-05-01

    We calculate the potential energy curves, the permanent dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X1?+ electronic state using the coupled cluster with singles doubles and triples method. All-electron quadruple-? basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-? quality basis sets are used for K, Rb, and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. A large one-electron basis set with additional core functions is needed for the accurate prediction of permanent dipole moments. The dissociation energies are overestimated by only 14 cm-1 for LiNa and by no more than 114 cm-1 for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm-1, and the discrepancies for the anharmonic correction are less than 0.1 cm-1. We show that correlation between atomic electronegativity differences and permanent dipole moment of heteronuclear alkali dimers is not perfect. To obtain the vibrational energies and wave functions the vibrational Schrödinger equation is solved with the B-spline basis set method. The transition dipole moments between all vibrational states, the Einstein coefficients, and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. In all studied heteronuclear alkali dimers the ground vibrational states have much longer lifetimes than any excited states.

  8. Analysis of Piezoelectric Materials for Energy Harvesting Devices under High-g Vibrations

    Microsoft Academic Search

    Dongna Shen; Song-Yul Choe; Dong-Joo Kim

    2007-01-01

    We analyzed the miniaturized energy harvesting devices (each volume within 0.3 cm3) fabricated by using three types of piezoelectric materials such as lead zirconium titanate (PZT) ceramic, macro fiber composite (MFC) and poly(vinylidene fluoride) (PVDF) polymer to investigate the capability of converting mechanical vibration into electricity under larger vibration amplitudes or accelerations conditions (>= 1g, gravitational acceleration). All prototypes based

  9. Accurate potential energy, dipole moment curves, and lifetimes of vibrational states of heteronuclear alkali dimers

    SciTech Connect

    Fedorov, Dmitry A.; Varganov, Sergey A., E-mail: svarganov@unr.edu [Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0216 (United States); Derevianko, Andrei [Department of Physics, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0220 (United States)] [Department of Physics, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0220 (United States)

    2014-05-14

    We calculate the potential energy curves, the permanent dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X{sup 1}?{sup +} electronic state using the coupled cluster with singles doubles and triples method. All-electron quadruple-? basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-? quality basis sets are used for K, Rb, and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. A large one-electron basis set with additional core functions is needed for the accurate prediction of permanent dipole moments. The dissociation energies are overestimated by only 14 cm{sup ?1} for LiNa and by no more than 114 cm{sup ?1} for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm{sup ?1}, and the discrepancies for the anharmonic correction are less than 0.1 cm{sup ?1}. We show that correlation between atomic electronegativity differences and permanent dipole moment of heteronuclear alkali dimers is not perfect. To obtain the vibrational energies and wave functions the vibrational Schrödinger equation is solved with the B-spline basis set method. The transition dipole moments between all vibrational states, the Einstein coefficients, and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. In all studied heteronuclear alkali dimers the ground vibrational states have much longer lifetimes than any excited states.

  10. Energy metabolism in human calf muscle performing isometric plantar flexion superimposed by 20Hz vibration

    Microsoft Academic Search

    Jochen Zange; Timo Haller; Klaus Müller; Anna-Maria Liphardt; Joachim Mester

    2009-01-01

    Vibration training is commonly expected to induce an active muscle contraction via a complex reflex mechanism. In calf muscles\\u000a of 20 untrained subjects, the additional energy consumption in response to vibration superimposed on an isometric contraction\\u000a was examined by 31P magnetic resonance spectroscopy and by near infrared spectroscopy. Subjects performed 3 min of isometric plantar flexion\\u000a exercise at 40% MVC under

  11. FRONTIERS ARTICLE Imaging bond breaking and vibrational energy transfer in small water

    E-print Network

    Reisler, Hanna

    FRONTIERS ARTICLE Imaging bond breaking and vibrational energy transfer in small water containing it is possible to generate accurate potential energy surfaces (PESs) for small clusters, such as those of water (REMPI) are used to determine accurate bond dissociation energies (D0) of (H2O)2, (H2O)3, HCl­H2O and NH3

  12. Vibrational Energy Transport in Molecules Studied by Relaxation-Assisted Two-Dimensional Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rubtsova, Natalia I.; Rubtsov, Igor V.

    2015-04-01

    This review presents an overview of the relaxation-assisted two-dimensional infrared (RA 2DIR) spectroscopy method for measuring structures and energy transport dynamics in molecules. The method strongly enhances the range of accessible distances compared to traditional 2DIR and offers new structural reporters, such as the energy transport time, cross-peak amplification factors, and connectivity patterns. The use of the method for assigning vibrational modes with various levels of delocalization is illustrated. RA 2DIR relies on vibrational energy transport in molecules; as such, the transport mechanism can be conveniently studied by the method. Applications to identify diffusive and ballistic energy transport are demonstrated.

  13. An elastic-support model for enhanced bistable piezoelectric energy harvesting from random vibrations

    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.

  14. Step-up converter for electromagnetic vibrational energy scavenger

    Microsoft Academic Search

    Chitta Saha; Terence O'donnell; J. Godsell; Louis Carlioz; Ningning Wang; Paul Mccloskey; Stephen P. Beeby; John Tudor; Russel N. Torah

    2008-01-01

    This paper introduces a voltage multiplier (VM) circuit which can step up a minimum voltage of 150 mV (peak). The operation and characteristics of this converter circuit are described. The voltage multiplier circuit is also tested with micro and macro scale electromagnetic vibrational generators and the effect of the VM on the optimum load conditions of the electromagnetic generator is

  15. Solar energy power generation system

    SciTech Connect

    Nilsson, J.E.; Cochran, C.D.

    1986-05-06

    A solar energy power generation system is described which consists of: (a) means for collecting and concentrating solar energy; (b) heat storage means; (c) Stirling engine means for producing power; (d) first heat transfer means for receiving the concentrated solar energy and for transferring heat to the heat storage means; and (e) second heat transfer means for controllably transferring heat from the storage means to the Stirling engine means and including a discharge heat pipe means for transferring heat to the Stirling engine means and further including means for inserting and withdrawing the discharge heat pipe means into and out of the heat storage means.

  16. Peculiarities of the third natural frequency vibrations of a cantilever for the improvement of energy harvesting.

    PubMed

    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

  17. Ab initio rotation-vibration energies and intensities for the H 2F + molecule

    NASA Astrophysics Data System (ADS)

    Bunker, P. R.; Jensen, Per; Wright, J. S.; Hamilton, I. P.

    1990-12-01

    In a previous publication [I. D. Petsalakis, G. Theodorakopoulos, J. S. Wright, and I. P. Hamilton, J. Chem. Phys., 92, 2440-2449 (1990)] we reported the ab initio multireference configuration interaction calculation of the three-dimensional potential energy surface of the H 2F + molecule in the ground X˜1A 1 electronic state at 119 nuclear geometries spanning an energy range up to about 50 000 cm -1 above equilibrium. We fitted the 71 points within 33 000 cm -1 of equilibrium to an analytic expression and performed variational calculation of the vibrational energies in Jacobi coordinates using the Discrete Variable Representation and Distributed Gaussian Basis functions (DVR-DGB) technique. In the present paper we examine the effect on the vibrational energies of using a surface obtained by fitting through 52 points within 25 000 cm -1 of equilibrium. We use this surface in a variational calculation of the J = 0, 1, and 2 rotation-vibration energies using the Morse Oscillator Rigid Bender Internal Dynamics Hamiltonian [P. Jensen, J. Mol. Spectrosc., 128, 478-501 (1988); J. Chem. Soc. Faraday Trans. 2, 84, 1315-1340 (1988)]. The vibrational energies obtained are compared with those obtained by the DVR-DGB technique. We also calculate ab initio the dipole moment function and rotation-vibration intensities, and we simulate the ?2 band, which has not yet been observed.

  18. Energy harvesting for self-powered aerostructure actuation

    NASA Astrophysics Data System (ADS)

    Bryant, Matthew; Pizzonia, Matthew; Mehallow, Michael; Garcia, Ephrahim

    2014-04-01

    This paper proposes and experimentally investigates applying piezoelectric energy harvesting devices driven by flow induced vibrations to create self-powered actuation of aerostructure surfaces such as tabs, flaps, spoilers, or morphing devices. Recently, we have investigated flow-induced vibrations and limit cycle oscillations due to aeroelastic flutter phenomena in piezoelectric structures as a mechanism to harvest energy from an ambient fluid flow. We will describe how our experimental investigations in a wind tunnel have demonstrated that this harvested energy can be stored and used on-demand to actuate a control surface such as a trailing edge flap in the airflow. This actuated control surface could take the form of a separate and discrete actuated flap, or could constitute rotating or deflecting the oscillating energy harvester itself to produce a non-zero mean angle of attack. Such a rotation of the energy harvester and the associated change in aerodynamic force is shown to influence the operating wind speed range of the device, its limit cycle oscillation (LCO) amplitude, and its harvested power output; hence creating a coupling between the device's performance as an energy harvester and as a control surface. Finally, the induced changes in the lift, pitching moment, and drag acting on a wing model are quantified and compared for a control surface equipped with an oscillating energy harvester and a traditional, static control surface of the same geometry. The results show that when operated in small amplitude LCO the energy harvester adds negligible aerodynamic drag.

  19. Carrier relaxation in colloidal nanocrystals: Bridging large electronic energy gaps by low-energy vibrations

    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.

  20. High resolution studies of dissociative electron attachment to molecules: dependence on electron and vibrational energy

    NASA Astrophysics Data System (ADS)

    Ruf, M.-W.; Braun, M.; Marienfeld, S.; Fabrikant, I. I.; Hotop, H.

    2007-11-01

    For several molecules which are important for plasma processing and gaseous dielectrics (CF3I, CF3Br, CH3Br, and SF6), we have studied the dependence of dissociative electron attachment (DEA) on both the electron energy and on the initial vibrational energy. With reference to electron swarm data, we determine highly-resolved absolute DEA cross sections over a broad energy range, using the Laser Photoelectron Attachment (LPA) method (E = 0-0.2 eV, ?E ? 1-3 meV) and the EXtended Laser Photoelectron Attachment (EXLPA) method (0-2 eV, ?E ? 15-30 meV). The experimental data are compared with the results of R-matrix calculations, involving ab initioinformation on the potential energy curves and semiempirical autodetachment widths. For CF3I and CF3Br, previous DEA cross sections are found to be substantially too high. For CH3Br, the measurements confirm a predicted vibrational Feshbach resonance, associated with the v3 = 4 vibrational threshold, and the value of the activation energy (due to an intermediate barrier) for this exothermic DEA process. For SF6, we report absolute cross sections for SF6- as well as SF5- formation for vibrational temperatures ranging from 200 to 500 K. Moreover, the first absoluteDEA cross sections (SF5- formation) for CO2-laser excited SF6 molecules have been obtained at different initial vibrational temperatures. The results indicate that the effect of the mode-selective energy input into the v3-mode (predominantly v3 = 1) on the enhancement of SF5- formation is very similar to that of a corresponding rise of the average vibrational energy by thermal heating; at E = 2 meV electron energy, the results indicate an activation energy of about 0.38 eV.

  1. Collisional vibrational energy transfer of OH (A 2Sigma + , v'=1)

    NASA Astrophysics Data System (ADS)

    Williams, Leah R.; Crosley, David R.

    1996-05-01

    Vibrational energy transfer (VET) and quenching of the v'=1 level of A 2?+ OH have been studied using laser-induced fluorescence in a discharge flow cell at room temperature. VET cross sections (Å2) are N2, 30.1±2.8; O2, 2.8±0.3; Ar, 0.56±0.05; H2O, 8.6±0.6. The rotational energy distribution in v'=0 following the VET event was determined for nine colliders. It is nonthermal, generally populating high rotational levels. There are three broad categories of colliders that cause varying degrees of vibrational to rotational energy transfer; H2, D2, and CH4 show the least; N2, CO2, CF4, and N2O more; and O2 and Ar the most, with about one-third of the vibrational energy appearing as OH rotation.

  2. POWER EVALUATION FOR FLUTTER-BASED ELCTROMAGNETIC ENERGY HARVESTER USING CFD SIMULATIONS

    E-print Network

    Stanford University

    harvesters. Wind induced vibrations have been used to mechanically strain piezoelectric transducersPOWER EVALUATION FOR FLUTTER-BASED ELCTROMAGNETIC ENERGY HARVESTER USING CFD SIMULATIONS J. Park 1 as an effective input source for small scale energy harvesters. The self exciting aerodynamic force exerted on a T

  3. Scandinavian power and energy resources

    Microsoft Academic Search

    Papamarcos

    1984-01-01

    Countries generally included in the Scandinavian grouping vary considerably in their energy resources, from Norway which is more than self-sufficient to Denmark which is almost wholly dependent on imported fuels. In electric power generation the variety is extreme, with Norway fully self-sufficient in hydro power, and Denmark wholly dependent on imported fuel for its fossil-fired generating stations. Only Sweden and

  4. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    SciTech Connect

    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.

  5. Erratum: Experimental Vibrational Zero-Point Energies: Diatomic Molecules J. Phys. Chem. Ref. Data 36, 389-397 ,,2007...

    E-print Network

    Magee, Joseph W.

    Erratum: Experimental Vibrational Zero-Point Energies: Diatomic Molecules J. Phys. Chem. Ref. Data energetics; uncertainty; vibrational spectroscopy; viscosity; zero-point energy. There is a typographical in the calculated zero point energy ZPE for SiF in Table 5 on page 395. The correct entry for SiF in this table

  6. Modal Analysis and Study of the Vibration Characteristics of the Thermoelectric Modules of Vehicle Exhaust Power-Generation Systems

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Mu, Yu; Zhai, Pengcheng; Yu, Rui; Li, Guodong; Zhang, Qingjie

    2014-06-01

    Thermoelectric (TE) materials and modules are important components of vehicle exhaust power-generation systems. The road and the engine, the main sources of vibration of TE modules, have substantial effects on the vibration characteristics of TE modules. In this work, modal analysis and the vibration characteristics of TE modules were investigated in detail. On the basis of the TE modules and their service environment, simulations for modal analysis were performed by use of the finite-element method, and the natural frequencies and mode shapes of the TE modules were obtained. The numerical results were used to compare the natural frequencies of TE modules under different contact stiffness with the range of excitation frequencies of road and engine, in an attempt to prevent severe resonance. The effects on the vibration characteristics of geometric dimensions, service temperature, and thermal stress of the TE modules are also discussed in detail. The results reveal the vibration characteristics of the TE modules and provide theoretical guidance for structure optimization in the design of vehicle exhaust power-generation systems.

  7. Rotation-Vibration Energies of the Pyramidal XY3 Molecular Model

    Microsoft Academic Search

    Wave Henry Shaffer

    1941-01-01

    Complete expressions have been derived for the rotation-vibration energies of the pyramidal XY3 molecular model in such a way as to include, through second order of approximation, all contributions to the energies arising from Coriolis interactions, anharmonicities, etc.

  8. Energy harvesting from coherent resonance of horizontal vibration of beam excited by vertical base motion

    SciTech Connect

    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.

  9. Effect of collision energy and vibrational excitation on endothermic ion-molecule reactions

    SciTech Connect

    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.

  10. Design of high-efficiency vibration energy harvesters and experimental functional tests for improving bandwidth and tunability

    NASA Astrophysics Data System (ADS)

    Somà, A.; De Pasquale, G.

    2013-05-01

    The reduction of power consumption of sensors allows the local power supply or wireless sensor networks. This paper introduces the results of design and experiments on devices for harvesting energy from vibrations of machines. The main contribution of this research is the empirical evaluation of different technical solutions able to improve harvester performances and sensing system duty cycle. Satisfactory results have been achieved in lowering of resonance by levitating suspensions and in increasing of Q-factor by studying the air flows. Output power values of 10mW (5.7Hz, 1.4g) and 115mW (3.2Hz, 0.2g) were obtained for piezoelectric and inductive harvesters respectively.

  11. Exotic power and energy storage

    Microsoft Academic Search

    M. O. Surface

    1977-01-01

    Consideration is given to a variety of near-term energy storage systems, including both conventional and underground hydro-pumped storage, compressed air storage for combustion turbines, thermal energy storage in central power plants, and the lead-acid battery. Potential intermediate-term systems, which may be developed during the 1985-2000 period, are identified, such as advanced batteries, flywheel storage, and hydrogen storage. The concept of

  12. Role of energy exchange in vibrational dephasing processes in liquids and solids

    NASA Astrophysics Data System (ADS)

    Marks, S.

    1981-08-01

    Three theories on the dephasing of molecular vibrations in condensed phase matter are presented. The theories predict that the widths and shifts of molecular vibrations will obey an Arrhenius temperature dependence. A model based on intermolecular energy exchange of low frequency modes, results in dephasing the high frequency modes when anharmonic coupling is present. Isotopic dilution resulted in a detailed picture of the energy transfer dynamics of the low frequency modes. Spontaneous Raman spectra support a model of inhomogeneous broadening in liquids based on results of picosecond stimulated Raman spectroscopy. The model distributes environmental sites created by a distribution in the local density and creates inhomogeneous broadening.

  13. 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.

  14. Wind power: Today's energy option

    Microsoft Academic Search

    2009-01-01

    The US has about 1,400 megawatts (MW) of installed wind turbine capacity on-line to utilities primarily in California and Hawaii. And according to a recent report by the Electric Power Research Institute (EPRI), the best of today's wind turbines are performing well. When located in sites with good wind resources, today's superior designs have energy costs of about 8 cents

  15. An optimized self-powered switching circuit for non-linear energy harvesting with low voltage output

    Microsoft Academic Search

    Mickaël Lallart; Daniel Guyomar

    2008-01-01

    Harvesting energy from environmental sources has been of particular interest these last few years. Microgenerators that can power electronic systems are a solution for the conception of autonomous, wireless devices. They allow the removal of bulky and costly wiring, as well as complex maintenance and environmental issues for battery-powered systems. In particular, using piezoelectric generators for converting vibrational energy to

  16. Stresa, Italy, 25-27 April 2007 CHARACTERISATION OF AN ELECTROSTATIC VIBRATION HARVESTER

    E-print Network

    Paris-Sud XI, Université de

    Stresa, Italy, 25-27 April 2007 CHARACTERISATION OF AN ELECTROSTATIC VIBRATION HARVESTER T. Sterken ambient vibration is proposed as an alternative to storage based power supplies for autonomous systems. The system presented converts the mechanical energy of a vibration into electrical energy by means

  17. Intramolecular and intermolecular vibrational energy relaxation of CH 2I 2 dissolved in supercritical fluid

    NASA Astrophysics Data System (ADS)

    Sekiguchi, K.; Shimojima, A.; Kajimoto, O.

    2002-04-01

    A pump-probe experiment was performed to examine vibrational population relaxation of diiodomethane (CH 2I 2) molecule dissolved in supercritical CO 2. Using an apparatus with femtosecond time resolution, we observed the contributions of intramolecular vibrational energy redistribution (IVR) and intermolecular vibrational energy transfer (VET) separately. IVR and VET rates were measured with varying solvent densities at a constant temperature. It is shown that the IVR rate is not density dependent while the VET rate increases with increasing density from 0.4 to 0.8 g cm-3. This observation suggests that the rate of the VET process is determined by solute-solvent collisions whereas the IVR rate is not much affected by solute-solvent interaction.

  18. Prevention strategy for vibration hazards by portable power tools, national forest model of comprehensive prevention system in Japan.

    PubMed

    Yamada, S; Sakakibara, H

    1998-04-01

    In the 1950s, the introduction of portable power tools into the production process of many industries began on a large scale around the world and resulted in many cases of occupational vibration syndrome after the 1960s. There was an urgent world wide need to undertake preventive steps, medical assessment and therapy. At the end of 1964, our investigation began in Japanese national forests, and then in mines and stone quarries. The Japanese Association of Industrial Hygiene established a "Committee for Local Vibration Hazards" (1965), and many researchers in the medical and technological fields joined this Committee. After 10 years, a comprehensive system for the prevention of vibration syndrome was established in the national forestry. It consists of 1) improvements in vibrating tools, 2) hygienic regulation of operation time with an alternative working system, 3) health care system involving early medical checks, early therapy and age limitations in operation of vibrating tools, 4) protection against cold in the workplace and while commuting, and 5) education and training for health and safety. The prevention strategy for vibration syndrome in our national forests is to establish a comprehensive prevention system in cooperation among researchers in the medical and technological fields, workers and administration. The Ministry of Labor presented that strategy as good model of prevention for other industries (1976). New designs for this model were developed and adapted according to the special conditions of each industry. Thus comprehensive system for prevention of vibration syndrome developed successfully from the late 1970s to 1980s in Japan. PMID:9583311

  19. 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.

  20. Fabrication, modelling and characterization of MEMS piezoelectric vibration harvesters

    Microsoft Academic Search

    M. Renaud; K. Karakaya; T. Sterken; P. Fiorini; C. Van Hoof; R. Puers

    2008-01-01

    Piezoelectric converters designed for harvesting energy from mechanical vibrations have been fabricated by micromachining technologies. They are characterized by applying a sinusoidal oscillation as mechanical input and by using a resistive load to measure the output power of the system. A maximum output power of 40?W has been measured for a PZT based harvester excited by an input vibration having

  1. Vibrational relaxation and energy migration of N-methylacetamide in water: the role of nonbonded interactions.

    PubMed

    Cazade, Pierre-André; Hédin, Florent; Xu, Zhen-Hao; Meuwly, Markus

    2015-02-19

    Nonequilibrium molecular dynamics (MD) simulations together with physics-based force fields are used to follow energy flow between vibrationally excited N-methylacetamide (NMA) and water. The simulations are carried out with a previously validated force field for NMA, based on a multipolar representation of the electrostatics, and with a new fluctuating point charge model. For the water solvent, a flexible and a rigid model was employed to distinguish between the role of inter- and intramolecular degrees of freedom. On a 10 ps time scale about 90% of the available energy goes into the solvent. The remaining energy resides within internal NMA-degrees of freedom from where energy flow takes place on longer time scales. The total amount of energy transferred to the solvent on the 10 ps time scale does not depend on whether the water molecules are rigid or flexible during the simulations. Vibrational energy relaxation time scales include two regimes: one on the several 100 fs time scale and a longer one, ranging from 6 to 10 ps. This longer time scale agrees with previous simulations but overestimates the experimentally determined relaxation time by a factor of 2, which can be explained by the classical treatment of the vibrations. Including a previously determined quantum correction factor brings the long time scale into quite favorable agreement with experiment. Coupling to the bending vibration of the water molecules in H-bonding contact with the excited C?O chromophore is substantial. The equilibrium and nonequilibrium distribution of the bending angles of the water molecules in contact with the local oscillator are non-Gaussian, and one approaches the other on the subpicosecond time scale. Analysis of the water velocity distribution suggests that the C?O vibrational energy relaxes into the solvent water shells in an impulsive fashion on a picosecond time scale. PMID:25581333

  2. A Study on the Vibration Phenomenon of a Power Transformer in Operation (154 kV\\/60MVA\\/Single-phase)

    Microsoft Academic Search

    Young-Dal Kim; Jae-Myung Shim; Woo-Yong Park; Sung-joong Kim; Dae-Dong Lee

    2008-01-01

    Most of the causes of the failures of power transformers in operations are mechanical defects due to vibration. To identify\\u000a these causes, the vibration phenomenon was measured from the power transformers in operation in the substations under the\\u000a Daejeon Power Transmission District Office of KEPCO. The measurement was performed in a 6x4 structure on one side of the transformer.\\u000a The

  3. Modeling of electron energy distribution functions and vibrational distributions in volume H/sup -/ ion sources

    SciTech Connect

    Bretagne, J.; Capitelli, M.; Gorse, C.

    1987-07-30

    The modeling of magnetic multicusp H/sub 2/ discharges is presented. The model is based on the coupling of the time-dependent Boltzmann equation for the electron energy distribution function with the system of master equations for the H/sub 2/ vibrational excitation and kinetic equations for H and H/sup -/ densities.

  4. SystemC-AMS Heterogeneous Modeling of a Capacitive Harvester of Vibration Energy

    Microsoft Academic Search

    K. Caluwaerts; D. Galayko; P. Basset

    2008-01-01

    This paper presents the results of modeling of a mixed non-linear, strongly coupled and multidomain electromechanical system designed to scavenge the energy of ambient vibrations and to generate an electrical supply for an embedded microsystem. The system is operating in three domains: purely mechanical (the resonator), coupled electromechanical (electrostatic transducer associated with the moving mass) and electrical circuit, including switches,

  5. Modeling vibrational dephasing and energy relaxation of intramolecular anharmonic modes for multidimensional infrared spectroscopies

    Microsoft Academic Search

    Akihito Ishizaki; Yoshitaka Tanimura

    2006-01-01

    Starting from a system-bath Hamiltonian in a molecular coordinate representation, we examine an applicability of a stochastic multilevel model for vibrational dephasing and energy relaxation in multidimensional infrared spectroscopy. We consider an intramolecular anharmonic mode nonlinearly coupled to a colored noise bath at finite temperature. The system-bath interaction is assumed linear plus square in the system coordinate, but linear in

  6. Effects of reagent translational and vibrational energy on the dynamics of endothermic reactions

    SciTech Connect

    Krajnovich, D.; Zhang, Z.; Huisken, F.; Shen, Y.R.; Lee, Y.T.

    1981-07-01

    The endothermic reactions Br + CH/sub 3/I ..-->.. CH/sub 3/ + IBr (..delta..H/sub 0//sup 0/ = 13 kcal/mole) and Br + CF/sub 3/I ..-->.. CF/sub 3/ + IBr (..delta..H/sub 0//sup 0/ = 11 kcal/mole) have been studied by the crossed molecular beams method. Detailed center-of-mass contour maps of the IBr product flux as a function of recoil velocity and scattering angle are derived. For both systems it is found that the IBr product is sharply backward scattered with respect to the incident Br dirction, and that most of the available energy goes into product translation. Vibrational enhancement of the Br + CF/sub 3/I reaction was investigated by using the infrared multiphoton absorption process to prepare highly vibrationally excited CF/sub 3/I. At a collision energy of 31 kcal/mole (several times the barrier height), reagent vibrational energy appears to be less effective than an equivalent amount of (additional) translational energy in promoting reaction. More forward scattered IBr is produced in reactions of Br with vibrationally hot CF/sub 3/I.

  7. Vibration modal analysis and energy decoupling optimization of commercial vehicle cab suspension system

    Microsoft Academic Search

    Kai-yan Wang; Yu-qian Shi; Chang-hai Yang; Hao Ya; Wen-ku Shi

    2010-01-01

    Based on a cab suspension system of a commercial vehicle, a multi-body dynamic model was built on ADAMS Software for the vibration modal analysis. An Experiment was taken for the verification of the model's accuracy. Through the energy decoupling theory, the cab suspension system was optimized. By analyzing the optimized parameters, the suspension's stiffness and position were determined, which gave

  8. Characteristics of the vibrating-mesh minimum ignition energy testing apparatus for dust clouds

    Microsoft Academic Search

    K. S. Choi; M. Yamaguma; T. Kodama; J. H. Joung; M. Takeuchi

    2001-01-01

    A novel apparatus for testing the minimum ignition energies of flammable dusts is introduced. Unlike the conventional apparatus (the Hartmann tube), this new apparatus employs a vibrating mesh to produce a dust cloud. Using three kinds of powders, namely lycopodium, anthraquinone and polyacrylonitrile, which are designated as the samples for calibration by the International Electrotechnical Commission (IEC, 1994) standards, fundamental

  9. Vibrational analysis of HOCl up to 98% of the dissociation energy with a Fermi resonance Hamiltonian

    E-print Network

    Vibrational analysis of HOCl up to 98% of the dissociation energy with a Fermi resonance and wave functions of HOCl obtained from previous ab initio calculations J. Chem. Phys. 109, 2662 1998 I. INTRODUCTION The HOCl molecule plays an important role in the chem- istry of the upper atmosphere

  10. On the ro–vibrational energies for the lithium dimer; maximum-possible rotational levels

    NASA Astrophysics Data System (ADS)

    Mustafa, Omar

    2015-03-01

    The Deng–Fan potential is used to discuss the reliability of the improved Greene–Aldrich approximation and the factorization recipe of Badawi et al [17] for the central attractive/repulsive core J?ft( J+1 \\right)/2? {{r}2}. The factorization recipe is shown to be a more reliable approximation and is used to obtain the rotational–vibrational energies for the {{a}3}? u+–7Li2 dimer. For each vibrational state only a limited number of the rotational levels are found to be supported by the {{a}3}? u+–7Li2 dimer.

  11. ENergy and Power Evaluation Program

    SciTech Connect

    NONE

    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.

  12. Applications of energy harvesting for ultralow power technology

    NASA Astrophysics Data System (ADS)

    Pop-Vadean, A.; Pop, P. P.; Barz, C.; Chiver, O.

    2015-06-01

    Ultra-low-power (ULP) technology is enabling a wide range of new applications that harvest ambient energy in very small amounts and need little or no maintenance – self-sustaining devices that are capable of perpetual or nearly perpetual operation. These new systems, which are now appearing in industrial and consumer electronics, also promise great changes in medicine and health. Until recently, the idea of micro-scale energy harvesting, and collecting miniscule amounts of ambient energy to power electronic systems, was still limited to research proposals and laboratory experiments.Today an increasing number of systems are appearing that take advantage of light, vibrations and other forms of previously wasted environmental energy for applications where providing line power or maintaining batteries is inconvenient. In the industrial world, where sensors gather information from remote equipment and hazardous processes; in consumer electronics, where mobility and convenience are served; and in medical systems, with unique requirements for prosthetics and non-invasive monitoring, energy harvesting is rapidly expanding into new applications.This paper serves as a survey for applications of energy harvesting for ultra low power technology based on various technical papers available in the public domain.

  13. IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 17, NO. 5, SEPTEMBER 2002 669 Adaptive Piezoelectric Energy Harvesting Circuit for

    E-print Network

    Hofmann, Heath F.

    to harvesting elec- trical energy from a mechanically excited piezoelectric element. A vibrating piezoelectric for a wireless electrical power supply has spurred an interest in piezoelectric energy harvesting approaches to harvesting energy generated by a piezoelectric device[2],[3],[5],[6]there hasnot been

  14. State-to-state rotational energy transfer in highly vibrationally excited acetylene

    Microsoft Academic Search

    J. D. Tobiason; A. L. Utz; F. F. Crim

    1992-01-01

    Vibrational overtone excitation of single rovibrational eigenstates in acetylene, followed by state-resolved, laser-induced fluorescence (LIF) interrogation of the collisionally populated quantum states, permits a direct determination of both the pathways and rates of state-to-state rotational energy transfer in a polyatomic molecule containing about 10 000 cm?1 of internal energy. The data, which we acquire under single-collision conditions, demonstrate the importance

  15. Relaxation of vibrational energy of deuterium on surface of solid carbon dioxide. II

    Microsoft Academic Search

    N. M. Vasilev; S. A. Kovalevskii; M. A. Kozhushner; B. R. Shub

    1982-01-01

    Various models have been examined for the relaxation of vibrational energy of excited deuterium molecules adsorbed on the surface of a frozen layer of COâ. Estimates of the probability of relaxation through different mechanisms led to the following basic mechanism: Dâ(v=1)+COâ(000)..-->..Dâ(v=0)+COâ(001)+..delta..E, where ..delta..E = 620 cm⁻¹ is the energy released to rotational and translational degrees of freedom of the deuterium

  16. An interface circuit prototype for a vibration-based electromagnetic energy harvester

    Microsoft Academic Search

    Arian Rahimi; Ozge Zorlu; Haluk Kulah; Ali Muhtaroglu

    2010-01-01

    This paper describes the interface electronics for a vibration based Electromagnetic (EM) energy harvester, which works on the mechanical frequency-up-conversion principle. The interface electronics is used to step up and rectify the harvested AC signal of the energy harvester through a two-stage charge-pump circuit. Output voltage of 4.5 V with 2.5% ripple has been demonstrated at a load current of

  17. The energy relaxation of Si–H vibration in the H\\/Si(111) system. Relaxation rate and potential energy surface anharmonicity

    Microsoft Academic Search

    Vladimir A. Ermoshin; Andrey K. Kazansky; Konstantin S. Smirnov; Daniel Bougeard

    1998-01-01

    The vibrational energy relaxation of the Si–H stretching vibration in the H\\/Si(111) system is investigated by application of the perturbation theory to the anharmonic Si–H oscillator. The eigenfunctions for the 3D motion of an adsorbed H atom are obtained with an ab initio potential energy surface calculated for the H–Si(SiH3)3 cluster. The transition matrix elements between the vibrational states involved

  18. THE JOURNAL OF CHEMICAL PHYSICS 134, 094110 (2011) Determination of molecular vibrational state energies using the ab initio

    E-print Network

    Brown, Alex

    2011-01-01

    THE JOURNAL OF CHEMICAL PHYSICS 134, 094110 (2011) Determination of molecular vibrational state 2011; published online 3 March 2011) We have demonstrated the use of ab initio molecular dynamics (AIMD) trajectories to compute the vibrational energy levels of molecular systems in the context of the semiclassical

  19. Development of Piezoelectric MEMS Vibration Energy Harvester Using (100) Oriented BiFeO3 Ferroelectric Film

    NASA Astrophysics Data System (ADS)

    Murakami, S.; Yoshimura, T.; Satoh, K.; Wakazono, K.; Kariya, K.; Fujimura, N.

    2013-12-01

    Piezoelectric vibration energy harvesters (VEHs) with unimorph structure have been developed using Si micro-electrical mechanical systems (MEMS) technology. Since we revealed that (100) epitaxial BiFeO3 (BFO) piezoelectric films have high figure-of-merit on energy conversion, (100)-oriented BFO films have been prepared on (100)-oriented LaNiO3 bottom electrodes by the sol-gel method. We fabricated the piezoelectric VEHs using BFO films with resonance frequencies of ~100 Hz. The maximum output power density of these VEHs was determined to be 10.5 ?Wmm-3G-2 (G=9.8 ms-2) at a load resistance of 1 M?, which exceeds or is comparable to those of the best-performing VEHs using other piezoelectric films.

  20. The Power Generation Characteristics and Durability of a Vibration Power Generation Device using Piezoelectric Thick Film Formed Directly by Screen Printing on a Stainless Steel Substrate

    NASA Astrophysics Data System (ADS)

    Oishi, A.; Okumura, H.; Katsumura, H.; Kagata, H.

    2014-11-01

    This paper presents a small, high-performance and novel device that generates power from vibrations, made using screen-printing to form a piezoelectric thick film directly on a stainless steel substrate. This simple and cheap method realizes a 20 – 40 ?m-thick piezoelectric film, otherwise difficult to achieve using thin-film techniques or ceramic sintering, on a stainless steel substrate. A maximum output power of 1.1 mW was recorded with acceleration of 0.1 G0p (0.98 ms?2) applied at a resonance frequency of 24 Hz. We also evaluated the durability of the device by repeatedly striking the tip of the element. Output power exceeding 100 mW under damped resonant vibration was generated at the instant of striking, with approximately 0.9 mJ of power measured per single damped vibration. No deterioration was seen in the integrity of the stainless steel substrate or the piezoelectric thick film after over 10 million strikes.

  1. Design study of piezoelectric energy-harvesting devices for generation of higher electrical power using a coupled piezoelectric-circuit finite element method

    Microsoft Academic Search

    Meiling Zhu; Emma Worthington; Ashutosh Tiwari

    2010-01-01

    This paper presents a design study on the geometric parameters of a cantilever-based piezoelectric energy-harvesting devices (EHD), which harvest energy from motion (vibration), for the purpose of scavenging more energy from ambient vibration energy sources. The design study is based on the coupled piezoelectric-circuit finite element method (CPCFEM), previously presented by Dr. Zhu. This model can calculate the power output

  2. On the nature of intramolecular vibrational energy transfer in dense molecular environments

    NASA Astrophysics Data System (ADS)

    von Benten, Rebekka S.; Abel, Bernd

    2010-12-01

    Transient femtosecond-IR-pump-UV-absorption probe-spectroscopy has been employed to shed light on the nature of intramolecular vibrational energy transfer (IVR) in dense molecular environments ranging from the diluted gas phase to the liquid. A general feature in our experiments and those of others is that IVR proceeds via multiple timescales if overtones or combination vibrations of high frequency modes are excited. It has been found that collisions enhance IVR if its (slower) timescales can compete with collisions. This enhancement is, however, much more weaker and rather inefficient as opposed to the effect of collisions on intermolecular energy transfer which is well known. In a series of experiments we found that IVR depends not significantly on the average energy transferred in a collision but rather on the number of collisions. The collisions are much less efficient in affecting IVR than VET. We conclude that collision induced broadening of vibrational energy levels reduces the energy gaps and enhances existing couplings between tiers. The present results are an important step forward to rationalize and understand apparently different and not consistent results from different groups on different molecular systems between gas and liquid phases.

  3. Is there a light collision partner effect in vibrational energy transfer? Relaxation of p-difluorobenzene by He and Ar

    NASA Astrophysics Data System (ADS)

    Mudjijono; Lawrence, Warren D.

    1994-06-01

    State-to-state branching ratios are reported for vibrational energy transfer (VET) from the 30 2 and 8 2 vibrational levels in S 1 ( 1B 2u) p-difluorobenzene by the collision partners He and Ar in the collision region of a supersonic free-jet expansion. For VET from the 8 2 level, He removes more energy than does Ar. This is the expected light collision partner effect. For the 30 2 level, however, Ar unexpectedly removes more energy than He. The opposing behaviour observed for relaxation by He and Ar from two vibrational levels of the same molecule is inconsistent with a universal 'light collision partner effect'.

  4. 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.

  5. Vibrational and Translational Energy Effects in the Reaction of Ammonia Ions with Water Michael A. Everest, John C. Poutsma, and Richard N. Zare*

    E-print Network

    Zare, Richard N.

    Vibrational and Translational Energy Effects in the Reaction of Ammonia Ions with Water Molecules of vibrationally state-selected ammonia ions with deuterated water is investigated with a quadrupole energies from 0.5 to 10.0 eV (center of mass) and ammonia ion vibrational states 1020-10 and 1122

  6. Fatigue assessment of vibrating rail vehicle bogie components under non-Gaussian random excitations using power spectral densities

    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

  7. 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.

  8. Electromagnetic energy harvesting from vibrations of multiple frequencies

    Microsoft Academic Search

    Bin Yang; Chengkuo Lee; Wenfeng Xiang; Jin Xie; Johnny Han He; Rama Krishna Kotlanka; Siew Ping Low; Hanhua Feng

    2009-01-01

    A novel multi-frequency energy harvester has been designed and fabricated, which consists of three permanent magnets, three sets of two-layer copper coils and a supported beam of acrylic, while these coils are made of thin fire resistant 4 (FR4) substrates using a standard printed circuit board. The energy under the first, second and third resonant modes can be harvested, corresponding

  9. Transient grating study on vibrational energy relaxation of bridged azulene anthracene’s

    NASA Astrophysics Data System (ADS)

    Fujiwara, H.; Terazima, M.; Kimura, Y.

    2008-03-01

    A transient grating study of intermolecular vibrational energy dissipation in competition with intramolecular vibrational energy re-distribution (IVR) is reported. The translational temperature rise rates of 1-alkylazulene and 1-(anthracene-9-yl-alkyl)azulene in organic solvents are compared with the kinetics obtained from transient absorption (TA) experiments [D. Schwarzer, P. Kutne, C. Schroder, J. Troe, J. Chem. Phys. 121 (2004) 1754]. The results of 1-alkylazulene suggest the dynamics assigned to IVR in the TA study could complete with the temperature rise kinetics of the solvent. The results of 1-(anthracene-9-yl-alkyl)azulene support the existence of the faster dissipation process than TA component. The different solvent effects are also discussed.

  10. Free vibrations of an uncertain energy pumping system

    NASA Astrophysics Data System (ADS)

    Cataldo, Edson; Bellizzi, Sergio; Sampaio, Rubens

    2013-12-01

    The aim of this paper is to study the energy pumping (the irreversible energy transfer from one structure, linear, to another structure, nonlinear) robustness considering the uncertainties of the parameters of a two DOF mass-spring-damper, composed of two subsystems, coupled by a linear spring: one linear subsystem, the primary structure, and one nonlinear subsystem, the so-called NES (nonlinear energy sink). Three parameters of the system will be considered as uncertain: the nonlinear stiffness and the two dampers. Random variables are associated to the uncertain parameters and probability density functions are constructed for the random variables applying the Maximum Entropy Principle. A sensitivity analysis is then performed, considering different levels of dispersion, and conclusions are obtained about the influence of the uncertain parameters in the robustness of the system.

  11. Alternative Energy and Remote Power Products

    NSDL National Science Digital Library

    Based in Alaska, ABS Alaskan provides batteries, alternative energy and remote and power products. The site contains a Library link, where users can explore a basic power system diagram, visit the document download center, and find information explaining alternative energy and power systems.

  12. Vibrational predissociation of the nitric oxide dimer: Total energy distribution in the fragments

    Microsoft Academic Search

    Michael P. Casassa; John C. Stephenson; David S. King

    1986-01-01

    Rotational, spin-orbit, lambda doublet, and kinetic energy distributions were measured by laser-excited fluorescence techniques for the nitric oxide fragments formed from the vibrational predissociation of nitric oxide dimers in a free jet expansion. The NO fragments, produced following excitation in the dimer ?1 fundamental, were described by a rotational ‘‘temperature’’ of TR&bartil;100 K, with full equilibration of lambda doublet states,

  13. SystemC-AMS Modeling of an Electromechanical Harvester of Vibration Energy

    Microsoft Academic Search

    Ken Caluwaerts; Dimitri Galayko

    2008-01-01

    We present the results of modeling of a mixed non-linear, strongly coupled and multidomain electromechanical system designed to scavenge the energy of ambient vibrations and to generate an\\u2029 electrical supply for an embedded micro system. The system is operating in three domains: purely\\u2029 mechanical (the resonator), coupled electromechanical (electrostatic transducer associated with the moving\\u2029 mass) and electrical circuit, including switches,

  14. Fully integrated micro electromagnetic vibration energy harvesters with micro-patterning of bonded magnets

    Microsoft Academic Search

    K. Tao; G. Ding; P. Wang; Z. Yang; Y. Wang

    2012-01-01

    This paper presents the fabrication and characterization of a novel fully integrated micro electromagnetic vibration energy harvester using micro-patterning of bonded magnets. The magnetic material utilized is a polymer composite, consisting of a commercially available NdFeB powder dispersed in epoxy resin to a weight loading percentage of 90%. The prototype is fabricated using UV-LIGA technology and microelectroplating technology. The whole

  15. Ab initio rotation-vibration energies and intensities for the HNC + molecule

    NASA Astrophysics Data System (ADS)

    Kraemer, W. P.; Jensen, Per; Roos, B. O.; Bunker, P. R.

    1992-05-01

    Accurate ab initio calculations at the multi-reference configuration interaction level of theory were carried out to determine the potential energy surface of the X˜2?+ electronic ground state of the HNC + molecular ion. The electronic energies and the electronically averaged dipole moment components were calculated at a total of 44 geometries with energies up to 14 000 cm -1 above equilibrium. Additional calculations were done to determine the barrier for isomerization to the X˜2? electronic ground state of HCN + ( H = 1.83 eV), the adiabatic ionization potential of the parent neutral HNC (IP = 11.88 eV), the dissociation energy for the process HNC + ? H + + CN ( X˜2?+)(D 0 = 5.36 eV) , and the energy separation between the electronic ground state and the first excited state ( 2?) of HNC + ( Te = 1.70 eV). An analytical function was fitted through the X˜2?+ ab initio points of HNC +, and relatively large stretch-bend interaction terms were obtained in the fitted function. The analytical potential function was used with the Morse Oscillator Rigid Bender Internal Dynamics Hamiltonian [ P. JENSEN, J. Mol. Spectrosc.128, 478-501 (1988); J. Chem. Soc., Faraday Trans. 284, 1315-1340 (1988)] in a variational calculation of the rotation-vibration energies with N ? 6 of the HNC + and DNC + molecules. This calculation neglects the possibility of the molecule tunneling into the HCN + minimum of the potential energy surface and the effects of the non-zero electronic spin in the X˜2?+ state of HNC +. We obtain ?1 = 3404 cm -1, ?2 = 523 cm -1, and ?3 = 2163 cm -1 for HNC +. We also calculate the vibrational transition moments using the dipole moment functions obtained from fits to the ab initio dipole moment data and obtain for HNC + that the vibrationally averaged dipole moment is 0.66 Debye in the vibrational ground state, and that the vibrational transition moments for the fundamental transitions ?1, ?2, and ?3 are 0.24, 0.48, and 0.02 Debye, respectively.

  16. Calculation of vibrational energy levels of triatomic molecules with the C 2v and C s symmetries by summing divergent series of the Rayleigh-Schrödinger perturbation theory

    NASA Astrophysics Data System (ADS)

    Bykov, A. D.; Kalinin, K. V.

    2012-03-01

    The Rayleigh-Schrödinger perturbation theory is applied to calculation of vibrational energy levels of triatomic molecules with the C 2v and C s symmetries: SO2, H2S, F2O, HOF, HOCl, and DOCl. Particular attention is given to the states coupled by anharmonic resonances; for such states, the perturbation theory series diverge. To sum these series, the known methods of Padé, Padé-Borel, and Padé-Hermite and the method of power moments are used. For low-lying levels, all the summation methods give satisfactory results, while the method of quadratic Padé-Hermite approximants appears to be more efficient for high-excited states. Using these approximants, the structure of singularities of the vibrational energy, as a function in the complex plane, is studied.

  17. Elastic Scattering and Vibrational Excitation of Tetrahydrofuran by Low Energy Electrons

    NASA Astrophysics Data System (ADS)

    Orton, Danny; Gauf, Alexsander; Jo, Amos; Tanner, Joshua; Khakoo, Murtadha A.; Walls, Todd; Winstead, Carl; McKoy, Vincent

    2012-10-01

    We report experimental and theoretical (Schwinger Multi-Channel method with polarization effects) differential cross-sections (DCS) for low energy elastic electron scattering from tetrahydrofuran. The data are for incident energies from 0.75 to 30eV and the experimental scattering angles range from 10^o to 130^o. Agreement between theory and experiment is very good across the range of this data. Comparisons with previous experiments is also very good in general. We will also report DCSs for vibrational excitation of this target for energies up to 15eV and similar scattering angles.

  18. Vibrational energy exchange between carbon dioxide and hydrogen sulfidea)

    Microsoft Academic Search

    Jeffrey Hoke; J. M. Preses; Ralph E. Weston Jr.

    1983-01-01

    A mixture of COâ and HâS was irradiated with a low-pressure Q-switched COâ laser, and the infrared emission from COâ(00°¹ was observed. The rates of collisional energy transfer to HâS were computed from the observed infrared fluorescence. (AIP)

  19. Piezoelectric Energy Harvesting under High PreStressed Cyclic Vibrations

    Microsoft Academic Search

    Hyeoung Woo Kim; Shashank Priya; Kenji Uchino; Robert E. Newnham

    2005-01-01

    Cymbal transducers have been found as a promising structure for piezoelectric energy harvesting under high force (? 100 N) at cyclic conditions (? 100–200 Hz). The thicker steel cap enhances the endurance of the ceramic to sustain higher ac loads along with stress amplification. This study reports the performance of the cymbal transducer under ac force of 70 N with

  20. Automatic differentiation method for numerical construction of the rotational-vibrational Hamiltonian as a power series in the curvilinear internal coordinates using the Eckart frame.

    PubMed

    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. PMID:26156463

  1. INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME

    E-print Network

    . The mission of the Photovoltaic Power Systems Programme is ,,to enhance the international collaboration obtained by weather forecast models. Digital atlases have been created as integrated information system#12;INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME TASK 2 ­ Performance

  2. Testing Skyrme energy-density functionals with the QRPA in low-lying vibrational states of rare-earth nuclei

    E-print Network

    Terasaki, J

    2011-01-01

    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.

  3. 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.

  4. Product energy partitioning in the unimolecular decomposition of vibrationally and rotationally state-selected hydrogen peroxide

    SciTech Connect

    Luo, X.; Rizzo, T.R. (Department of Chemistry, University of Rochester, Rochester, New York 14627 (United States))

    1992-04-01

    Infrared-optical double resonance prepares HOOH molecules in single rotational levels of the 6{nu}{sub OH}, 5{nu}{sub OH}+{nu}{sub OOH}, 5{nu}{sub OH}+{nu}{sub OO}, and 4{nu}{sub OH}+{nu}{sub OH{prime}} vibrational states which range from 3 to 2287 cm{sup {minus}1} of excess energy above the unimolecular dissociation threshold. Laser-induced fluorescence probes the nascent OH rotational state distributions from the decomposition of rovibrationally selected reactants. The nascent rotational state distributions reveal that both OH spin--orbit states can be populated by the decomposition of a single molecule and hence that electronic angular momentum is not conserved throughout the dissociation process. The product state distributions from reactants excited to the 6{nu}{sub OH} and 4{nu}{sub OH}+{nu}{sub OH{prime}} vibrational levels are generally in good agreement with the predictions of phase-space theory provided electronic angular momentum is treated statistically. Reactants decomposing from single rotational states in the 5{nu}{sub OH}+{nu}{sub OOH} combination level (and to a lesser extent the 5{nu}{sub OH}+{nu}{sub OO} level) show product state distributions which are systematically colder than phase-space theory predictions. This observation indicates that energy redistribution in vibrationally excited HOOH is not complete on the time scale of unimolecular decomposition.

  5. 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 Tietz–Hua oscillator potential. We discuss how to relate our deformed Schiöberg 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 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.

  6. Extensivity of Energy and Electronic and Vibrational Structure Methods for Crystals

    NASA Astrophysics Data System (ADS)

    Hirata, So; Keçeli, 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.

  7. Power management in energy harvesting sensor networks

    Microsoft Academic Search

    Aman Kansal; Jason Hsu; Sadaf Zahedi; Mani B. Srivastava

    2007-01-01

    Power management is an important concern in sensor networks, because a tethered energy infrastructure is usually not available and an obvious concern is to use the available battery energy efficiently. However, in some of the sensor networking applications, an additional facility is available to ameliorate the energy problem: harvesting energy from the environment. Certain considerations in using an energy harvesting

  8. Vibrational ground-state population distributions of an N2 flowing afterglow deduced from electron energy-loss spectra

    Microsoft Academic Search

    M. D. White; K. J. Ross

    1976-01-01

    The vibrationally excited populations of ground-state N2 in a flowing afterglow have been determined from energy-loss spectra in the energy-loss region 7.0-10.5 eV. The data of White et al. (1976) for energy-loss spectra in the energy-loss region 10.5-12.5 eV have been re-analysed and confirm a non-Boltzmann population distribution of the vibrational levels. An electron energy-loss spectrum of the afterglow is

  9. Scavenging vibration energy from seismically isolated bridges using an electromagnetic harvester

    NASA Astrophysics Data System (ADS)

    Lu, Qiuchen; Loong, Chengning; Chang, Chih-Chen; Dimitrakopoulos, Elias G.

    2014-04-01

    The increasing worldwide efforts in securing renewable energy sources increase incentive for civil engineers to investigate whether the kinetic energy associated with the vibration of larger-scale structures can be harvested. Such a research remains challenging and incomplete despite that hundreds of related articles have been published in the last decade. Base isolation is one of the most popular means of protecting a civil engineering structure against earthquake forces. Seismic isolation hinges on the decoupling of the structure from the shaking ground, hence protecting the structure from stress and damage during an earthquake excitation. The low stiffness isolator inserted between the structure and the ground dominates the response leading to a structural system of longer vibration period. As a consequence of this period shift, the spectral acceleration is reduced, but higher response displacements are produced. To mitigate this side effect, usually isolators are combined with the use of additional energy dissipation. In this study, the feasibility of scavenging the need-to-be dissipated energy from the isolator installed in a seismically isolated bridge using an electromagnetic (EM) energy harvester is investigated. The EM energy harvester consists of an energy harvesting circuit and a capacitor for energy storage. A mathematical model for this proposed EM energy harvester is developed and implemented on an idealized base-isolated single-degree-of-freedom system. The effect of having this EM energy harvester on the performance of this seismic isolated system is analyzed and discussed. The potential of installing such an EM energy harvester on a seismically isolated bridge is also addressed.

  10. Bonneville Power Administration's Purchasing of Energy Savings 

    E-print Network

    Schick, H.

    1985-01-01

    The Bonneville Power Administration (BPA) is conducting a commercial buildings retrofit program in the Pacific Northwest by making payments to a sponsor, such as an energy service company or architectural and engineering firm, for energy savings...

  11. Stabilization of peptide helices by length and vibrational free energies: Ab initio case study of polyalanine

    NASA Astrophysics Data System (ADS)

    Rossi, Mariana; Blum, Volker; Scheffler, Matthias

    2012-02-01

    Helices are one of the most abundant secondary structure ``building blocks" of polypeptides and proteins. Here, we explore helix stabilization as a function of peptide length and temperature [harmonic approximation to the vibrational free energy (FE)], for the alanine-based peptide, Ac-Alan-LysH^+ n=4-15, in the gas phase. For n=4-8, we predict the lowest energy structures in density-functional theory, using the van der Waals (vdW) corrected[1] PBE exchange-correlation potential. ?-helices become the lowest energy structures at n 7-8 on the potential energy surface, but only barely and if including vdW interactions. At finite temperatures, the helices are further stabilized over compact conformers. While the vibrational entropy is the leading stabilizing term at 300 K, also the zero-point-energies favor the helical structures. For n>=8, the ?-helix should be the only accessible conformer in the FE surface at 300 K, in agreement with experiment[2] and with our own comparison[3] of calculated ab initio anharmonic IR spectra to experimental IR multiple photon dissociation data for n=5, 10, and 15. [1] Tkatchenko and Scheffler, PRL 102, 073055 (2009); [2] Kohtani and Jarrold, JACS 108, 8454 (2004); [3] Rossi et al., JPCL 1, 3465 (2010).

  12. The Assistance of Molecular Vibrations on Coherent Energy Transfer in Photosynthesis from the View of Quantum Heat Engine

    E-print Network

    Zhang, Zhedong

    2015-01-01

    Recently the quantum nature in the energy transport in solar cell and light-harvesting complexes have 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 intra-molecule vibrational modes on the coherent energy transfer process and quantum transport. 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, with theexciton-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 en...

  13. Vibrational vs. translational energy in promoting a prototype metal–hydrocarbon insertion reaction

    PubMed Central

    Proctor, David L.; Davis, H. Floyd

    2008-01-01

    The reaction Y + CH4 ? HYCH3 ? YCH2 + H2 is initiated by C–H 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 C–H 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

  14. Energy function analysis for power system stability

    Microsoft Academic Search

    M. A. Pai

    1989-01-01

    Energy Function Analysis for Power System Stability presents the concept of energy function, which has found wide-spread applications for power systems in recent years. The most recent advances in five distinct areas are reviewed: Development of energy functions for structure preserving models, which can incorporate non-linear load models; energy functions which include a detailed model of the generating unit (i.e.

  15. Electrostatic Force-induced Broadband Effect in Electret- based Vertical Vibration Energy Harvesters using Finegrained Stainless Steel Oscillator

    NASA Astrophysics Data System (ADS)

    Asanuma, H.; Hara, M.; Oguchi, H.; Kuwano, H.

    2014-11-01

    We propose a fine-grained stainless-steel as a promising material for a robust oscillator and investigate the dependence of frequency band width, resonance frequency, and output power on initial air gaps in electret-based vertical vibration energy harvesters. Beams of the oscillator showed a shallow side-etched depth less than 10 ?m, as well as smooth edges. The oscillator succeeded in travelling over 1-mm displacement without fracture. Also, we found that broader frequency band, as well as lower resonance frequency, can be achieved with reducing the initial air gap, whereas the output power exhibited a peak value at an optimal initial air gap. The results may be attributed to the soft spring effect induced by the stronger electrostatic force. Maximum output power density and FWHM of frequency band width of our harvester are 4.7 ?W/cm3 and 14 Hz at initial air gap 0.3 mm and acceleration 4.9 m/s2.

  16. Vibrational and rotational relaxation of HCl in collisions with Ar. Quasiclassical trajectories on model potential-energy surfaces

    Microsoft Academic Search

    Thompson

    1982-01-01

    State-to-state energy-transfer cross sections are calculated for Ar + HCl collisions by using quasiclassical trajectories and model potentials. Interest is focused upon relaxation from high vibration-rotation states. Calculations are reported for initial vibrational states v\\/sub i\\/ = 0, 2, 4, and 6 and initial rotational states J\\/sub i\\/ = 10, 20, and 30. Most of the calculations are for relative

  17. Vibrational coherence and energy transfer in two-dimensional spectra with the optimized mean-trajectory approximation

    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.

  18. An exact variational method to calculate vibrational energies of five atom molecules beyond the normal mode approach

    Microsoft Academic Search

    Hua-Gen Yu

    2002-01-01

    A full dimensional variational algorithm to calculate vibrational energies of penta-atomic molecules is presented. The quantum mechanical Hamiltonian of the system for J=0 is derived in a set of orthogonal polyspherical coordinates in the body-fixed frame without any dynamical approximation. The vibrational Hamiltonian has been obtained in an explicitly Hermitian form. Variational calculations are performed in a direct product discrete

  19. IEEE SENSORS JOURNAL, VOL. 9, NO. 7, JULY 2009 731 A Vibration-Based PMN-PT Energy Harvester

    E-print Network

    Yi, Jingang

    , and ex- perimental study of a vibration-based piezoelectric energy harvester. The energy harvester piezoelectric harvesters. Index Terms--Composite cantilever beam, energy harvester, in- terdigited electrodes (IDEs), piezoelectric harvester, PMN-PT. I. INTRODUCTION OVER the past decade, there has been

  20. Power electronics and alternative energy generation

    Microsoft Academic Search

    James P Lyons; Vlatko Vlatkovic

    2004-01-01

    Growth in alterative energy generation technologies and markets will have a major impact on the development of power electronics in the future. The paper discusses some of these implications, and outlines the technological and performance challenges for power electronic systems in alternative energy applications.

  1. From solar energy to mechanical power

    Microsoft Academic Search

    Fujii

    1990-01-01

    This book describes general methods of converting solar thermal energy to mechanical power, concentrating particularly on those having a small or moderate conversion scale. Beginning with a historical overview and an outline of requirements for a solar-mechanical power conversion system, the book describes in detail several energy conversion system, paying particular attention to the Rankine, Stirling and Brayton cycle engines.

  2. Analyzing intramolecular vibrational energy redistribution via the overlap intensity-level velocity correlator

    E-print Network

    Srihari Keshavamurthy; Nicholas R. Cerruti; Steven Tomsovic

    2002-02-02

    Numerous experimental and theoretical studies have established that intramolecular vibrational energy redistribution (IVR) in isolated molecules has a heirarchical tier structure. The tier structure implies strong correlations between the energy level motions of a quantum system and its intensity-weighted spectrum. A measure, which explicitly accounts for this correaltion, was first introduced by one of us as a sensitive probe of phase space localization. It correlates eigenlevel velocities with the overlap intensities between the eigenstates and some localized state of interest. A semiclassical theory for the correlation is developed for systems that are classically integrable and complements earlier work focusing exclusively on the chaotic case. Application to a model two dimensional effective spectroscopic Hamiltonian shows that the correlation measure can provide information about the terms in the molecular Hamiltonian which play an important role in an energy range of interest and the character of the dynamics. Moreover, the correlation function is capable of highlighting relevant phase space structures including the local resonance features associated with a specific bright state. In addition to being ideally suited for multidimensional systems with a large density of states, the measure can also be used to gain insights into the phase space transport and localization. It is argued that the overlap intensity-level velocity correlation function provides a novel way of studying vibrational energy redistribution in isolated molecules. The correlation function is ideally suited to analyzing the parametric spectra of molecules in external fields.

  3. Energy storage options for space power

    Microsoft Academic Search

    H. W. Hoffman; J. F. Martin; M. Olszewski

    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

  4. 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.

  5. Nuclear Power Trends Energy Economics and Sustainability

    E-print Network

    Nuclear Power Trends Energy Economics and Sustainability L. H. Tsoukalas Purdue University Nuclear;National Research Council of Greece, May 8, 2008 Outline · The Problem · Nuclear Energy Trends · Energy Economics · Life Cycle Analysis · Nuclear Sustainability · Nuclear Energy in Greece? #12;National Research

  6. VIBRATION-INDUCED TWO-PHASE COOLING TECHNOLOGIES FOR HIGH POWER THERMAL MANAGEMENT

    Microsoft Academic Search

    S. Heffington; A. Glezer; S. Tillery; M. Smith

    2004-01-01

    Two technologies for cooling of high-heat flux microelectronics based on enhanced phase-change are described. The first technology is based on a submerged vibration-induced bubble ejection process in which small vapor bubbles that form on and are attached to a submerged heated solid surface are dislodged and propelled into the cooler bulk liquid. This ejection technique involves forced removal of the

  7. A refined quartic potential energy surface and large scale vibrational calculations for S0 thiophosgene.

    PubMed

    Rashev, Svetoslav; Moule, David C

    2015-04-01

    In this work we present a full 6D quartic potential energy surface (PES) for S0 thiophosgene in curvilinear symmetrized bond-angle coordinates. The PES was refined starting from an ab initio field derived from acc-pVTZ basis set with CCSD(T) corrections for electron correlation. In the present calculations we used our variational method that was recently tested on formaldehyde and some of its isotopomers, along with additional improvements. The lower experimentally known vibrational levels for 35Cl2CS were reproduced quite well in the calculations, which can be regarded as a test for the feasibility of the obtained quartic PES. PMID:25615683

  8. Comparison of DFT with Traditional Methods for the Calculation of Vibrational Frequencies and Bond Energies

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W.; Arnold, James O. (Technical Monitor)

    1997-01-01

    The vibrational frequencies of MO2 are computed at many levels of theory, including HF, B3LYP, BP86, CASSCF, MP2, and CCSD(T). The computed results are compared with the available experimental results. Most of the methods fail for at least one state of the systems considered. The accuracy of the results and the origin of the observed failures are discussed. The B3LYP bond energies are compared with traditional methods for a variety of systems, ranging from FeCOn+ to SiCln and its positive ions. The cases where B3LYP differs from the traditional methods are discussed.

  9. Vibration absorption in systems with a nonlinear energy sink: Nonlinear damping

    NASA Astrophysics Data System (ADS)

    Starosvetsky, Y.; Gendelman, O. V.

    2009-07-01

    In this work, response regimes are investigated in a system comprising of a linear oscillator (subject to harmonic excitation) and a nonlinear energy sink (NES) with nonlinear damping characteristics. An analytical technique for the treatment of certain class of nonlinear damping functions is developed. Special attention is paid to the case of piecewise-quadratic damping, motivated by possible applications. It is demonstrated that the NES with a properly tuned piecewise-quadratic damping element allows complete elimination of undesirable periodic regimes. In this way, an efficient system of vibration absorption is obtained, and its performance can overcome that of a tuned mass damper (TMD). Numerical results agree satisfactorily with the analytical predictions.

  10. A refined quartic potential energy surface and large scale vibrational calculations for S0 thiophosgene

    NASA Astrophysics Data System (ADS)

    Rashev, Svetoslav; Moule, David C.

    2015-04-01

    In this work we present a full 6D quartic potential energy surface (PES) for S0 thiophosgene in curvilinear symmetrized bond-angle coordinates. The PES was refined starting from an ab initio field derived from acc-pVTZ basis set with CCSD(T) corrections for electron correlation. In the present calculations we used our variational method that was recently tested on formaldehyde and some of its isotopomers, along with additional improvements. The lower experimentally known vibrational levels for 35Cl2CS were reproduced quite well in the calculations, which can be regarded as a test for the feasibility of the obtained quartic PES.

  11. Vibrational energy transfer in OH A 2?+ between 195 and 295 K

    NASA Astrophysics Data System (ADS)

    Steffens, Kristen L.; Crosley, David R.

    2000-06-01

    Vibrational energy transfer (VET) v'=1?0 and electronic quenching of v'=1 and 0 in the A 2?+ electronically excited state of the OH radical has been studied over the temperature range 195 to 295 K. The colliders investigated were N2, O2, and CO2. Laser-induced fluorescence experiments were conducted in a flow cell with photolytic production of OH; both fluorescence intensity and time decay measurements were made. The VET cross sections are found to increase with decreasing temperature, suggestive of attractive force interactions in the VET process.

  12. Spectroscopic investigations of the vibrational potential energy surfaces in electronic ground and excited states

    E-print Network

    Yang, Juan

    2007-09-17

    , the equilibrium configuration is non-planar. As an example, the dihedral angle for cyclobutane 23 is about 33°. Therefore the potential curve for the puckering vibration has two identical minima corresponding to the ring being puckered up or down.... There is clearly an energy barrier between these two minima and this corresponds to the planar configuration of the molecule. To introduce such a barrier, a quadratic term is added to the potential function, giving 24 xxV(x) ba += . (2.23) The sign...

  13. Pulsed Power Driven Fusion Energy

    SciTech Connect

    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.

  14. Compact inductive energy storage pulse power system

    NASA Astrophysics Data System (ADS)

    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.

  15. Self-powered smart blade: helicopter blade energy harvesting

    NASA Astrophysics Data System (ADS)

    Bryant, Matthew; Fang, Austin; Garcia, Ephrahim

    2010-04-01

    A novel energy harvesting device powered by aeroelastic flutter vibrations is proposed to generate power for embedded wireless sensors on a helicopter rotor blade. Such wireless sensing and on-board power generation system would eliminate the need for maintenance intensive slip ring systems that are required for hardwired sensors. A model of the system has been developed to predict the response and output of the device as a function of the incident wind speed. A system of coupled equations that describe the structural, aerodynamic, and electromechanical aspects of the system are presented. The model uses semi-empirical, unsteady, nonlinear aerodynamics modeling to predict the aerodynamic forces and moments acting on the structure and to account for the effects of vortex shedding and dynamic stall. These nonlinear effects are included to predict the limit cycle behavior of the system over a range of wind speeds. The model results are compared to preliminary wind tunnel tests of a low speed aeroelastic energy harvesting experiment.

  16. Variational calculations of rotational-vibrational energies of CH{sub 4} and isotopomers using an adjusted ab initio potential

    SciTech Connect

    Carter, S.; Bowman, J.M.

    2000-03-23

    The authors report variational calculations of vibrational energies of CH{sub 4}, CH{sub 3}D, CH{sub 2}D{sub 2}, CHD{sub 3}, and CD{sub 4} using the code Multimode and the ab initio force field of Lee and co-workers [Lee, T.J.; Martin, J.M.L.; Taylor, P.R.--J.Chem.Phys. 1995, 102, 254], re-expressed using Morse variables in the stretch displacements. Comparisons are made with experimental energies for CH{sub 4} with this potential, and then small adjustments are made to the potential to improve agreement with experiment for CH{sub 4}. Calculations for the isotopomers are done using the adjusted potential and compared with experiment. Additional vibrational energies and assignments not reported experimentally are also given for CH{sub 4} and the isotopomers. Exact rotational-vibrational energies of CH{sub 4} are also reported for J = 1.

  17. Spectroscopic probes of vibrationally excited molecules at chemically significant energies. Progress report, August 15, 1991--August 14, 1992

    SciTech Connect

    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.

  18. Energy $ Savings From Power Capacitors

    E-print Network

    Harder, J. E.

    1982-01-01

    penalty or a reduction in the kVA demand, or a similar reduction in the power bill for improved power factor. In addition, some users will add power capacitors to improve voltage regulation or reduce the loading of heavily loaded transformers... (TL) of a transformer can be divided into no load loss (NL) and load loss (LL) where: TL .. NL + LL The no load loss is affected very little by the addition of capacitors. The load loss varies as the square of the current or the square of the k...

  19. The ab initio potential energy surface and vibrational-rotational energy levels of dilithium monoxide, Li20

    SciTech Connect

    Koput, Jacek (Adam Mickiewicz University, Poland) [Adam Mickiewicz University, Poland; Peterson, Kirk A.(WASHINGTON STATE UNIV TC) [WASHINGTON STATE UNIV TC

    2002-01-01

    The equilibrium structure and potential energy surface of lithium monoxide, Li2O, has been determined from large-scale ab initio calculations using the coupled-cluster method, CCSD(T), with basis sets of double- through quintuple-zeta quality. The effects of core-electron correlation on the calculated molecular parameters were investigated. The vibrational-rotational energy levels of the 7LiO7Li and 6LiO7Li isotopic species were calculated by a variational approach. A comparison with results of recent experimental high-resolution studies is presented.

  20. Ab initio ground-state potential energy function and vibration-rotation energy levels of imidogen, NH.

    PubMed

    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. © 2015 Wiley Periodicals, Inc. PMID:25920622

  1. High resolution IR diode laser study of collisional energy transfer between highly vibrationally excited monofluorobenzene and CO2: The effect of donor fluorination on strong collision energy transfer

    NASA Astrophysics Data System (ADS)

    Kim, Kilyoung; Johnson, Alan M.; Powell, Amber L.; Mitchell, Deborah G.; Sevy, Eric T.

    2014-12-01

    Collisional energy transfer between vibrational ground state CO2 and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm-1) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E' = ˜41 000 cm-1 was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S1?S0*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO2 via collisions was measured by probing the scattered CO2 using the IR diode laser. The absolute state specific energy transfer rate constants and scattering probabilities for single collisions between hot MFB and CO2 were measured and used to determine the energy transfer probability distribution function, P(E,E'), in the large ?E region. P(E,E') was then fit to a bi-exponential function and extrapolated to the low ?E region. P(E,E') and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E') and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E'). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency.

  2. High resolution IR diode laser study of collisional energy transfer between highly vibrationally excited monofluorobenzene and CO2: the effect of donor fluorination on strong collision energy transfer.

    PubMed

    Kim, Kilyoung; Johnson, Alan M; Powell, Amber L; Mitchell, Deborah G; Sevy, Eric T

    2014-12-21

    Collisional energy transfer between vibrational ground state CO2 and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm(-1)) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E' = ?41,000 cm(-1) was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S1?S0*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO2 via collisions was measured by probing the scattered CO2 using the IR diode laser. The absolute state specific energy transfer rate constants and scattering probabilities for single collisions between hot MFB and CO2 were measured and used to determine the energy transfer probability distribution function, P(E,E'), in the large ?E region. P(E,E') was then fit to a bi-exponential function and extrapolated to the low ?E region. P(E,E') and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E') and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E'). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency. PMID:25527934

  3. Intermediate-energy differential and integral cross sections for vibrational excitation in ?-tetrahydrofurfuryl alcohol

    SciTech Connect

    Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Chiari, L.; Jones, D. B.; Pettifer, Z. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, G. [Instituto de Física Fundamental, CSIC, Madrid E-28006 (Spain); White, R. D. [School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia)

    2014-06-07

    Differential and integral cross section measurements, for incident electron energies in the 20–50 eV range, are reported for excitation of several composite vibrational modes in ?-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.

  4. Optimizing a Hybrid Energy Storage System for a Virtual Power Plant for Improved Wind Power

    E-print Network

    Teodorescu, Remus

    Optimizing a Hybrid Energy Storage System for a Virtual Power Plant for Improved Wind Power power plant. In this paper it means the combination of the hybrid energy storage system and wind power. Index Terms--Virtual power plant, hybrid energy storage, wind power, sizing energy storage 1

  5. 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.

  6. Laser energy converted into electric power

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1973-01-01

    Apparatus verifies concepts of converting laser energy directly into electric energy. Mirror, placed in beam and inclined at angle to it, directs small amount of incident radiation to monitor which establishes precise power levels and other beam characteristics. Second mirror and condensing lens direct bulk of laser energy into laser plasmadynamic converter.

  7. Second Proof Work, Power, and Energy

    E-print Network

    Kostic, Milivoje M.

    , United States 1. Basic Concepts 2. Forms, Classifications, and Conservation of Energy 3. Work that they will be depleted in a finite time period at the current rate of consumption. power The energy rate per unit of time. renewable energy sources The continuously or frequently available (renewed daily or at least annually

  8. Energy Storage for the Power Grid

    SciTech Connect

    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.

  9. Potential energy scans and vibrational assignments of cyclopropanecarboxylic acid and cyclopropanecarboxamide.

    PubMed

    Badawi, H M; Al-Saadi, A A; Al-Khaldi, M A A; Al-Abbad, S A; Al-Sunaidi, Z H A

    2008-12-15

    The structural stability and internal rotations in cyclopropanecarboxylic acid and cyclopropanecarboxamide were investigated by the DFT-B3LYP and the ab initio MP2 calculations using 6-311G** and 6-311+G** basis sets. The computations were extended to the MP4//MP2/6-311G** and CCSD(T)//MP2/6-311G** single-point calculations. From the calculations the molecules were predicted to exist predominantly in the cis (C=O group eclipses the cyclopropane ring) with a cis-trans barrier of about 4-6kcal/mol. The OCOH torsional barrier in the acid was estimated to be about 12-13kcal/mol while the corresponding OCNH torsional barrier in the amide was calculated to be about 20kcal/mol. The equilibrium constant k for the cis<-->trans interconversion in cyclopropanecarboxylic acid was calculated to be 0.1729 at 298.15K that corresponds to an equilibrium mixture of about 85% cis and 15% trans. The vibrational frequencies were computed at the DFT-B3LYP level. Normal coordinate calculations were carried out and potential energy distributions were calculated for the low energy cis conformer of the molecules. Complete vibrational assignments were made on the basis of normal coordinate calculations and comparison with experimental data of the molecules. PMID:18599341

  10. Theoretical and experimental studies on vibrational energy relaxation of the CO stretching mode of acetone in alcohol solutions.

    PubMed

    Higashi, Masahiro; Hirai, Satori; Banno, Motohiro; Ohta, Kaoru; Saito, Shinji; Tominaga, Keisuke

    2013-04-25

    The vibrational energy relaxations (VERs) of the CO stretching mode of acetone and its complexes with alcohols are investigated by sub-picosecond pump-probe spectroscopy and molecular dynamics simulation. The time constants of the vibrational energy relaxation of the free acetone and that of the 1:1 complex are 4.4 and 2.3 ps for methanol solvent and 5.2 and 1.8 ps for 1-proponal solvent, respectively. The VER rate is accelerated a few times by formation of the hydrogen bond. This acceleration of the vibrational energy relaxation is successfully reproduced by the Landau-Teller method calculated from the molecular dynamics simulation. Molecular dynamics simulations reveal that the VER time of acetone with the hydrogen bond is largely affected by the solute polarization induced by solvent molecules. PMID:23305327

  11. Wireless power transfer for scaled electronic biomedical implants

    E-print Network

    Theilmann, Paul Thomas

    2012-01-01

    of MEMS piezoelectric vibration harvesters,” Sensorsharvesters convert mechanical energy to electrical power using electromagnetic (moving coils), electrostatic (moving metallic plates) or piezoelectric

  12. Good Vibrations: An Evaluation of Vibrotactile Impedance Matching for Low Power Wearable Applications

    E-print Network

    , and prevents development of more sophisticated, miniaturized and low- power mobile tactile devices/3 of the power. By greatly reducing the size and power constraints of vibrotactile actuators, this technology ubiquitously for haptic feedback--they are built into every smartphone and modern game controller and are used

  13. Energy storage options for space power

    Microsoft Academic Search

    H. W. Hoffman; J. F. Martin; M. Olszewski

    1987-01-01

    Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels are assessed; the results obtained suggest that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal

  14. SPS Energy Conversion Power Management Workshop

    NASA Astrophysics Data System (ADS)

    1980-06-01

    Energy technology concerning photovoltaic conversion, solar thermal conversion systems, and electrical power distribution processing is discussed. The manufacturing processes involving solar cells and solar array production are summarized. Resource issues concerning gallium arsenides and silicon alternatives are reported. Collector structures for solar construction are described and estimates in their service life, failure rates, and capabilities are presented. Theories of advanced thermal power cycles are summarized. Power distribution system configurations and processing components are presented.

  15. SPS Energy Conversion Power Management Workshop

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Energy technology concerning photovoltaic conversion, solar thermal conversion systems, and electrical power distribution processing is discussed. The manufacturing processes involving solar cells and solar array production are summarized. Resource issues concerning gallium arsenides and silicon alternatives are reported. Collector structures for solar construction are described and estimates in their service life, failure rates, and capabilities are presented. Theories of advanced thermal power cycles are summarized. Power distribution system configurations and processing components are presented.

  16. Lumped parameter models of vortex induced vibration with application to the design of aquatic energy harvester

    NASA Astrophysics Data System (ADS)

    Dhanwani, Manish A.; Sarkar, Abhijit; Patnaik, B. S. V.

    2013-11-01

    In the present study, a lumped parameter model for vortex-induced vibrations is analysed. In this work, the vortex-induced vibrations of an elastically mounted rigid cylinder are able to move in-line and transverse to the flow with equal mass ratio and natural frequencies. A simplified lumped mass model is proposed to study the two degree of freedom (dof) structural oscillator. A classical van der Pol equation along with acceleration coupling, models the near wake dynamics describing the fluctuating nature of vortex shedding. The model dynamics is investigated analytically and the results are compared for moderate mass ratios. The results predicted using this model show a good agreement with the experimental data. The dependence of stream-wise displacement on mass and damping is explored. The cause of cross-flow displacement magnification due to freedom to move in stream-wise direction is also explored using the proposed model. Apart from these two degrees of freedom, the cylinder can also undergo rotation about its centre of mass. The effect of freedom to move in this rotational degree of freedom is exploited to our advantage by applying it to the VIVACE (Vortex induced vibration aquatic clean energy) design which was originally proposed by Bernitsas et al. (2008). The original design was not reported to be the optimal one and the set-up was shown to work only for a given flow velocity. But, the flow environment keeps changing and hence there is a need to bring in robustness and optimize the proposed design. The values of optimized spring stiffness have been found using the lumped mass model. The design is made robust by exploiting the rotational mode. This mode is triggered by varying the overhang lengths in accordance with the varying flow velocity in order to strike resonance for a certain flow regime.

  17. Broadband energy harvesting by exploiting nonlinear oscillations around the second vibration mode of a rectangular piezoelectric bistable laminate

    NASA Astrophysics Data System (ADS)

    Li, Hao; Dai, Fuhong; Du, Shanyi

    2015-04-01

    Recently bistable composite laminates have been investigated for broadband energy harvesting, by taking advantage of their nonlinear oscillations around the first vibration mode. However, it has been reported that the excitation acceleration needed for the desired large amplitude limit cycle oscillation is too high, if the first vibration mode is elevated to relative higher frequencies (60 Hz e.g.). This study investigates the feasibility of exploiting the nonlinear oscillations around the second vibration mode of a rectangular piezoelectric bistable laminate (RPBL), for broadband vibration energy harvesting at relative higher frequencies, but with relative low excitation acceleration. The proposed RPBL has three oscillation patterns around the second vibration mode, including single-well oscillation, chaotic intermittency oscillation and limit cycle oscillation. The broadband characteristics and the considerable energy conversion efficiency of the RPBL are demonstrated in experiments. The static nonlinearity and the dynamic responses of the RPBL are investigated by finite element method. Finite element analysis (FEA) reveals that the enhanced dynamic responses of the RPBL are due to its softening bending stiffness and the local snap through phenomenon. The FEA results coincide reasonably well with experimental results.

  18. An autonomous battery-less sensor module powered by piezoelectric energy harvesting with RF transmission of multiple measurement signals

    Microsoft Academic Search

    Marco Ferrari; Vittorio Ferrari; Michele Guizzetti; Daniele Marioli

    2009-01-01

    An energy-autonomous battery-less sensor module is presented, entirely powered by a piezoelectric energy converter driven by mechanical vibrations from the environment. The module manages and stores the converted energy, interfaces to one or more passive sensors and periodically sends the corresponding measurement signals over a radio-frequency (RF) link. As an additional variant, the module can send a programmable identification (ID)

  19. From solar energy to mechanical power

    SciTech Connect

    Fujii, I.

    1990-01-01

    This book describes general methods of converting solar thermal energy to mechanical power, concentrating particularly on those having a small or moderate conversion scale. Beginning with a historical overview and an outline of requirements for a solar-mechanical power conversion system, the book describes in detail several energy conversion system, paying particular attention to the Rankine, Stirling and Brayton cycle engines. For each engine, the principles of operation, efficiency and performance are discussed and working examples of each type are described.

  20. Vibrational spectroscopy in the electron microscope

    NASA Astrophysics Data System (ADS)

    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.

  1. Vibrational spectroscopy in the electron microscope.

    PubMed

    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

  2. The development of reactor coolant pump vibration monitoring and a diagnostic system in the nuclear power plant

    Microsoft Academic Search

    In Soo Koo; Whan Woo Kim

    2000-01-01

    Monitoring abnormalities within reactor coolant pumps due to vibration, we introduce a Wigner distribution (WD) to a vibration monitoring system for analyzing vibration signals, and develop an on-line diagnostic method using the neural network employing back propagation algorithm. A rotor kit is used to simulate the abnormal conditions in the pump such as bearing rubbing, shaft bending, misalignment, etc. The

  3. Accurate variational calculations and analysis of the HOCl vibrational energy spectrum

    SciTech Connect

    Skokov, S.; Qi, J.; Bowman, J.M. [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Altanta, Georgia 30322 (United States)] [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Altanta, Georgia 30322 (United States); Yang, C.; Gray, S.K. [Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Peterson, K.A. [Department of Chemistry, Washington State University, Richland, Washington 99352 (United States)] [Department of Chemistry, Washington State University, Richland, Washington 99352 (United States); [the Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Mandelshtam, V.A. [Department of Chemistry, University of California at Irvine, Irvine, California 92697 (United States)] [Department of Chemistry, University of California at Irvine, Irvine, California 92697 (United States)

    1998-12-01

    Large scale variational calculations for the vibrational states of HOCl are performed using a recently developed, accurate {ital ab initio} potential energy surface. Three different approaches for obtaining vibrational states are employed and contrasted; a truncation/recoupling scheme with direct diagonalization, the Lanczos method, and Chebyshev iteration with filter diagonalization. The complete spectrum of bound states for nonrotating HOCl is computed and analyzed within a random matrix theory framework. This analysis indicates almost entirely regular dynamics with only a small degree of chaos. The nearly regular spectral structure allows us to make assignments for the most significant part of the spectrum, based on analysis of coordinate expectation values and eigenfunctions. Ground state dipole moments and dipole transition probabilities are also calculated using accurate {ital ab initio} data. Computed values are in good agreement with available experimental data. Some exact rovibrational calculations for J=1, including Coriolis coupling, are performed. The exact results are nearly identical with those obtained from the adiabatic rotation approximation and very close to those from the centrifugal sudden approximation, thus indicating a very small degree of asymmetry and Coriolis coupling for the HOCl molecule. {copyright} {ital 1998 American Institute of Physics.}

  4. Correlations of instantaneous transition energy and intensity of absorption peaks during molecular vibration: toward potential hyper-surface

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takayoshi; Wang, Zhuan

    2008-06-01

    Time-resolved spectrum after ultrashort pulse excitation revealed fine structure of instantaneous vibronic absorption spectra in a thiophene derivative. The probe photon energy-dependent amplitudes of molecular vibration coupled to the induced absorption were composed of several peaks. An absorbance-change peak-tracking method revealed four vibronic transitions buried in the time-integrated spectra over several vibrational periods of typical molecular vibration. Four vibronic transitions located at 2.024, 1.921, 1.818 and 1.731 eV were found to be correlated among themselves with respect to the photon energies and intensities of the peaks in the difference absorbance change spectra. From the size and sign of the correlation strengths the mechanism of the vibronic coupling was related to non-Condon mechanism and Herzberg Teller vibronic coupling.

  5. 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.

  6. Experiments on active control of vibrational power flow using piezoceramic actuators and sensors

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Fuller, Chris R.

    1990-01-01

    The active control of flexural power flow in both semiinfinite and finite elastic beams is experimentally investigated. The experimental results demonstrate that piezoceramic transducers when used in conjunction with an adaptive least mean squares controller, can effectively control flexural power flow in thin beam systems. The piezoceramic transducers offer distinct size and weight advantages over conventional transducers. The experiments also demonstrate the use of an axial scanning laser vibrometer to determine out of plane velocity and power flow.

  7. Bulletin of the Seismological Society of America, Vol. 95, No. 1, pp. 117, February 2005, doi: 10.1785/0120030261 Powerful Low-Frequency Vibrators for Active Seismology

    E-print Network

    Korneev, Valeri A.

    1 Bulletin of the Seismological Society of America, Vol. 95, No. 1, pp. 1­17, February 2005, doi: 10.1785/0120030261 Powerful Low-Frequency Vibrators for Active Seismology by A. S. Alekseev, I. S. Chichinin, and V. A. Korneev Abstract In the past two decades, active seismology studies in Russia have made

  8. Saving Energy Through Advanced Power Strips (Poster)

    SciTech Connect

    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.

  9. Analyses of power output of piezoelectric energy-harvesting devices directly connected to a load resistor using a coupled piezoelectric-circuit finite element method

    Microsoft Academic Search

    Meiling Zhu; Emma Worthington; James Njuguna

    2009-01-01

    This paper presents, for the first time, a coupled piezoelectric-circuit finite element model (CPC-FEM) to analyze the power output of a vibration-based piezoelectric energy-harvesting device (EHD) when it is connected to a load resistor. Special focus is given to the effect of the load resistor value on the vibrational amplitude of the piezoelectric EHD, and thus on the current, voltage,

  10. Optimal Power Allocation for Renewable Energy Source

    E-print Network

    Sinha, Abhinav

    2011-01-01

    Battery powered transmitters face energy constraint, replenishing their energy by a renewable energy source (like solar or wind power) can lead to longer lifetime. We consider here the problem of finding the optimal power allocation under random channel conditions for a wireless transmitter, such that rate of information transfer is maximized. Here a rechargeable battery, which is periodically charged by renewable source, is used to power the transmitter. All of above is formulated as a Markov Decision Process. Structural properties like the monotonicity of the optimal value and policy derived in this paper will be of vital importance in understanding the kind of algorithms and approximations needed in real-life scenarios. The effect of curse of dimensionality which is prevalent in Dynamic programming problems can thus be reduced. We show our results under the most general of assumptions.

  11. Role of energy exchange in vibrational dephasing processes in liquids and solids

    SciTech Connect

    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.

  12. A Study on Design and Analysis of Hybrid Vibration Damper with Energy Harvesting and Optimal Damping Effect

    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.

  13. An experimental study of vibration based energy harvesting in dynamically tailored structures with embedded acoustic black holes

    NASA Astrophysics Data System (ADS)

    Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio

    2015-06-01

    In this paper, we present an experimental investigation on the energy harvesting performance of dynamically tailored structures based on the concept of embedded acoustic black holes (ABHs). Embedded ABHs allow tailoring the wave propagation characteristics of the host structure creating structural areas with extreme levels of energy density. Experiments are conducted on a tapered plate-like aluminum structure with multiple embedded ABH features. The dynamic response of the structure is tested via laser vibrometry in order to confirm the vibration localization and the passive wavelength sweep characteristic of ABH embedded tapers. Vibrational energy is extracted from the host structure and converted into electrical energy by using ceramic piezoelectric discs bonded on the ABHs and shunted on an external electric circuit. The energy harvesting performance is investigated both under steady state and transient excitation. The experimental results confirm that the dynamic tailoring produces a drastic increase in the harvested energy independently from the nature of the excitation input.

  14. Vibration analyzer

    NASA Technical Reports Server (NTRS)

    Bozeman, Richard J., Jr. (inventor)

    1990-01-01

    The invention relates to monitoring circuitry for the real time detection of vibrations of a predetermined frequency and which are greater than a predetermined magnitude. The circuitry produces an instability signal in response to such detection. The circuitry is particularly adapted for detecting instabilities in rocket thrusters, but may find application with other machines such as expensive rotating machinery, or turbines. The monitoring circuitry identifies when vibration signals are present having a predetermined frequency of a multi-frequency vibration signal which has an RMS energy level greater than a predetermined magnitude. It generates an instability signal only if such a vibration signal is identified. The circuitry includes a delay circuit which responds with an alarm signal only if the instability signal continues for a predetermined time period. When used with a rocket thruster, the alarm signal may be used to cut off the thruster if such thruster is being used in flight. If the circuitry is monitoring tests of the thruster, it generates signals to change the thruster operation, for example, from pulse mode to continuous firing to determine if the instability of the thruster is sustained once it is detected.

  15. 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…

  16. Power conditioning system for energy sources

    DOEpatents

    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.

  17. Vibrationally resolved translational energy release spectra from the ultraviolet photodissociation of methyl mercaptan

    SciTech Connect

    Segall, J.; Wen, Y.; Singer, R.; Dulligan, M.; Wittig, C. (Department of Chemistry, University of Southern California, Los Angeles, California 90089 (United States))

    1993-11-01

    Product translational energy release spectra resulting from 248 and 193 nm photodissociation of methyl mercaptan are obtained for the hydrogen atom channels (CH[sub 3]SH+[ital h][nu][r arrow]CH[sub 3]S+H) by using the high-[ital n] Rydberg time-of-flight technique. The spectra exhibit vibrational structure that is assigned to a CH[sub 3]--S stretch progression. At 248 nm, the progression extends only to [ital v]=2, while at 193 nm levels up to approximately [ital v]=17 are populated. The progression observed at 193 nm is bimodal, with the higher kinetic energy component showing greater spatial anisotropy than the lower energy component, suggesting that two different processes occurring on different time scales are responsible for the two components. The results at 248 nm are consistent with excitation to a repulsive electronic surface. For 193 nm excitation, the high kinetic energy component is consistent with direct photoexcitation to a repulsive surface and/or rapid intramolecular access to a repulsive surface. The lower kinetic energy component presumably derives from the molecule spending more time on an excited surface. A simple model is applied to estimate the extent of C--S bond extension for the various processes.

  18. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    PubMed

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4?keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3?meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4?h to about 30?min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements. PMID:23955030

  19. Effect of energy storage on variations in wind power

    Microsoft Academic Search

    Jukka V. Paatero; Peter D. Lund

    2005-01-01

    Irregularities in power output are characteristic of intermittent energy, sources such as wind energy, affecting both the power quality and planning of the energy system. In this work the effects of energy storage to reduce wind power fluctuations are investigated. Integration of the energy storage with wind power is modelled using a filter approach in which a time constant corresponds

  20. 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.

  1. Low dimensional modeling of a non-uniform, buckled piezoelectric beam for vibrational energy harvesting

    NASA Astrophysics Data System (ADS)

    Van Blarigan, Louis; Moehlis, Jeff; McMeeking, Robert

    2015-06-01

    A model is developed for a non-uniform piezoelectric beam suitable for analyzing energy harvesting behavior. System dynamics are projected onto a numerically developed basis to produce energy functions which are used to derive equations of motion for the system. The resulting model reproduces the experimentally observed transition to chaos while providing a conservative estimate of power output and bandwidth.

  2. Peroxyacetyl radical: electronic excitation energies, fundamental vibrational frequencies, and symmetry breaking in the first excited state.

    PubMed

    Copan, Andreas V; Wiens, Avery E; Nowara, Ewa M; Schaefer, Henry F; Agarwal, Jay

    2015-02-01

    Peroxyacetyl radical [CH3C(O)O2] is among the most abundant peroxy radicals in the atmosphere and is involved in OH-radical recycling along with peroxyacetyl nitrate formation. Herein, the ground (X?) and first (A?) excited state surfaces of cis and trans peroxyacetyl radical are characterized using high-level ab initio methods. Geometries, anharmonic vibrational frequencies, and adiabatic excitation energies extrapolated to the complete basis-set limit are reported from computations with coupled-cluster theory. Excitation of the trans conformer is found to induce a symmetry-breaking conformational change due to second-order Jahn-Teller interactions with higher-lying excited states. Additional benchmark computations are provided to aid future theoretical work on peroxy radicals. PMID:25662641

  3. Radiative Activity of Magnetic White Dwarf Undergoing Lorentz-Force Torsional Vibrations

    NASA Astrophysics Data System (ADS)

    Bastrukov, S. I.; Yu, J. W.; Xu, R. X.; Molodtsova, I. V.

    We study radiative activity of magnetic white dwarf undergoing torsional vibrations about axis of its own dipole magnetic moment under the action of Lorentz restoring force. It is shown that pulsating white dwarf can convert its vibration energy into the energy of magneto-dipole emission, oscillating with the frequency equal to the frequency of Alfvén torsional vibrations, provided that internal magnetic field is decayed. The most conspicuous feature of the vibration energy powered radiation in question is the lengthening of periods of oscillating emission; the rate of period elongation is determined by the rate magnetic field decay.

  4. Energy storage options for space power

    NASA Astrophysics Data System (ADS)

    Hoffman, H. W.; Martin, J. F.; Olszewski, M.

    Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels are assessed; the results obtained suggest 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 kJ/kg to 2000 kJ/kg at temperatures to 1675 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 (about 500 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.

  5. Rapid vibrational and rotational energy-transfer rates in heated carbon dioxide collisions by double-resonance laser spectroscopy

    Microsoft Academic Search

    M. D. Thomason

    1982-01-01

    Rates for resonant vibrational and rotational energy transfer from the 001 state by CO2 + CO2 collisions were measured. All data were obtained by double resonance spectroscopy with CO2 lasers in a 2.5 meter absorption cell at 700 K. Results for rotation transfer include pumped level relaxation and the response of other 001 levels with delta up to 18. These

  6. Thermal vibration amplitude of surface atoms measured by specialized low-energy ion scattering spectroscopy: TiC(111)

    Microsoft Academic Search

    R. Souda; M. Aono; C. Oshima; S. Otani; Y. Ishizawa

    1983-01-01

    The thermal vibration amplitude of Ti atoms in the top layer of the TiC(111) surface has been measured by a specialized technique in low-energy ion scattering spectroscopy. The root-mean-square amplitude of the surface Ti atoms is ˜0.076 Å along the surface normal at room temperature.

  7. Non-equilibrium vibrational and electron energy distributions functions in atmospheric nitrogen ns pulsed discharges and \\mus post-discharges: the role of electron molecule vibrational excitation scaling-laws

    E-print Network

    Colonna, Gianpiero; Celiberto, Roberto; Capitelli, Mario; Tennyson, Jonathan

    2015-01-01

    The formation of the electron energy distribution function in nanosecond atmospheric nitrogen discharges is investigated by means of self-consistent solution of the chemical kinetics and the Boltzmann equation for free electrons. The post-discharge phase is followed to few microseconds. The model is formulated in order to investigate the role of the cross section set, focusing on the vibrational-excitation by electron-impact through resonant channel. Four different cross section sets are considered, one based on internally consistent vibrational-excitation calculations which extend to the whole vibrational ladder, and the others obtained by applying commonly used scaling-laws.

  8. Non-equilibrium vibrational and electron energy distributions functions in atmospheric nitrogen ns pulsed discharges and ?s post-discharges: the role of electron molecule vibrational excitation scaling-laws

    NASA Astrophysics Data System (ADS)

    Colonna, Gianpiero; Laporta, Vincenzo; Celiberto, Roberto; Capitelli, Mario; Tennyson, Jonathan

    2015-06-01

    The formation of the electron energy distribution function in nanosecond atmospheric nitrogen discharges is investigated by means of self-consistent solution of the chemical kinetics and the Boltzmann equation for free electrons. The post-discharge phase is followed to few microseconds. The model is formulated in order to investigate the role of the cross section set, focusing on the vibrational-excitation by electron-impact through resonant channel. Four different cross section sets are considered, one based on internally consistent vibrational-excitation calculations which extend to the whole vibrational ladder, and the others obtained by applying commonly used scaling-laws.

  9. 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.

  10. Scaling factors for fundamental vibrational frequencies and zero-point energies obtained from HF, MP2, and DFT\\/DZP and TZP harmonic frequencies

    Microsoft Academic Search

    S. G. Andrade; Luísa C. S. Gonçalves; F. E. Jorge

    2008-01-01

    Recently, segmented contracted basis sets of double, triple, and quadruple zeta valence quality plus polarization functions (XZP, X=D, T, and Q) for the atoms from H to Ar were presented by Jorge et al. Scaling factors for the fundamental vibrational frequencies, low-frequency vibrations, and zero-point vibrational energies (ZPVEs) evaluated at 14 levels of theory are reported. The ab initio Hartree–Fock

  11. 'People Power' Saves Plant Energy 

    E-print Network

    Davidson, B. G., Jr.; Kanewske, F. J.

    1981-01-01

    burner air registers ? Poor burner performance ? Leaking flue gas and draft sample lines ? Air leaks into firebox ? Refractory damage If inspections are not made until heaters are shut down, many of the above items will be hard to detect... and compressed air leaks, faulty insulation, incorrect drivers in service, and faulty burner adjustment on fired heaters ? Visits to "talk up" energy conservation with the foremen and operators These engineers also monitor the operation of several on...

  12. Vibrational spectra, theoretical calculations, and two-dimensional potential energy surface for the ring-puckering vibrations of 2,4,7-trioxa[3.3.0]octane.

    PubMed

    Chun, Hye Jin; Meinander, Niklas; Villarreal, John R; Laane, Jaan

    2015-01-15

    2,4,7-Trioxa[3.3.0]octane (247TOO) is an unusual bicyclic molecule which can exist in four different conformational forms which are determined by the directions of the two ring- puckering motions. The vibrational assignments of 247TOO have been made based on its infrared and Raman spectra and theoretical density functional theory (DFT) calculations. The two ring-puckering motions (in-phase and out-of-phase) were observed in the Raman spectra of the liquid at 249 and 205 cm(-1) and these values correspond well to the DFT values of 247 and 198 cm(-1). Ab initio calculations were utilized to calculate the structures and conformational energies for the four energy minima and the barriers to interconversion and the data was utilized to generate a two-dimensional potential energy surface (PES) for the two ring-puckering motions. The resulting quantum state energies for this PES were then calculated in order to better understand the patterns that are produced when the PES has four energy minima at different energy values. The wave functions corresponding to the different quantum states were also calculated. The NMR spectrum of 247TOO showed the presence of the two lowest energy conformations, consistent with the results of the ab initio calculations. PMID:25514365

  13. Experimental and analytical parametric study of single-crystal unimorph beams for vibration energy harvesting.

    PubMed

    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

  14. Absolute cross sections for vibrational excitations of cytosine by low energy electron impact

    PubMed Central

    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 1.5–2.1 eV, 5.2–6.8 eV, and 9.5–10.9 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

  15. A Single Inductor, Multiple Input Piezoelectric Interface Circuit Capable of Harvesting Energy from Asynchronously Vibrating Sources

    E-print Network

    Ribeiro, Roland

    2014-10-23

    electromagnetic energy harvester c©IEEE 1998 [4] 10 1.7 Pavegen Systems floor tile [5] . . . . . . . . . . . . . . . . . . . . . . 11 1.8 Energy harvesting from piezoelectric shoe insert c©IEEE 1998 [6] . . . 13 2.1 Equivalent lumped spring mass system of a... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.1 Typical piezoelectric energy harvesting system . . . . . . . . . . . . . 28 3.2 Full wave rectifier c©IEEE 2010 [8] . . . . . . . . . . . . . . . . . . . 29 3.3 Output power vs output voltage for full wave rectifier . . . . . . . . . 31 3...

  16. Vibrational and rotational energy transfers involving the CH B 2?- v=1 vibrational level in collisions with Ar, CO, and N2O

    NASA Astrophysics Data System (ADS)

    Huang, Hong-Yi; Tsai, Ming-Tsang; Lin, King-Chuen

    2006-04-01

    With photolysis-probe technique, we have studied vibrational and rotational energy transfers of CH involving the B ?-2 (v =1, 0?N?6, F) state by collisions with Ar, CO, and N2O. For the vibrational energy transfer (VET) measurements, the time-resolved fluorescence of the B-X(0,0) band is monitored following the (1,0) band excitation. For the rotational energy transfer (RET) measurements, the laser-induced fluorescence of the initially populated state is dispersed using a step-scan Fourier transform spectrometer. The time-resolved spectra obtained in the nanosecond regime may yield the RET information under a single pressure of the collider. The rate constants of intramolecular energy transfers are evaluated with simulation of kinetic models. The VET lies in the range of 4×10-12to4×10-11cm3molecule-1s-1, with efficiency following the order of Ar vibrational excitation is considered. For the polyatomic collider, the strong long-range dipole-dipole interaction may have the chance to vary the rotational orientation to increase the fine-structure-changing transitions.

  17. Power management solutions for energy management, power quality and environment using battery energy storage systems

    Microsoft Academic Search

    D. Sutanto

    1999-01-01

    Summary form only as given. The emergency of new breeds of power electronics and improved battery technology has created renewed interests in battery energy storage system (BESS). BESS is a modern cost-effective solution that can help both electric utilities and industrial and commercial businesses to meet the growing need of controlling peak energy usage, power quality and environmental problems. BESS

  18. Power smoothing and power ramp control for wind energy using energy storage

    Microsoft Academic Search

    Ali Esmaili; Adel Nasiri

    2011-01-01

    Due to randomness of wind speed, the wind farm output power varies drastically. These fluctuations make undesirable effects on the voltage, frequency, and transient stability of the utility grid. In this paper, two types of energy storage devices are integrated with a wind farm to support the short-term shortcomings of wind energy. The support specifically improves power ramp rate control

  19. Intramolecular vibrational energy redistribution and conformational isomerization in vibrationally excited 2-fluoroethanol: High-resolution, microwave-infrared double-resonance spectroscopy investigation of the asymmetric CH2(F) stretch near 2980 cm-1

    Microsoft Academic Search

    David Green; Sarah Hammond; John Keske; Brooks H. Pate

    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

  20. Energy prediction of Amonix solar power plants

    NASA Astrophysics Data System (ADS)

    Kinsey, Geoffrey S.; Stone, Kenneth; Garboushian, Vahan

    2010-08-01

    Amonix has installed over 300 kW of systems using III-V multijunction cells. The Amonix 7500 Solar Power Generator, rated at 38 kWAC, generated over 90 MW-hr during its first twelve months of operation. A model of system performance using a meteorological database and applying the effects of losses in the optical and power paths predicted field performance to within 1% after twelve months of operation. The energy yield of power plants employing Amonix systems is expected to exceed 2700 kW-hr/kW. Systems installed in 2010 are expected to deliver a 10% increase in performance.

  1. HARVESTING ENERGY FROM MOTH VIBRATIONS DURING FLIGHT S.C. Chang1, F.M. Yaul1, A. Dominguez-Garcia3, F. O'Sullivan2, D.M. Otten1, J.H. Lang1

    E-print Network

    Liberzon, Daniel

    energy harvesting has compared concepts for moths [1], studied piezoelectric-based vibration harvestersHARVESTING ENERGY FROM MOTH VIBRATIONS DURING FLIGHT S.C. Chang1, F.M. Yaul1, A. Dominguez-Garcia3 the design, fabrication, and testing of a harvester that extracts energy from moth-body vibrations during

  2. Vibration manual

    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.

  3. 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.

  4. Lattice vibrations in the Frenkel-Kontorova model. I. phonon dispersion, number density, and energy

    DOE PAGESBeta

    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

  5. Energy saving potential of office equipment power management

    Microsoft Academic Search

    Kaoru Kawamoto; Yoshiyuki Shimoda; Minoru Mizuno

    2004-01-01

    While many studies have estimated the energy saving potential of office equipment power management, there is no recent study about the energy saving potential of shortening the power management delay time. In this paper, we estimated the energy saving potential of the complete saturation of power management, and also the additional energy saving potential of shortening the power management delay

  6. Post-threshold energy dependence of the cross section for endoergic processes - Vibrational excitation and reactive scattering.

    NASA Technical Reports Server (NTRS)

    Levine, R. D.; Bernstein, R. B.

    1972-01-01

    The essential features of the translational energy dependence or excitation function for two types of endoergic collisional processes are deduced on the basis of information on the inverse, exoergic processes. Microreversibility is conveniently exploited via the symmetric field function, Y(E), which is uniquely determined at a given total energy, E. In the case of the vibrational excitation of diatomic molecules by atomic or molecular impact, use is made of the abundant data on the temperature dependence of the relaxation time.

  7. Vibrational-rotational-translational energy transfer in Ar + OH. Quasiclassical trajectory state-to-state cross sections

    Microsoft Academic Search

    Donald L. Thompson

    1982-01-01

    A study has been made of the energy transfer in Ar + OH using quasiclassical trajectories and a pairwise additive potential. The calculations were carried out for initial vibrational states nu\\/sub i\\/ = 0, 2, and 4 and initial rotational states J⁠= 0, 10, and 20 for initial relative translational energies 0.2, 0.5, and 1.0 eV. State-to-state cross sections

  8. Power flow as a complement to statistical energy analysis and finite element analysis

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1987-01-01

    Present methods of analysis of the structural response and the structure-borne transmission of vibrational energy use either finite element (FE) techniques or statistical energy analysis (SEA) methods. The FE methods are a very useful tool at low frequencies where the number of resonances involved in the analysis is rather small. On the other hand SEA methods can predict with acceptable accuracy the response and energy transmission between coupled structures at relatively high frequencies where the structural modal density is high and a statistical approach is the appropriate solution. In the mid-frequency range, a relatively large number of resonances exist which make finite element method too costly. On the other hand SEA methods can only predict an average level form. In this mid-frequency range a possible alternative is to use power flow techniques, where the input and flow of vibrational energy to excited and coupled structural components can be expressed in terms of input and transfer mobilities. This power flow technique can be extended from low to high frequencies and this can be integrated with established FE models at low frequencies and SEA models at high frequencies to form a verification of the method. This method of structural analysis using power flo and mobility methods, and its integration with SEA and FE analysis is applied to the case of two thin beams joined together at right angles.

  9. Power conversion mechanisms for wave energy

    Microsoft Academic Search

    S H Salter; J R M Taylor; N J Caldwell

    2002-01-01

    It is easy to make a device that will respond vigorously to the action of sea waves. Indeed, it is quite hard to make one that will not. However, the conversion of the slow, random, reversing energy flows with very high extreme values into phase-locked synchronous electricity with power quality acceptable to a utility network is very much harder. This

  10. Technical Note TN-56 Power and Energy

    E-print Network

    Flinn, Jason

    WRL Technical Note TN-56 Power and Energy Characterization of the Itsy Pocket Computer (Version 1 Alto, California 94301 USA #12;WRL TECHNICAL NOTE TN- 1 Research group. Our focus is research on information technology that is relevant to the technical strategy

  11. Adaptive power management in energy harvesting systems

    Microsoft Academic Search

    Clemens Moser; Lothar Thiele; Davide Brunelli; Luca Benini

    2007-01-01

    Recently, there has been a substantial interest in the de- sign of systems that receive their energy from regenerative sources such as solar cells. In contrast to approaches that attempt to minimize the power consumption we are con- cerned with adapting parameters of the application such that a maximal utility is obtained while respecting the lim- ited and time-varying amount

  12. 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)

  13. Radiant energy to electrical power conversion system

    Microsoft Academic Search

    Brunson

    1980-01-01

    A radiant energy to electrical power thermionic conversion system is disclosed that uses a transducer structure with very closely spaced cathode and anode elements in a vacuum to minimize space charge buildup and to optimize cross transfer of electrons from cathode to anode. The materials chosen are for a high work function high melt temperature cathode, tungsten for example with

  14. Issues in mathematical modeling of piezoelectric energy harvesters

    Microsoft Academic Search

    A. Erturk; D. J. Inman

    2008-01-01

    The idea of vibration-to-electric energy conversion for powering small electronic components by using the ambient vibration energy has been investigated by researchers from different disciplines in the last decade. Among the possible transduction mechanisms, piezoelectric transduction has received the most attention for converting ambient vibrations to useful electrical energy. In the last five years, there have been a considerable number

  15. Renewable energy from vortex induced vibrations in a slow moving fluid

    Microsoft Academic Search

    A. S. Kashyap; K. V. Vidya Shankar; S. Vignesh

    2010-01-01

    Our motive is to show that useful energy can be extracted from fluids flowing at velocities of less than 2 knots (approximately 1.02m\\/s) and to also propose a mechanism to harness that energy for the generation of electricity at very little risk and damage to the surrounding environment. The means of achieving this is by tapping the power available in

  16. The fitting of potential energy surfaces using neural networks: Application to the study of vibrational levels of H3+

    NASA Astrophysics Data System (ADS)

    Prudente, Frederico V.; Acioli, Paulo H.; Neto, J. J. Soares

    1998-11-01

    A back-propagation neural network is utilized to fit the potential energy surfaces of the H3+ ion, using the ab initio data points of Dykstra and Swope, and the Meyer, Botschwina, and Burton ab initio data points. We used the standard back-propagation formulation and have also proposed a symmetric formulation to account for the symmetry of the H3+ molecule. To test the quality of the fits we computed the vibrational levels using the correlation function quantum Monte Carlo method. We have compared our results with the available experimental results and with results obtained using other potential energy surfaces. The vibrational levels are in very good agreement with the experiment and the back-propagation fitting is of the same quality of the available potential energy surfaces.

  17. Dissociative attachment and vibrational excitation in low-energy electron-CF3I collisions

    NASA Astrophysics Data System (ADS)

    Fabrikant, I.; Marienfeld, S.

    2005-05-01

    Trifluoroiodomethane (CF3I) is a plasma etching gas that provides CF3 radicals and I^- anions through an efficient dissociative electron attachment (DEA) process at near zero electron energies.^1 We have carried out a combined experimental and theoretical study of DEA to CF3I at electron energies below 1 eV. Measurements, performed at high resolution with two variants of the laser photoelectron attachment method,^2 yielded a joint DEA cross section over the range 1-500 meV, normalized in absolute size to the thermal DEA rate coefficient from swarm data.^1 At the onsets for excitation of one and two quanta for the C-I stretching mode ?3, clear downward cusps are detected. Calculations were performed by using the resonance R-matrix theory and the result for the thermal DEA rate coefficient.^1 The calculated DEA cross section shows good overall agreement with the experimental result in both shape and absolute size. In addition, we present theoretical cross sections for vibrational excitation of the ?3 mode which exhibit strong threshold peaks. ^1 L. G. Christophorou, J. K. Olthoff, J. Phys. Chem. Ref. Data 29, 553 (2000). ^2 H. Hotop, M.-W. Ruf, M. Allan, I. I. Fabrikant, Adv. At. Mol. Opt. Phys. 49, 85 (2003).

  18. Communication: MULTIMODE calculations of low-lying vibrational states of NO3 using an adiabatic potential energy surface

    NASA Astrophysics Data System (ADS)

    Homayoon, Zahra; Bowman, Joel M.

    2014-10-01

    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 15NO3 are also presented and these are also in good agreement with experiment.

  19. An accurate {ital ab initio} HOCl potential energy surface, vibrational and rotational calculations, and comparison with experiment

    SciTech Connect

    Skokov, S. [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Altanta, Georgia 30322 (United States)] [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Altanta, Georgia 30322 (United States); Peterson, K.A. [Department of Chemistry, Washington State University and the Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)] [Department of Chemistry, Washington State University and the Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Bowman, J.M. [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)] [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)

    1998-08-01

    Accurate {ital ab initio} multireference configuration interaction (CI) calculations with large correlation-consistent basis sets are performed for HOCl. After extrapolation to the complete basis set limit, the {ital ab initio} data are precisely fit to give a semiglobal three-dimensional potential energy surface to describe HOCl{r_arrow}Cl+OH from high overtone excitation of the OH-stretch. The average absolute deviation between the {ital ab initio} and fitted energies is 4.2thinspcm{sup {minus}1} for energies up to 60 kcal/mol relative to the HOCl minimum. Vibrational energies of HOCl including the six overtones of the OH-stretch are computed using a vibrational-Cl method on the fitted potential and also on a slightly adjusted potential. Near-spectroscopic accuracy is obtained using the adjusted potential; the average absolute deviation between theory and experiment for 19 experimentally reported states is 4.8thinspcm{sup {minus}1}. Very good agreement with experiment is also obtained for numerous rotational energies for the ground vibrational state, the ClO-stretch fundamental, and the fifth overtone of the OH-stretch. {copyright} {ital 1998 American Institute of Physics.}

  20. Financing renewable energy for Village Power application

    SciTech Connect

    Santibanez-Yeneza, G.

    1997-12-01

    When one talks of rural development, no doubt, the issue of rural energy is not far behind. As a significant component of any development strategy, rural energy is seen as the engine for growth that can bring about economic upliftment in the countryside. Many approaches to rural energy development have been tried. These approaches differ from country to country. But regardless of structure and approach, the goal remain essentially the same: to provide rural communities access to reliable energy services at affordable prices. In recent years, as global concern for the environment has increased, many governments have turned to renewable energy as a more environment friendly alternative to rural electrification. Technological advances in renewable energy application has helped to encourage this use. System reliability has improved, development costs have, to some extent been brought down and varied application approaches have been tried and tested in many areas. Indeed, there is huge potential for the development of renewable energy in the rural areas of most developing countries. At the rural level, renewable energy resources are almost always abundantly available: woodwaste, agricultural residues, animal waste, small-scale hydro, wind, solar and even sometimes geothermal resources. Since smaller scale systems are usually expected in these areas, renewable energy technologies can very well serve as decentralized energy systems for rural application. And not only for rural applications, new expansion planning paradigms have likewise led to the emergence of decentralized energy systems not only as supply options but also as corrective measures for maintaining end of line voltage levels. On the other hand, where renewable energy resource can provide significant blocks of power, they can be relied upon to provide indigenous power to the grids.

  1. Estimation of Vibrational Power in Built-Up Systems Involving Box-Like Structures, Part 1: Uniform Force Distribution

    NASA Astrophysics Data System (ADS)

    FULFORD, R. A.; PETERSSON, B. A. T.

    2000-05-01

    For the vibration analysis of built-up structures traditional point-like connections cannot be applied where the interface is large and the wavelength is small. In these situations the spatially distributed wavefield has to be accounted for, whereby the field properties associated with the interface (i.e., velocity, force) have to be considered to be continuous over a surface or, for a one-dimensional contact, along a line. Due to the perceived complexity of these distributions it is most common for analyses to employ a numerical technique which, whilst efficient as a methodology, is limited in that little is revealed about the physics of the system. The solutions can therefore be rather esoteric and in conjunction with design this makes the techniques cumbersome to use. As a move towards overcoming the problem the work presented considers a simplified analytical approach from which a model of a box-like structure is obtained. The basis of the approach is to consider the spatial properties of distributed forces in terms of their Fourier components and then hypothesize that the zero order, i.e., the uniform component, is dominant. In this way, the true spatial characteristics of the forces are retained but in a reduced and elementary form. This greatly simplifies the modelling. For the box-like structure, supported by an infinite plate-like recipient, a prediction of the vibratory power is considered and qualifying results established.

  2. Vibration Suppression and Flywheel Energy Storage in a Drillstring Bottom-Hole-Assembly 

    E-print Network

    Saeed, Ahmed

    2012-07-16

    In this study, a novel concept for a downhole flywheel energy storage module to be embedded in a bottom-hole-assembly (BHA) is presented and modeled, as an alternative power source to existing lithium-ion battery packs currently deployed...

  3. Nuclear Power and the World's Energy Requirements

    E-print Network

    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.

  4. Integrating thermal energy storage in power plants

    SciTech Connect

    Somasundaram, S.; Drost, M.K.; Brown, D.R.; Antoniak, Z.I. (Pacific Northwest Lab., Richland, WA (United States))

    1993-09-01

    This article describes a system that stores thermal energy in a natural gas-fired cogeneration facility uses a gas turbine, a heat recovery salt heater, and salt-heated steam generator. The National Energy Strategy forecast estimates that 200,000 megawatts-electric (MWe) of new electric-generating capacity will need to be added to the US nationally by the year 2010. Approximately 40 percent of this new generating capacity will be for peak or intermediate loads, with the rest providing continuous baseload power generation. Natural gas-fired combustion turbine technologies, including cogeneration, combined-cycle, and integrated gasification combined-cycle power plants, are becoming the generating options of choice because of their flexibility, relatively low capital cost, reduced environmental impact, and increasing thermal efficiency. Thermal energy storage (TES) for utility applications includes a range of technologies that can further improve the efficiency, flexibility, and economics of gas turbine options.

  5. Wireless vibration monitoring on human machine operator

    Microsoft Academic Search

    Frederik Petré; Frank Bouwens; Steven Gillijns; Fabien Massé; Marc Engels; Bert Gyselinckx; Kris Vanstechelman; Christophe Thomas

    2010-01-01

    Human machine operators are often subject to extreme shocks and vibrations while operating production machines and vehicles. To assess the impact on perceived comfort objectively, a wireless vibration monitoring system is needed that measures whole-body vibrations directly on the human body. To this end, we have developed a wireless body area network consisting of low-power vibration sensor nodes that have

  6. Sleep Control for Base Stations Powered by Heterogeneous Energy Sources

    E-print Network

    to the power grid, some BSs are purely powered by the renewable energy. BS sleep is introduced not only to save grid power, but also to store renewable energy for future use when the temporal traffic variation does of those BS powered by the renewable energy, and this will lead to network coverage hole and thus severely

  7. A piezoelectric energy harvester with increased bandwidth based on beam flexural vibrations in perpendicular directions.

    PubMed

    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

  8. A review of two-phase flow-induced vibration

    Microsoft Academic Search

    S. S. Chen

    1987-01-01

    Two-phase flow exists in many shell-and-tube heat exchangers and power generation components. The flowing fluid is a source of energy that can induce small-amplitude subcritical oscillations and large-amplitude dynamic instabilities. In fact, many practical system components have experienced excessive flow-induced vibrations. To prevent unacceptable flow-induced vibration, we must understand excitation mechanisms, develop analytical and experimental techniques, and provide reliable design

  9. Development and commercialization strategy for piezoelectric energy-harvesting power sources for gun-fired munitions

    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.

  10. 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

  11. 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.

  12. Vibration Based Structural Health Monitoring and the Modal Strain Energy Damage Index Algorithm Applied to a Composite T-Beam

    Microsoft Academic Search

    R. Loendersloot; T. H. Ooijevaar; L. Warnet; A. de Boer; R. Akkerman; C. M. A. Vasques; J. Dias Rodrigues

    2011-01-01

    \\u000a A Finite Element based numerical model for a vibration based damage identification method for a thin-walled slender composite\\u000a structure is discussed in this chapter. The linear dynamic response of an intact and a locally delaminated 16-layer unidirectional\\u000a carbon fibre PEKK reinforced T-beam is analysed. The capabilities of the modal strain energy damage index algorithm to detect\\u000a and localize a delamination

  13. Rapid Vibrational and Rotational Energy Transfer Rates in Heated Carbon-Dioxide Collisions by Double Resonance Laser Spectroscopy

    Microsoft Academic Search

    Michael David Thomason

    1982-01-01

    Rates for resonant vibrational and rotational energy transfer from the 001 state by CO(,2) + CO(,2) collisions have been measured. All data were obtained by double resonance spectroscopy with CO(,2) lasers in a 2.5 meter absorption cell at 700(DEGREES)K. Results for rotation transfer include pumped-level relaxation and the response of other 001 levels with (DELTA)j up to 18. These data

  14. The surface structure and thermal vibrations of Ag( 1 1 0 ) studied by low energy ion scattering

    NASA Astrophysics Data System (ADS)

    Pedemonte, L.; Bracco, G.; Tatarek, R.; Beikler, R.; Taglauer, E.; Brüning, K.; Heiland, W.

    2002-06-01

    The properties of the Ag(1 1 0) surface are investigated by comparing the low-energy ion scattering data collected along the main azimuthal directions in the NICISS mode with the results of simulations performed with the MARLOWE code. The main suggestion is that scattering contributions due to focusing effects between atoms belonging to different surface layers have to be taken into account to explain the data. The influence of the thermal vibration amplitude on the scattered intensity distributions is also discussed.

  15. Elastic and vibrationally inelastic cross sections and energy loss spectra for electron collisions with GeH4

    Microsoft Academic Search

    M. A. Dillon; L. Boesten; H. Tanaka; M. Kimura; H. Sato

    1993-01-01

    Absolute vibrationally elastic cross sections for e-GeH4 collisions have been determined for electrons of 1, 2, 2.5, 3, 5, 7.5, 10, 15, 20, 60 and 100 eV incidence energy over a scattering angular range of 10 degrees -130 degrees . The observed angular distributions correspond, at least qualitatively, to theoretical formulations using the continuum-multiple-scattering method, the parameter-free static-exchange-polarization approximation, and

  16. 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.

  17. Velocity map imaging of the photodissociation of CF3I: Vibrational energy dependence of the recoil anisotropy

    NASA Astrophysics Data System (ADS)

    Aguirre, F.; Pratt, S. T.

    2003-01-01

    The photodissociation of jet-cooled CF3I into CF3+I(2P3/2) and CF3+I*(2P1/2) has been investigated between 304 and 277 nm by using velocity map ion imaging. The two-dimensional images provide detailed information on the partition of available energy into kinetic and internal energy of the photofragments. Vibrational structure with spacing of 695±100 cm-1 is resolved in both I and I* images, indicating excitation of the umbrella mode ?2 of the CF3 photofragment. The fragment recoil anisotropies ?(I) and ?(I*) are determined as a function of the excitation wavelength and their variations are interpreted in terms of the crossing between the 3Q0 and 1Q1 dissociative electronic states. The high-resolution images allow the determination of the variation of the anisotropy parameter ? as a function of the vibrational level of CF3 fragment, and provide a complementary method for the determination of the C-I bond energy. The vibrational dependence of the anisotropy values is discussed in terms of final-state interactions between the CF3 umbrella motion and the C-I dissociation coordinate, as discussed previously by Hennig et al. [J. Chem. Phys. 84, 544 (1986)].

  18. A simple curvilinear internal coordinate model for vibrational energy levels of hydrogen sulfide and sulfur dioxide

    Microsoft Academic Search

    Esa Kauppi; Lauri Halonen

    1992-01-01

    A simple curvilinear internal-coordinate Hamiltonian model for vibrational-term values of well-bent XY2 molecules is developed. The stretching vibrations are described in the zero-order picture by Morse oscillators and the bend by a harmonic oscillator. Coupling terms are approximated by harmonic oscillator formulas. Van Vleck perturbation theory is used to transform the Hamiltonian matrix to a block diagonal form. Analytical expressions

  19. Power Management for Energy Harvesting Wireless Sensors

    Microsoft Academic Search

    S. W. Arms; C. P. Townsend; D. L. Churchill; J. H. Galbreath; S. W. Mundell

    2005-01-01

    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

  20. Electric Power From Ambient Energy Sources

    SciTech Connect

    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.

  1. Power Electronics and Motor Drives Laboratory Integrating Energy Storage withIntegrating Energy Storage with

    E-print Network

    Saldin, Dilano

    Energy Storage Integrated with Renewable Energy Energy Storage Analysis for Wind and Solar #12;Power;Power Electronics and Motor Drives Laboratory Wind and Solar Energy Outlook The U.S. wind power industry HG VH PO LO MD HG HG VH #12;Power Electronics and Motor Drives Laboratory Wind Power Generation vs

  2. An application of stochastic resonance for energy harvesting in a bistable vibrating system

    NASA Astrophysics Data System (ADS)

    Zheng, Rencheng; Nakano, Kimihiko; Hu, Honggang; Su, Dongxu; Cartmell, Matthew P.

    2014-06-01

    The application of stochastic resonance to mechanical energy harvesting is currently of topical interest, and this paper concentrates on an analytical and experimental investigation in which stochastic resonance is deliberately exploited within a bistable mechanical system for optimised energy harvesting. The condition for the occurrence of stochastic resonance is defined conventionally by the Kramers rate, and the modelling of a theoretical nonlinear oscillator driven by a small periodic modulating excitation and a harvestable noise source, which, together satisfy this condition, is developed in the paper. A novel experiment is also discussed which validates this particular form of stochastic resonance, showing that the response can indeed be amplified when the frequency of the weak periodic modulating excitation fulfills the correct occurrence condition. The experimental results indicate that the available power generated under this condition of stochastic resonance is noticeably higher than the power that can be collected under other harvesting conditions.

  3. Sound Absorption in Molecular Gas Mixtures: Master Equation for Rotational and Vibrational Excitation, Relaxation, and Energy Transfer

    NASA Astrophysics Data System (ADS)

    Huestis, D. L.

    2008-12-01

    Laboratory sound absorption measurements provide much of what we know about the vibrational kinetics of air mixtures, forming the core basis for retrieving the altitude profile of water in the mesosphere from infrared emissions between 6.3 and 6.9 ?m. Here we show that sound-absorption and laser-excitation experiments follow exactly the same kinetics, reflect the same underlying reaction rates, and can be vulnerable to similar ambiguities. This has not been obvious because the literature lacks a consistent prescription for calculating the sound absorption frequency spectrum from the reaction rate coefficients. We have developed the first general theoretical formalism for calculating the absolute magnitude of sound absorption per-unit-length, versus sound frequency, for any number of collisional excitation, relaxation, and energy transfer processes, for any mixture of atomic and molecular gases. This new formalism, and the computer code that implements it, provide the first systematic means for inferring collisional rate coefficients from sound absorption measurements in which more than one rotational or vibrational mode is active, such as N2/O2/H2O/CO2 gas mixtures in the laboratory and the atmosphere. When a sound wave travels through a gas, the alternating compression and expansion cycles heat and cool the gas. If the acoustic frequency roughly matches the rate of vibrational relaxation, then the effective vibrational temperature lags behind the translational temperature and the energy in the sound wave is attenuated. The measured frequency of maximum absorption is proportional to the vibrational relaxation rate. In the simplest laser-based experiment, we excite a single molecular level and record its exponential time decay, with the vibrational relaxation rate being proportional to the decay frequency. In both experiments we derive the relaxation rate coefficient from the linear graph versus gas pressure. The technical problem is that any mixture of molecular gases will have more than one relaxation time constant. Thus we write the chemical kinetics master equation as (1) (d/dt) Nm = ?npq [ - kmn?pq Nm Nn + kpq?mn Np Nq ] which has the well-known time-dependent solution given by (2) Nm(t) = ?n Cmn exp(-?n t) where the ?n values are the decay frequencies and the Cmn coefficients depend on how the gas was initially excited. What we have contributed is the frequency-dependent sound absorption solution to Equation (1): (3) cvint(?) = ?nk Wn / (1 + i ?/?n) where cvint(?) is the complex heat capacity (per molecule), ? is the circular sound frequency, 2?f, the ?n are the calculated decay frequencies [as in Equation (2)] and k Wn is the real effective heat capacity for decay mode n. As pointed out by Landau and Teller [Phys. Z. Sowjet. 10, 34-43 (1936)], for a simple case when the decay modes correspond to vibrational modes, Wn is the ordinary heat capacity of the vibrational mode. In the more complicated case involving one or more reversible energy-transfer steps, e.g., water and oxygen, the vibrational modes and the decay modes do not correspond to each other, and we need to use the rate coefficients in Equation (1) to calculate both ?n and Wn.

  4. Micropower energy harvesting

    Microsoft Academic Search

    R. J. M. Vullers; R. van Schaijk; I. Doms; C. Van Hoof; R. Mertens

    2009-01-01

    More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC–DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

  5. Power and energy [1999 technology analysis and forecast

    Microsoft Academic Search

    W. Sweet

    1999-01-01

    This article presents a power and energy technology analysis and forecast for 1999. The subjects covered include photovoltaics, PV power systems, solar arrays, nuclear power and free market spot electricity pricing

  6. ENERGY PAYBACK OPTIMIZATION OF THERMOELECTRIC POWER GENERATOR SYSTEMS

    E-print Network

    ENERGY PAYBACK OPTIMIZATION OF THERMOELECTRIC POWER GENERATOR SYSTEMS Kazuaki Yazawa Dept model for optimizing thermoelectric power generation system is developed and utilized for parametric a fractional area of ~1%. The role of the substrate heat spreading for thermoelectric power generation

  7. Testing Skyrme energy-density functionals with the quasiparticle random-phase approximation in low-lying vibrational states of rare-earth nuclei

    SciTech Connect

    Terasaki, J.; Engel, J. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States)

    2011-07-15

    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 presence of multiparticle-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.

  8. Static power conversion techniques for unique energy devices 

    E-print Network

    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...

  9. Power processing and active protection for photovoltaic energy extraction

    E-print Network

    Chan, 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 ...

  10. Multi-layer Lanczos iteration approach to calculations of vibrational energies and dipole transition intensities for polyatomic molecules.

    PubMed

    Yu, Hua-Gen

    2015-01-28

    We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An application is illustrated by calculating the infrared vibrational dipole transition spectrum of CH4 based on the ab initio T8 potential energy surface of Schwenke and Partridge [Spectrochimica Acta, Part A 57, 887 (2001)] and the low-order truncated ab initio dipole moment surfaces of Yurchenko et al. [J. Mol. Spectrosc. 291, 69 (2013)]. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra. PMID:25637968

  11. Multi-layer Lanczos iteration approach to calculations of vibrational energies and dipole transition intensities for polyatomic molecules

    DOE PAGESBeta

    Yu, Hua-Gen

    2015-01-28

    We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An applicationmore »is illustrated by calculating the infrared vibrational dipole transition spectrum of CH? based on the ab initio T8 potential energy surface of Schwenke and Partridge and the low-order truncated ab initio dipole moment surfaces of Yurchenko and co-workers. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra.« less

  12. Multi-layer Lanczos iteration approach to calculations of vibrational energies and dipole transition intensities for polyatomic molecules

    DOE PAGESBeta

    Yu, Hua-Gen [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-01-28

    We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An application is illustrated by calculating the infrared vibrational dipole transition spectrum of CH? based on the ab initio T8 potential energy surface of Schwenke and Partridge and the low-order truncated ab initio dipole moment surfaces of Yurchenko and co-workers. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra.

  13. Do state-to-state propensity rules for vibrational energy transfer remain valid in the intermediate state density region?

    NASA Astrophysics Data System (ADS)

    Mudjijono; Lawrance, Warren D.

    1994-09-01

    State-to-state branching ratios are reported for vibrational energy transfer (VET) from the 8 2 and 7 18 1 levels in S 1 ?-difluoro-benzene by He and H 2 in a supersonic free jet expansion. 8 2 is in the sparse region of the vibrational manifold ( Evib=350 cm -1; ? vib?0.05 states / cm -1) while 7 18 1 is in the intermediate state density region ( Evib=751 cm -1; pvib?0.4 states / cm -1). Two principal results emerge: (i) the propensity rules that apply for 8 2 (sparse region) are not followed for 7 18 1 (intermediate region) and (ii) He and H 2 show virtually identical state-to-state branching ratios for 8 2 but not for 7 18 1.

  14. Interconnection of electrical energy storage systems for power quality improvement

    Microsoft Academic Search

    M. Brenna; G. C. Lazaroiu; R. Rotaru; E. Tironi

    2009-01-01

    Energy storage is playing an increasingly important role in the electrical power system thanks to the development and advance in various energy storage and power electronics technologies in recent years. The paper inquires into energy storage examining electrical energy storage devices, especially supercapacitors. Relative on these energy storage concerns, different dc\\/dc converters were analyzed using the EMTP\\/ATPDraw program to observe

  15. Future Energy Systems: Integrating Renewable Energy Sources into the Smart Power Grid Through Industrial Electronics

    Microsoft Academic Search

    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.

  16. Near spectroscopically accurate ab initio potential energy surface for NH4(+) and variational calculations of low-lying vibrational levels.

    PubMed

    Han, Huixian; Song, Hongwei; Li, Jun; Guo, Hua

    2015-04-01

    A nine-dimensional potential energy surface (PES) for the ammonium cation has been constructed by fitting ?30?000 AE-CCSD(T)-F12a/cc-pCVTZ-F12 points up to 32?262 cm(-1) (4.0 eV) from the minimum. The fitting using the permutation invariant polynomial-neural network method has high fidelity, with a root-mean-square error of merely 2.34 cm(-1). The low-lying vibrational energy levels of NH4(+) have been determined quantum mechanically using both Jacobi and normal coordinates, and the fundamental frequencies are in excellent agreement with available experimental data. PMID:25781209

  17. PulsedPower Transient Plasma: Energy, Engines, and

    E-print Network

    Levi, Anthony F. J.

    -32) #12;5Gundersen PulsedPower USC ONR 1990s Transient Plasma NO Removal Results Energy cost function of V1Gundersen PulsedPower USC Transient Plasma: Energy, Engines, and Aerospace Applications USC: Dan energy electrons in streamer head produce radicals, ions · Nsec pulsed power enables! Transient plasma

  18. Wind energy-hydrogen storage hybrid power generation

    Microsoft Academic Search

    Wen-Jei Yang; Orhan Aydin

    2001-01-01

    SUMMARY In this theoretical investigation, a hybrid power generation system utilizing wind energy and hydrogen storage is presented. Firstly, the available wind energy is determined, which is followed by evaluating the e$ciency of the wind energy conversion system. A revised model of windmill is proposed from which wind power density and electric power output are determined. When the load demand

  19. UNCERTAINTY EVALUATION OF AVAILABLE ENERGY AND POWER

    SciTech Connect

    Jon P. Christophersen; John L. Morrison

    2006-05-01

    The Idaho National Laboratory does extensive testing and evaluation of advanced technology batteries and ultracapacitors for applications in electric and hybrid vehicles. The testing is essentially acquiring time records of voltage, current and temperature from a variety of charge and discharge time profiles. From these three basic measured parameters, a complex assortment of derived parameters (resistance, power, etc.) is computed. Derived parameters are in many cases functions of multiple layers of other derived parameters that eventually work back to the three basic measured parameters. The purpose of this paper is to document the methodology used for the uncertainty analysis of the most complicated derived parameters broadly grouped as available energy and available power. This work is an analytical derivation. Future work will report the implementation of algorithms based upon this effort.

  20. Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces

    NASA Astrophysics Data System (ADS)

    Bae, Kwang Ho; Choi, Soon-Mok; Kim, Kyung-Hun; Choi, Hyoung-Seuk; Seo, Won-Seon; Kim, Il-Ho; Lee, Soonil; Hwang, Hae Jin

    2015-06-01

    Reliability tests for thermoelectric unicouples were carried out to investigate the adhesion properties of CoSb3/Ti/Mo(Cu) interfaces. The n-type In0.25 Co3.95Ni0.05Sb12 and p-type In0.25Co3FeSb12 bulks were prepared for fabricating a thermoelectric unicouple (one p- n couple) by an induction melting and a spark plasma sintering process. Mo-Cu alloy was selected as an electrode for the unicouples due to its high melting temperature and proper work function value. Many thermoelectric unicouples with the CoSb3/Ti/Mo(Cu) interfaces were fabricated with the proper brazing materials by means of a repeated firing process. Reliability of the unicouples with the interfaces was evaluated by a vibration test and a thermal cycling test. After the thermal cycling and vibration tests, the power-generation characteristics of the unicouples were compared with the unicouples before the tests. Even after the vibration test, electrical power with a power density of 0.5 W/cm2 was generated. The Ti-interlayer is considered as a possible candidate for making a reliable unicouple with high adhesion strength. With the thermal cycling test, the resistance of the unicouple increased and the electrical power from the unicouple decreased. A failure mode by the thermal cycling test was ascribed to a complex effect of micro-cracks originated from the thermal stress and oxidation problem of the thermoelectric materials; that is, a thick oxide layer more than 300 ?m was detected after a high-temperature durability test of n-type In0.25Co3.95Ni0.05Sb12 material at 773 K in air for 7 days.

  1. String Vibrations

    NSDL National Science Digital Library

    Davidhazy, Andrew

    This site, by Andrew Davidhazy at the Rochester Institute of Technology, describes how to make interesting and artistic photographs of a vibrating string. Davidhazy explains how the string is vibrated, how the string is lit, and even the exposure time and the effect it has on the resulting image. Four images of the vibrating string are included.

  2. ATOMIC AND MOLECULAR PHYSICS: High order correlation-polarization potential for vibrational excitation scattering of diatomic molecules by low-energy electrons

    NASA Astrophysics Data System (ADS)

    Feng, Hao; Sun, Wei-Guo; Zeng, Yang-Yang

    2009-11-01

    This paper introduces a correlation-polarization potential with high order terms for vibrational excitation in electron-molecule scattering. The new polarization potential generalizes the two-term approximation so that it can better reflect the dependence of correlation and polarization effects on the position coordinate of the scattering electron. It applies the new potential on the vibrational excitation scattering from N2 in an energy range which includes the 2?g shape resonance. The good agreement of theoretical resonant peaks with experiments shows that polarization potentials with high order terms are important and should be included in vibrational excitation scattering.

  3. Vibrational Conical Intersections: Implications for Ultrafast Vibrational Dynamics

    NASA Astrophysics Data System (ADS)

    Dawadi, Mahesh; Prasad Thapaliya, Bishnu; Bhatta, Ram; Perry, David

    2015-03-01

    The presence of conical intersections (CIs) between electronic potential energy surfaces is known to play a key role in ultrafast electronic relaxation in diverse circumstances. Recent reports have documented the existence of vibrational CIs connecting vibrationally adiabatic surfaces. Just as electronic CIs are now appreciated to be ubiquitous, controlling the rates of many photochemical processes, the present work on methanol and methyl mercaptan suggests that vibrational CIs may also be widespread, possibly controlling the outcome of some high-energy processes where vibrationally excited species are present. Other examples of vibrational CIs include the vibrational Jahn-Teller effect in C3V organic molecules and transition metal complexes. While the present work addresses only the couplings within bound molecules, the concept of vibrational CIs providing pathways for ultrafast relaxation also applies to molecular collisions. This work is supported by DOE (DEFG02-90ER14151).

  4. Investigation on behavior of the vibration-based piezoelectric energy harvester array in ultracapacitor charging

    NASA Astrophysics Data System (ADS)

    Yang, Yangyiwei; Shi, Xiang; Lan, Haoran; Xiao, Zhao; Dong, Ying; Liu, Yaoze; Yang, Tongqing

    2015-04-01

    In this article, behaviors are investigated when the piezoelectric harvester array, consisting of four lead zirconate-titanate (PZT) circular diaphragms, charges ultracapacitors. It exhibits that V-I characteristic of the harvester array is approximately linear within 3RC, demonstrates that the array could be equivalent as the linear source. Relevant factors on ultracapacitor charging power P, including equivalent circuitry impedance R, charging capacitor C, operating frequency f, and connection patterns, are also studied. Meanwhile, interrelation between energy charging efficiency ? and maximum charging power PMS is demonstrated, which is also used to find out the best condition for the harvester array's operation. It exhibits that PZT harvester array connected in pattern of rectifying-parallel will have higher charging efficiency.

  5. Radiant Energy Power Source for Jet Aircraft

    SciTech Connect

    Doellner, O.L.

    1992-02-01

    This report beings with a historical overview on the origin and early beginnings of Radiant Energy Power Source for Jet Aircraft. The report reviews the work done in Phase I (Grant DE-FG01-82CE-15144) and then gives a discussion of Phase II (Grant DE-FG01-86CE-15301). Included is a reasonably detailed discussion of photovoltaic cells and the research and development needed in this area. The report closes with a historical perspective and summary related to situations historically encountered on projects of this nature. 15 refs.

  6. Energy and power limits for microbial activity

    NASA Astrophysics Data System (ADS)

    LaRowe, D.; Amend, J.

    2014-12-01

    The goal of this presentation is to describe a quantitative framework for determining how energy limits microbial activity, biomass and, ultimately, biogeochemical processes. Although this model can be applied to any environment, its utility is demonstrated in marine sediments, which are an attractive test habitat because they encompass a broad spectrum of energy levels, varying amounts of biomass and are ubiquitous. The potential number of active microbial cells in Arkonas Basin (Baltic Sea) sediments are estimated as a function of depth by quantifying the amount of energy that is available to them and the rate at which it is supplied: power. The amount of power supplied per cubic centimeter of sediment is determined by calculating the Gibbs energy of fermentation and sulfate reduction in combination with the rate of particulate organic carbon, POC, degradation. The Reactive Continuum Model (Boudreau and Ruddick, 1991), RCM, is used to determine the rate at which POC is made available for microbial consumption. The RCM represents POC as containing a range of different types of organic compounds whose ability to be consumed by microorganisms varies as a function of the age of the sediment and on the distribution of compound types that were initially deposited. The sediment age model and RCM parameters determined by (Mogollon et al., 2012) are used. The power available for fermentation and sulfate reduction coupled to H2 and acetate oxidation varies from 10-8 W cm-3 at the sediment water interface to between 10-11 - 10-12 W cm-3 at 3.5 meters below the seafloor, mbsf. Using values of maintenance powers for each of these catabolic activities taken from the literature, the total number of active cells in these sediments similarly decreases from just less than 108 cell cm-3 at the SWI to 4.6 x 104 cells cm-3 at 3.5 mbsf. The number of moles of POC decreases from 2.6 x 10-5 to 9.5 x 10-6, also becoming more recalcitrant with depth. Boudreau, B. P. and Ruddick, B. R. (1991) On a reactive continuum representation of organic matter diagenesis. Amer. J. Sci. 291, 507-538. Mogollon, J. M., Dale, A. W., Fossing, H. and Regnier, P. (2012) Timescales for the development of methanogenesis and free gas layers in recently-deposited sediments of Arkona Bason (Baltic Sea). Biogeosciences 9, 1915-1933.

  7. Electric power processing, distribution, management and energy storage

    NASA Technical Reports Server (NTRS)

    Giudici, R. J.

    1980-01-01

    Power distribution subsystems are required for three elements of the SPS program: (1) orbiting satellite, (2) ground rectenna, and (3) Electric Orbiting Transfer Vehicle (EOTV). Power distribution subsystems receive electrical power from the energy conversion subsystem and provide the power busses rotary power transfer devices, switchgear, power processing, energy storage, and power management required to deliver control, high voltage plasma interactions, electric thruster interactions, and spacecraft charging of the SPS and the EOTV are also included as part of the power distribution subsystem design.

  8. A Comparison of Energy-Resolved Vibrational Activation/Dissociation Characteristics of Protonated and Sodiated High Mannose N-Glycopeptides

    NASA Astrophysics Data System (ADS)

    Aboufazeli, Forouzan; Kolli, Venkata; Dodds, Eric D.

    2015-04-01

    Fragmentation of glycopeptides in tandem mass spectrometry (MS/MS) plays a pivotal role in site-specific protein glycosylation profiling by allowing specific oligosaccharide compositions and connectivities to be associated with specific loci on the corresponding protein. Although MS/MS analysis of glycopeptides has been successfully performed using a number of distinct ion dissociation methods, relatively little is known regarding the fragmentation characteristics of glycopeptide ions with various charge carriers. In this study, energy-resolved vibrational activation/dissociation was examined via collision-induced dissociation for a group of related high mannose tryptic glycopeptides as their doubly protonated, doubly sodiated, and hybrid protonated sodium adduct ions. The doubly protonated glycopeptide ions with various compositions were found to undergo fragmentation over a relatively low but wide range of collision energies compared with the doubly sodiated and hybrid charged ions, and were found to yield both glycan and peptide fragmentation depending on the applied collision energy. By contrast, the various doubly sodiated glycopeptides were found to dissociate over a significantly higher but narrow range of collision energies, and exhibited only glycan cleavages. Interestingly, the hybrid protonated sodium adduct ions were consistently the most stable of the precursor ions studied, and provided fragmentation information spanning both the glycan and the peptide moieties. Taken together, these findings illustrate the influence of charge carrier over the energy-resolved vibrational activation/dissociation characteristics of glycopeptides, and serve to suggest potential strategies that exploit the analytically useful features uniquely afforded by specific charge carriers or combinations thereof.

  9. Dissociation energy and electronic and vibrational spectroscopy of Co(+)(H2O) and its isotopomers.

    PubMed

    Kocak, Abdulkadir; Austein-Miller, Geoff; Pearson, Wright L; Altinay, Gokhan; Metz, Ricardo B

    2013-02-14

    The electronic spectra of Co(+)(H(2)O), Co(+)(HOD), and Co(+)(D(2)O) have been measured from 13,500 to 18,400 cm(-1) using photodissociation spectroscopy. Transitions to four excited electronic states with vibrational and partially resolved rotational structure are observed. Each electronic transition has an extended progression in the metal-ligand stretch, v(3), and the absolute vibrational quantum numbering is assigned by comparing isotopic shifts between Co(+)(H(2)(16)O) and Co(+)(H(2)(18)O). For the low-lying excited electronic states, the first observed transition is to v(3)' = 1. This allows the Co(+)-(H(2)O) binding energy to be determined as D(0)(0 K)(Co(+)-H(2)O) = 13730 ± 90 cm(-1) (164.2 ± 1.1 kJ/mol). The photodissociation spectrum shows a well-resolved K(a) band structure due to rotation about the Co-O axis. This permits determination of the spin rotation constants ?(aa)" = -6 cm(-1) and ?(aa)' = 4 cm(-1). However, the K(a) rotational structure depends on v(3)'. These perturbations in the spectrum make the rotational constants unreliable. From the nuclear spin statistics of the rotational structure, the ground state is assigned as (3)B(1). The electronic transitions observed are from the Co(+)(H(2)O) ground state, which correlates to the cobalt ion's (3)F, 3d(8) ground state, to excited states which correlate to the (3)F, 3d(7)4s and (3)P, 3d(8) excited states of Co(+). These excited states of Co(+) interact less strongly with water than the ground state. As a result, the excited states are less tightly bound and have longer metal-ligand bonds. Calculations at the CCSD(T)/aug-cc-pVTZ level also predict that binding to Co(+) increases the H-O-H angle in water from 104.1° to 106.8°, as the metal removes electron density from the oxygen lone pairs. The O-H stretching frequencies of the ground electronic state of Co(+)(H(2)O) and Co(+)(HOD) have been measured by combining IR excitation with visible photodissociation in a double resonance experiment. In Co(+)(H(2)O) the O-H symmetric stretch is ?(1)" = 3609.7 ± 1 cm(-1). The antisymmetric stretch is ?(5)" = 3679.5 ± 2 cm(-1). These values are 47 and 76 cm(-1), respectively, lower than those in bare H(2)O. In Co(+)(HOD) the O-H stretch is observed at 3650 cm(-1), a red shift of 57 cm(-1) relative to bare HOD. PMID:22835001

  10. Vibrational overtone spectroscopy, energy levels, and intensities of (CH3)3C-C?C-H.

    PubMed

    Perez-Delgado, Yasnahir; Barroso, Jenny Z; Garofalo, Lauren A; Manzanares, Carlos E

    2012-03-01

    The vibrational overtone spectra of the acetylenic (?? = 4, 5) and methyl (?? = 5, 6) C-H stretch transitions of tert-butyl acetylene [(CH(3))(3)C-C?C-H] were obtained using the phase shift cavity ring down (PS-CRD) technique at 295 K. The C-H stretch fundamental and overtone absorptions of the acetylenic (?? = 2 and 3) and methyl (?? = 2-4) C-H bonds have been obtained using a Fourier transform infrared and near-infrared spectrophotometer. Harmonic frequency ?(?(1)) and anharmonicities x(?(1)) and x(?(1), ?(24)) are reported for the acetylenic C-H bond. Molecular orbital calculations of geometry and vibrational frequencies were performed. A harmonically coupled anharmonic oscillator (HCAO) model was used to determine the overtone energy levels and assign the absorption bands to vibrational transitions of methyl C-H bonds. Band strength values were obtained experimentally and compared with intensities calculated in terms of the HCAO model where only the C-H modes are considered. No adjustable parameters were used to get order of magnitude agreement with experimental intensities for all pure local mode C-H transitions. PMID:22263573

  11. Stresa, Italy, 26-28 April 2006 DESIGN AND FABRICATION OF A MICRO ELECTROSTATIC VIBRATION-TO-

    E-print Network

    Boyer, Edmond

    Stresa, Italy, 26-28 April 2006 DESIGN AND FABRICATION OF A MICRO ELECTROSTATIC VIBRATION electrostatic vibration-to- electricity energy converter. For the 3.3 V supply voltage and 1cm2 chip area monitoring [2], where remote or independent power supply is critical for building more compact or longer

  12. Vibration--rotation relaxation in bimolecular collisions with application to para-hydrogen. [Three-dimensional quantum mechanical calculations, effective-potential approximation, energy transfer, cross sections, rates

    Microsoft Academic Search

    R. Ramaswamy; H. Rabitz

    1977-01-01

    Three-dimensional quantum mechanical calculations in the effective potential approximation have been made on the para-hydrogen system. At low temperatures, vib--rotationally inelastic collisions were examined while breathing sphere calculations were used to probe the high-temperature regime. It was found that simultaneous vibrational and rotational processes contribute to the overall mechanism of vibrational relaxation. Collisionally induced intra- and intermolecular energy transfer is

  13. A voltage-multiplying self-powered ac\\/dc converter with 0.35 V minimum input voltage for energy harvesting applications

    Microsoft Academic Search

    Shuo Cheng; Rutvik Sathe; Raj D. Natarajan; David P. Arnold

    2011-01-01

    This paper demonstrates a highly efficient, low- voltage ac\\/dc converter using a voltage multiplier (octupler) circuit architecture intended for vibrational energy harvesting applications where a low-voltage ac waveform is used to charge a battery. The circuit employs output-powered active diodes and does not require any external power supply or startup circuitry. The circuit rectifies and boosts input ac voltages in

  14. A Voltage-Multiplying Self-Powered AC\\/DC Converter with 0.35-V Minimum Input Voltage for Energy Harvesting Applications

    Microsoft Academic Search

    Shuo Cheng; Rutvik Sathe; Raj Dayal Natarajan; David P. Arnold

    2011-01-01

    This paper demonstrates a highly efficient, low- voltage ac\\/dc converter using a voltage multiplier (octupler) circuit architecture intended for vibrational energy harvesting applica- tions where a low-voltage ac waveform is used to charge a battery. The circuit employs output-powered active diodes and does not require any external power supply or startup circuitry. The circuit rectifies and boosts input ac voltages

  15. A study of hand vibration on chipping and grinding operators, part III: Power levels into the hands of operators of pneumatic tools used in chipping and grinding operations

    NASA Astrophysics Data System (ADS)

    Reynolds, D. D.; Basel, R.; Wasserman, D. E.; Taylor, W.

    1984-08-01

    This paper presents a method for calculating power transmitted to the hands of operators who use vibrating hand tools. Results that relate to a comprehensive multidisciplined NIOSH field study of several hundred chipper and grinder workers who used pneumatic hand tools are presented. The results of this study indicated that the power in the frequency range of 6·3 Hz to 1000 Hz transmitted to the hand ranged from 1·08 × 10 3 to 7·23 × 10 3 J/s for the chisel and from 8·52 × 10 -1 to 1·57 × 10 2 J/s for the handle of chipping hammers. For pneumatic grinders the power transmitted to the hands of the tool operators was in the range of 6·58 × 10 -3 to 2·35 × 10 -3 J/s over the same frequency range.

  16. Smart electrical energy storage system for small power wind turbines

    Microsoft Academic Search

    M. Georgescu; L. Barote; C. Marinescu; L. Clotea

    2010-01-01

    Energy storage devices and solutions are required for power quality and balance within wind systems. In the context of rapidly expanding of distributed energy sources, the wind energy converters are in the center of interest. In this case, the direct dependence of the power generation capability for a given wind speed represents a major problem of wind energy conversion with

  17. Local energy function methods for power system transient stability

    Microsoft Academic Search

    Rastgoufard

    1983-01-01

    Energy function, the first integral of the accelerating power equation, is used to investigate the problem of power system transient stability. In contrast to the total system (global) energy function, the partial (local) energy function, which is the energy existing between and within an accelerated and a stationary group of generators, is considered in the analysis. Based on simulation, it

  18. Wind Power Today: 2000 Wind Energy Program Highlights

    Microsoft Academic Search

    Weis-Taylor

    2001-01-01

    Wind Power Today is an annual publication that provides an overview of the U.S. Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers

  19. Wind power today: 1999 Wind Energy program highlights

    Microsoft Academic Search

    Weis-Taylor

    2000-01-01

    Wind Power Today is an annual publication that provides an overview for the Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy for the 21st century. Content objectives

  20. Power Allocation for Energy Harvesting Transmitter with Causal Information

    E-print Network

    Greenberg, Albert

    1 Power Allocation for Energy Harvesting Transmitter with Causal Information Zhe Wang, Vaneet- controlled transmitter with energy harvesting capability based on causal observations of the channel fading powered by a renewable energy source and the energy harvesting process can practically be predicted