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1

Power sensitivity of vibration energy harvester  

Microsoft Academic Search

This paper deals with a power sensitivity improvement of an electromagnetic vibration energy harvester which generates electrical\\u000a energy from ambient vibrations. The harvester provides an autonomous source of energy for wireless applications, with an expected\\u000a power consumption of several mW, placed in environment excited by ambient mechanical vibrations. An appropriately tuned up\\u000a design of the harvester with adequate sensitivity provides

Zdenek Hadas; Cestmir Ondrusek; Vladislav Singule

2010-01-01

2

Autonomous Low Power Microsystem Powered by Vibration Energy Harvesting  

Microsoft Academic Search

This paper reports, for the first time, the implementation of a microsystem powered entirely from ambient vibrations. Sufficient electrical energy is harvested to power a radio-frequency (RF) linked accelerometer based microsystem. The microsystem is energy aware and will adjust the measurement\\/transmit duty cycle according to the available energy; this is typically every 50 seconds during normal operation. The system is

R. N. Torah; M. J. Tudor; K. Patel; I. N. Garcia; S. P. Beeby

2007-01-01

3

LINEAR AND NONLINEAR POWER PROCESSING OF VIBRATION BASED ENERGY SCAVENGERS  

Microsoft Academic Search

In this contribution, the power output of a vibration-driven energy scavenger is optimized when connected to a resistive, linear load and a nonlinear load, an AC-DC converter. The optimization of the power output is constrained by the limited generator size. The optimal loading is calculated for both load cases in various operating conditions, and the optimal generated power is compared.

R. D'hulst; J. Driesen

4

Electromagnetic Vibration Power Generator  

Microsoft Academic Search

This paper shows an alternative for supplying wireless sensors with energy: electrical power is generated from an ambient mechanical vibration by use of a vibration power generator. As the generator is excited by ambient mechanical vibration, its construction produces a relative movement of a magnetic circuit. This movement induces a current into an electrical coil due to Faraday's law. For

Z. Hadas; M. Kluge; V. Singule; C. Ondrusek

2007-01-01

5

Power Processing Circuits for Piezoelectric Vibration-Based Energy Harvesters  

Microsoft Academic Search

The behavior of a piezoelectric vibration-driven energy harvester with different power processing circuits is evaluated. Two load types are considered: a resistive load and an ac-dc rectifier load. An optimal resistive and optimal dc-voltage load for the harvester is analytically calculated. The difference between the optimal output power flow from the harvester to both load circuits depends on the coupling

R. D'hulst; T. Sterken; R. Puers; G. Deconinck; J. Driesen

2010-01-01

6

Optimum power and efficiency of piezoelectric vibration energy harvesters with sinusoidal and random vibrations  

NASA Astrophysics Data System (ADS)

Assuming a sinusoidal vibration as input, an inertial piezoelectric harvester designed for maximum efficiency of the electromechanical energy conversion does not always lead to maximum power generation. In this case, what can be gained by optimizing the efficiency of the device? Detailing an answer to this question is the backbone of this paper. It is shown that, while the maximum efficiency operating condition does not always lead to maximum power generation, it corresponds always to maximum power per square unit deflection of the piezoelectric harvester. This understanding allows better optimization of the generated power when the deflection of the device is limited by hard stops. This is illustrated by experimental measurements on vacuum-packaged MEMS harvesters based on AlN as piezoelectric material. The results obtained for a sinusoidal vibration are extended to random vibrations. In this case, we demonstrate that the optimum generated power is directly proportional to the efficiency of the harvester, thus answering the initial question. For both types of studied vibrations, simple closed-form formulas describing the generated power and efficiency in optimum operating conditions are elaborated. These formulas are based on parameters that are easily measured or modeled. Therefore, they are useful performance metrics for existing piezoelectric harvesters.

Renaud, M.; Elfrink, R.; Jambunathan, M.; de Nooijer, C.; Wang, Z.; Rovers, M.; Vullers, R.; van Schaijk, R.

2012-10-01

7

Vibration energy harvesting for low power and wireless applications  

NASA Astrophysics Data System (ADS)

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.

Challa, Vinod Reddy

8

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

Microsoft Academic Search

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

R. Amirtharajah; S. Meninger; J. O. Mur-Miranda; A. Chandrakasan; J. Lang

2000-01-01

9

Improving power output for vibration-based energy scavengers  

Microsoft Academic Search

Pervasive networks of wireless sensor and communication nodes have the potential to significantly impact society and create large market opportunities. For such networks to achieve their full potential, however, we must develop practical solutions for self-powering these autonomous electronic devices. We've modeled, designed, and built small cantilever-based devices using piezoelectric materials that can scavenge power from low-level ambient vibration sources.

Shad Roundy; Eli S. Leland; Jessy Baker; Eric Carleton; Elizabeth K. Reilly; Elaine Lai; Brian Otis; Jan M. Rabaey; Paul K. Wright; V. Sundararajan

2005-01-01

10

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

Microsoft Academic Search

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

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

2006-01-01

11

Linear and nonlinear energy harvesters for powering pacemakers from heart beat vibrations  

NASA Astrophysics Data System (ADS)

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 the pacemakers is very low. At the same time, after about 10 years from the original implantation of the pacemakers, patients have to go through another surgical operation just to replace the batteries of their pacemakers. We investigate using vibration energy harvesters to significantly increase the battery life of the pace makers. The major source of vibrations in chest area is due to heartbeats. Linear low frequency and nonlinear mono-stable and bi-stable energy harvesters are designed according to especial signature of heart vibrations. The proposed energy harvesters are robust to variations of heart beat frequency and can meet the power requirement of the pacemakers.

Karami, M. Amin; Inman, Daniel J.

2011-03-01

12

Vibration Based Electromagnetic Energy Harvesting - Microgenerator, Power Conversion and Control  

NASA Astrophysics Data System (ADS)

Energy harvesting has been a research focus for many years. The idea that energy can be harvested from ambient environment and a device can operate without a battery is very attractive for low power electronic applications. The slow growth of battery technology and development of low power semiconductor technology has positioned energy harvesting as a feasible power source for low power applications. The present work emphasizes on microgenerator design and power processing circuits for electromagnetic energy harvesting. The main objective is to develop a complete system for low voltage electromagnetic energy harvesting. The thesis work has been designed and developed in consecutive stages – (a) novel converter topologies for low voltage microgenerators, (b) unified design of microgenerators and converter topologies, (c) design of efficient auxiliary circuits, (d) optimal energy harvesting control. A number of suitable converter topologies are first presented for low voltage, low power energy harvesting. Their operation, analysis and modeling are discussed in detail. The loss analysis is developed to properly characterize the performance of different converters developed in this thesis. Multiple methods to interface the microgenerator with the converters are presented. Based on the interface mechanism, a suitable unified design approach is also formulated for both the microgenerator and the converters. To realize a self-sufficient energy harvesting system, design of auxiliary circuits like start-up circuits, controller and gate driver circuits is very important. In this work, they are fabricated to consume very low power while satisfying the converter requirements. Finally, a new low power control system is developed to maximize the output of the energy harvesting system. Two types of control are envisaged in this work. The first type is a simpler voltage regulation mechanism. The second, more interesting type of control is based on controlling the converter to maximize the harvested energy from the source.

Dayal, Rohan

13

Piezoelectric-based power sources for harvesting energy from platforms with low-frequency vibration  

NASA Astrophysics Data System (ADS)

This paper presents a new class of highly efficient piezoelectric based energy harvesting power sources for mounting on platforms that vibrate at very low frequencies as compared to the frequencies at which energy can be efficiently harvested using piezoelectric elements . These energy harvesting power sources have a very simple design and do not require accurate tuning for each application to match the frequency of the platform vibration. The developed method of harvesting mechanical energy and converting it to electrical energy overcomes problems that are usually encountered with harvesting energy from low frequency vibration of various platforms such as ships and other platforms with similar vibratory (rocking or translational) motions. Omnitek Partners has designed several such energy harvesting power sources and is in the process of constructing prototypes for testing. The developed designs are modular and can be used to construct power sources for various power requirements. The amount of mechanical energy available for harvesting is obviously dependent on the frequency and amplitude of vibration of the platform, and the size and mass of the power source.

Rastegar, J.; Pereira, C.; Nguyen, H.-L.

2006-04-01

14

Self-powered autonomous wireless sensor node using vibration energy harvesting  

Microsoft Academic Search

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

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

2008-01-01

15

Self-powered autonomous wireless sensor node using vibration energy harvesting  

Microsoft Academic Search

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

16

Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters  

NASA Astrophysics Data System (ADS)

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.

Amin Karami, M.; Inman, Daniel J.

2012-01-01

17

Design and simulation of SOI-MEMS electrostatic vibration energy harvester for micro power generation  

Microsoft Academic Search

The micro power generation using vibration energy sources appears to be attractive due to its applicability on many situations and environmental conditions. The electrostatic energy harvester has various advantageous over piezoelectric and electromagnetic systems such as reduction in fabrication process complexity and cost, feasibility on MEMS and IC integration, improves the possibility level of integration with silicon based microelectronics and

Othman Sidek; Muhammad Afif Khalid; Mohammad Zulfikar Ishak; Muhamad Azman Miskam

2011-01-01

18

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

NASA Astrophysics Data System (ADS)

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.

Tang, Xiudong; Lin, Teng; Zuo, Lei

2012-03-01

19

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

Microsoft Academic Search

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

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

2006-01-01

20

Analysis of self-powered vibration-based energy scavenging system  

Microsoft Academic Search

This paper analyses a complete self-powered vibration based energy scavenging system. For the purpose of the analysis, the energy scavenging system (comprising of a SPICE model of Piezoelectric Bender Generator (PBG), an integrated semi-active bridge rectifier and a voltage regulator circuit) has been implemented in SPICE and presented in this paper. The semi-active bridge rectifier proposed in this paper uses

Luigi Pinna; Ravinder S. Dahiya; Fabrizio De Nisi; Maurizio Valle

2010-01-01

21

Broadband electromagnetic vibration energy harvesting system for powering wireless sensor nodes  

NASA Astrophysics Data System (ADS)

This paper reports the design of an electromagnetic vibration energy harvesting system that provides high power density and broad bandwidth. The ‘double cell’ harvester was chosen as the generator for this system. In order to harvest power over a broad range of frequencies, four ‘double cell’ harvesters with varying resonances were incorporated in the system architecture. The average AC to regulated DC power conversion efficiency across the 4 Hz bandwidth was 78%, which is one of the highest reported magnitudes for an electromagnetic vibration harvesting system. The magnetic flux density variation within the double cell array was modeled using the finite element method and compared to a single cell with equivalent tip mass and magnet volume. The double cell array was found to generate a similar magnitude of power to a single cell but three times higher bandwidth. The average generator conversion efficiency for the double cell array was 45.3%, which approaches the maximum theoretical limit of 50%.

Marin, Anthony; Turner, John; Ha, Dong Sam; Priya, Shashank

2013-07-01

22

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

Microsoft Academic Search

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

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

2007-01-01

23

Self-powered autonomous wireless sensor node using vibration energy harvesting  

NASA Astrophysics Data System (ADS)

This paper reports the development and implementation of an energy aware autonomous wireless condition monitoring sensor system (ACMS) powered by ambient vibrations. An electromagnetic (EM) generator has been designed to harvest sufficient energy to power a radio-frequency (RF) linked accelerometer-based sensor system. The ACMS is energy aware and will adjust the measurement/transmit duty cycle according to the available energy; this is typically every 3 s at 0.6 m s-2rms acceleration and can be as low as 0.2 m s-2rms with a duty cycle around 12 min. The EM generator has a volume of only 150 mm3 producing an average power of 58 µW at 0.6 m s-2rms acceleration at a frequency of 52 Hz. In addition, a voltage multiplier circuit is shown to increase the electrical damping compared to a purely resistive load; this allows for an average power of 120 µW to be generated at 1.7 m s-2rms acceleration. The ACMS has been successfully demonstrated on an industrial air compressor and an office air conditioning unit, continuously monitoring vibration levels and thereby simulating a typical condition monitoring application.

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

2008-12-01

24

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

Microsoft Academic Search

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

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

25

Adaptive vibration energy harvesting  

Microsoft Academic Search

By scavenging energy from their local environment, portable electronic devices such as mobile phones, radios and wireless sensors can achieve greater run-times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy, through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources

Sam Behrens; John Ward; Josh Davidson

2007-01-01

26

Ferroelectric dipole electrets for output power enhancement in electrostatic vibration energy harvesters  

NASA Astrophysics Data System (ADS)

We propose a ferroelectric dipole electret composed of polarized lead zirconate titanate. Deep insight into the physics behind the parallel plate capacitor theoretically predicts that we can extract large electric field near the surface of the ferroelectric dipole electret by increasing its surface charge density and thickness. Experiment for ferroelectric dipole electret shows good agreement with the theory. The maximum output power density of electrostatic vibration energy harvesters using the ferroelectric dipole electret was 78 ?W/cm3, a three-fold increase over a conventional polymer electret. Our results will pave the way for use of ferroelectrics as electrets.

Asanuma, Haruhiko; Oguchi, Hiroyuki; Hara, Motoaki; Yoshida, Ryo; Kuwano, Hiroki

2013-10-01

27

Pulsating magneto-dipole radiation of quaking neutron star powered by energy of Alfven seismic vibrations  

Microsoft Academic Search

The impact of magnetic field decay on radiative activity of quaking neutron\\u000astar undergoing Lorentz-force-driven torsional seismic vibrations about axis of\\u000aits dipole magnetic moment is studied. We found that monotonic depletion of\\u000ainternal magnetic field pressure is accompanied by the loss of vibration energy\\u000aof the star that causes its vibration period to lengthen at a rate proportional\\u000ato

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

2010-01-01

28

A bidirectional vibration powered electric energy generator based on electrostatic transduction using In-Plane Overlap Plate (IPOP) mechanism  

Microsoft Academic Search

In this paper, the design, fabrication and initial characterization results of a bidirectional, vibration powered, bulk silicon-based electric energy generator are addressed. The converter is based on an In-Plane Overlap Plate (IPOP) configuration. Its mechanical design is inspired from 2D gyroscope. In most of real systems, the axis of the external vibrations is not known and if we assume that

Ayyaz Mahmood Paracha; Philippe Basset; Dimitri Galayko; Frederic Marty; Tarik Bourouina

2009-01-01

29

Increasing sensitivity of vibration energy harvester  

Microsoft Academic Search

This paper deals with an electromagnetic vibration energy harvester which generates electrical energy from ambient vibrations. This harvester provides an autonomous source of energy for wireless applications, with an expected power consumption of several mW, placed in an environment excited by ambient vibrations. A tuned up design of the harvester with an electromagnetic converter provides sufficient generating of electrical energy

Z. Hadas; C. Ondrusek; V. Singule

2009-01-01

30

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

Microsoft Academic Search

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

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

2009-01-01

31

On Hoyle-Narlikar-Wheeler mechanism of vibration energy powered magneto-dipole emission of neutron stars  

Microsoft Academic Search

We revisit the well-known Hoyle-Narlikar-Wheeler proposition that neutron star emerging in the magnetic-flux-conserving process\\u000a of core-collapse supernova can convert the stored energy of Alfvén vibrations into power of magneto-dipole radiation. We show\\u000a that the necessary requirement for the energy conversion is the decay of internal magnetic field. In this case the loss of\\u000a vibration energy of the star causes its

Sergey Bastrukov; Junwei Yu; Irina Molodtsova; Renxin Xu

2011-01-01

32

A vibration energy harvesting device with bidirectional resonance frequency tunability  

Microsoft Academic Search

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

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

2008-01-01

33

Pulsating magneto-dipole radiation of a quaking neutron star powered by energy of Alfvén seismic vibrations  

Microsoft Academic Search

We compute the characteristic parameters of the magneto-dipole radiation of a neutron star undergoing torsional seismic vibrations under the action of Lorentz restoring force about an axis of a dipolar magnetic field experiencing decay. After a brief outline of the general theoretical background of the model of a vibration-powered neutron star, we present numerical estimates of basic vibration and radiation

Sergey Bastrukov; Jun-Wei Yu; Ren-Xin Xu; Irina Molodtsova

2011-01-01

34

Potential system efficiencies for MEMS vibration energy harvesting  

Microsoft Academic Search

Reliable power sources are needed for portable micro-electromechanical systems (MEMS) devices such as wireless automobile tire pressure sensors. Vibration is an ubiquitous energy source that maybe 'harvested' as electrical energy at the site of the MEMS device. Existing vibration energy harvesting systems use either a piezoelectric or an electromagnetic transducer to convert vibrations into electrical energy. This electrical energy is

S. Behrens

2007-01-01

35

On energy harvesting from ambient vibration  

Microsoft Academic Search

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

N. G. Stephen

2006-01-01

36

Energy harvesting vibration sources for microsystems applications  

Microsoft Academic Search

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,

S P Beeby; M J Tudor; N M White

2006-01-01

37

Increasing sensitivity of vibration energy harvester  

NASA Astrophysics Data System (ADS)

This paper deals with an electromagnetic vibration energy harvester which generates electrical energy from ambient vibrations. This harvester provides an autonomous source of energy for wireless applications, with an expected power consumption of several mW, placed in an environment excited by ambient vibrations. A tuned up design of the harvester with an electromagnetic converter provides sufficient generating of electrical energy for wireless applications. The output power depends on a frequency and level of the vibration and sensitivity of the energy harvester. Our harvester includes a unique spring-less resonance mechanism where stiffness is provided by repelled magnetic forces. The sensitivity is affected only by friction forces inside the mechanism of the harvester. Ways of decreasing friction, it means an increasing sensitivity, are investigated in this paper. The increasing sensitivity of the harvester provides more generated energy or decrease of the harvester size and weight.

Hadas, Z.; Ondrusek, C.; Singule, V.

2009-05-01

38

Quaking neutron star deriving radiative power of oscillating magneto-dipole emission from energy of Alfv\\\\'en seismic vibrations  

Microsoft Academic Search

It is shown that depletion of the magnetic field pressure in a quaking neutron star undergoing Lorentz-force-driven torsional seismic vibrations about axis of its dipole magnetic moment is accompanied by the loss of vibration energy of the star that causes its vibration period to lengthen at a rate proportional to the rate of magnetic field decay. Highlighted is the magnetic-field-decay

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

2010-01-01

39

Design and Fabrication Issues of a Silicon-Based Vibration Powered Electric Energy Generator Using Parallel Plate and In-Plane Mechanism  

Microsoft Academic Search

This paper focuses on the design and fabrication issues of a silicon-based, vibration powered, electric energy generator. Its architecture is based on the parallel plate configuration. It uses electrostatic damping of variable MEMS capacitor as the energy converting mechanism. Variable capacitance is achieved by in-plane movement of the top electrode. Hence capacitance variation is achieved by means of change in

A. M. Paracha; P. Basset; C. L. P. Lim; F. Marty; P. Poulichet; G. Amendola; T. Bourounia

2006-01-01

40

An energy harvesting system using the wind-induced vibration of a stay cable for powering a wireless sensor node  

NASA Astrophysics Data System (ADS)

This paper proposes an electromagnetic energy harvesting system, which utilizes the wind-induced vibration of a stay cable, and investigates its feasibility for powering a wireless sensor node on the cable through numerical simulations as well as experimental tests. To this end, the ambient acceleration responses of a stay cable installed in an in-service cable-stayed bridge are measured, and then they are used as input excitations in cases of both numerical simulations and experimental tests to evaluate the performance of the proposed energy harvesting system. The results of the feasibility test demonstrate that the proposed system generates sufficient electricity for operation of a wireless sensor node attached on the cable under the moderate wind conditions.

Jung, Hyung-Jo; Kim, In-Ho; Jang, Seon-Jun

2011-07-01

41

Wideband excitation of an electrostatic vibration energy harvester with power-extracting end-stops  

NASA Astrophysics Data System (ADS)

An electrostatic energy harvester with two-stage transduction is investigated for enhancement of bandwidth and dynamic range. The harvester includes a primary proof mass with two main transducers and end-stops for the proof mass functioning as secondary transducers. In the small acceleration regime, the power is primarily obtained from the main transducers. In the high acceleration regime, the mass impacts the end-stops and actuates the secondary transducers, generating additional output power. The device is designed and fabricated using the SOIMUMPs process and has a total active area of 4 × 5 mm2. Under wideband acceleration at high levels, the experimental results show that the total output power increases to about twice the output power of the main transducers, while the 3 dB-bandwidth is enlarged by a factor of 6.7 compared to the linear-response bandwidth at low levels. In comparison with a reference device made with the same die dimensions, the two-stage device improves output power instead of saturating when the maximum mass displacements of both devices reach the same limit. Measurement of output power demonstrates that the device with the transducing end-stops give an efficiency of 23.6%, while this value is 14.1% for the reference device with the conventional end-stops, at an acceleration spectral density of Sa = 19.2 × 10?3 g2 Hz?1. The efficiency is improved about by 9.5% in the impact regime.

Phu Le, Cuong; Halvorsen, Einar; Søråsen, Oddvar; Yeatman, Eric M.

2013-07-01

42

Energy scavenging from environmental vibration.  

SciTech Connect

The goal of this project is to develop an efficient energy scavenger for converting ambient low-frequency vibrations into electrical power. In order to achieve this a novel inertial micro power generator architecture has been developed that utilizes the bi-stable motion of a mechanical mass to convert a broad range of low-frequency (< 30Hz), and large-deflection (>250 {micro}m) ambient vibrations into high-frequency electrical output energy. The generator incorporates a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromagnetic scavenger. This frequency up-conversion technique enhances the electromechanical coupling and increases the generated power. This architecture is called the Parametric Frequency Increased Generator (PFIG). Three generations of the device have been fabricated. It was first demonstrated using a larger bench-top prototype that had a functional volume of 3.7cm3. It generated a peak power of 558{micro}W and an average power of 39.5{micro}W at an input acceleration of 1g applied at 10 Hz. The performance of this device has still not been matched by any other reported work. It yielded the best power density and efficiency for any scavenger operating from low-frequency (<10Hz) vibrations. A second-generation device was then fabricated. It generated a peak power of 288{micro}W and an average power of 5.8{micro}W from an input acceleration of 9.8m/s{sup 2} at 10Hz. The device operates over a frequency range of 20Hz. The internal volume of the generator is 2.1cm{sup 3} (3.7cm{sup 3} including casing), half of a standard AA battery. Lastly, a piezoelectric version of the PFIG is currently being developed. This device clearly demonstrates one of the key features of the PFIG architecture, namely that it is suitable for MEMS integration, more so than resonant generators, by incorporating a brittle bulk piezoelectric ceramic. This is the first micro-scale piezoelectric generator capable of <10Hz operation. The fabricated device currently generates a peak power of 25.9{micro}W and an average power of 1.21{micro}W from an input acceleration of 9.8m/s{sup -} at 10Hz. The device operates over a frequency range of 23Hz. The internal volume of the generator is 1.2cm{sup 3}.

Galchev, Tzeno (University of Michigan); Apblett, Christopher Alan; Najafi, Khalil (University of Michigan)

2009-10-01

43

An electromagnetic, vibration-powered generator for intelligent sensor systems  

Microsoft Academic Search

This paper describes the design of miniature generators capable of converting ambient vibration energy into electrical energy for use in powering intelligent sensor systems. Such a device acts as the power supply of a microsystem which can be used in inaccessible areas where wires can not be practically attached to provide power or transmit sensor data. Two prototypes of miniature

P. Glynne-Jones; M. J. Tudor; S. P. Beeby; N. M. White

2004-01-01

44

Vibration-to-electric energy conversion  

Microsoft Academic Search

A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low-power electronic systems. The energy is transduced through the use of a variable capacitor, which has been designed with MEMS (microelectromechanical systems) tech- nology. A low-power controller IC has been fabricated in a 0 6µm CMOS pro- cess and has been tested and

Scott Meninger; Jose Oscar Mur-Miranda; Rajeevan Amirtharajah; Anantha Chandrakasan; Jeffrey Lang

1999-01-01

45

A High Power Density Electrostatic Vibration-to-Electric Energy Converter Based On An In-Plane Overlap Plate (IPOP) Mechanism  

Microsoft Academic Search

In this paper, design, fabrication and characterization issues of a bulk silicon-based, vibration powered, electric energy generator are addressed. The converter is based on an In-Plane Overlap Plate (IPOP) configuration (1). Measurements have shown that with a theoretically lossless electronics and a starting voltage of 5 V, power density of 58 µW\\/cm 3 is achievable at the resonance frequency of

Ayyaz Mahmood Paracha; Philippe Basset; Frédéric Marty; Adrian Vaisman Chasin; Patrick Poulichet; Tarik Bourouina

2008-01-01

46

Vibration based energy harvesting using piezoelectric material  

Microsoft Academic Search

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.

M. N Fakhzan; Asan G. A. Muthalif

2011-01-01

47

Capacitive vibration energy harvesting with resonance tuning  

Microsoft Academic Search

Electromechanical conversion of mechanical vibration into electrical energy looks very attractive for industrial applications recently proposed and involving wireless sensors networks. A preliminary analysis of the energy scavenger configuration is proposed by investigating the performance of microsystems based on the electrostatic coupling and testing the power scavenged by a capacitive microscavenger, with out-of-plane gap closing layout. This study includes some

G. De Pasquale; E. Brusa; A. Soma

2009-01-01

48

A low-frequency vibration-to-electrical energy harvester  

Microsoft Academic Search

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

Min Zhang; Daniel Brignac; Pratul Ajmera; Kun Lian

2008-01-01

49

Resonance tuning of piezoelectric vibration energy scavenging generators using compressive axial preload  

Microsoft Academic Search

Vibration energy scavenging, harvesting ambient vibrations in structures for conversion into usable electricity, provides a potential power source for emerging technologies including wireless sensor networks. Most vibration energy scavenging devices developed to date operate effectively at a single specific frequency dictated by the device’s design. However, for this technology to be commercially viable, vibration energy scavengers that generate usable power

Eli S Leland; Paul K Wright

2006-01-01

50

Harvesting vibration energy using nonlinear oscillations of an electromagnetic inductor  

Microsoft Academic Search

Harvesting energy from ambient vibration is a promising method for providing a continuous source of power for wireless sensor nodes. However, traditional energy harvesters are often derived from resonant linear oscillators which are capable of providing sufficient output power only if the dominant frequency of input vibrations closely matches the device resonant frequency. The limited scope of such devices has

Christopher Lee; David Stamp; Nitin R. Kapania; José Oscar Mur-Miranda

2010-01-01

51

Multiple cell configuration electromagnetic vibration energy harvester  

Microsoft Academic Search

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

Anthony Marin; Scott Bressers; Shashank Priya

2011-01-01

52

PERFORMANCE OF MICROFABRICATED PIEZOELECTRIC VIBRATION ENERGY HARVESTERS  

Microsoft Academic Search

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

NOËL DUTOIT; BRIAN WARDLE

2006-01-01

53

Self-powered signal processing using vibration-based power generation  

Microsoft Academic Search

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

Rajeevan Amirtharajah; Anantha P. Chandrakasan

1998-01-01

54

Vibration Powered Radiation of Quaking Magnetar  

Microsoft Academic Search

In juxtaposition with the standard model of rotation powered pulsar, the model of vibration powered magnetar undergoing quake-induced torsional Alfven vibrations in its own ultra strong magnetic field experiencing decay is considered. The presented line of argument shows that gradual decrease of frequencies (lengthening of periods) of long-periodic pulsed radiation detected from set of X-ray sources can be attributed to

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

2011-01-01

55

Vibrations increase available power at the bit  

SciTech Connect

Drill string vibrations generally are considered to be detrimental to downhole drilling equipment because they produce cyclic or fatigue loading. Tool joint failures, tubular washouts, and bit breakage are often fatigue related. On the positive side, dynamic forces applied to roller cone rock bits have the potential to increase penetration. This article quantifies the available vibration energy at the bit and shows how to control the level of energy through bottom hole assembly design and rotary speed. This work identifies the level of energy transmitted into the bottom of drill strings to maintain vibrations. This energy, which is available for making hole, is taken from rotary speed and torque supplied by the rotary table. Energy consumed by axial and torsional modes is approximately equal to steady drilling at the bit. Force level and location of impact point affects whether vibration energy is reflected back to the drill string or transmitted into the formation to make hole. MWD sensors can key force, displacement, and phase angle at the bit to establish vibration losses in the drill string. Vibration energy levels at the bit and direction of energy flow (into collars or into formation) can be controlled by bottom hole assembly design and rotary speed.

Dareing, D.W.

1984-03-05

56

Vibration power generator for a linear MR damper  

Microsoft Academic Search

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

Bogdan Sapinski

2010-01-01

57

Microelectromechanical power generator and vibration sensor  

SciTech Connect

A microelectromechanical (MEM) apparatus is disclosed which can be used to generate electrical power in response to an external source of vibrations, or to sense the vibrations and generate an electrical output voltage in response thereto. The MEM apparatus utilizes a meandering electrical pickup located near a shuttle which holds a plurality of permanent magnets. Upon movement of the shuttle in response to vibrations coupled thereto, the permanent magnets move in a direction substantially parallel to the meandering electrical pickup, and this generates a voltage across the meandering electrical pickup. The MEM apparatus can be fabricated by LIGA or micromachining.

Roesler, Alexander W. (Tijeras, NM); Christenson, Todd R. (Albuquerque, NM)

2006-11-28

58

Vibrational energy transfer of very highly vibrationally excited NO  

NASA Astrophysics Data System (ADS)

The PUMP-DUMP-PROBE method has been used to study the collisional vibrational energy transfer dynamics of very highly vibrationally excited NO. At vibrational energies up to 3 eV, the qualitative trends observed in the experiments, such as the mass effect and the multiquantum relaxation, can be explained by the Schwartz-Slawsky-Herzfeld theory. A simple explanation is also given for the anomalously high NO self-relaxation rate observed in the experiments.

Yang, Xueming; Kim, Eun H.; Wodtke, Alec M.

1992-04-01

59

Enhanced Vibrational Energy Harvesting Using Non-linear Stochastic Resonance  

Microsoft Academic Search

Stochastic resonance has seen wide application in the physical sciences as a tool to understand weak signal ampliflcation by noise. However, this apparently counter- intuitive phenomenon does not appear to have been exploited as a tool to enhance vibrational energy harvesting. In this note we demonstrate that by adding periodic forcing to a vibrationally excited energy harvesting mechanism, the power

C. R. McInnes; D. G. Gorman; M. P. Cartmell

2008-01-01

60

Adaptive learning algorithms for vibration energy harvesting  

Microsoft Academic Search

By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a

John K. Ward; Sam Behrens

2008-01-01

61

Electromagnetic vibration energy harvesting device optimization by synchronous energy extraction  

Microsoft Academic Search

This paper investigates a new application of nonlinear techniques for vibration energy harvesting. The Synchronous Electric Charge Extraction (SECE) energy harvesting technique for piezoelectric generators is extended and adapted to electromagnetic generators. This new circuit, which is the dual of the SECE circuit, is named SMFE for Synchronous Magnetic Flux Extraction. A theoretical model is developed, and the harvested power

E. Arroyo; A. Badel

2011-01-01

62

Piezoelectric Vibration Energy Harvesting Device.  

National Technical Information Service (NTIS)

A piezoelectric vibration energy harvesting device which is made up of a first mass, a second, a first spring coupled to the first mass, and a second spring coupled to the second mass. A piezoelectric element is bonded between the first mass and the secon...

K. Andic K. K. Deng

2005-01-01

63

Design and performance of a microelectromagnetic vibration powered generator  

Microsoft Academic Search

In this paper we, report on the design, simulation and initial results of a microgenerator, which converts external vibrations into electrical energy. Power is generated by means of electromagnetic transduction with static magnets positioned either side of a moving coil located on a silicon structure designed to resonate laterally in the plane of the chip. The development and fabrication of

S. P. Beeby; M. J. Tudor; E. Koukharenko; N. M. White; T. O'Donnell; C. Saha; S. Kulkarni; S. Roy

2005-01-01

64

Smart Wireless Sensor Network Powered by Random Ambient Vibrations  

Microsoft Academic Search

Over the past years, there has been a lot of efforts on the development of wireless sensor networks. However, the major constraint on broad application of wireless sensor network is still the battery lifetime on the wireless sensor nodes. In this paper, a complete power efficient sensor network system will be presented, and energy harvesting from ambient vibrations to further

Wen-Jong Wu; Yi-Fan Chen; Yu-Yin Chen; Chao-Sheng Wang; Yun-Hsuan Chen

2006-01-01

65

Feasibility of structural monitoring with vibration powered sensors  

NASA Astrophysics Data System (ADS)

Wireless sensors and sensor networks are beginning to be used to monitor structures. In general, the longevity, and hence the efficacy, of these sensors are severely limited by their stored power. The ability to convert abundant ambient energy into electric power would eliminate the problem of drained electrical supply, and would allow indefinite monitoring. This paper focuses on vibration in civil engineering structures as a source of ambient energy; the key question is can sufficient energy be produced from vibrations? Earthquake, wind and traffic loads are used as realistic sources of vibration. The theoretical maximum energy levels that can be extracted from these dynamic loads are computed. The same dynamic loads are applied to a piezoelectric generator; the energy is measured experimentally and computed using a mathematical model. The collected energy levels are compared to the energy requirements of various electronic subsystems in a wireless sensor. For a 5 cm3 sensor node (the volume of a typical concrete stone), it is found that only extreme events such as earthquakes can provide sufficient energy to power wireless sensors consisting of modern electronic chips. The results show that the optimal generated electrical power increases approximately linearly with increasing sensor mass. With current technology, it would be possible to self-power a sensor node with a mass between 100 and 1000 g for a bridge under traffic load. Lowering the energy consumption of electronic components is an ongoing research effort. It is likely that, as electronics becomes more efficient in the future, it will be possible to power a wireless sensor node by harvesting vibrations from a volume generator smaller than 5 cm3.

Elvin, Niell G.; Lajnef, Nizar; Elvin, Alex A.

2006-08-01

66

A wideband vibration-based energy harvester  

Microsoft Academic Search

We present a new architecture for wideband vibration-based micro-power generators (MPGs). It replaces a linear oscillator with a piecewise-linear oscillator as the energy harvesting element of the MPG. A prototype of an electromagnetic MPG designed accordingly is analyzed analytically, numerically and experimentally. We find that the new architecture increases the bandwidth of the MPG during a frequency up-sweep, while maintaining

M S M Soliman; E M Abdel-Rahman; E F El-Saadany; R R Mansour

2008-01-01

67

A MEMS vibration energy harvester for automotive applications  

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

68

Vibrational structure theory: new vibrational wave function methods for calculation of anharmonic vibrational energies and vibrational contributions to molecular properties.  

PubMed

A number of recently developed theoretical methods for the calculation of vibrational energies and wave functions are reviewed. Methods for constructing the appropriate quantum mechanical Hamilton operator are briefly described before reviewing a particular branch of theoretical methods for solving the nuclear Schrödinger equation. The main focus is on wave function methods using the vibrational self-consistent field (VSCF) as starting point, and includes vibrational configuration interaction (VCI), vibrational Møller-Plesset (VMP) theory, and vibrational coupled cluster (VCC) theory. The convergence of the different methods towards the full vibrational configuration interaction (FVCI) result is discussed. Finally, newly developed vibrational response methods for calculation of vibrational contributions to properties, energies, and transition probabilities are discussed. PMID:17551617

Christiansen, Ove

2007-03-23

69

Evaluating vehicular-induced bridge vibrations for energy harvesting applications  

NASA Astrophysics Data System (ADS)

Highway bridges are vital links in the transportation network in the United States. Identifying possible safety problems in the approximately 600,000 bridges across the country is generally accomplished through labor-intensive, visual inspections. Ongoing research sponsored by NIST seeks to improve inspection practices by providing real-time, continuous monitoring technology for steel bridges. A wireless sensor network with a service life of ten years that is powered by an integrated energy harvester is targeted. In order to achieve the target ten-year life for the monitoring system, novel approaches to energy harvesting for use in recharging batteries are investigated. Three main sources of energy are evaluated: (a) vibrational energy, (b) solar energy, and (c) wind energy. Assessing the energy produced from vehicular-induced vibrations and converted through electromagnetic induction is the focus of this paper. The goal of the study is to process acceleration data and analyze the vibrational response of steel bridges to moving truck loads. Through spectral analysis and harvester modeling, the feasibility of vibration-based energy harvesting for longterm monitoring can be assessed. The effects of bridge conditions, ambient temperature, truck traffic patterns, and harvester position on the power content of the vibrations are investigated. With sensor nodes continually recharged, the proposed real-time monitoring system will operate off the power grid, thus reducing life cycle costs and enhancing inspection practices for state DOTs. This paper will present the results of estimating the vibration energy of a steel bridge in Texas.

Reichenbach, Matthew; Fasl, Jeremiah; Samaras, Vasilis A.; Wood, Sharon; Helwig, Todd; Lindenberg, Richard

2012-03-01

70

Vibration energy harvesting for unmanned aerial vehicles  

NASA Astrophysics Data System (ADS)

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.

Anton, Steven R.; Inman, Daniel J.

2008-05-01

71

Vibration energy harvesting from random force and motion excitations  

NASA Astrophysics Data System (ADS)

A vibration energy harvester is typically composed of a spring-mass system with an electromagnetic or piezoelectric transducer connected in parallel with a spring. This configuration has been well studied and optimized for harmonic vibration sources. Recently, a dual-mass harvester, where two masses are connected in series by the energy transducer and a spring, has been proposed. The dual-mass vibration energy harvester is proved to be able to harvest more power and has a broader bandwidth than the single-mass configuration, when the parameters are optimized and the excitation is harmonic. In fact, some dual-mass vibration energy harvesters, such as regenerative vehicle suspensions and buildings with regenerative tuned mass dampers (TMDs), are subjected to random excitations. This paper is to investigate the dual-mass and single-mass vibration harvesters under random excitations using spectrum integration and the residue theorem. The output powers for these two types of vibration energy harvesters, when subjected to different random excitations, namely force, displacement, velocity and acceleration, are obtained analytically with closed-form expressions. It is also very interesting to find that the output power of the vibration energy harvesters under random excitations depends on only a few parameters in very simple and elegant forms. This paper also draws some important conclusions on regenerative vehicle suspensions and buildings with regenerative TMDs, which can be modeled as dual-mass vibration energy harvesters. It is found that, under white-noise random velocity excitation from road irregularity, the harvesting power from vehicle suspensions is proportional to the tire stiffness and road vertical excitation spectrum only. It is independent of the chassis mass, tire-wheel mass, suspension stiffness and damping coefficient. Under random wind force excitation, the power harvested from buildings with regenerative TMD will depends on the building mass only, not on the parameters of the TMD subsystem if the ratio of electrical and mechanical damping is constant.

Tang, Xiudong; Zuo, Lei

2012-07-01

72

Optimisation of electromagnetic vibrational energy harvesting device  

Microsoft Academic Search

This paper describes a model for an electromagnetic based, vibrational power generator and investigates the optimum conditions for load resistance, displacement and voltage in order to extract maximum electrical power from mechanical vibrations. Two macro-generators have been built and tested in order to verify the model.

C. R. Saha; T. O'Donnell; H. Loder

2006-01-01

73

Multiple cell configuration electromagnetic vibration energy harvester  

NASA Astrophysics Data System (ADS)

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.

Marin, Anthony; Bressers, Scott; Priya, Shashank

2011-07-01

74

A study of low level vibrations as a power source for wireless sensor nodes  

Microsoft Academic Search

Advances in low power VLSI design, along with the potentially low duty cycle of wireless sensor nodes open up the possibility of powering small wireless computing devices from scavenged ambient power. A broad review of potential power scavenging technologies and conventional energy sources is first presented. Low-level vibrations occurring in common household and office environments as a potential power source

Shad Roundy; Paul K. Wright; Jan M. Rabaey

2003-01-01

75

Design of nonlinear springs for wideband magnetic vibration energy harvester  

Microsoft Academic Search

This paper compares four nonlinear springs for the micro power generator (MPG) application which convert low level vibration energy into electrical power. The magnet-spring system decides the generator's resonant frequency, and this work proves that the spring's nonlinearity level influences the width of the operating frequency. The four different planar springs have the same outer\\/inner dimensions and the same linear

Linghe Sui; Xuhan Dai; Xiaolin Zhao; Peihong Wang; Hailin Zhou

2011-01-01

76

A micro electromagnetic generator for vibration energy harvesting  

Microsoft Academic Search

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

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

2007-01-01

77

Modeling and analysis of piezoelectric bimorph cantilever used for vibration energy harvesting  

Microsoft Academic Search

Piezoelectric vibration energy harvester has the advantage of high power density, and is promising in self-powered wireless sensor networks. The electromechanical coupling model has been formulated for cantilever bimorph vibration energy harvester under capacitive loads using piezoelectric theory and Euler-Bernoulli beam theory. Simulink simulation is used to obtain the steady-state characteristics, and the relationship between maximum output power, vibration frequency

Tao Yang; Yi Lin; Xianji Tan; Yuehui Feng

2010-01-01

78

Vibration characteristics about thermal variation of BFP in power plant  

NASA Astrophysics Data System (ADS)

BFPs(Boiler Feedwater Pump) in power plants are used for pumping high pressure and high temperature water. The pressure pulsation of high pressure pumps is the vibration caused by fluid forces. If the frequency of the exciting source is adjacent to one of the natural frequencies of the pump, it can cause high vibration by resonance. The natural vibration characteristics of pump depend on thermal variation. This paper examines vibration characteristics due to thermal variation experimentally and analytically.

Song, A. H.; Song, J. D.; Kim, H. S.; Jung, G. C.

2012-11-01

79

Vibration Monitoring of Power Distribution Poles  

SciTech Connect

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.

Clark Scott; Gail Heath; John Svoboda

2006-04-01

80

Vibrational structure theory: new vibrational wave function methods for calculation of anharmonic vibrational energies and vibrational contributions to molecular properties  

Microsoft Academic Search

A number of recently developed theoretical methods for the calculation of vibrational energies and wave functions are reviewed. Methods for constructing the appropriate quantum mechanical Hamilton operator are briefly described before reviewing a particular branch of theoretical methods for solving the nuclear Schrodinger equation. The main focus is on wave function methods using the vibrational self-consistent field (VSCF) as starting

Ove Christiansen

2007-01-01

81

Design and fabrication of a micro electromagnetic vibration energy harvester  

Microsoft Academic Search

This paper presents a new micro electromagnetic energy harvester that can convert transverse vibration energy to electrical power. It mainly consists of folded beams, a permanent magnet and copper planar coils. The calculated value of the natural frequency is 274 Hz and electromagnetic simulation shows that the magnetic flux density will decrease sharply with increasing space between the magnet and

Wang Peng; Li Wei; Che Lufeng

2011-01-01

82

The vibrational energy levels of ammonia  

NASA Astrophysics Data System (ADS)

A variational 6-dimensional method is used to determine the low lying vibrational energy levels of ammonia. The six internal coordinates were chosen to be appropriate for the symmetry and inversion motion of the molecule; they were the three NH bond lengths, r1,r2,r3, the unique angle beta which each bond makes with the trisector of them, and two (of the three) angles, theta2 and theta3, between the bonds when projected on to a plane perpendicular to the trisector. The Wilson G matrix was determined for these internal coordinates both by computer algebra and by hand. An appropriate Jacobian for the motion was determined and the full Hermitian kinetic energy operator was obtained using the Podolsky transformation. Expansion functions were in the usual product form. Special attention was given to the , theta2,theta3 expansion functions so that appropriate A1,A2 and E symmetry vibrational modes were obtained explicitly. Matrix elements of the kinetic energy operator were expressed in terms of one-dimensional integrals. Variational calculations have been performed with two six-dimensional surfaces: (i) that due to Martin, Lee and Taylor; and (ii) that due to Spirko and Kraemer. Although some of the vibrational levels for both surfaces are accurate, both have inadequacies: (a) because it is a Taylor expansion about an equilibrium, based on ab initio calculations, with no attention paid to planarity; and (b) because the non-inversion part of the surface was treated perturbatively in its derivation, and in fact some of the quartic displacement powers have negative coefficients. Therefore, neither surface gave good results overall, and there is a need for a refined 6 dimensional NH surface.

Handy, Nicholas C.

1999-02-01

83

Design and fabrication of a linear generator for vibration energy harvesting  

Microsoft Academic Search

Energy harvesting device which scavenges energy from the ambient and powers micro systems is receiving more and more attentions. In this paper, a linear generator for vibration energy harvesting is designed and fabricated. Volume of the generator core is 60.8 cm3, the mass of the device is 338 g, and the designed resonance frequency is 41 Hz. The vibration energy

Y. C. Wang; D. Shi; J. X. Shen; K. Wang; M. J. Jin

2010-01-01

84

Piezoelectric MEMS energy harvesting systems driven by harmonic and random vibrations  

Microsoft Academic Search

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

Lars-Cyril Blystad; Einar Halvorsen; Svein Husa

2010-01-01

85

Noise powered nonlinear energy harvesting  

NASA Astrophysics Data System (ADS)

The powering of small-scale electronic mobile devices has been in recent years the subject of a great number of research efforts aimed primarily at finding an alternative solution to standard batteries. The harvesting of kinetic energy present in the form of random vibrations (from non-equilibrium thermal noise up to machine vibrations) is an interesting option due to the almost universal presence of some kind of motion. Present working solutions for vibration energy harvesting are based on oscillating mechanical elements that convert kinetic energy via capacitive, inductive or piezoelectric methods. These oscillators are usually designed to be resonantly tuned to the ambient dominant frequency. However, in most cases the ambient random vibrations have their energy distributed over a wide spectrum of frequencies, especially at low frequency, and frequency tuning is not always possible due to geometrical/dynamical constraints. We present a new approach to the powering of small autonomous sensors based on vibration energy harvesting by the exploitation of nonlinear stochastic dynamics. Such a method is shown to outperform standard linear approaches based on the use of resonant oscillators and to overcome some of the most severe limitations of present strategies, like narrow bandwidth, need for continuous frequency tuning and low power efficiency. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.

Gammaitoni, Luca; Neri, Igor; Vocca, Helios

2011-04-01

86

Embedded fragmentation of vibrational energies.  

PubMed

Can the zero-point vibrational energies (ZPVE) of molecular clusters and crystals be evaluated as sums of ZPVE of constituent molecular fragments embedded in the cluster or crystal electrostatic environment? What is the appropriate unit of fragmentation: monomers or overlapping dimers? Can the contributions of acoustic phonons, which are fundamentally delocalized, be recuperated at satisfactory accuracy? These questions are answered by this study applying embedded monomer- and dimer-fragmentation methods to the harmonic ZPVE of hydrogen fluoride clusters, hydrogen fluoride crystal, and water clusters. Our findings are as follows: (1) ZPVE are reproduced accurately by both fragmentation schemes within a few percents of exact values or a few tenths of 1 kcal mol(-1) per molecule even for crystalline hydrogen fluoride, which has acoustic phonons. (2) Both the monomer- and dimer-based fragmentation are nearly equally accurate and useful for the absolute values of ZPVE, but the latter is more reliable than the former in reproducing the relative ZPVE of cluster isomers of the same size. (3) The embedding field is essential as it renders nonzero frequencies to the translational and rotational motions of monomers and dimers, accounting for the pseudo-translational and librational motions of the entire clusters or crystals. (4) Some of these low-frequency modes of fragments are calculated to have imaginary frequencies because the fragments are not at their equilibrium geometries, causing ZPVE to be complex. The imaginary part of ZPVE, which is nonphysical and is guaranteed to vanish in the exact limit of the many-body expansion, is nonetheless a useful estimate of errors in the real part. PMID:23145714

Sode, Olaseni; Hirata, So

2012-11-01

87

Equivalent damping and frequency change for linear and nonlinear hybrid vibrational energy harvesting systems  

Microsoft Academic Search

A unified approximation method is derived to illustrate the effect of electro-mechanical coupling on vibration-based energy harvesting systems caused by variations in damping ratio and excitation frequency of the mechanical subsystem. Vibrational energy harvesters are electro-mechanical systems that generate power from the ambient oscillations. Typically vibration-based energy harvesters employ a mechanical subsystem tuned to resonate with ambient oscillations. The piezoelectric

M. Amin Karami; Daniel J. Inman

2011-01-01

88

Design Feasibility of a Vortex Induced Vibration Based Hydro-Kinetic Energy Harvesting System  

Microsoft Academic Search

The vortex induced vibration (VIV) based power generating system discussed in this paper is a new concept in power generation from fluid flows in oceans, rivers and streams. The possibility of harnessing energy from the vibrations incurred in a bluff body due to the phenomenon known as VIV, in which motion is induced on a body facing an external flow

Varun Lobo; Nyuykighan Mainsah; Arindam Banerjee; Jonathan W. Kimball

2011-01-01

89

Harvesting vibration energy using nonlinear oscillations of an electromagnetic inductor  

NASA Astrophysics Data System (ADS)

Harvesting energy from ambient vibration is a promising method for providing a continuous source of power for wireless sensor nodes. However, traditional energy harvesters are often derived from resonant linear oscillators which are capable of providing sufficient output power only if the dominant frequency of input vibrations closely matches the device resonant frequency. The limited scope of such devices has sparked an interest in the use of nonlinear oscillators as mechanisms for broadband energy harvesting. In this study, we investigate the harvesting performance of an electromagnetic harvester sustaining oscillations through the phenomena of magnetic levitation. The nonlinear behavior of the device is effectively modeled by Duffing's equation, and direct numerical integration confirms the broadband frequency response of the nonlinear harvester. The nonlinear harvester's power generation capabilities are directly compared to a linear electromagnetic harvester with similar dynamic parameters. Experimental testing shows that the presence of both high and low amplitude solutions for the nonlinear energy harvester results in a tendency for the oscillator to remain in a low energy state for non-harmonic vibration inputs, unless continuous energy impulses are provided. We conclude by considering future applications and improvements for such nonlinear devices.

Lee, Christopher; Stamp, David; Kapania, Nitin R.; Mur-Miranda, José Oscar

2010-04-01

90

Vibration energy harvesting by magnetostrictive material  

Microsoft Academic Search

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

Lei Wang; F. G. Yuan

2008-01-01

91

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

PubMed

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

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

2010-04-01

92

Vibration energy scavenging via piezoelectric bimorphs of optimized shapes  

Microsoft Academic Search

Compact autonomous power sources are one of the prerequisites for the development of wireless sensor networks. In this work\\u000a vibration energy harvesting via piezoelectric resonant bimorph beams is studied. The available analytical approaches for the\\u000a modeling of the coupled electromechanical behavior are critically evaluated and compared with a finite element (FEM) numerical\\u000a model. The latter is applied to analyze thoroughly

Denis Benasciutti; Luciano Moro; Saša Zelenika; Eugenio Brusa

2010-01-01

93

Vibration stability of main circulation pipelines in nuclear power plants  

Microsoft Academic Search

Pipelines intended for different purposes, the most critical of which are main circulation pipelines (IVICP), are incorporated in power-equipment assemblies at nuclear power plants. The importance of investigation of the dynamic properties of MCP is determined by the high requirements set forth for their reliability. For the case in question, provision for vibration stability is required for both normal operation

K. V. Frolov; N. A. Makhutov; S. M. Kaplunov; V. A. Petushkov; L. V. Smirnov; V. F. Ovchinnikov

1985-01-01

94

Evaluation of coupled piezoelectric and electromagnetic technique for vibration energy harvesting  

Microsoft Academic Search

Vibration energy harvesting is an attractive technique for potential powering of wireless sensors and other low power micro devices. In order for the device to have maximum power output, it is necessary to match electrical and mechanical damping. In this work a coupled piezoelectric and electromagnetic energy harvesting device is evaluated for its efficiency and compared with optimized standalone piezoelectric

Vinod R. Challa; M. G. Prasad; Frank T. Fisher

2008-01-01

95

Vibrational energy transport in the presence of intrasite vibrational energy redistribution  

NASA Astrophysics Data System (ADS)

The mechanism of vibrational energy flow is studied in a regime where a diffusion equation is likely to break down, i.e., on length scales of a few chemical bonds and time scales of a few picoseconds. This situation occurs, for example, during photochemical reactions in protein environment. To that end, a toy model is introduced that on the one hand mimics the vibrational normal mode distribution of proteins, and on the other hand is small enough to numerically time propagate the system fully quantum mechanically. Comparing classical and quantum-mechanical results, the question is addressed to what extent the classical nature of the molecular dynamics simulations (which would be the only choice for the modeling of a real molecular system) affects the vibrational energy flow mechanism. Small differences are found which are due to the different ways classical and quantum mechanics distribute thermal energy over vibrational modes. In either case, a ballistic and a diffusive phase can be identified. For these small length and time scales, the latter is governed by intrasite vibrational energy redistribution, since vibrational energy does not necessarily thermalize completely within individual peptide units. Overall, the model suggests a picture that unifies many of the observations made recently in experiments.

Schade, Marco; Hamm, Peter

2009-07-01

96

DESIGN CONSIDERATIONS FOR MEMS-SCALE PIEZOELECTRIC MECHANICAL VIBRATION ENERGY HARVESTERS  

Microsoft Academic Search

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

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

2005-01-01

97

A vibration-based electromagnetic energy harvester system with highly efficient interface electronics  

Microsoft Academic Search

This paper presents a vibration-based electromagnetic (EM) energy harvester system utilizing novel and highly efficient interface electronics. The energy harvesting module up-converts the environmental low frequency vibrations for increased AC power output. The interface circuit employs a boot-strap technique to reduce the threshold voltage of the rectifiers further increasing the power conversion efficiency of the overall system. The complete system,

Arian Rahimi; Ozge Zorlu; Ali Muhtaroglu; Haluk Kulah

2011-01-01

98

Experimental comparison of macro and micro scale electromagnetic vibration powered generators  

Microsoft Academic Search

Electromagnetic vibration powered generators convert kinetic energy present in the application environment into electric energy.\\u000a Such generators may be used as an alternative power supply to batteries in wireless sensor systems enabling indefinite and\\u000a maintenance free operation. This paper presents an experimental comparison between macro and micro scale electromagnetic generators\\u000a based upon an identical magnetic circuit and explores the influence

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

2007-01-01

99

Vibrational energy dynamics of normal and deuterated liquid benzene.  

PubMed

Ultrafast Raman spectroscopy with infrared (IR) excitation is used to study vibrational energy dynamics of ambient temperature liquids benzene and benzene-d(6). After IR pumping of a CH-stretch or CD-stretch parent excitation, the redistribution of vibrational energy is probed with anti-Stokes Raman. Ten benzene or 12 benzene-d(6) vibrations out of 30 total have large enough cross sections to be observed. The pathways, quantum yields, and lifetimes for energy transfer among these vibrations are quantified. Using a CCl(4) molecular thermometer, we demonstrate an ultrafast Raman calorimetry method which allows measurement of the rate that benzene vibrational energy is dissipated into the bath. On the basis of energy conservation, we then determine the time-dependent dissipation of aggregate vibrational energy from the unobserved, "invisible" vibrations. During the approximately 1 ps IR excitation process, vibrational energy is coherently redistributed to several vibrational modes ("coherently" means the rate is faster than (T(2))(-1) of the pumped transition). This energy is then further redistributed in an incoherent intramolecular vibrational relaxation process with a 6 ps T(1) time constant. The subsequent dynamics involve energy transfer processes accompanied by vibrational energy dissipation to the bath. This vibrational cooling process has a half-life of 30 ps in benzene and 20 ps in benzene-d(6), and thermalization is complete in approximately 100 ps. The observed strongly Raman-active vibrations have about the same amount of energy per mode as the invisible vibrations. The invisible vibrational energy in benzene decays somewhat faster than the observed energy. These two decay rates are about the same in benzene-d(6). PMID:19186952

Seong, Nak-Hyun; Fang, Ying; Dlott, Dana D

2009-02-02

100

Vibrational power flow characteristics of circular plate structures with peripheral surface crack  

Microsoft Academic Search

In the view of structure-borne sound, the vibrational power flow of circular plates with peripheral surface crack is investigated. The peripheral surface crack is modelled as a joint of a local spring. The local stiffness of the rotational spring is deduced by using fracture mechanics and strain energy arguments. At high frequencies, the motion of bending wave and the input

T. Y Li; J. X. Liu; T. Zhang

2004-01-01

101

Vibrational energy levels of CH5+  

Microsoft Academic Search

We present a parallelized contracted basis-iterative method for calculating numerically exact vibrational energy levels of CH5+ (a 12-dimensional calculation). We use Radau polyspherical coordinates and basis functions that are products of eigenfunctions of bend and stretch Hamiltonians. The bend eigenfunctions are computed in a nondirect product basis with more than 200×106 functions and the stretch functions are computed in a

Xiao-Gang Wang; Tucker Carrington

2008-01-01

102

Fundamental issues in nonlinear wideband-vibration energy harvesting.  

PubMed

Mechanically nonlinear energy harvesters driven by broadband vibrations modeled as white noise are investigated. We derive an upper bound on output power versus load resistance and show that, subject to mild restrictions that we make precise, the upper-bound performance can be obtained by a linear harvester with appropriate stiffness. Despite this, nonlinear harvesters can have implementation-related advantages. Based on the Kramers equation, we numerically obtain the output power at weak coupling for a selection of phenomenological elastic potentials and discuss their merits. PMID:23679394

Halvorsen, Einar

2013-04-29

103

Compliant bistable mechanism for low frequency vibration energy harvester inspired by auditory hair bundle structures  

NASA Astrophysics Data System (ADS)

This paper presents a bio-inspired mechanism for the performance enhancement of piezoelectric power generation in vibration energy harvesting. A compliant bistable mechanism for vibration energy harvesting was explored based on the negative stiffness inspired by the auditory hair bundle structures. The proposed mechanism consists of a compliant, four-bar linkage system to mimic the hair bundle structure inside an inner ear. Our initial prototype energy harvester demonstrates that the compliant bistable mechanism featuring negative stiffness outperforms the conventional vibration energy harvester in the infra-low frequency range (1-10 Hz).

Kim, Gi-Woo; Kim, Jaehwan

2013-01-01

104

PIEZOELECTRIC MICRO POWER GENERATOR FOR ENERGY HARVESTING  

Microsoft Academic Search

A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), power generating device is developed. It is designed to resonate at specific vibrational frequencies from an ambient, vibrational energy source, thereby creating electrical energy via the piezoelectric effect. The energy harvesting device uses the piezoelectric d33 mode and is fabricated with three mask steps. Our cantilever device was designed to have a

R. Sood; Y. B. Jeon; S. G. Kim

105

Determination of Vibrational and Rotational Energy Levels of Water Vapor.  

National Technical Information Service (NTIS)

Water vapor absorbs energy in the infrared and invisible portions of the electromagnetic spectrum by two methods: Absorption of energy to increase its vibrational energy and/or absorption of energy to increase its rotational energy. Computer programs were...

D. L. Dobbins A. H. LaGrone

1967-01-01

106

Vibration Monitoring of Power Distribution Poles.  

National Technical Information Service (NTIS)

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 su...

C. Scott G. Heath J. Svoboda

2006-01-01

107

Production, Delivery and Application of Vibration Energy in Healthcare  

NASA Astrophysics Data System (ADS)

In Rehabilitation Medicine therapeutic application of vibration energy in specific clinical treatments and in sport rehabilitation is being affirmed more and more.Vibration exposure can have positive or negative effects on the human body depending on the features and time of the characterizing wave. The human body is constantly subjected to different kinds of vibrations, inducing bones and muscles to actively modify their structure and metabolism in order to fulfill the required functions. Like every other machine, the body supports only certain vibration energy levels over which long term impairments can be recognized. As shown in literature anyway, short periods of vibration exposure and specific frequency values can determine positive adjustments.

Abundo, Paolo; Trombetta, Chiara; Foti, Calogero; Rosato, Nicola

2011-02-01

108

Power absorbed during whole-body vertical vibration: Effects of sitting posture, backrest, and footrest  

Microsoft Academic Search

Previous studies have quantified the power absorbed in the seated human body during exposure to vibration but have not investigated the effects of body posture or the power absorbed at the back and the feet. This study investigated the effects of support for the feet and back and the magnitude of vibration on the power absorbed during whole-body vertical vibration.

Naser Nawayseh; Michael J. Griffin

2010-01-01

109

Vibration energy harvesting using a piezoelectric circular diaphragm array.  

PubMed

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

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

2012-09-01

110

A micro electromagnetic low level vibration energy harvester based on MEMS technology  

Microsoft Academic Search

This paper presents a micro electromagnetic energy harvester which can convert low level vibration energy to electrical power.\\u000a It mainly consists of an electroplated copper planar spring, a permanent magnet and a copper planar coil with high aspect\\u000a ratio. Mechanical simulation shows that the natural frequency of the magnet-spring system is 94.5 Hz. The resonant vibration\\u000a amplitude of the magnet is

Peihong Wang; Katsuhiko Tanaka; Susumu Sugiyama; Xuhan Dai; Xiaolin Zhao; Jingquan Liu

2009-01-01

111

Vibration energy harvesting from random force and motion excitations  

Microsoft Academic Search

A vibration energy harvester is typically composed of a spring–mass system with an electromagnetic or piezoelectric transducer connected in parallel with a spring. This configuration has been well studied and optimized for harmonic vibration sources. Recently, a dual-mass harvester, where two masses are connected in series by the energy transducer and a spring, has been proposed. The dual-mass vibration energy

Xiudong Tang; Lei Zuo

2012-01-01

112

Experimental study of a self-powered and sensing MR-damper-based vibration control system  

NASA Astrophysics Data System (ADS)

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.

Sapi?ski, Bogdan

2011-10-01

113

A micro electromagnetic generator for vibration energy harvesting  

NASA Astrophysics Data System (ADS)

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 a wound coil located within the moving magnetic field. Magnet size and coil properties were optimized, with the final device producing 46 µW in a resistive load of 4 k? from just 0.59 m s-2 acceleration levels at its resonant frequency of 52 Hz. A voltage of 428 mVrms was obtained from the generator with a 2300 turn coil which has proved sufficient for subsequent rectification and voltage step-up circuitry. The generator delivers 30% of the power supplied from the environment to useful electrical power in the load. This generator compares very favourably with other demonstrated examples in the literature, both in terms of normalized power density and efficiency.

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

2007-07-01

114

Low Head, Vortex Induced Vibrations River Energy Converter  

Microsoft Academic Search

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 âAeolian Tones.â For decades, engineers have attempted to prevent this type of vibration from damaging structures, such

Michael B. Bernitsas; Tad Dritz

2006-01-01

115

Novel piezoelectric bistable oscillator architecture for wideband vibration energy harvesting  

NASA Astrophysics Data System (ADS)

Bistable vibration energy harvesters are attracting more and more interest because of their capability to scavenge energy over a large frequency band. The bistable effect is usually based on magnetic interaction or buckled beams. This paper presents a novel architecture based on amplified piezoelectric structures. This buckled spring-mass architecture allows the energy of the dynamic mass to be converted into electrical energy in the piezoelectric materials as efficiently as possible. Modeling and design are performed and a normalized expression of the harvester behavior is given. Chirp and band-limited noise excitations are used to evaluate the proposed harvester’s performances. Simulation and experimental results are in good agreement. A method of using a spectrum plot for investigating the interwell motion is presented. The effect of the electric load impedance matching strategy is also studied. Results and comparisons with the literature show that the proposed device combines a large bandwidth and a high power density.

Liu, W. Q.; Badel, A.; Formosa, F.; Wu, Y. P.; Agbossou, A.

2013-03-01

116

Design and fabrication of a micro electromagnetic vibration energy harvester  

NASA Astrophysics Data System (ADS)

This paper presents a new micro electromagnetic energy harvester that can convert transverse vibration energy to electrical power. It mainly consists of folded beams, a permanent magnet and copper planar coils. The calculated value of the natural frequency is 274 Hz and electromagnetic simulation shows that the magnetic flux density will decrease sharply with increasing space between the magnet and coils. A prototype has been fabricated using MEMS micromachining technology. The testing results show that at the resonant frequency of 242 Hz, the prototype can generate 0.55 ?W of maximal output power with peak-peak voltage of 28 mV for 0.5g (g = 9.8 m/s2) external acceleration.

Peng, Wang; Wei, Li; Lufeng, Che

2011-10-01

117

Absorption of energy during vertical whole-body vibration exposure  

Microsoft Academic Search

Absorbed power (PAbs) during exposure to vertical whole-body vibration in a sitting posture was measured on 15 male and 15 female subjects. Different experimental conditions were applied, such as vibration level (0.5–1.4ms-2) and frequency (2–100Hz), body weight (54–93kg) and, relaxed and erected upper body positions. Results show that PAbs was strongly related to the frequency of the vibration, peaking within

Ronnie Lundström; Patrik Holmlund; Lennart Lindberg

1998-01-01

118

ABSORPTION OF ENERGY DURING WHOLE-BODY VIBRATION EXPOSURE  

Microsoft Academic Search

Absorbed power,PAbs, during exposure to vertical and horizontal whole-body vibration in sitting posture was measured using 15 male and 15 female subjects. Different experimental conditions were applied, such as vibration level (0·25–1·4 m\\/s2), frequency (1·13–80 Hz), body weight (54–93 kg), relaxed and erect upper body posture. Results show thatPAbswas strongly related to frequency of the vibration peaking, within the range

R. Lundstrom; P. Holmlund

1998-01-01

119

Resonance tracking and vibration stablilization for high power ultrasonic transducers.  

PubMed

Resonant frequency shift and electrical impedance variation are common phenomena in the application of high power ultrasonic transducers, e.g. in focused ultrasound surgery and in cutting. They result in low power efficiency and unstable vibration amplitude. To solve this problem, a driving and measurement system has been developed to track the resonance of high power transducers and to stabilise their vibration velocity. This has the ability to monitor the operating and performance parameters of the ultrasonic transducers in real time. The configuration of the system, with its control algorithm implemented in LabVIEW (National Instruments, Newbury, UK), ensures flexibility to suit different transducers and load conditions. In addition, with different programs, it can be utilised as a high power impedance analyser or an instantaneous electrical power measurement system for frequencies in the MHz range. The effectiveness of this system has been demonstrated in detailed studies. With it, high transducer performance at high power can be achieved and monitored in real time. PMID:23928264

Kuang, Y; Jin, Y; Cochran, S; Huang, Z

2013-07-11

120

Vibrational Population Depletion in Thermal Dissociation for Nonequilibrium Energy Distribution  

NASA Astrophysics Data System (ADS)

The generalized depletion equations, considering state-to-state kinetics of dissociating Nitrogen, are solved to predict the extent of vibrational depletion in the temperature range of 3000-10000 K. For the case of dissociation from the last vibrational quantum level, depletion of vibrational population is high. Vibration-translation (V-T) energy transfers make a major contribution to depletion whereas the effect of vibration-vibration (V-V) exchanges is minor. The dissociation rates predicted using the vibration-dissociation coupling model are significantly lower than the Park's rates and helps explain the restricted success of the Park's dissociation model in certain temperature ranges of hypersonic flow past a blunt body. Underprediction of shock-standoff distance of 17% by Park dissociation model for a Mach 11.18 flow past a blunt body is predicted well by the present model.

Josyula, Eswar; Bailey, William F.

2003-05-01

121

On the Effectiveness of Vibration-based Energy Harvesting  

Microsoft Academic Search

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

Shad Roundy

2005-01-01

122

A broadband vibration energy harvester using magnetoelectric transducer  

Microsoft Academic Search

In order for vibration energy harvesters to be efficiently applicable over a range of source frequencies, recently much research has been done to broaden the frequency range of the harvesters using piezoelectric, electromagnetic and electrostatic transductions, but little has been investigated in the harvesters using magnetoelectric transducers. In this paper, a new broadband vibration energy harvester using magneto electric transducer

Jin Yang; Yumei Wen; Ping Li; Xianzhi Dai; Ming Li

2010-01-01

123

Equivalent damping and frequency change for linear and nonlinear hybrid vibrational energy harvesting systems  

NASA Astrophysics Data System (ADS)

A unified approximation method is derived to illustrate the effect of electro-mechanical coupling on vibration-based energy harvesting systems caused by variations in damping ratio and excitation frequency of the mechanical subsystem. Vibrational energy harvesters are electro-mechanical systems that generate power from the ambient oscillations. Typically vibration-based energy harvesters employ a mechanical subsystem tuned to resonate with ambient oscillations. The piezoelectric or electromagnetic coupling mechanisms utilized in energy harvesters, transfers some energy from the mechanical subsystem and converts it to an electric energy. Recently the focus of energy harvesting community has shifted toward nonlinear energy harvesters that are less sensitive to the frequency of ambient vibrations. We consider the general class of hybrid energy harvesters that use both piezoelectric and electromagnetic energy harvesting mechanisms. Through using perturbation methods for low amplitude oscillations and numerical integration for large amplitude vibrations we establish a unified approximation method for linear, softly nonlinear, and bi-stable nonlinear energy harvesters. The method quantifies equivalent changes in damping and excitation frequency of the mechanical subsystem that resembles the backward coupling from energy harvesting. We investigate a novel nonlinear hybrid energy harvester as a case study of the proposed method. The approximation method is accurate, provides an intuitive explanation for backward coupling effects and in some cases reduces the computational efforts by an order of magnitude.

Karami, M. Amin; Inman, Daniel J.

2011-11-01

124

Adaptive piezoelectric energy harvesting circuit for wireless remote power supply  

Microsoft Academic Search

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

Geffrey K. Ottman; Heath F. Hofmann; Archin C. Bhatt; George A. Lesieutre

2002-01-01

125

A Review of Power Harvesting from Vibration Using Piezoelectric Materials  

Microsoft Academic Search

The process of acquiring the energy surround- ing a system and converting it into usable electrical energy is termed power harvesting. In the last few years, there has been a surge of research in the area of power harvesting. This increase in research has been brought on by the mod- ern advances in wireless technology and low-power electron- ics such

Henry A. Sodano; Daniel J. Inman

2004-01-01

126

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

NASA Astrophysics Data System (ADS)

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.

Yu, Aifang; Zhao, Yong; Jiang, Peng; Wang, Zhong Lin

2013-02-01

127

A digital controlled energy scavenger power converter  

Microsoft Academic Search

This work proposes an autonomous energy scavenger battery-free switching power supply. A piezoelectric transducer is used to get electric energy from a mechanical vibrating source. Piezoelectric device has been modelled by means of its equivalent electric resonant model. All system has been designed and then simulated at system level by means of SystemC-WMS environment.

R. d'Aparo; S. Orcioni; M. Conti

2009-01-01

128

A variable-capacitance vibration-to-electric energy harvester  

Microsoft Academic Search

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

Bernard C. Yen; Jeffrey H. Lang

2006-01-01

129

Vibrational energy transfer from highly excited anharmonic oscillators. Dependence on quantum state and interaction potential  

SciTech Connect

In order to elucidate the general features of vibrational deactivation of highly excited anharmonic oscillators, we present quasiclassical trajectory calculations on prototype collinear I/sub 2/ (v)-inert gas collision systems. The results for vibrational-translational energy transfer reveal several interesting trends as a function of initial vibrational quantum state, projectile mass, and projectile--oscillator interaction potential. (1) Vibrational deactivation is inefficient from all quantum levels and for all projectile masses. The average energy transfer per collision ..delta..E is strongly peaked at intermediate vibrational levels (vroughly-equal80) and is observed to be at most roughly-equal-k/sub b/T. Furthermore, when scaled to h..omega..(E), the ''local'' oscillator energy spacing, ..delta..E can be accurately represented by a simple power law in vibrational quantum number over a wide range of bound states. (2) Energy transfer is progressively less efficient from levels in the neighborhood of and approaching dissociation. (3) Vibrational energy loss for high levels of initial vibrational excitation (v>90) is rather insensitive to the nature of the interaction potential. Smooth exponential and hard-sphere interaction results differ by less than an order of magnitude. This observed insensitivity motivates the development of an analytic collision model, in which simple hard-sphere geometry and dynamics are used to calculate ..delta..E. The model results are in qualitatively good agreement with trajectory calculations and also indicate that nonuniform sampling of the anharmonic oscillator velocity and phase are responsible for decreased energy transfer efficiency from high vibrational states.

Nesbitt, D.J.; Hynes, J.T.

1982-06-15

130

Electroelastic modeling and experimental validations of piezoelectric energy harvesting from broadband random vibrations of cantilevered bimorphs  

NASA Astrophysics Data System (ADS)

We present electroelastic modeling, analytical and numerical solutions, and experimental validations of piezoelectric energy harvesting from broadband random vibrations. The modeling approach employed herein is based on a distributed-parameter electroelastic formulation to ensure that the effects of higher vibration modes are included, since broadband random vibrations, such as Gaussian white noise, might excite higher vibration modes. The goal is to predict the expected value of the power output and the mean-square shunted vibration response in terms of the given power spectral density (PSD) or time history of the random vibrational input. The analytical method is based on the PSD of random base excitation and distributed-parameter frequency response functions of the coupled voltage output and shunted vibration response. The first of the two numerical solution methods employs the Fourier series representation of the base acceleration history in an ordinary differential equation solver while the second method uses an Euler-Maruyama scheme to directly solve the resulting electroelastic stochastic differential equations. The analytical and numerical simulations are compared with several experiments for a brass-reinforced PZT-5H bimorph under different random excitation levels. The simulations exhibit very good agreement with the experimental measurements for a range of resistive electrical boundary conditions and input PSD levels. It is also shown that lightly damped higher vibration modes can alter the expected power curve under broadband random excitation. Therefore, the distributed-parameter modeling and solutions presented herein can be used as a more accurate alternative to the existing single-degree-of-freedom solutions for broadband random vibration energy harvesting.

Zhao, S.; Erturk, A.

2013-01-01

131

Active Monitoring Using Powerful Vibrators in Seismic Regions of Siberia  

NASA Astrophysics Data System (ADS)

Current methods of mid-term and short-term earthquake forecasts can not guarantee acceptable level of reliability for public announcement. Physical analysis of available precursors has serious problems when precursors contradict each other. However, Nature can't be contradictory - it is our ideas on deformation process in the Earth are contradictory because of lack of data and analysis. In this connection, we see growing interest in measurement and analysis of appearances of reflected waves from focal zones of imminent earthquakes. Methods of active monitoring can provide necessary data and analysis. Authors see the main source of vital information in quantitative and qualitative physical characteristics (of structure and properties of focal zones), which are measured in a process of active geophysical monitoring. We suggest that this approach enables forecasts of earthquakes with acceptable reliability. We give a review of seismicity and seismological observations in the Siberia territory, as well as of geophysical monitoring results obtained for the south of Baikal Lake, in the Altay-Sayan area in the Western Siberia. Special attention is given to the methods of active monitoring with powerful vibrators which have been actively developed in Siberian Branch of the Russian Academy of Sciences. There are data recorded for "near" and "far" fields from powerful 60-100 tons vibration sources which are obtained for the active seismic zones and for the zone of a large reservoir. Usage of powerful vibrators enables not just passive observations of stress built up, but management of average stress changes without affecting the background seismicity.

Seleznev, V.; Soloviev, V.

2007-12-01

132

Vibrations  

NASA Astrophysics Data System (ADS)

Low frequent vibrations may cause from disturbing up to damaging effects. There is no precise distinction between structure-borne sound and vibrations. However - depending on the frequency range - measurements and predictions require different techniques. In a wide frequency range, the generation, transmission and propagation of vibrations can be investigated similar to structure-borne sound (see Chap. 9).

Guggenberger, Johannes; Müller, Gerhard

133

Comparison of vibrational conductivity and radiative energy transfer methods  

Microsoft Academic Search

This paper is concerned with the comparison of two methods well suited for the prediction of the wideband response of built-up structures subjected to high-frequency vibrational excitation. The first method is sometimes called the vibrational conductivity method and the second one is rather known as the radiosity method in the field of acoustics, or the radiative energy transfer method. Both

A. Le Bot

2005-01-01

134

Characterization of Direct Piezoelectric Properties for Vibration Energy Harvesting  

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

135

Energy harvesting from underwater torsional vibrations of a patterned ionic polymer metal composite  

NASA Astrophysics Data System (ADS)

In this paper, we study underwater energy harvesting from torsional vibrations of an ionic polymer metal composite (IPMC) with patterned electrodes. We focus on harmonic base excitation of a centimeter-size IPMC, which is modeled as a slender beam with thin cross-section vibrating in a viscous fluid. Large-amplitude torsional vibrations are described using a complex hydrodynamic function, which accounts for added mass and nonlinear hydrodynamic damping from the surrounding fluid. A linear black box model is utilized to predict the IPMC electrical response as a function of the total twist angle. Model parameters are identified from in-air transient response, underwater steady-state vibrations, and electrical discharge experiments. The resulting electromechanical model allows for predicting energy harvesting from the IPMC as a function of the shunting resistance and the frequency and amplitude of the base excitation. Model results are validated against experimental findings that demonstrate power harvesting densities on the order of picowatts per millimeter cubed.

Cha, Youngsu; Shen, Linfeng; Porfiri, Maurizio

2013-05-01

136

Vacuum-packaged piezoelectric vibration energy harvesters: damping contributions and autonomy for a wireless sensor system  

NASA Astrophysics Data System (ADS)

This paper describes the characterization of thin-film MEMS vibration energy harvesters based on aluminum nitride as piezoelectric material. A record output power of 85 µW is measured. The parasitic-damping and the energy-harvesting performances of unpackaged and packaged devices are investigated. Vacuum and atmospheric pressure levels are considered for the packaged devices. When dealing with packaged devices, it is found that vacuum packaging is essential for maximizing the output power. Therefore, a wafer-scale vacuum package process is developed. The energy harvesters are used to power a small prototype (1 cm3 volume) of a wireless autonomous sensor system. The average power consumption of the whole system is less than 10 µW, and it is continuously provided by the vibration energy harvester.

Elfrink, R.; Renaud, M.; Kamel, T. M.; de Nooijer, C.; Jambunathan, M.; Goedbloed, M.; Hohlfeld, D.; Matova, S.; Pop, V.; Caballero, L.; van Schaijk, R.

2010-10-01

137

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

NASA Astrophysics Data System (ADS)

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

Miller, Lindsay Margaret

138

Collisional Quenching of Competitive Unimolecular Reactions. Vibrational Energy Transfer.  

National Technical Information Service (NTIS)

A method for the investigation of vibrational energy collisional transfer by competitive chemical reaction 'spectroscopy' is described, the theory given and application made to several chemically activated alkyl radicals. (Author)

C. W. Larson B. S. Rabinovitch

1969-01-01

139

A Multimode Relayed Piezoelectric Cantilever for Effective Vibration Energy Harvesting  

NASA Astrophysics Data System (ADS)

A piezoelectric cantilever with an eccentrically connected wire-mass relay is proposed for extensive energy harvesting from broadband vibration responses. The relay mass is chosen to be much greater than that of the cantilever. The vibration source is magnified by the relay as a bending-swinging-torsional excitation to drive the cantilever. Thus, multiple vibration modes of the cantilever are effectively employed to enhance energy harvesting. A prototype device was developed and characterized. The results show that the proposed structure can generate much more electricity over a broader bandwidth than conventional structures.

Li, Chuan; Hong, Daewoong; Kwon, Kwang-Ho; Jeong, Jaehwa

2013-05-01

140

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths  

PubMed Central

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio.

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y.

2010-01-01

141

Electromagnetic energy harvester with repulsively stacked multilayer magnets for low frequency vibrations  

NASA Astrophysics Data System (ADS)

This paper investigates the applicability of an electromagnetic generator with repulsively stacked magnets for harvesting energy from traffic-induced bridge vibrations. First, the governing equation for electro-mechanical coupling is presented. The magnetic field for repulsive pole arrangements is discussed and the model is validated from a magnet falling test. The detailed design, fabrication, and test results of a prototype device are presented in the paper. An experimental vibration shaker test is conducted to assess the performance of the energy harvester. Field test and numerical simulation at the 3rd Nongro Bridge in South Korea shows that the device can generate an average power of 0.12 mW from an input rms acceleration of 0.25 m s-2 at 4.10 Hz. With further frequency tuning and design improvement, an average power of 0.98 mW could be potentially harvested from the ambient vibration of the bridge.

Kwon, Soon-Duck; Park, Jinkyoo; Law, Kincho

2013-05-01

142

A two-mass cantilever beam model for vibration energy harvesting applications  

Microsoft Academic Search

While vibration energy harvesting has become a viable means to power wireless sensors, narrow bandwidth is still a hurdle to the practical use of the technology. For conventional piezoelectric or electromagnetic harvesters, having multiple proof masses mounted on a beam is one way to widen the effective bandwidth. This is because the addition of proof masses increases the number of

Qing Ou; XiaoQi Chen; Stefanie Gutschmidt; Alan Wood; Nigel Leigh

2010-01-01

143

Researche of the Earth's crust structure with powerful vibrational controlled sources  

NASA Astrophysics Data System (ADS)

The paper presents the results of experimental researches of the Earth's structure, geodynamic processes and physical phenomena carried out using vibrational sources in Institutes of Siberian Branch RAS. Powerful seismic vibrators are the large mechanical devises and are installed stationary on the vibroseismic test site near Novosibirsk (Russia). The vibro-DSS experiments were carried out on 100 km-long profile from Novosibirsk to Kuzbass region and on 620 km profile between Novosibirsk and Semipalatinsk test site. Specially developed field recording systems based on multichannel three component seismic arrays were used. It allowed us to observe the main crustal waves and waves refracted on Moho boundary. In the experiments on the 620 km profile the comparison of the seismic vibrator and special 100 tons calibration explosion wave fields was made. The possibility to detect small changes of wave velocities by vibroseismic methods were shown in the experiments on the setoff 356 and 430 km, where the relative variations of velocities of seismic waves about 10-5 - 10-6 caused by the Earth's tides deformations of the crust were defined. Some new physical phenomena connected with resonance mechanism of radiation of seismic energy in low-frequency range, the radiation of acoustic waves simultaneously with seismic waves and their interaction on long distances from vibrators were detected.

Alekseev, A.; Glinsky, B.; Kovalevsky, V.

2003-04-01

144

Development and experiments of a micro piezoelectric vibration energy storage device  

NASA Astrophysics Data System (ADS)

According to the difficult replacement and poor endurance of the battery for wireless sensor network nodes, a micro piezoelectric vibration energy storage device was developed in this paper. The electric generating performance of the device was then tested on a self-made experimental system. It is shown that the developed energy storage device can collect effectively surrounding vibrations. What is more, the inherent frequency of the device can be expanded by adjusting the span between its two piezoelectric vibrators. It is also found that the output of the device depends badly on the external load resistance. With the increasing of load resistance, the output voltage increases while the output power increases first then decreases. The output power has an optimal associated load resistance. The output power achieves a maximum value 115.2?W when the load resistance is 200k?. With the energy storing circuit, the output electric energy of the device can effectively act as a power source for any low power micro electron devices such as wireless sensor network nodes. It is believed that this work may be practical for energy supplying of the low power micro electron devices.

Chen, Guangzhu; Meng, Qingchun; Fu, Hailing; Bao, Jiusheng

2013-10-01

145

Operational Vibration Test An Alternative to NEBS Seismic Test for Telecom Power Equipment  

Microsoft Academic Search

Power systems for telecommunications are required to function at high level of reliability in harsh environmental conditions of vibrations, shocks and earthquakes. The main objective of this paper is to discuss the Operational Vibration Test as an alternative to the NEBS seismic test of power equipment at shelf level. The paper discusses the rationale for an alternative to NEBS seismic

Basil Serban

2006-01-01

146

Lower limbs power and stiffness after whole-body vibration.  

PubMed

The interest in whole-body vibration (WBV) for the enhancement of neuromuscular performance has received considerable attention. However, scientific evidence supporting the optimal prescription of WBV settings is lacking. This study investigated the acute effect of WBV combining high frequency/high peak-to-peak displacement (HH) or low frequency/low peak-to-peak displacement (LL) vs. sham intervention (SHAM) on lower limb muscle power and stiffness. A total of 223 volunteers were randomly assigned to either the HH, LL or SHAM group. Countermovement jump (CMJ) height, maximal and average power, maximal and average lower limbs stiffness obtained during a hopping test were recorded before and after the respective intervention. After the intervention, the HH group showed an increase of 4.64% in CMJ height (p<0.001) whereas the values of both the LL and SHAM groups did not change. In addition, maximal and average power of the lower limbs were significantly increased in all groups (p<0.001; 10.89% and 12.82%, respectively) while no effect on lower limbs stiffness was observed. Our data show that high frequency combined with high peak-to-peak displacement is the most optimal WBV setting for CMJ height enhancement. Further investigation should be undertaken to ascertain the effectiveness of WBV on lower limbs stiffness. PMID:23143701

Colson, S S; Petit, P-D

2012-11-09

147

Portable Power Scavenging from Structural Vibrations using Autonomous Self-Powered Device  

NASA Astrophysics Data System (ADS)

We propose a digital autonomous power scavenger with a microprocessor. The proposed system is a completely self-powered one that does not require any external power supply at all, and can thus be used portably at any site. Nevertheless, the digital approach enables the power scavenger to be programmable and thus, it affords some versatility with regard to control schemes. The proposed digitalautonomous system is much more advanced and progressive than clumsy analog-autonomous ones. It can be implemented in multiple-input multiple-output systems to scavenge electrical power from even complicated structural vibrations. We determined the value of the storage capacitance that gives the best balance between scavenging power and consumed power.

Makihara, Kanjuro; Takeuchi, Shinsuke; Shimose, Shigeru; Onoda, Junjiro

148

Quantum chemical calculation of intramolecular vibrational redistribution and vibrational energy transfer of water clusters  

NASA Astrophysics Data System (ADS)

In present letter the adiabatic approximation is applied to the intramolecular vibrational redistribution (IVR) of water clusters. The isotope, blocking and cluster-size effects are investigated. This letter also examines the assumption associated with the transition state theory applied to unimolecular reactions; that is, IVR is assumed to be completed before the reaction takes place. For this purpose, we choose to study (H2O)2H+ ? H2O + H3O+, and (H2O)2 ? 2H2O processes. In molecular clusters, the vibrational excitation energy transfer between different normal modes has been observed. This will also be investigated for the deuterated species of (HOD)2H+.

Niu, Y. L.; Pang, R.; Zhu, C. Y.; Hayashi, M.; Fujimura, Y.; Lin, S. H.; Shen, Y. R.

2013-10-01

149

Investigation of concurrent energy harvesting from ambient vibrations and wind using a single piezoelectric generator  

NASA Astrophysics Data System (ADS)

In this letter, a single vibratory energy harvester integrated with an airfoil is proposed to concurrently harness energy from ambient vibrations and wind. In terms of its transduction capabilities and power density, the integrated device is shown to have a superior performance under the combined loading when compared to utilizing two separate devices to harvest energy independently from the two available energy sources. Even below its flutter speed, the proposed device was able to provide 2.5 times the power obtained using two separate harvesters.

Bibo, A.; Daqaq, M. F.

2013-06-01

150

Apparent Mass and Absorbed Power during Exposure to Whole-Body Vibration and Repeated Shocks  

NASA Astrophysics Data System (ADS)

Exposure to mechanical shocks might pose a greater health risk than exposure to continuous vibration. Previous studies have investigated subjective responses, muscle activity or transmission of vibration to the spine or head during shock. If there is a difference between biomechanic responses of the seated body to shocks when compared to continuous vibration, then this may indicate a more, or less, hazardous vibration waveform. This paper presents measurements of apparent mass and absorbed power during exposure to random vibration, repeated shocks and combinations of shocks and random vibration. Eleven male and 13 female subjects were exposed to 15 vibration conditions generated using an electro-dynamic shaker. Subjects were exposed to five 20 s acceleration waveforms with nominally identical power spectra (random vibration, equally spaced shocks, unequally spaced shocks, random combined with equally spaced shocks, random combined with unequally spaced shocks) at each of 0.5, 1.0 and 1.5 m/s2r.m.s. The general shapes of the apparent mass or absorbed power curves were not affected by stimulus type, indicating that the biomechanical response of the body is fundamentally the same when exposed to shocks or random vibration. Two non-linear effects were observed: apparent mass resonance frequencies were slightly higher for exposure to shocks; apparent mass and absorbed power resonance frequencies decreased with increases in vibration magnitude for each stimulus type. It is concluded that the two non-linear mechanisms operate simultaneously: a stiffening effect during exposure to shocks and a softening effect as vibration magnitudes increase. Total absorbed powers were greatest for shock stimuli and least for random vibration.

Mansfield, N. J.; Holmlund, P.; Lundström, R.

2001-11-01

151

Probing Inhomogeneous Vibrational Reorganization Energy Barriers of Interfacial Electron Transfer  

SciTech Connect

We report an atomic force microscopy (AFM) and confocal Raman microscopy study on the interfacial electron transfer of a dye-sensitization system, alizarin adsorbed upon TiO2 nanoparticles. Resonance Raman and absorption spectral analyses revealed the distribution of the mode-specific vibrational reorganization energies encompassing different local sites (~250 nm spatial resolution), suggesting spatially inhomogeneous vibrational reorganization energy and different Franck-Condon coupling factors of the interfacial electron transfer. We found that the total vibrational reorganization energy was inhomogeneous from site to site, and specifically, the mode-specific analyses indicated that the energy distributions were inhomogeneous for bridging normal modes and homogeneous for nonbridging normal modes, especially for modes far away from the alizarin- TiO2 coupling hydroxyl modes. Our results demonstrate a significant step forward in characterizing site-specific inhomogeneous interfacial charge transfer dynamics.

Pan, Duohai; Hu, Dehong; Lu, H. Peter

2005-09-01

152

Spectroscopic probes of vibrationally excited molecules at chemically significant energies  

SciTech Connect

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.

Rizzo, T.R.

1992-03-01

153

Diversion of energy flow near crack tips of a vibrating plate using the structural intensity technique  

NASA Astrophysics Data System (ADS)

The structural intensity (SI) of a vibrating rectangular plate with a crack is computed using the finite element method. The overall behavior of power flow patterns of the cracked plate is investigated. The presence of the crack can be identified by the changes of the directions of SI vectors near the crack. The effects of orientation of the crack and crack length on the energy flow pattern are also investigated. The SI method is then used to explore the positioning of dampers in vibrating thin plates to divert the vibration energy flow away from crack tips. This approach is proposed as a temporary measure to prevent further propagation of the crack before repair of the crack can be done.

Lee, H. P.; Lim, S. P.; Khun, M. S.

2006-09-01

154

Screen printed PZT\\/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting  

Microsoft Academic Search

We present a MEMS-based PZT\\/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The most common piezoelectric energy harvesting devices utilize a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric material. It provides mechanical support but it also reduces the power output. Our device replaces the support with another layer

R. Xu; A. Lei; T. L. Christiansen; K. Hansen; M. Guizzetti; K. Birkelund; E. V. Thomsen; O. Hansen

2011-01-01

155

Development of a Cantilever Beam Generator Employing Vibration Energy Harvesting  

Microsoft Academic Search

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

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

156

Electrostatic vibration energy harvester with piezoelectric start-up generator  

Microsoft Academic Search

The search for compact autonomous devices has been increasing in the microelectronics industry. These devices have the capacity to generate their own energy in order to be charged. One of the ways of harvesting environmental energy for charging such devices is by using mechanical vibrations through the use of variable capacitor. Taking this principle a basis, this work presents a

Helder R. Florentino; Raimundo C. S. Freire; Alan V. S. Sa; Caio Florentino; Dimitri Galayko

2011-01-01

157

Mechanical analysis of piezoelectric vibration energy harvesting devices  

Microsoft Academic Search

A modal model of the dynamics behavior of a bimorph vibration energy scavenger aimed at wireless system networks is proposed and validated via FEM simulations. Experimental set-ups are developed with the aim of assessing the validity of the model. The set-ups are tested by measuring the performances of commercially available energy scavengers. Repetitive bending tests allow determining the equivalent bending

D. Blazevic; S. Zelenika; G. Gregov

2010-01-01

158

A vibration energy harvester using magnetostrictive\\/piezoelectric composite transducer  

Microsoft Academic Search

An energy harvester is presented to convert ambient mechanical vibration into electrical energy. The harvester consists of a cantilever beam, a magnetic circuit and a magnetostrictive\\/piezoelectric laminate magnetoelectric (ME) transducer. The magnetic circuit is arranged on the free end of the beam and produces a concentrated flux gradient. When the harvester is excited, the magnetic circuit moves relative to the

Xianzhi Dai; Yumei Wen; Ping Li; Jin Yang; Xiaofang Jiang

2009-01-01

159

Comparative modelling for vibration scavengers [MEMS energy scavengers  

Microsoft Academic Search

Conversion of the mechanical energy stored in vibrations into useful electrical energy is possible using three principles: electromagnetic, electrostatic and piezoelectric conversion. In order to build the appropriate device for a given application, a unifying model is proposed for these three principles. A methodology for comparison is presented based on this model in order to match the generator type to

T. Sterken; K. Baert; C. Van Hoof; R. Puers; G. Borghs; P. Fiorini

2004-01-01

160

MEMS-based thick film PZT vibrational energy harvester  

Microsoft Academic Search

We present a MEMS-based unimorph silicon\\/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The

A. Lei; R. Xu; A. Thyssen; A. C. Stoot; T. L. Christiansen; K. Hansen; R. Lou-Moller; E. V. Thomsen; K. Birkelund

2011-01-01

161

An Autoparametric, Electromagnetic Ambient Vibration Energy Harvester  

Microsoft Academic Search

Results are presented for the design and testing of an electromagnetic device to convert ambient mechanical vibration into electricity. The design of the device is based on an L-shaped beam structure which is tuned so that the first two (bending) natural frequencies have a (near) two-to-one ratio. This creates an internal resonance or autoparmetic condition that can result in a

Johannes Santen; Nitin R. Kapania; Christopher L. Lee

2011-01-01

162

Low Head, Vortex Induced Vibrations River Energy Converter  

SciTech Connect

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.

Bernitsas, Michael B.; Dritz, Tad

2006-06-30

163

Feasibility study of a 3D vibration-driven electromagnetic MEMS energy harvester with multiple vibration modes  

NASA Astrophysics Data System (ADS)

A novel electromagnetic energy harvester (EH) with multiple vibration modes has been developed and characterized using three-dimensional (3D) excitation at different frequencies. The device consists of a movable circular-mass patterned with three sets of double-layer aluminum (Al) coils, a circular-ring system incorporating a magnet and a supporting beam. The 3D dynamic behavior and performance analysis of the device shows that the first vibration mode of 1285 Hz is an out-of-plane motion, while the second and third modes of 1470 and 1550 Hz, respectively, are in-plane at angles of 60° (240°) and 150° (330°) to the horizontal (x-) axis. For an excitation acceleration of 1 g, the maximum power density achieved are 0.444, 0.242 and 0.125 µW cm-3 at vibration modes of I, II and III, respectively. The experimental results are in good agreement with the simulation and indicate a good potential in the development of a 3D EH device.

Liu, Huicong; Soon, Bo Woon; Wang, Nan; Tay, C. J.; Quan, Chenggen; Lee, Chengkuo

2012-12-01

164

Energy harvesting of radio frequency and vibration energy to enable wireless sensor monitoring of civil infrastructure  

NASA Astrophysics Data System (ADS)

To power distributed wireless sensor networks on bridges, traditional power cables or battery replacement are excessively expensive or infeasible. This project develops two power harvesting technologies. First, a novel parametric frequency-increased generator (PFIG) is developed. The fabricated PFIG harvests the non-periodic and unprecedentedly low frequency (DC to 30 Hz) and low acceleration (0.55-9.8 m/s2) mechanical energy available on bridges with an average power > 2 ?W. Prototype power conversion and storage electronics were designed and the harvester system was used to charge a capacitor from arbitrary bridge-like vibrations. Second, an RF scavenger operating at medium and shortwave frequencies has been designed and tested. Power scavenging at MHz frequencies allows for lower antenna directivities, reducing sensitivity to antenna positioning. Furthermore, ambient RF signals at these frequencies have higher power levels away from cities and residential areas compared to the UHF and SHF bands utilized for cellular communication systems. An RF power scavenger operating at 1 MHz along with power management and storage circuitry has been demonstrated. It powers a LED at a distance of 10 km from AM radio stations.

Galchev, Tzeno; McCullagh, James; Peterson, Rebecca L.; Najafi, Khalil; Mortazawi, Amir

2011-03-01

165

Vibrational analysis of power tools using a novel three-dimensional scanning vibrometer  

NASA Astrophysics Data System (ADS)

Scanning Laser Doppler Vibrometers (SLDV) are widely used in product development. Power tools as for example percussion drilling machines are known to be noisy and vibrating. It is state of the art to reduce the noise and vibration by finding the sources therefrom with LDV. Although these data give important information about the vibrational behavior, for a deeper understanding three dimensional vibration data is required. Therefore, for the first time measurements on power tools have been performed using a novel 3D SLDV, which simultaneously measures three components of the vibration vectors using three vibrometers. Power tools are observed under operating conditions close to reality, operated by a human. As the device under test performs movements in all directions, the three laser beams do not perfectly intersect. It is shown, that the introduced error can be neglected for low frequencies. Results are presented for a percussion drilling machine and a random orbit sander.

Bendel, Karl; Fischer, Martin; Schuessler, Matthias

2004-06-01

166

A multi-frequency sandwich type electromagnetic vibration energy harvester  

NASA Astrophysics Data System (ADS)

We proposed a multi-frequency sandwich type vibration energy harvester to widen the effective frequency range of vibration energy harvester. The harvester is composed of three resonant structures with different natural frequencies. The resonant structures are two cantilevers each with bi-layer coils and a plane spring with a magnet. The maximum peak-peak voltages of the three different frequencies are 172 mV, 104 mV, and 112 mV at the frequencies of 235 Hz, 330 Hz, and 430 Hz, respectively. The first maximum voltage is much higher than the others, because the coils in both cantilevers can produce voltages.

Chen, Jingdong; Chen, Di; Yuan, Tao; Chen, Xiang

2012-05-01

167

An Active Zero-Power Control with a Passive Technique for Vibration Isolation System  

Microsoft Academic Search

This paper presents a vibration isolation system by using an active zero-power control incorporated with a passive technique. A positive stiffness spring is connected to a negative spring of equal magnitude in series to generate a high stiffness for on-board generated direct disturbances. The system is capable of isolating floor vibration as well due to the use of lower positive

M. E. Hoque; T. Mizuno; M. Takasaki; Y. Ishino

2006-01-01

168

High level vibration test of nuclear power piping: Overall plan, input motion development and analysis  

Microsoft Academic Search

As part of cooperative agreements between the United States and Japan, tests have been performed on the seismic vibration table at the Tadotsu Engineering Laboratory of Nuclear Power Engineering Test Center (NUPEC) in Japan. The tests involved increasing the excitation up to the limits of the vibration table in order to induce inelastic response in a reactor coolant system piping

C. H. Hofmayer; J. R. Curreri; Y. J. Park; W. Y. Kato; J. F. Costello; H. T. Tang; S. Kawakami

1989-01-01

169

Research on the hydraulic turbine vertical vibration power flow in the head cover system  

NASA Astrophysics Data System (ADS)

On the basis of the prior models about the vertical vibration of the hydraulic vibration source, this research introduced a sub-system—head cover. Head cover is one of the main paths when vibration is transferred from the water vibration source to the stable structure. This essay aims to analyze the hydraulic turbine vertical vibration power flow in the head cover system. The research is based on the power flow theory and the probability perturbation method; meanwhile, it considered on the reciprocal coupling effect of the water machine parts and power house structure, etc. Therefore, the results of can clearly provide the random power flow of the vibration transfer path system, which including the head cover system, in frequency domain by given of some uncertain factors in one project. In conclusions, the research provide an overall analysis on the hydropower station vertical vibration transfer path; and it suggest some simplified and efficient solutions in the analysis on the vibration path with some random parameters.

Zhi, B. P.; Ma, Z. Y.

2012-11-01

170

Development of Vibration Condition Monitoring System Applying Optical Sensors for Generator Winding Integrity of Power Utilities  

NASA Astrophysics Data System (ADS)

This paper describes the vibration condition monitoring diagnosis system developed for stator and rotor winding integrity assessment of 100MW class gas turbine generator in combined-cycle thermal power plant. High reliability of windings is one of the most essential prerequisite for generators of power utilities. Assessing the condition of stator winding insulation systems requires objective information from condition monitoring system. In-service monitoring is essential if a power plant is following a condition-based maintenance strategy. Generator damages are caused by the high vibration and the power system instability by secondary impacts of an unannounced plant stop and the life of the generator is decreased. The mechanical vibration in generator is induced by both mechanical and magnetic forces. The vibration condition monitoring system is required for the improved savings of operation and maintenance cost in terms of reliability in power plant.

Kim, Yeon Whan; Ho, Ju-Young; Lee, Young Shin

171

Modeling and analysis of a micromachined piezoelectric energy harvester stimulated by ambient random vibrations  

NASA Astrophysics Data System (ADS)

Piezoelectric energy microgenerators are devices that continuously generate electricity when they are subjected to varying mechanical strain due to vibrations. They can generate electrical power up to 100 ?W which can be used to drive various sensing and actuating MEMS devices. Today, piezoelectric energy harvesters are considered autonomous and reliable energy sources to actuate low power microdevices such as wireless sensor networks, indoor-outdoor monitoring, facility management and biomedical applications. The advantages of piezoelectric energy harvesters including high power density, moderate output power and CMOS compatible fabrication in particular with aluminum nitride (AlN) have fuelled and motivated researchers to develop MEMS based energy harvesters. Recently, the use of AlN as a piezoelectric material has increased fabrication compatibility, enabling the realization of smart integrated systems on chip which include sensors, actuators and energy storage. Piezoelectric MEMS energy microgenerator is used to capture and transform the available ambient mechanical vibrations into usable electric energy via resonant coupling in the thin film piezoelectric material. Analysis and modeling of piezoelectric energy generators are very important aspects for improved performance. Aluminum nitride as the piezoelectric material is sandwiched between two electrodes. The device design includes a silicon cantilever on which the AlN film is deposited and which features a seismic mass at the end of the cantilever. Beam theory and lumped modeling with circuit elements are applied for modeling and analysis of the device operation at various acceleration values. The model shows good agreement with the experimental findings, thus giving confidence in the model.

Alamin Dow, Ali B.; Al-Rubaye, Hasan A.; Koo, David; Schneider, Michael; Bittner, Achim; Schmid, Ulrich; Kherani, Nazir P.

2011-05-01

172

Energy Measurement of Bubble Bursting Based on Vibration Signals  

NASA Astrophysics Data System (ADS)

An experimental study of the energy of bubble bursting at the surface of a high-viscosity liquid on a cantilever beam is reported. The sudden bursting event of a bubble at the liquid surface can cause a vibration of the cantilever beam besides the acoustic wave and jet wave. The peaks of the vibration signal from the beam slightly lag the peaks of the acoustic signal, and the energy transferred to the vibration is larger than that transferred to the acoustic wave. The amplitude of the jet wave depends on the thickness of the liquid film and the size of the bubble. The results of the investigation can be used to understand the dynamic characteristics of bubble bursting.

Liu, Xiao-Bo; Zhang, Jian-Run; Li, Pu; Le, Van-Quynh

2012-06-01

173

Electronic energy transfer: vibrational control and nonlinear wavepacket interferometry  

NASA Astrophysics Data System (ADS)

The time-development of photoexcitations in molecular aggregates exhibits specific dynamics of electronic states and vibrational wavefunction. We discuss the dynamical formation of entanglement between electronic and vibrational degrees of freedom in molecular aggregates with theory of electronic energy transfer and the method of vibronic 2D wavepackets [ J. Chem. Phys. 118, 46 (2003); quant-ph/0412219]. The vibronic dynamics is also described by applying Jaynes-Cummings model to the electronic energy transfer [J. Chem. Phys. 120, 11209 (2004); math-ph/0403023]. Following the ultrafast excitation of donor [ J. Phys. Chem 99, 2568 (1995); chem-ph/9411004] the population of acceptor rises by small portions per each vibrational period, oscillates force and back between donor and acceptor with later damping and partial revivals of this oscillation. The transfer rate gets larger as donor wavepacket approaches the acceptor equilibrium configuration, which is possible at specific energy differences of donor and acceptor and at maximal amount of the vibrational motion along the line that links donor and acceptor equilibria positions. The four-pulse phase-locked nonlinear wavepacket 2D interferograms reflect the shape of the relevant 2D vibronic wavepackets and have maxima at longer delay between excitation pulses for dimers with equal donor-acceptor energy difference compare to dimers with activationless energy configuration [Cina, Fleming, J. Phys. Chem. A. 108, 11196 (2004)].

Prezhdo, Oleg V.; Cina, Jeffrey A.; Kilin, Dmitri S.

2005-04-01

174

Development of MEMS-based Piezoelectric Vibration Energy Harvesters  

Microsoft Academic Search

\\u000a In this paper, the development of a first generation MEMS-based piezoelectric energy harvester capable of converting ambient\\u000a vibrations into storable electrical energy is presented. The energy harvester is designed using a validated analytical electromechanical\\u000a Lumped Element Model (LEM) that accurately predicts the behavior of a piezoelectric composite structure. The MEMS device is\\u000a fabricated using standard sol gel PZT and conventional

175

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

NASA Astrophysics Data System (ADS)

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.

Moro, L.; Benasciutti, D.

2010-11-01

176

On Mechanical Modeling of Cantilevered Piezoelectric Vibration Energy Harvesters  

Microsoft Academic Search

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

A. Erturk; D. J. Inman

2008-01-01

177

High resolution electron energy loss studies of surface vibrations  

SciTech Connect

New experimental studies of surface vibrational properties of materials with high-resolution electron energy loss spectroscopy (EELS) are reported. This document summarizes recent progress on surface phonon dispersion measurements on copper (001); silver (001) and (111); oxygen adsorption on ultrathin films of cobalt and nickel; aluminum on silicon (111); and copper-oxide based superconductors.

Kesmodel, L.L.

1992-05-01

178

Vibration energy harvesting using highly (001)-oriented Pb(Zr,Ti)O3 thin film  

NASA Astrophysics Data System (ADS)

Energy conversion from mechanical vibration into electric power was investigated using the piezoelectric Pb(Zr,Ti)O3 lead zirconate titanate (PZT) thin film with highly (001)-orientation. The piezoelectric d31 constant was found to be as large as -150 pC/N. The generated electric voltage under vibration acceleration of 45 m/s2 at 2450 Hz for the PZT/Si cantilever exceeded 2 V and the operation of light emitting diode lighting was demonstrated. The average output power of 100 ?W was obtained at the impedance-matched load resistance of 2.2 k?. The generated power density of 50 ?W/mm3 was much larger than that of conventional piezoelectric harvesters.

Harigai, Takakiyo; Adachi, Hideaki; Fujii, Eiji

2010-05-01

179

Renewable Energy Powered Bicycle  

Microsoft Academic Search

The goal of the project is to convert a standard twenty inch bicycle wheel into a retrofit hydraulic powered wheel. The wheel will harness energy in a self-contained storage unit (the high-pressure accumulator) which will drive a power train including various gears, a motor and a pump.\\u000aThe bike wheel converts braking energy from deceleration to fluid energy at high

Huiming Gong

2012-01-01

180

Vibration of L-shaped plates under a deterministic force or moment excitation: a case of statistical energy analysis application  

Microsoft Academic Search

Analytical and closed form solutions are presented in this paper for the vibration response of an L-shaped plate under a point force or a moment excitation. Inter-relationships between wave components of the source and the receiving plates are clearly defined. Explicit expressions are given for the quadratic quantities such as input power, energy flow and kinetic energy distributions of the

Tian Ran Lin; Andy C. C. Tan; Cheng Yan; Douglas Hargreaves

2011-01-01

181

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

PubMed

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

Radwin, R G; Armstrong, T J; Vanbergeijk, E

1990-09-01

182

The role of coupling strength in the performance of electrodynamic vibrational energy harvesters  

NASA Astrophysics Data System (ADS)

This paper explores the role of a key dimensionless design parameter, denoted ‘coupling strength’, that governs the power generation performance of electrodynamic (electromagnetic) vibrational energy harvesters. The importance of coupling strength—and not just the electrodynamic transduction coefficient—on the output power and efficiency of the vibration energy harvesting device is presented analytically using a standard electromechanical model and validated using experimental results. It is shown that, up to a certain point, increasing the coupling strength of the harvester substantially increases the output power, resulting in improved electrodynamic coupling effectiveness and device efficiency. An electrodynamic harvester is designed such that the coupling strength can be varied through manual adjustments without altering the input vibration characteristics. Experimentally, the harvester is tested at a constant input acceleration amplitude of 0.74 m s-2 at the device natural frequency of 28.1 Hz. By increasing the coupling strength of the device from 2.6 to 49.2, the output power increased from 0.64 to 1.06 mW. The corresponding electrodynamic coupling effectiveness increased from 0.53 to 0.92, and the mechanical-to-electrical device efficiency increased from 21% to 45.3%.

Challa, Vinod R.; Cheng, Shuo; Arnold, David P.

2013-02-01

183

A Vibration-Based PMN-PT Energy Harvester  

Microsoft Academic Search

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

Alex Mathers; Kee S. Moon; Jingang Yi

2009-01-01

184

Electron energy transfer rates for vibrational excitation of N2.  

SciTech Connect

The calculation of the electron density and electron temperature distribution in our ionosphere (from {approx} 150-600 km) requires a knowledge of the various heating, cooling and energy flow processes that occur. The energy transfer from electrons to neutral gases and ions is one of the dominant electron cooling processes in the ionosphere, and the role of vibrationally excited N2 in this is particularly significant.

Campbell, L. (Laurence); Cartwright, D. C. (David C.); Tuebner, P. J. O.; Brunger, M. J. (Michael J.)

2003-01-01

185

Experimental study of a hybrid vibration energy harvesting mechanism  

Microsoft Academic Search

In this paper, a novel hybrid vibration energy harvesting mechanism integrating effects of both electromagnetic induction and piezoelectricity have been presented. The structure topologically consists of three modules. The first is electromagnetic induction module comprising of two pairs of bulk NdFeB permanent magnet and one hand-wound enameled copper coil. The second is piezoelectric energy harvesting module utilizing impact mode. The

Song-mao Chen; Jun-hui Hu

2011-01-01

186

Copper foil-type vibration-based electromagnetic energy harvester  

Microsoft Academic Search

This paper presents the modeling, simulation, fabrication and experimental results of a vibration-based electromagnetic power generator (EMPG). A novel, low-cost, one-mask technique is used to fabricate the planar coils and the planar spring. This fabrication technique can provide an alternative for processes such as lithographie galvanoformung abformung (LIGA) or SU-8 molding and MEMS electroplating. Commercially available copper foils of 20

Farid Khan; Farrokh Sassani; Boris Stoeber

2010-01-01

187

An energy-preserving description of nonlinear beam vibrations in modal coordinates  

NASA Astrophysics Data System (ADS)

Conserved quantities are identified in the equations describing large-amplitude free vibrations of beams projected onto their linear normal modes. This is achieved by writing the geometrically exact equations of motion in their intrinsic, or Hamiltonian, form before the modal transformation. For nonlinear free vibrations about a zero-force equilibrium, it is shown that the finite-dimensional equations of motion in modal coordinates are energy preserving, even though they only approximate the total energy of the infinite-dimensional system. For beams with constant follower forces, energy-like conserved quantities are also obtained in the finite-dimensional equations of motion via Casimir functions. The duality between space and time variables in the intrinsic description is finally carried over to the definition of a conserved quantity in space, which is identified as the local cross-sectional power. Numerical examples are used to illustrate the main results.

Wynn, Andrew; Wang, Yinan; Palacios, Rafael; Goulart, Paul J.

2013-10-01

188

Role of solvent on vibrational energy transfer in solution  

NASA Astrophysics Data System (ADS)

ADVANCES in pulsed laser technology have made available ultra-short, tunable light pulses which permit the study of ultrafast energy-transfer processes within and between molecules. This information is essential for an understanding of chemical reactions on a molecular scale. Here we report results of a time-resolved study of the transfer of vibrational energy after excitation of the C-H stretch vibration in chloroform (CHCl3) and bromoform (CHBr3) dissolved in polar (deuterated acetone, CD3COCD3) and non-polar (carbon tetrachloride, CCl4) solvents. We obtain quantitative information on the influence of the solvent on the rates of ultrafast intra- and intermolecular vibrational energy transfer. We find that the dipole-dipole interaction between an excited molecule and polar solvent molecules can lead to a strong acceleration of intramolecular energy-transfer processes. These results provide some insight into the way in which the rate of energy transfer and chemical reactivity are influenced by the polarity of the molecular environment.

Bakker, H. J.; Planken, P. C. M.; Lagendijk, A.

1990-10-01

189

Coherent vibrational energy transfer along a peptide helix.  

PubMed

To measure the transport of vibrational energy along a peptide helix, Hamm and co-workers [J. Phys. Chem. B 112, 9091 (2008)] performed time-resolved vibrational experiments, which showed that the energy transport rate increases by at least a factor of 4, when a localized C=O mode of the peptide instead of an attached chromophore is excited. This finding raises the question if coherent excitonic energy transfer between the C=O modes may be of importance for the overall energy transport in peptides. With this idea in mind, nonequilibrium molecular dynamics simulations as well as quantum-classical calculations are performed, which qualitatively reproduce the experimental findings. Moreover, the latter model (an exciton Hamiltonian whose matrix elements depend on the instantaneous positions of the peptide and solvent atoms) indeed exhibits the signatures of coherent quantum energy transport, at least within the first few picoseconds and at low temperatures. The origin of the observed decoherence, the absence of vibrational self-trapping, and the possibility of quantum interference between various transport paths are discussed in some detail. PMID:21456687

Kobus, Maja; Nguyen, Phuong H; Stock, Gerhard

2011-03-28

190

Experimental Study of Energy Absorption Properties of Granular Materials Under Low Frequency Vibrations  

NASA Astrophysics Data System (ADS)

The low frequency vibration energy absorption properties of granular materials have been investigated on an Invert Torsion Pendulum (ITP). The energy absorption rate of granular material changes nonlinearly with amplitude under low frequency vibration. The frequency of ITP system increases a little with granular materials in the holding cup. The vibration frequency of ITP system does not change with time.

Hu, Mao-Bin; Kong, Xiang-Zhao; Wu, Qing-Song; Zhu, Zhen-Gang

191

Design, Modeling, and Performance Measurements of a Broadband Vibration Energy Harvester Using a Magnetoelectric Transducer  

Microsoft Academic Search

This article presents a new broadband vibration energy harvester using a magnetoelectric (ME) transducer. In order for vibration energy harvesters to be efficiently applicable over a range of vibration frequencies, many techniques have recently been investigated to broaden the frequency ranges of the harvesters using piezoelectric, electromagnetic, or electrostatic transductions, but few have been studied in the harvesters using ME

Jin Yang; Yumei Wen; Ping Li; Xianzhi Dai

2011-01-01

192

Mass Energy Equivalence Formula Must Include Rotational and Vibrational Kinetuic Energies as Well As Potential Energies  

NASA Astrophysics Data System (ADS)

Originally Einstein proposed the the mass-energy equivalence at low speeds as E=mc^2 + 1/2 mv^2. However, a mass may also be rotating and vibrating as well as moving linearly. Although small, these kinetic energies must be included in formulating a true mathematical statement of the mass-energy equivalence. Also, gravitational, electromagneic and magnetic potential energies must be included in the mass-energy equivalence mathematical statement. While the kinetic energy factors may differ in each physical situation such as types of vibrations and rotations, the basic equation for the mass- energy equivalence is therefore E = m0c^2 + 1/2m0v^2 + 1/2I2?+ 1/2kx^2 + WG+ WE+ WM.

Brekke, Stewart

2010-11-01

193

Acute Effects of Whole-Body Vibration on Muscle Activity, Strength, and Power  

Microsoft Academic Search

Cormie, P., R.S. Deane, N.T. Triplett, and J.M. McBride. Acute effects of whole-body vibration on muscle activ- ity, strength, and power. J. Strength Cond. Res. 20(2):257-261. 2006.—The purpose of this study was to investigate the effects of a single bout of whole-body vibration on isometric squat (IS) and countermovement jump (CMJ) performance. Nine moder- ately resistance-trained men were tested for

Prue Cormie; Russell S. Deane; N. Travis Triplett; Jeffrey M. McBride

2006-01-01

194

A review of vibration problems in power station boiler feed pumps  

NASA Astrophysics Data System (ADS)

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.

France, David

1994-01-01

195

A 3DOF modular vibration isolation system using zero-power magnetic suspension with adjustable negative stiffness  

Microsoft Academic Search

This paper presents a 3-DOF vibration isolation system combining three vibration isolation modules. Each vibration isolation module is constructed by connecting a positive stiffness spring in series with a negative stiffness spring. The positive and negative spring is realized by an active controlled magnetic suspension. In the previous system, conventional zero-power control system has been used to generate negative stiffness,

M. E. Hoque; T. Mizuno; Y. Ishino; M. Takasaki

2010-01-01

196

Calculations of vibration-rotation energy levels of HD+  

Microsoft Academic Search

An artificial-channels scattering method [M. Shapiro and G. G. Balint-Kurti, J. Chem. Phys. 71, 1461 (1979)] is used with a transformed Hamiltonian [R. E. Moss and I. A. Sadler, Molec. Phys. 66, 591 (1989)] to calculate the energies of vibration-rotation levels for the ground electronic state of HD+. All nonadiabatic effects, except for part of the coupling of rotational and

G. G. Balint-Kurti; R. E. Moss; I. A. Sadler; M. Shapiro

1990-01-01

197

Nonresonant and resonant mode-specific intermolecular vibrational energy transfers in electrolyte aqueous solutions.  

PubMed

The donor/acceptor energy mismatch and vibrational coupling strength dependences of interionic vibrational energy transfer kinetics in electrolyte aqueous solutions were investigated with ultrafast multiple-dimensional vibrational spectroscopy. An analytical equation derived from the Fermi's Golden rule that correlates molecular structural parameters and vibrational energy transfer kinetics was found to be able to describe the intermolecular mode specific vibrational energy transfer. Under the assumption of the dipole-dipole approximation, the distance between anions in the aqueous solutions was obtained from the vibrational energy transfer measurements, confirmed with measurements on the corresponding crystalline samples. The result demonstrates that the mode-specific vibrational energy transfer method holds promise as an angstrom molecular ruler. PMID:21916443

Bian, Hongtao; Chen, Hailong; Li, Jiebo; Wen, Xiewen; Zheng, Junrong

2011-09-30

198

EFFECT OF MAGNITUDE OF VERTICAL WHOLE-BODY VIBRATION ON ABSORBED POWER FOR THE SEATED HUMAN BODY  

Microsoft Academic Search

The power absorbed by 12 male subjects during exposure to vertical whole-body vibration at six magnitudes of random vibration (0·25, 0·5, 1·0, 1·5, 2·0 and 2·5 ms?2r.m.s.) has been measured in the laboratory. All subjects showed greatest absorbed power at about 5 Hz, but the frequency of this peak in the absorbed power reduced with increasing vibration magnitude. The total

N. J. Mansfield; M. J. Griffin

1998-01-01

199

Transmission of vibration energy to different parts of the human hand-arm system.  

PubMed

The aim of this study was to investigate the transmission of vibration energy to three selected points along the hand and arm (knuckle, wrist and elbow) and to compare the energy transmission for two different kinds of vibration exposures, i.e. random and sinusoidal. The transmission of vibration energy was estimated for ten subjects during exposure to random (within the frequency range 20-5000 Hz) and sinusoidal vibration at eight different frequencies (20, 40, 80, 160, 320, 630, 1250 and 1600 Hz). The random and sinusoidal vibrations had a frequency-weighted acceleration level of 3 m/s2. The energy transmission was determined by simultaneous vibration measurements at the vibrating handle and in the hand-arm system. The measurements were made with a laser-velocity transducer and specially constructed equipment. The grip and feed forces were held constant at 40 N. The results show that the energy transmission decreases with the distance from the source. The results also show that the energy transmission is dependent on the frequency for the random vibration exposures. No clear frequency dependence of the energy transmission could be found for the sinusoidal vibrations. It may also be concluded that there are differences in the energy transmission due to types of exposure, sinusoidal vibration showing higher transmission of energy to the hand-arm system than random vibration, especially at higher frequencies. PMID:9298403

Sörensson, A; Burström, L

1997-01-01

200

Rotation-vibration energies for the HO2 molecule  

NASA Astrophysics Data System (ADS)

Walch and Duchovic [J. Chem. Phys.94, 7068-7075 (1991)] recently carried out complete active space SCF and externally contracted configuration interaction (CASSCF-CCI) ab initio calculations to determine the potential energy surface of the X~2A'' electronic ground state of the HO2 radical over a wide range of nuclear geometries. By fitting to 192 of their ab initio points, covering energies up to 12 000 cm-1 above the energy of the equilibrium geometry, we determine an analytical expression for the potential energy function in terms of the bond lengths and bond angle. The fitted potential gives Re(OH) = 0.971 Å (0.971 Å), Re(OO) = 1.330 Å (1.331 Å), and ?e = 104.3° (104.3°), where the experimental values are in parentheses. We use the analytical ab initio potential function with the Morse Oscillator Rigid Bender Internal Dynamics (MORBID) Hamiltonian [J. Mol. Spectrosc.128, 478-501 (1988); J. Chem. Soc. Faraday Trans. 284, 1315-1340 (1988)] in a calculation of vibrational energies. We adjust four parameters in the potential in a fitting to experimental vibrational energies, and then calculate the energies of N = 0 and 1 levels up to 8000 cm-1 above the zero-point level using the MORBID approach. We have also used the Discrete Variable Representation and Distributed Gaussian Basis (DVR-DGB) approach to calculate the energies of the N = 0 levels for comparison. The aim of this work is to obtain a zeroth-order set of vibrational states (with their associated rotational constants) in the region between 7000 and 8000 cm-1 where there will be interaction with the low-lying A~2A' state for which T0 = 7029 cm-1.

Bunker, P. R.; Hamilton, I. P.; Jensen, Per

1992-09-01

201

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

Microsoft Academic Search

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

Naser Nawayseh; Michael J. Griffin

2012-01-01

202

Harvestable vibrational energy from an avian source: theoretical predictions vs. measured values  

NASA Astrophysics Data System (ADS)

For many reasons, it would be beneficial to have the capability of powering a wildlife tag over the course of multiple migratory seasons. Such an energy harvesting system would allow for more data collection and eliminate the need to replace depleted batteries. In this work, we investigate energy harvesting on birds and focus on vibrational energy harvesting. We review a method of predicting the amount of power that can be safely harvested from the birds such that the effect on their longterm survivability is not compromised. After showing that the safely harvestable power is significant in comparison to the circuits used in avian tags, we present testing results for the flight accelerations of two species of birds. Using these measured values, we then design harvesters that matched the flight acceleration frequency and are sufficiently low mass to be carried by the birds.

Shafer, Michael W.; MacCurdy, Robert; Garcia, Ephrahim; Winkler, David

2012-03-01

203

On the Definitions of Characteristic Molecular Vibrations and the Distribution of Vibrational Energy.  

National Technical Information Service (NTIS)

The relationship of the definition of a completely characteristic normal vibration to the stationary properties of force and compliance constants is examined. The corresponding properties of various distributions of potential, kinetic, and total vibration...

A. J. P. Alix D. E. Freeman A. Mueller

1974-01-01

204

Separation of time variant vibration sources by short time coherent output power  

NASA Astrophysics Data System (ADS)

This effort describes the use of time variant coherence causality based analysis to separate the effects of nonstationary time variant vibration excitation sources. A time variant coherence function using the Short Time Fourier Transform (STFT) is first discussed. The concept of a time variant coherent output power for source separation of systems with time variant transfer functions is developed. A parametric study is performed to examine the coherent output power separation capabilities with respect to the data processing parameters. The study guided the selection of the time-frequency processing parameters judged to provide a suitable compromise between the time event localization and output amplitude source separation. The time variant coherent output power is then applied to separate the effects of the two possible excitation sources on the prototype vibration isolation floor. The application was a subscale prototype isolation floor for a proposed vibration sensitive equipment site adjacent to a busy freight rail line. The moving train created time variant transmission paths. As there was a direct line of sight between the prototype floor and the rail line there was an airborne acoustic excitation path in addition to a ground path. The short time coherent output power was applied to separate prototype isolation floor vibration into respective components related to the two candidate sources. The analysis and discussion of the results focuses upon the interpretation and issues in such a complicated realistic environment. Ultimately the application was successful providing an explanation as to why the observed vibration isolation was degraded at higher frequencies.

Trethewey, Martin W.

2011-02-01

205

Bimolecular reactions and energy-transfer processes of highly vibrationally excited molecules related to energetic materials  

NASA Astrophysics Data System (ADS)

Infrared Multiphoton Absorption (IRMPA) was used to produce populations of vibrationally excited 1,1,2-trifluoroethane, which were characterized by optoacoustic measurements of absorbed laser power and collision free decomposition yields. The measurements were accurately fitted with a Master Equation that included Quack's theory of IRMPA, three RKM unimolecular reaction channels, and collisional energy transfer. The highly constrained adjustable parameters indicate that the optical coupling matrix elements are dramatically reduced in magnitude near reaction threshold energies where vibrational anharmonicity becomes important. Observed infrared fluorescence from the excited molecules is in excellent agreement with Master Equation predictions and it was used to monitor collisional deactivation of the excited molecules. The energy transfer exhibits a weak vibrational energy on bimolecular reactions of 1,1 2-trifluorethane (TFE), but no such effects have yet been observed. A Monte Carlo method is described for efficient multidimensional integration not restricted to hyper-dimensional rectangles, but applied to more complicated domains. When known, the boundaries of a arbitrary integration region can be used to define the sampling domain, resulting in sampling with unit efficiency.

Barker, John R.

1987-12-01

206

Intermolecular vibrational energy exchange directly probed with ultrafast two dimensional infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Ultrafast two dimensional infrared (2D IR) spectroscopy has been applied to probe the intermolecular vibrational energy exchange between two model molecules, benzonitrile and acetonitrile-d3. The vibrational energy exchange between these two molecules is manifested through the growth of cross peaks in their 2D IR spectra. In experiments, their nitrile groups (CN) are not involved in the energy exchange but serve as reporters of the process. Our experiments demonstrate that intermolecular vibrational energy transfer can be directly probed with the 2D IR method. Results also show that the mode specific energy transfer can be important in intermolecular vibrational energy transfers.

Bian, Hongtao; Zhao, Wei; Zheng, Junrong

2009-09-01

207

Comparison of vibrational conductivity and radiative energy transfer methods  

NASA Astrophysics Data System (ADS)

This paper is concerned with the comparison of two methods well suited for the prediction of the wideband response of built-up structures subjected to high-frequency vibrational excitation. The first method is sometimes called the vibrational conductivity method and the second one is rather known as the radiosity method in the field of acoustics, or the radiative energy transfer method. Both are based on quite similar physical assumptions i.e. uncorrelated sources, mean response and high-frequency excitation. Both are based on analogies with some equations encountered in the field of heat transfer. However these models do not lead to similar results. This paper compares the two methods. Some numerical simulations on a pair of plates joined along one edge are provided to illustrate the discussion.

Le Bot, A.

2005-05-01

208

Vibrational Energy Distribution Analysis (VEDA): Scopes and limitations  

NASA Astrophysics Data System (ADS)

The principle of operations of the VEDA program written by the author for Potential Energy Distribution (PED) analysis of theoretical vibrational spectra is described. Nowadays, the PED analysis is indispensible tool in serious analysis of the vibrational spectra. To perform the PED analysis it is necessary to define 3N-6 linearly independent local mode coordinates. Already for 20-atomic molecules it is a difficult task. The VEDA program reads the input data automatically from the Gaussian program output files. Then, VEDA automatically proposes an introductory set of local mode coordinates. Next, the more adequate coordinates are proposed by the program and optimized to obtain maximal elements of each column (internal coordinate) of the PED matrix (the EPM parameter). The possibility for an automatic optimization of PED contributions is a unique feature of the VEDA program absent in any other programs performing PED analysis.

Jamróz, Micha? H.

2013-10-01

209

Vibrationally averaged isotropic dispersion energy coefficients of the parahydrogen dimer  

NASA Astrophysics Data System (ADS)

We compare the sum-over-states and coupled cluster linear response formalisms for the determination of imaginary-frequency polarizabilities of H2. Using both approaches, we compute isotropic dispersion energy coefficients Cn (n = 6, 8, 10) for H2-H2 molecular pairs over a wide range of H2 bond lengths. We present vibrationally averaged dispersion energy coefficients for H2-H2, H2-D2, and D2-D2 molecular pairs and examine the coefficients' convergence with respect to basis set.

Lillestolen, Timothy C.; Hinde, Robert J.

2012-05-01

210

Fabrication and characterization of MEMS-based PZT/PZT bimorph thick film vibration energy harvesters  

NASA Astrophysics Data System (ADS)

We describe the fabrication and characterization of a significantly improved version of a microelectromechanical system-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass; the harvester is fabricated in a fully monolithic process. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical support materials since only Pb(ZrxTi1-x)O3 (PZT) is strained; as a result, the effective system coupling coefficient is increased, and thus a potential for significantly higher output power is released. In addition, when the two layers are connected in series, the output voltage is increased, and as a result the relative power loss in the necessary rectifying circuit is reduced. We describe an improved process scheme for the energy harvester, which resulted in a robust fabrication process with a record high fabrication yield of 98%. The robust fabrication process allowed a high pressure treatment of the screen printed PZT thick films prior to sintering. The high pressure treatment improved the PZT thick film performance and increased the harvester power output to 37.1 ?W at 1 g root mean square acceleration. We also characterize the harvester performance when only one of the PZT layers is used while the other is left open or short circuit.

Xu, R.; Lei, A.; Dahl-Petersen, C.; Hansen, K.; Guizzetti, M.; Birkelund, K.; Thomsen, E. V.; Hansen, O.

2012-09-01

211

Comparison of Subjective Responses to Vibration and Shock with Standard Analysis Methods and Absorbed Power  

NASA Astrophysics Data System (ADS)

Evaluation of human exposure whole-body vibration (WBV) and shock can be carried out in a variety of ways. The most commonly used standards for predicting discomfort from WBV are BS6841 (1987) and ISO2631-1 (1997) which offer different frequency weightings (Wband Wk) and three methods of assessment: vibration dose value (VDV), estimated VDV (eVDV) and maximum transient vibration value (MTVV). Previous studies have also used DRI and absorbed power for assessments of shock and WBV. This paper reports a laboratory study in which 24 human subjects were exposed to 15 vertical vibration stimuli comprising of random vibration, repeated shocks and combinations of random vibration and shocks at 0.5, 1.0 and 1.5 m/s2r.m.s. Subjects rated the discomfort from the vibration on a numerical scale after each exposure. Acquired acceleration signals were analyzed using VDV, r.m.s. and MTVV for unweighted, Wb, Wkand DRI weighted signals. Acceleration and force were combined to give a measure of absorbed power. Subjective responses were correlated to vibration magnitude for the 13 analysis types. VDV was the best standard method of assessment; MTVV was the worst. Wband Wkfrequency weightings showed slightly greater correlations between vibration magnitude and discomfort than DRI weighted or unweighted signals. For VDV, there were no significant differences between the correlations obtained using any frequency weighting. For assessment of all stimuli types together, absorbed power gave higher correlations with subjective discomfort than acceleration-based methods. It is concluded that the methods described in ISO2631-1 should be clarified and simplified. Due to the difficulty in measuring absorbed power in the field, methods proposed in BS6841 are recommended as the most appropriate for assessment of discomfort from continuous vibration or repeated shocks.

Mansfield, N. J.; Holmlund, P.; Lundström, R.

2000-02-01

212

Power and energy  

Microsoft Academic Search

Any lingering doubt that the world's electric power industries are driven primarily by politics was probably dispelled last year. Global reverberations of the crisis in the Persian Gulf offered the most striking confirmation, causing wide fluctuations in oil prices and prompting utilities all over the world to reconsider energy technologies not taken seriously since the last oil crisis. In Europe,

Zorpette

1991-01-01

213

Dielectric Electroactive Polymer energy harvesting system forward path design for different vibration input patterns  

Microsoft Academic Search

Energy harvesting is a new emerging technology which is used to gathering ambient energy from surroundings. In this paper, we propose a new application idea that to harvest ambient vibration energy and store it into a Li-ion rechargeable battery by using Dielectric Electroactive Polymer (DEAP) generator. For proposed energy harvesting prototyping system, according to two different vibration input patterns in

Wei Wang; Peiwen He; Setiawan Soekamtoputra; Feng Ge; Ken Choi; Gyungsoo Kang; SooHyun Kim

2011-01-01

214

Optimal design of a vibration-based energy harvester using magnetostrictive material (MsM)  

NASA Astrophysics Data System (ADS)

In this study, an optimal vibration-based energy harvesting system using magnetostrictive material (MsM) was designed and tested to enable the powering of a wireless sensor. In particular, the conversion efficiency, converting from magnetic to electric energy, is approximately modeled from the magnetic field induced by the beam vibration. A number of factors that affect the output power such as the number of MsM layers, coil design and load matching are analyzed and explored in the design optimization. From the measurements, the open-circuit voltage can reach 1.5 V when the MsM cantilever beam operates at the second natural frequency 324 Hz. The AC output power is 970 µW, giving a power density of 279 µW cm - 3. The attempt to use electrical reactive components (either inductors or capacitors) to resonate the system at any frequency has also been analyzed and tested experimentally. The results showed that this approach is not feasible to optimize the power. Since the MsM device has low output voltage characteristics, a full-wave quadrupler has been designed to boost the rectified output voltage. To deliver the maximum output power to the load, a complex conjugate impedance matching between the load and the MsM device is implemented using a discontinuous conduction mode (DCM) buck-boost converter. The DC output power after the voltage quadrupler reaches 705 µW and the corresponding power density is 202 µW cm - 3. The output power delivered to a lithium rechargeable battery is around 630 µW, independent of the load resistance.

Hu, J.; Xu, F.; Huang, A. Q.; Yuan, F. G.

2011-01-01

215

Energy harvesting circuit for sensor system power supply  

NASA Astrophysics Data System (ADS)

The paper presents two example approaches to energy harvesting. Mechanical energy harvesting system is based on vibrational minigenerator. Basic relations of its analytical model are given in order to obtain an idea about the operating conditions. Electromagnetic harvesting system is based on tuned resonant nano-structure. Its concepts allows impedance matching in order to operate in given frequency range. The matching properties are verified by means of numerical finite element analysis. For power management of vibration energy harvesting system several circuit design concepts are presented together with simulation results and basic properties comparison.

Fiala, P.; Drexler, P.

2011-05-01

216

A wideband, frequency up-converting bounded vibration energy harvester for a low-frequency environment  

NASA Astrophysics Data System (ADS)

This paper presents a bounded vibration energy harvester to effectively harvest energy from a wide band of low-frequency environmental vibrations ranging from 10 to 18 Hz. Rigid mechanical stoppers are used to confine the seismic mass movement within the elastic limits of the spring. Experimental results show the effectiveness of the proposed technique in increasing the efficiency of the energy harvester. When excited at a frequency of 10 Hz with a peak acceleration of 1 g, the harvester responds at a higher frequency of 20 Hz and gives a peak power of 2.68 mW and a peak to peak voltage of 2.62 V across a load of 220 ?. The average power density of 65.74 ?W cm-3 obtained at 10 Hz 1 g excitation monotonically increases with frequency up to 341.86 ?W cm-3 at 18 Hz. An analytical model describing the nonlinear dynamics of the proposed harvester is also presented. A simple technique to estimate the energy losses during impact and thereof a method to incorporate these losses in the model are suggested. The presented model not only predicts the experimental voltage waveform and frequency response of the device with good similarity but also predicts the RMS voltage from the harvester for the whole range of operating frequencies with an RMS error of 5.2%.

Ashraf, K.; Khir, M. H. Md; Dennis, J. O.; Baharudin, Z.

2013-02-01

217

Molecular vibrations: Iterative solution with energy selected bases  

NASA Astrophysics Data System (ADS)

An efficient and accurate quantum method for the calculations of many large amplitude vibrational states of polyatomic molecules is proposed and tested on three triatomic molecules; H2O, SO2, and HCN. In this approach we define zero-order reduced dimensional Hamiltonians ?k using minimum energy reduced dimensional potentials. The eigenfunctions and eigenvalues of ?k, ?n(k), and ?n(k), are used to form an energy selected basis (ESB) for the full system including all the product functions ?k?n(k) for which ??(k)<=Ecut. We show that ESB can be used efficiently in an iterative solution of the Schrödinger equation by the transformation between the ESB and the direct product quadrature grid. Application of the ESB of one-dimensional basis functions is shown to be very efficient for vibrational states of H2O and SO2 up to 30 000 and 23 000 cm-1, respectively. A combined two-dimensional/one-dimensional basis is used very effectively for HCN above the isomerization energy to HNC. The present approach is shown to be substantially more efficient than either the direct product discrete variable representation (DVR) bases or compact bases from the DVR with the sequential diagonalization/truncation method.

Lee, Hee-Seung; Light, John C.

2003-02-01

218

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

NASA Astrophysics Data System (ADS)

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.

Sapi?ski, Bogdan; Krupa, Stanis?aw

2013-04-01

219

Fault diagnosis of auxiliaries in power plants based on wireless sensor networks with vibration transducer  

Microsoft Academic Search

There are many auxiliaries in a power plant (APP) with high rotating speed, such as pumps, fans, motors and so on. To warrant their safe and reliable operation, their state of vibration has to be monitored. But because of their scattered locations, the traditional way of online monitoring with shielded cable connections is costly and work expensive and the precision,

Tongying Li; Minrui Fei

2010-01-01

220

Separation of time variant vibration sources by short time coherent output power  

Microsoft Academic Search

This effort describes the use of time variant coherence causality based analysis to separate the effects of nonstationary time variant vibration excitation sources. A time variant coherence function using the Short Time Fourier Transform (STFT) is first discussed. The concept of a time variant coherent output power for source separation of systems with time variant transfer functions is developed. A

Martin W. Trethewey

2011-01-01

221

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

222

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

NASA Astrophysics Data System (ADS)

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.

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

2009-04-01

223

Vibration amplitude and induced temperature limitation of high power air-borne ultrasonic transducers.  

PubMed

The acoustic impedances of matching layers, their internal loss and vibration amplitude are the most important and influential parameters in the performance of high power airborne ultrasonic transducers. In this paper, the optimum acoustic impedances of the transducer matching layers were determined by using a genetic algorithm, the powerful tool for optimizating domain. The analytical results showed that the vibration amplitude increases significantly for low acoustic impedance matching layers. This enhancement is maximum and approximately 200 times higher for the last matching layer where it has the same interface with the air than the vibration amplitude of the source, lead zirconate titanate-pizo electric while transferring the 1kW is desirable. This large amplitude increases both mechanical failure and temperature of the matching layers due to the internal loss of the matching layers. It has analytically shown that the temperature in last matching layer with having the maximum vibration amplitude is high enough to melt or burn the matching layers. To verify suggested approach, the effect of the amplitude of vibration on the induced temperature has been investigated experimentally. The experimental results displayed good agreement with the theoretical predictions. PMID:23664304

Saffar, Saber; Abdullah, Amir

2013-04-19

224

Energy-dependent characteristics of collisinal vibration-energy exchange in vapors of polyatomic molcules  

SciTech Connect

CO{sub 2} laser-induced delayed fluorescence was used to study the collisional vibration-energy exchange between the polyatomic molecules in gases. The efficiency of collisional exchange, the mean amount of energy transfer in one collision, as well as their correlation with the vibration energy and with the size of excited molecule were determined for diacetyl, acetophenone, benzophenone, and anthraquinone molecules form the experimentally observed pressure dependences of the decay rates and fluorescence intensities. It was shown that the mean amount of energy transfer per collision decreases with the molecular size and increases as E{sup m}, with m>2, with increasing the vibration energy. 25 refs., 4 figs., 1 tab.

Zalesskaya, G.A.; Yakovlev, D.L. [Institute of Molecular and Atomic Physics, Minsk (Belarus)

1995-02-01

225

Low power energy harvesting and storage techniques from ambient human powered energy sources  

NASA Astrophysics Data System (ADS)

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.

Yildiz, Faruk

226

Determination of stepsize parameters for intermolecular vibrational energy transfer  

SciTech Connect

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.

Tardy, D.C.

1992-03-01

227

Vibration-vibration and vibration-translation energy transfer in H2-H2 collisions: A critical test of experiment with full-dimensional quantum dynamics  

NASA Astrophysics Data System (ADS)

Quantum scattering calculations of vibration-vibration (VV) and vibration-translation (VT) energy transfer for non-reactive H2-H2 collisions on a full-dimensional potential energy surface are reported for energies ranging from the ultracold to the thermal regime. The efficiency of VV and VT transfer is known to strongly correlate with the energy gap between the initial and final states. In H2(v = 1, j = 0) + H2(v = 0, j = 1) collisions, the inelastic cross section at low energies is dominated by a VV process leading to H2(v = 0, j = 0) + H2(v = 1, j = 1) products. At energies above the opening of the v = 1, j = 2 rotational channel, pure rotational excitation of the para-H2 molecule leading to the formation of H2(v = 1, j = 2) + H2(v = 0, j = 1) dominates the inelastic cross section. For vibrationally excited H2 in the v = 2 vibrational level colliding with H2(v = 0), the efficiency of both VV and VT process is examined. It is found that the VV process leading to the formation of 2H2(v = 1) molecules dominates over the VT process leading to H2(v = 1) + H2(v = 0) products, consistent with available experimental data, but in contrast to earlier semiclassical results. Overall, VV processes are found to be more efficient than VT processes, for both distinguishable and indistinguishable H2-H2 collisions confirming room temperature measurements for v = 1 and v = 2.

dos Santos, S. Fonseca; Balakrishnan, N.; Forrey, R. C.; Stancil, P. C.

2013-03-01

228

Adhesion energy characterization of monolayer graphene by vibrational spectroscopy  

NASA Astrophysics Data System (ADS)

As at nano/micro-scale van der Waals forces often dominate various other types of forces, the accurate adhesion characterization of graphene (Gr) is essential to its processing, manipulation, and possible integration into integrated circuits and other nano/micro-scale devices. Since 2010, the reported (experimental) adhesion energy of monolayer Gr with silicon dioxide (SiO2) has increased from 151 +/- 28 mJ/m2 to 450 +/- 20 mJ/m2. Here, we report a set of adhesion energy values for Gr monolayers on a SiO2 substrate by adopting a unique vibrational spectroscopy approach based on the motion of adhesive microparticles on a vibrating substrate. The reported results indicate that the work-of-adhesion measurements of monolayer Gr on SiO2 could be highly scattered and its mean value is determined as WSiO2-Gr = 1160.26 mJ/m2, which is the highest value reported to date. Unlike the reported existing methods, the current non-contact and non-destructive spectral technique requires no knowledge of the mechanical properties of Gr. Based on the reported data, with the current approach, it is also demonstrated that the weak adhesive interactions between a polystyrene latex microparticle and SiO2 substrate across the monolayer Gr can be detected as well.

Vahdat, Armin Saeedi; Cetinkaya, Cetin

2013-10-01

229

DSMC Modeling of Vibration-Vibration Energy Transfer Between Diatomic Molecules  

SciTech Connect

Larsen-Borgnakke model, widely used in the DSMC method to simulate rotation-translation and vibration-translation exchanges in molecular collisions, is applied for the first time to resonant exchange between the vibrational modes of diatomic molecules (VV exchange). The validation of the model is performed through comparisons with experimental data on VV exchange in nitrogen.

Bondar, Ye. A.; Ivanov, M. S. [Khristianovich Institute of Theoretical and Applied Mechanics, Institutskaya 4/1, Novosibirsk 630090 (Russian Federation); Gimelshein, S. F. [University of Southern California, Los Angeles, CA 90089 (United States)

2008-12-31

230

Design, fabrication and characterization of a micromachined piezoelectric energy harvester excited by ambient vibrations  

NASA Astrophysics Data System (ADS)

This research work presents the design, fabrication and characterization of micromachined piezoelectric energy harvester stimulated by ambient random vibrations utilizing AlN as a piezoelectric material. The device design consists of a silicon cantilever beam on which AlN is sandwiched between two electrodes and a silicon seismic mass at the end of the cantilever beam. The generated electric power of the devices was experimentally measured at various acceleration levels. A maximum power of 34 ?W was obtained at an acceleration value of 2g for the device which measures 5.6 x 5.6 mm2. Various unpackaged devices were tested and assessed in terms of the generated power and resonant frequency at various acceleration values.

Alamin Dow, Ali B.; Bittner, Achim; Schmid, Ulrich; Kherani, Nazir P.

2013-05-01

231

Piezoelectric energy harvesting from vortex-induced vibrations of circular cylinder  

NASA Astrophysics Data System (ADS)

The concept of harvesting energy from a circular cylinder undergoing vortex-induced vibrations is investigated. The energy is harvested by attaching a piezoelectric transducer to the transverse degree of freedom. Numerical simulations are performed for Reynolds numbers (Re) in the range 96?Re?118, which covers the pre-synchronization, synchronization, and post-synchronization regimes. Load resistances (R) in the range 500??R?5M? are considered. The results show that the load resistance has a significant effect on the oscillation amplitude, lift coefficient, voltage output, and harvested power. The results also show that the synchronization region widens when the load resistance increases. It is also found that there is an optimum value of the load resistance for which the harvested power is maximum. This optimum value does not correspond to the case of largest oscillations, which points to the need for a coupled analysis as performed here.

Mehmood, A.; Abdelkefi, A.; Hajj, M. R.; Nayfeh, A. H.; Akhtar, I.; Nuhait, A. O.

2013-09-01

232

Fabrication of a vibration-driven electromagnetic energy harvester with integrated NdFeB/Ta multilayered micro-magnets  

NASA Astrophysics Data System (ADS)

This paper describes the fabrication of MEMS-based electromagnetic energy harvesters for scavenging energy from the ambient vibration. The novel energy harvester is fabricated by bonding a vibrator with embedded micro-magnets and a stator with integrated microcoils. The micro-magnets are formed by using sputtering deposition of NdFeB/Ta multilayered magnetic films with a thickness of 10 µm and silicon molding techniques. High-aspect-ratio silicon micro-springs are fabricated using deep reactive ion etching to achieve large vibration amplitude. The microcoils fabricated by electroplating processes are serially connected for multiplication of the output voltages from individual magnet-coil units. The energy harvester is successfully fabricated and wire-bonded for characterization. The maximum voltage output of the energy harvester at 115 Hz is approximately 2 mV, which corresponds to a power density of 1.2 nW cm-3. The performance of the energy harvester could be greatly improved by protecting the micro-magnets from oxidation and decreasing the spacing between the vibrator layer and the stator layer.

Jiang, Yonggang; Masaoka, Shingo; Fujita, Takayuki; Uehara, Minoru; Toyonaga, Tomohiko; Fujii, Kouhei; Higuchi, Kohei; Maenaka, Kazusuke

2011-09-01

233

A method for analyzing vibration power absorption density in human fingertip  

NASA Astrophysics Data System (ADS)

In the current study, we hypothesize that the vibration power absorption density (VPAD) is a good measure for the vibration exposure intensity of the soft tissues of the fingers. In order to calculate the VPAD at a fingertip, we proposed a hybrid modeling approach, which combines a 2D finite element (FE) model with a lumped parameter model. Whereas the lumped components are used to represent the global biodynamic characteristics of the hand-arm system, the FE component is used to predict the detailed stresses, strains, and VPAD in the fingertip. The lumped parameters are determined by using the vibration transmissibilities measured at the fingertip, while the material parameters of the soft and hard tissues of the FE model are adopted from the published experimental data. The proposed model was applied to predict the distributions of dynamic displacement, velocity, and VPAD in the soft tissues of the fingertip. Furthermore, we have derived the frequency weighting based on the VPAD of the soft tissue. The preliminary analysis indicated that the VPAD-based frequency weighting is substantially different from the ISO weighting in that the ISO frequency weighting emphasizes the effect of the vibration at frequencies lower than 25 Hz whereas the VPAD-based weighting generally emphasizes the resonant responses of the finger. Our analysis indicated that the VPAD-based weighting was fairly consistent with the finger surface vibration transmissibility at frequencies greater than the first resonance, suggesting that the finger surface transmissibility may be used as an alternative frequency weighting for assessing the finger vibration exposure. The proposed method provides a practical and efficient tool to simulate the detailed biodynamic responses of a complex biological system to vibration.

Wu, John Z.; Dong, Ren G.; Welcome, Daniel E.; Xu, Xueyan S.

2010-12-01

234

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

Microsoft Academic Search

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

Vinod R Challa; M G Prasad; Frank T Fisher

2009-01-01

235

Full-Scale 3D Vibration Simulator of an Entire Nuclear Power Plant on Simple Orchestration Application Framework  

Microsoft Academic Search

\\u000a So far, we have developed grid-enabled application for “Full-Scale 3D Vibration Simulator for an Entire Nuclear Power Plant”\\u000a which is simulation platform to analyze seismic response of a whole digitalized nuclear power plant. In the 3D Vibration Simulator,\\u000a components of a nuclear power plant are treated in hierarchical manner in which large components are grouped at primary level\\u000a and small

Guehee Kim; Kohei Nakajima; Takayuki Tatekawa; Naoya Teshima; Yoshio Suzuki; Hiroshi Takemiya

236

Design, Fabrication, and Modeling of a Four-bar Electromagnetic Vibration Power Generator  

Microsoft Academic Search

In this article, we report an electromagnetic vibration energy harvesting structure with efficiency approaching close to the theoretical limit. The structure was modeled to account for geometrical variation in magnetic field, velocity field, and the conductor orientation with respect to magnetic field patterns. A four-bar magnet geometry was selected, which allows for an easily manufactured device with high amount of

Josiah M. Oliver; Shashank Priya

2010-01-01

237

Analysis of frequency up-conversion based vibration energy harvesting  

Microsoft Academic Search

Mechanical frequency up-conversion has been suggested by many researchers in order to increase power density of kinetic energy harvesters. In this paper analytical analysis of frequency up-conversion mechanism has been carried out in some detail. It has been shown that sources of actuation for a frequency increased generator can be categorized as force limited and displacement limited sources. Maximum energy

Khalid Ashraf; John Ojur Dennis

2011-01-01

238

Power management for energy harvesting wireless sensors  

NASA Astrophysics Data System (ADS)

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.

Arms, S. W.; Townsend, C. P.; Churchill, D. L.; Galbreath, J. H.; Mundell, S. W.

2005-05-01

239

An energy harvester using piezoelectric cantilever beams undergoing coupled bending-torsion vibrations  

NASA Astrophysics Data System (ADS)

Recently, piezoelectric cantilevered beams have received considerable attention for vibration-to-electric energy conversion. Generally, researchers have investigated a classical piezoelectric cantilever beam with or without a tip mass. In this paper, we propose the use of a unimorph cantilever beam undergoing bending-torsion vibrations as a new piezoelectric energy harvester. The proposed design consists of a single piezoelectric layer and a couple of asymmetric tip masses; the latter convert part of the base excitation force into a torsion moment. This structure can be tuned to be a broader band energy harvester by adjusting the first two global natural frequencies to be relatively close to each other. We develop a distributed-parameter model of the harvester by using the Euler-beam theory and Hamilton's principle, thereby obtaining the governing equations of motion and associated boundary conditions. Then, we calculate the exact eigenvalues and associated mode shapes and validate them with a finite element (FE) model. We use these mode shapes in a Galerkin procedure to develop a reduced-order model of the harvester, which we use in turn to obtain closed-form expressions for the displacement, twisting angle, voltage output, and harvested electrical power. These expressions are used to conduct a parametric study for the dynamics of the system to determine the appropriate set of geometric properties that maximizes the harvested electrical power. The results show that, as the asymmetry is increased, the harvester's performance improves. We found a 30% increase in the harvested power with this design compared to the case of beams undergoing bending only. We also show that the locations of the two masses can be chosen to bring the lowest two global natural frequencies closer to each other, thereby allowing the harvesting of electrical power from multi-frequency excitations.

Abdelkefi, A.; Najar, F.; Nayfeh, A. H.; Ben Ayed, S.

2011-11-01

240

Minimizing radiated sound power from vibrating shell structures: Theory and experiment  

NASA Astrophysics Data System (ADS)

A new design methodology is presented here for finding optimal structural designs of shell structures for minimum sound power. Two optimization techniques are presented: the use of lumped masses and tuned absorbers. Thin shell structures were targeted for noise reduction because of their ubiquity in industry. They are used to cover and protect noisy devices, such as gearboxes and electrical transformers, and also to keep dirt and other contaminants away from moving parts, as in the case of automotive valve covers. The design strategy presented here involves three major computational tasks: predicting vibration of the structure, predicting the sound power created by the vibrating structure and finding optimal designs for minimum noise. A discrete Kirchhoff shell finite element is used to calculate vibration response, and a wave superposition boundary element method is used to calculate sound power. A combined gradient- based/stochastic optimization algorithm is used to find optimal lumped mass and absorber locations, as well as absorber design parameters (mass, stiffness and damping.) Three case studies are examined in this research: a flat plate, a half-cylindrical shell and a gearbox enclosure. Numerical and experimental results are presented for each study. It is shown that the optimization strategy presented here is capable of finding optimal designs which produce significant reductions in sound power in all three cases.

Constans, Eric William

1998-12-01

241

Vibrational excitation of H2 by electron impact: An energy-dependent vibrational-frame-transformation approach  

Microsoft Academic Search

An energy-dependent rovibrational-frame-transformation method, combined with the multichannel quantum-defect theory, has been applied to study the vibrational excitations of H2 by electron collision in the energy range below 5 eV. A class of nonadiabatic effects resulting from large collision time delay has been accounted for. Using a special set of short-range Born-Oppenheimer eigenstates, this approach does not explicitly introduce electron-molecule

Hong Gao

1992-01-01

242

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

PubMed

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

Shen, Xiao-Yan; Wang, Shu-Ying; Liu, Jing; Dai, Kang; Shen, Yi-Fan

2011-01-01

243

New DRIE-Patterned Electrets for Vibration Energy Harvesting  

NASA Astrophysics Data System (ADS)

This paper is about a new manufacturing process aimed at developing stable SiO2/Si3N4 patterned electrets using a Deep Reactive Ion Etching (DRIE) step for an application in electret-based Vibration Energy Harvesters (e-VEH). This process consists in forming continuous layers of SiO2/Si3N4 electrets in order to limit surface conduction phenomena and is a new way to see the problem of electret patterning. Experimental results prove that patterned electrets charged by a positive corona discharge show excellent stability with high surface charge densities that may reach 5mC/m2 on 1.1?m-thick layers, even with fine patterning and harsh temperature conditions (up to 250°C). This paves the way to new e-VEH designs and manufacturing processes.

Boisseau, S.; Duret, A.-B.; Chaillout, J.-J.; Despesse, G.

2012-10-01

244

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

NASA Astrophysics Data System (ADS)

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.

Rdzanek, W. P.

2002-01-01

245

Electron energy distributions, vibrational population distributions, and negative-ion concentrations in hydrogen discharges  

SciTech Connect

We consider the negative ion concentrations in hydrogen discharges caused by electron excitation and dissociative attachment processes. The principal formation and destruction processes are discussed for electron densities in the range 10/sup 8/ to 10/sup 13/ electrons cm/sup -3/. Expressions are developed for calculating the high energy portion of the electron energy distribution in the discharge; using these energy distributions the electron excitation rates are evaluated. At low densities, the vibrational distribution arises from singlet electronic excitations and triplet excitations through the /sup 3/..pi../sub u/ state, in equilibrium with wall de-excitation processes. At high densities singlet excitations predominate in equilibrium with atom-molecule de-excitation processes. Possibilities for negative ion generation in a two-chamber tandem system are discussed in which the vibrational excitation occurs in a high power, high electron temperature discharge, kT/sub e/ = 5 eV, and dissociative attachment occurs in a low temperature kT/sub e/ = 1 eV, plasma chamber.

Hiskes, J.R.; Karo, A.M.

1982-06-28

246

Radiant energy power source structure  

Microsoft Academic Search

This patent describes a radiant energy power source structure for providing electrical power to a vehicle utilizing radiant energy from a jet engine, the jet engine of the type having a radiant energy emitting combustion chamber formed from spaced apart inner and outer concentric elongated cylindrical liners, the combustion chamber outer liner concentrically surrounded by an elongated annular outer combustion

Doellner

1992-01-01

247

Ultrafast vibrational energy transfer at the water/air interface revealed by two-dimensional surface vibrational spectroscopy  

NASA Astrophysics Data System (ADS)

Water is very different from liquids of similar molecular weight, and one of its unique properties is the very efficient transfer of vibrational energy between molecules, which arises as a result of strong dipole-dipole interactions between the O-H oscillators. Although we have a sound understanding of such energy transfer in bulk water, we know less about how, and how quickly, transfer occurs at its interface with a hydrophobic phase, because specifically addressing the outermost monolayer is difficult. Here, we use ultrafast two-dimensional surface-specific vibrational spectroscopy to probe the interfacial energy dynamics of heavy water (D2O) at the water/air interface. The measurements reveal the presence of surprisingly rapid energy transfer, both between hydrogen-bonded interfacial water molecules (intermolecular), and between O-D groups sticking out from the water surface and those located on the same molecule and pointing towards the water bulk (intramolecular). Vibrational energy transfer occurs on sub-picosecond timescales, and its rates and pathways can be quantified directly.

Zhang, Zhen; Piatkowski, Lukasz; Bakker, Huib J.; Bonn, Mischa

2011-11-01

248

A test rig for the measurement of vibration in hand-held power tools.  

PubMed

The purpose of the present project was to study the possibility of using a test rig for the measurement of vibration and noise from hand-held power tools. A test rig was designed to give the same effect on tool handle vibration as the human hand/arm system. Work was simulated by feeding the material to be processed against the tool, clamped into the rig, with the aid of a co-ordinate table. It was designed for use in studies of impact drills, chain saws, grinders and similar power tools. The report describes a proposal for testing the vibration properties of impact drills. Drilling with the test rig was compared with manual drilling. The difference in the acceleration level between the two methods was about 1 dB for ISO-weighted values in the critical direction. Both methods showed good reproducibility. The possibility of conducting noise level tests of a power tool in the rig was studied and the results are reported separately. PMID:15676459

Hansson, J E; Kihlberg, S

1983-03-01

249

Energy 101: Concentrating Solar Power  

ScienceCinema

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.

250

Enhancement of piezoelectric energy harvesting with multi-stable nonlinear vibrations  

NASA Astrophysics Data System (ADS)

The need for long-term solutions to power various wireless sensor systems has been driving the research in the area of energy harvesting for the past decade. The present paper brings forth an investigation into the realm of piezoelectric energy harvesting (PEH) using nonlinear vibrations. A piezoelectric cantilever beam with a magnetic tip mass interacting with additional magnets around it forms a multi-stable nonlinear PEH configuration. The study indicates that the multistable configuration provides a widened bandwidth as compared to the conventional linear PEH devices and an increased voltage output as compared to many other PEH devices. An experimental parametric study is conducted to arrive at an optimal configuration for the performance enhancement of the harvester along with a glimpse into the enhanced magnetostatic interactions equations and various possible magnetic nonlinear configurations for the given conditions.

Avvari, Panduranga Vittal; Tang, Lihua; Yang, Yaowen; Soh, Chee Kiong

2013-04-01

251

Application of the energy flow method to vibration control of buildings with multiple tuned liquid dampers  

Microsoft Academic Search

The energy flow method is used to study the vibrations of tall buildings coupled to rectangular tanks as vibration absorbers and also for a primary structure coupled to a rotary tuned liquid column damper. The tall building is studied using the receptance approach, with harmonic and wind loads. The formulation deals with one beam simulating the building, coupled to many

K. Shankar; T. Balendra

2002-01-01

252

Vibrational energy funneling in viruses—simulations of impulsive stimulated Raman scattering in M13 bacteriophage  

Microsoft Academic Search

The vibrational excitation of a tubular M13 bacteriophage capsid is simulated using classical molecular dynamics. The excitation occurs through impulsive stimulated Raman scattering by ultra-short laser pulses which ping the vibrational modes of the capsid. Tuning the laser pulse temporal width determines the frequency region of the capsid that is excited. The simulations reveal that electromagnetic energy transferred to the

Eric C Dykeman; Otto F Sankey

2009-01-01

253

Report of workshop on vibration related to fluid in atomic energy field. 7.  

National Technical Information Service (NTIS)

Because of the nonlinearity of the equation that governs flow, sometimes vibration occurs in an unexpected system, and it causes trouble. This 7th workshop on vibration related to fluid in atomic energy field was held at Nuclear Engineering Research Labor...

1997-01-01

254

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

NASA Astrophysics Data System (ADS)

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.

Nawayseh, Naser; Griffin, Michael J.

2012-01-01

255

Anharmonic vibrational properties in periodic systems: energy, electron-phonon coupling, and stress  

NASA Astrophysics Data System (ADS)

A unified approach is used to study vibrational properties of periodic systems with first-principles methods and including anharmonic effects. Our approach provides a theoretical basis for the determination of phonon-dependent quantities at finite temperatures. The low-energy portion of the Born-Oppenheimer energy surface is mapped and used to calculate the total vibrational energy including anharmonic effects, electron-phonon coupling, and the vibrational contribution to the stress tensor. We report results for the temperature dependence of the electronic band gap and the linear coefficient of thermal expansion of diamond, lithium hydride, and lithium deuteride.

Monserrat, Bartomeu; Drummond, N. D.; Needs, R. J.

2013-04-01

256

Spectroscopic and vibrational energy transfer studies in molecular bromine  

NASA Astrophysics Data System (ADS)

Vibrational transfer and electronic quenching in the lower vibrational levels (v' less than or equal to 3) of the B(sup 3)pi(O(u)(+)) state of (79)Br2 were investigated using spectrally resolved, temporally resolved laser induced fluorescence techniques. Spectrally resolved emissions from collisionally populated Br2(B) vibrational levels were observed for Br2 and rare gas collision partners. Vibrational transfer was efficient in the non-predissociative vibrational levels and was adequately described by the Montroll-Shuler model for harmonic oscillators. A single fundamental rate coefficient for vibrational transfer from v' = 1 to v'= 0, kv(1,0), characterizes vibrational relaxation. For Br2, the value was kv(1,0) = 3.6 +/- 0.4 x 10(exp -11) cu cm/molec(sec). For rare gas collisions, values ranged from kv(1,0) = 2.5 +/- 0.3 x 10(exp -11) cu cm/molec(sec) for helium to kv(1,0) = 3.1 +/- 0.4 x 10(exp -11) cu cm/molec(sec) for xenon.Electronic quenching rates for the observed vibrational levels were obtained from the same data. For Br2, the quenching rate coefficient was kq = 3.7 +/- 1.2 x 10(exp -11) cu cm/molec(sec). Quenching rate coefficients for the rare gases were smaller, kq = 8.0 +/- 1.2 x 10(exp -12) cu cm/molec(sec).

Holmberg, Courtney D.

1993-12-01

257

Wave energy power station  

SciTech Connect

A wave energy power station comprises two water-filled chambers in communication at the bottom, wherein a first chamber is in communication with the sea at the upper end thereof and the second chamber is defined by one or more walls which project above the surface of the sea, such that pressure variations in the sea owing to the waves will set the water in an oscillating movement between the two chambers, and energy being tapped from the oscillating system, for example, by allowing the water in the chamber which is not in communication with the sea to overflow periodically into a reservoir, from which it is led back to the sea through a turbine, or by utilizing the water column in the second chamber for drawing in and compressing air which drives an air turbine. A water-filled tank is permanently installed on the sea bed or floating in the sea, and has a bottom and one or more walls, at least one wall or a portion of one wall being terminated at the upper edge thereof below the surface of the sea , the submerged upper edge and a partition wall which can be fixed or movable up and down in the water in the tank together defining the upper end of the chamber which communicates with the sea, the partition wall also, alone or together with one or more of the tank walls which project up above the surface of the water , defining the second chamber end which is not in communication with the sea, there being provided in the case of a fixed partition wall an adjacent tank wall section which is adapted for movement toward and away from the partition wall at the end of the second chamber for regulating the cross-sectional surface at that chamber end.

Ambli, N.

1982-07-27

258

Modeling of magnetic vibrational energy harvesters using equivalent circuit representations  

NASA Astrophysics Data System (ADS)

This paper develops and analyzes an equivalent circuit model of magnetic energy harvesters using reduced-order lumped element modeling (LEM) methods. This model is intended to enhance the design and analysis of a magnetic energy harvesting system by enabling direct physical insight into the system dynamics and simple circuit analysis techniques to extract all relevant performance parameters. Moreover, the model provides the ability to use circuit simulation software (e.g. PSPICE) to model the entire system in conjunction with nonlinear and/or active power electronic circuits. The circuit model is experimentally validated through electrical and mechanical measurements on a prototypical electromagnetic energy harvester.

Cheng, Shuo; Wang, Naigang; Arnold, David P.

2007-11-01

259

A hybrid electromagnetic energy harvesting device for low frequency vibration  

NASA Astrophysics Data System (ADS)

An electromagnetic energy harvesting device, which converts a translational base motion into a rotational motion by using a rigid bar having a moving mass pivoted on a hinged point with a power spring, has been recently developed for use of civil engineering structures having low natural frequencies. The device utilizes the relative motion between moving permanent magnets and a fixed solenoid coil in order to harvest electrical power. In this study, the performance of the device is enhanced by introducing a rotational-type generator at a hinged point. In addition, a mechanical stopper, which makes use of an auxiliary energy harvesting part to further improve the efficiency, is incorporated into the device. The effectiveness of the proposed hybrid energy harvesting device based on electromagnetic mechanism is verified through a series of laboratory tests.

Jung, Hyung-Jo; Kim, In-Ho; Min, Dong Yi; Sim, Sung-Han; Koo, Jeong-Hoi

2013-04-01

260

TOPICAL REVIEW: Strategies for increasing the operating frequency range of vibration energy harvesters: a review  

NASA Astrophysics Data System (ADS)

This review presents possible strategies to increase the operational frequency range of vibration-based micro-generators. Most vibration-based micro-generators are spring-mass-damper systems which generate maximum power when the resonant frequency of the generator matches the frequency of the ambient vibration. Any difference between these two frequencies can result in a significant decrease in generated power. This is a fundamental limitation of resonant vibration generators which restricts their capability in real applications. Possible solutions include the periodic tuning of the resonant frequency of the generator so that it matches the frequency of the ambient vibration at all times or widening the bandwidth of the generator. Periodic tuning can be achieved using mechanical or electrical methods. Bandwidth widening can be achieved using a generator array, a mechanical stopper, nonlinear (e.g. magnetic) springs or bi-stable structures. Tuning methods can be classified into intermittent tuning (power is consumed periodically to tune the device) and continuous tuning (the tuning mechanism is continuously powered). This review presents a comprehensive review of the principles and operating strategies for increasing the operating frequency range of vibration-based micro-generators presented in the literature to date. The advantages and disadvantages of each strategy are evaluated and conclusions are drawn regarding the relevant merits of each approach.

Zhu, Dibin; Tudor, Michael J.; Beeby, Stephen P.

2010-02-01

261

Natural Energy Power and Energy Storing Technology  

NASA Astrophysics Data System (ADS)

With effectuation of Kyoto protocol to reduce CO2 discharging, conventional energy resources are gradually giving way to renewable natural generators. However their weak point of impossibility to control their output themselves will cause some problems with respect to power quality such as voltage and frequency fluctuation. In the meanwhile some kind of electrical energy storage devices like storage batteries, electric double layer capacitors, flywheels are put into practical use. This paper describes the combination of natural energy power and energy storing technologies to solve the power quality problem and to improve their generation values in use.

Takano, Tomihiro

262

A systematic study of the vibrational free energies of polypeptides in folded and random states.  

PubMed

Molecular vibrations, especially low frequency motions, may be used as an indication of the rigidity or the flatness of the protein folding energy landscape. We have studied the vibrational properties of native folded as well as random coil structures of more than 60 polypeptides. The picture we obtain allows us to perceive how and why the energy landscape progressively rigidifies while still allowing potential flexibility. Compared with random coil structures, both alpha-helices and beta-hairpins are vibrationally more flexible. The vibrational properties of loop structures are similar to those of the corresponding random coil structures. Inclusion of an alpha-helix tends to rigidify peptides and so-called building blocks of the structure, whereas the addition of a beta-structure has less effect. When small building blocks coalesce to form larger domains, the protein rigidifies. However, some folded native conformations are still found to be vibrationally more flexible than random coil structures, for example, beta(2)-microglobulin and the SH3 domain. Vibrational free energy contributes significantly to the thermodynamics of protein folding and affects the distribution of the conformational substates. We found a weak correlation between the vibrational folding energy and the protein size, consistent with both previous experimental estimates and theoretical partition of the heat capacity change in protein folding. PMID:11053147

Ma, B; Tsai, C J; Nussinov, R

2000-11-01

263

Limit Cycle Oscillations of a Nonlinear Piezo-magneto-elastic Structure for Broadband Vibration Energy Harvesting  

Microsoft Academic Search

\\u000a Vibration-based energy harvesting has been investigated by several researchers over the last decade. Typically, devices employing\\u000a piezoelectric, electromagnetic, electrostatic and magnetostrictive transductions have been designed in order to convert ambient\\u000a vibrations into electricity under resonance excitation. Regardless of the transduction mechanism, a primary issue in resonant\\u000a energy harvesters is that the best performance of the device is limited to resonance

A. Erturk; J. Hoffmann; D. J. Inman

264

Analysis and synthesis of self-powered linear structural control with imperfect energy storage  

Microsoft Academic Search

Self-powered vibration control systems are characterized by a distributed network of regenerative force actuators, which are interfaced with a common power bus. Also connected to the power bus is an energy-storing subsystem, such as a supercapacitor, flywheel, or battery. The entire system is controlled using switch-mode power electronics, and the only power required for system operation is that necessary to

J. T. Scruggs

2009-01-01

265

The Effects of Tai Chi Chuan Combined with Vibration Training on Balance Control and Lower Extremity Muscle Power  

PubMed Central

The aim of this study was to determine whether performing Tai Chi Chuan on a customized vibration platform could enhance balance control and lower extremity muscle power more efficiently than Tai Chi Chuan alone in an untrained young population. Forty-eight healthy young adults were randomly assigned to the following three groups: a Tai Chi Chuan combined with vibration training group (TCV), a Tai Chi Chuan group (TCC) or a control group. The TCV group underwent 30 minutes of a reformed Tai Chi Chuan program on a customized vibration platform (32 Hz, 1 mm) three times a week for eight weeks, whereas the TCC group was trained without vibration stimuli. A force platform was used to measure the moving area of a static single leg stance and the heights of two consecutive countermovement jumps. The activation of the knee extensor and flexor was also measured synchronously by surface electromyography in all tests. The results showed that the moving area in the TCV group was significantly decreased by 15.3%. The second jump height in the TCV group was significantly increased by 8.14%, and the activation of the knee extensor/flexor was significantly decreased in the first jump. In conclusion, Tai Chi Chuan combined with vibration training can more efficiently improve balance control, and the positive training effect on the lower extremity muscle power induced by vibration stimuli still remains significant because there is no cross-interaction between the two different types of training methods. Key points Eight weeks of Tai Chi Chuan combined with vibration training can more efficiently improve balance control for an untrained young population. The positive training effect on the lower extremity muscle power induced by vibration stimuli during Tai Chi Chuan movements still remains significant because of SSC mechanism. Combining Tai Chi Chuan with vibration training is more efficient and does not decrease the overall training effects due to a cross-interaction of each other.

Chung, Pao-Hung; Lin, Guan-Lun; Liu, Chiang; Chuang, Long-Ren; Shiang, Tzyy-Yuang

2013-01-01

266

A study of several vortex-induced vibration techniques for piezoelectric wind energy harvesting  

NASA Astrophysics Data System (ADS)

This paper discusses a preliminary study on harnessing energy from piezoelectric transducers by using bluff body and vortex-induced vibration phenomena. Structures like bridges and buildings tend to deform and crack due to chaotic fluid-structure interactions. The rapid variation of pressure and velocity can be tapped and used to power structural health monitoring systems. The proposed device is a miniature, scalable wind harvesting device. The configuration consists of a bluff body with a flexible piezoelectric cantilever attached to the trailing edge. Tests are run for different characteristic dimensions or shapes for the bluff body and optimized for maximum power over a wide range of flow velocities. The main motive here is to seek a higher synchronized region of frequencies for the oscillation amplitudes. The multi-physics software package COMSOL is used to vary the design parameters to optimize the configuration and to identify the significant parameters in the design. The simulation results obtained show a wider lock-in bandwidth and higher average power for the cylindrical bluff body compared to the other two bluff body shapes investigated, the greatest average power being 0.35mW at a Reynolds number of 900, beam length of 0.04m, and bluff body diameter of 0.02m.

Sivadas, Vishak; Wickenheiser, Adam M.

2011-03-01

267

Improved design of linear electromagnetic transducers for large-scale vibration energy harvesting  

NASA Astrophysics Data System (ADS)

This paper presents the design and optimization of tubular Linear Electromagnetic Transducers (LETs) with applications to large-scale vibration energy harvesting, such as from vehicle suspensions, tall buildings or long bridges. Four types of LETs are considered and compared, namely, single-layer configuration using axial magnets, double-layer configuration using axial magnets, single-layer configuration using both axial and radial magnets, double-layer configuration using both axial and radial magnets. In order to optimize the LETs, the parameters investigated in this paper include the thickness of the magnets in axial direction and the thickness of the coils in the radial direction. Finite element method is used to analyze the axisymmetric two-dimensional magnetic fields. Both magnetic flux densities Br [T] in the radial direction and power density [W/m3] are calculated. It is found that the parameter optimization can increase the power density of LETs to 2.7 times compared with the initial design [Zuo et al, Smart Materials and Structures, v19 n4, 2010], and the double-layer configuration with both radial and axial magnets can improve the power density to 4.7 times, approaching to the energy dissipation rate of traditional oil dampers. As a case study, we investigate its application to energy-harvesting shock absorbers. For a reasonable retrofit size, the LETs with double-layer configuration and both axial and radial NdFeB magnets can provide a damping coefficient of 1138 N·s/m while harvesting 35.5 W power on the external electric load at 0.25 m/s suspension velocity. If the LET is shorten circuit, it can dissipate energy at the rate of 142.0 W, providing of a damping coefficient of 2276 N·s/m. Practical consideration of number of coil phases is also discussed.

Tang, Xiudong; Zuo, Lei; Lin, Teng; Zhang, Peisheng

2011-03-01

268

Real-time detection of doorway states in the intramolecular vibrational energy redistribution of the OH/OD stretch vibration of phenol  

NASA Astrophysics Data System (ADS)

A picosecond time-resolved IR-UV pump-probe spectroscopic study was carried out for the intramolecular vibrational energy redistribution of the OH/OD stretching vibration of isolated phenol and its isotopomers in supersonic beams. The time evolution due to IVR showed a significant isotope effect; the OH stretch vibration showed a single exponential decay and its lifetime is greatly lengthened upon the deuterium substitution of the CH group. The OD stretch vibration exhibited prominent quantum beats. Especially, in phenol-d1 (C6H5OD), the electronic transitions from the doorway states were clearly observed. They exhibited an out-of-phase quantum beat with respect to that of the OD stretch level and disappeared due to further IVR to the dense bath states. The transient spectra as well as the time evolution clearly evidenced the tier-model of the description of intramolecular vibrational energy redistribution.

Yamada, Yuji; Mikami, Naohiko; Ebata, Takayuki

2004-12-01

269

A three-axis vibration isolation system using modified zero-power controller with parallel mechanism technique  

Microsoft Academic Search

This paper proposes a module-type three-degree-of-freedom vibration isolation system using modified zero-power control. Three vibration isolation modules are connected together using parallel mechanism to control 3-DOF motions. Each module consists of a common base, an individual middle mass and a common isolation table. The base to the middle mass is suspended by positive springs generated by active and passive system,

Takeshi Mizuno; Yuji Ishino; Masaya Takasaki

2011-01-01

270

General model with experimental validation of electrical resonant frequency tuning of electromagnetic vibration energy harvesters  

NASA Astrophysics Data System (ADS)

This paper presents a general model and its experimental validation for electrically tunable electromagnetic energy harvesters. Electrical tuning relies on the adjustment of the electrical load so that the maximum output power of the energy harvester occurs at a frequency which is different from the mechanical resonant frequency of the energy harvester. Theoretical analysis shows that for this approach to be feasible the electromagnetic vibration energy harvester’s coupling factor must be maximized so that its resonant frequency can be tuned with the minimum decrease of output power. Two different-sized electromagnetic energy harvesters were built and tested to validate the model. Experimentally, the micro-scale energy harvester has a coupling factor of 0.0035 and an untuned resonant frequency of 70.05 Hz. When excited at 30 mg, it was tuned by 0.23 Hz by changing its capacitive load from 0 to 4000 nF its effective tuning range is 0.15 Hz for a capacitive load variation from 0 to 1500 nF. The macro-scale energy harvester has a coupling factor of 552.25 and an untuned resonant frequency of 95.1 Hz and 95.5 Hz when excited at 10 mg and 25 mg, respectively. When excited at 10 mg, it was tuned by 3.8 Hz by changing its capacitive load from 0 to 1400 nF it has an effective tuning range of 3.5 Hz for a capacitive load variation from 0 to 1200 nF. When excited at 25 mg, its resonant frequency was tuned by 4.2 Hz by changing its capacitive load from 0 to 1400 nF it has an effective tuning range of about 5 Hz. Experimental results were found to agree with the theoretical analysis to within 10%.

Zhu, Dibin; Roberts, Stephen; Mouille, Thomas; Tudor, Michael J.; Beeby, Stephen P.

2012-10-01

271

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

PubMed

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

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

2013-07-01

272

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

Microsoft Academic Search

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

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

2003-01-01

273

Simulation and experiment validation of simultaneous vibration control and energy harvesting from buildings using Tuned Mass Dampers  

Microsoft Academic Search

For the protection of the structure safety and occupant comfort, the vibrations of the tall buildings are serious concerns for both engineers and architects. In order to mitigate the vibration, different approaches have been proposed, among which Tuned Mass Dampers (TMDs) are one of the most preferable and have been widely used in practice. Instead of dissipating the vibration energy

Xiudong Tang; Lei Zuo

2011-01-01

274

Energy, A Crisis in Power.  

ERIC Educational Resources Information Center

|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

Holdren, John; Herrera, Philip

275

Energy, A Crisis in Power.  

ERIC Educational Resources Information Center

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

Holdren, John; Herrera, Philip

276

Wind power and other energy options  

Microsoft Academic Search

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

D. R. Inglis

1978-01-01

277

Wind power and other energy options  

Microsoft Academic Search

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

Inglis

1979-01-01

278

An Explicit Linearized State-Space Technique for Accelerated Simulation of Electromagnetic Vibration Energy Harvesters  

Microsoft Academic Search

Vibration energy harvesting systems pose significant modeling and design challenges due to their mixed-technology nature, extremely low levels of available energy and disparate time scales between different parts of a complete harvester. An energy harvester is a complex system of tightly coupled components modeled in the mechanical, magnetic, as well as electrical analog and digital domains. Currently available design tools

Tom J. Kazmierski; Leran Wang; Bashir M. Al-Hashimi; Geoff V. Merrett

2012-01-01

279

Quantum dynamics of ArI{sub 2} vibrational predissociation including low total angular momenta: The role of intramolecular vibrational energy redistribution  

SciTech Connect

Full-dimensional quantum dynamics calculations on ArI{sub 2}({ital B},{ital v}{sub {ital i}}) vibrational predissociation with total angular momenta {ital J}=0, 1, and 2 are presented. Models based on a few interacting states are shown to reproduce important aspects of the dynamics, confirming that vibrational predissociation is mediated by a few-state intramolecular vibrational energy redistribution effect. As a consequence, vibrational predissociation rate constants exhibit large oscillations with {ital v}{sub {ital i}}, the initial I{sub 2} vibrational quantum number in the complex. The qualitative effect persists when alternative choices for the interaction potential parameters are considered. Similarly, despite the importance of Coriolis coupling, the effect persists as {ital J} is varied from 0 to 2. We also discuss how the effect may be difficult to observe in typical experiments that involve higher {ital J} values. {copyright} {ital 1996 American Institute of Physics.}

Roncero, O. [Instituto de Matematicas y Fisica Fundamental, C.S.I.C., Serrano 123, 28006 Madrid (Spain); Gray, S.K. [Theoretical Chemistry Group, Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

1996-04-01

280

Step-up converter for electromagnetic vibrational energy scavenger  

Microsoft Academic Search

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

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

2008-01-01

281

Energy dissipation in polymers undergoing electromagnetically excited vibration  

Microsoft Academic Search

is calculated from the relative frequency ~ and the force r atio ~ = P1\\/P0. When the quantity ~ is given (detuning method), ~ is found experimentally from the ratio of the squares of the currents corresponding to the electromagnetic forces exciting the vibrations. If the quantity ~ is given (resonance cavity halfwidth method), then the frequency } which corresponds

S. K. Abramov; Yu. V. Efremushkin

1971-01-01

282

Measurement and Analysis of Power Pulse Energy Fluctuations in the IBR-2 Reactor.  

National Technical Information Service (NTIS)

The results of the experimental study of the power impulse energy fluctuations obtained during the IBR-2 energy start-up are presented. The influence of accidental oscillations of the core cooling system basic parameters and the vibrations of the moving r...

Y. N. Pepelyshev

1988-01-01

283

The influence of translational and vibrational energy on the reaction of Cl with CH3D.  

PubMed

The reaction of Cl atoms with CH3D proceeds either by abstraction of hydrogen to produce HCl + CH2D or by abstraction of deuterium to produce DCl + CH3. Using Cl atoms with different amounts of translational energy, produced by photolysis of Cl2 with 309, 355, or 416 nm light, reveals the influence of translational energy on the relative reaction probability for the two channels. These measurements give an estimate of the energy barrier for the reaction for comparison to theory and indicate that tunneling is the dominant reaction mechanism at low collision energies. Adding two quanta of C-H stretching vibration causes the reaction to proceed readily at all collision energies. Detecting the vibrational state of the CH2D product shows that vibrational energy initially in the surviving C-H bond appears as vibrational excitation of the product, an example of spectator behavior in the reaction. The reaction produces both stretch and stretch-bend excited products except at the lowest collision energy. A subtle variation in the reaction probability of the lowest energy rotational states with translational energy may reflect the presence of a van der Waals well in the entrance channel. PMID:23781794

Berke, Andrew E; Volpa, Ethan H; Annesley, Christopher J; Crim, F Fleming

2013-06-14

284

The influence of translational and vibrational energy on the reaction of Cl with CH3D  

NASA Astrophysics Data System (ADS)

The reaction of Cl atoms with CH3D proceeds either by abstraction of hydrogen to produce HCl + CH2D or by abstraction of deuterium to produce DCl + CH3. Using Cl atoms with different amounts of translational energy, produced by photolysis of Cl2 with 309, 355, or 416 nm light, reveals the influence of translational energy on the relative reaction probability for the two channels. These measurements give an estimate of the energy barrier for the reaction for comparison to theory and indicate that tunneling is the dominant reaction mechanism at low collision energies. Adding two quanta of C-H stretching vibration causes the reaction to proceed readily at all collision energies. Detecting the vibrational state of the CH2D product shows that vibrational energy initially in the surviving C-H bond appears as vibrational excitation of the product, an example of spectator behavior in the reaction. The reaction produces both stretch and stretch-bend excited products except at the lowest collision energy. A subtle variation in the reaction probability of the lowest energy rotational states with translational energy may reflect the presence of a van der Waals well in the entrance channel.

Berke, Andrew E.; Volpa, Ethan H.; Annesley, Christopher J.; Crim, F. Fleming

2013-06-01

285

A six-axis hybrid vibration isolation system using active zero-power control supported by passive weight support mechanism  

NASA Astrophysics Data System (ADS)

This paper presents a six-degree-of-freedom hybrid vibration isolation system integrated with an active negative suspension, an active-passive positive suspension and a passive weight support mechanism. The aim of the research consists in maximizing the system and control performances, and minimizing the system development and maintenance costs. The vibration isolation system is, fundamentally, developed by connecting an active negative suspension realized by zero-power control in series with an active-passive positive suspension. The system could effectively isolate ground vibrations in addition to suppress the effect of on-board generated direct disturbances of the six-axis motions, associated with vertical and horizontal directions. The system is further reinforced by introducing a passive weight support mechanism in parallel with the basic system. The modified system with zero-power control allows simplified design of the isolation table without power consumption. It also offers enhanced performance on direct disturbance suppression and large payload supporting capabilities, without degrading transmissibility characteristics. A mathematical model of the system is presented and, therefore, analyzed to demonstrate that zero-compliance to direct disturbance could be generated by the developed system. Experimental demonstrations validate the proposed concept that exhibits high stiffness of the isolation table to static and dynamic direct disturbances, and good transmissibility characteristics against ground vibration. Further improvements of the vibration isolation system and the control system are discussed as well.

Emdadul Hoque, Md.; Mizuno, Takeshi; Ishino, Yuji; Takasaki, Masaya

2010-08-01

286

Trajectory studies of vibrational energy transfer in gas--surface collisions  

SciTech Connect

We have applied the stochastic trajectory method to the scattering of NO from the (001) surface of an LiF crystal. The surface was represented by a 32 atom primary zone and the effects of the rest of the surface atoms were included using the Generalized Langevin Equation method. The forces between the surface atoms were treated using a shell model and the gas--surface interactions included short-range repulsions, attractive dispersion forces, and the interaction of the dipole moment of NO and the surface ions. The dependence of the dipole moment and the dependence of the molecular polarizability on the internuclear separation of NO were also included. The calculated vibrational energy accommodation coefficient was less than 1% when trapping of the gas diatom was negligible. By modifying the vibrational frequency of the scattered diatom we have examined the dependence of vibrational energy transfer on frequency. An exponential dependence on the ratio of the molecular frequency to the surface Debye frequency was found, similar to behavior observed for vibrational relaxation in condensed phases. We have also examined the relative efficiency of the coupling of the vibrational mode to the translational and rotational modes of the gas diatom and to the phonon modes of the surface. We found that the vibrational mode is most strongly coupled to the surface phonons with a much weaker coupling to the rotational and translational modes.

Lucchese, R.R.; Tully, J.C.

1984-04-01

287

Mass-Energy Relationship Must Include Factors For Vibrational and Rotational Kinetic Energies as Well as Various Potential Energies  

Microsoft Academic Search

Einstein proposed that at low speeds E=M0c^2 + 1\\/2M0v^2. However, a mass may also have vibrating and rotating kinetic energies and may also have various potential energies such as gravitational, electric and magnetic potential energies which must be part of the total mass-energy equivalence. Therefore, the basic equation for the mass-energy equivalence should be E=M0c^2 + 1\\/2M0v^2 + 1\\/2I2ˆ+ 1\\/2kx^2

Stewart Brekke

2011-01-01

288

A Frequency Band Energy Analysis of Vibration Signals for Tool Condition Monitoring  

Microsoft Academic Search

The cutting vibration signals in different milling wear conditions are decomposed and reconstructed by using the wavelet packet transform and feature extraction with conditions information is obtained by using proper and scientific methods to extract from signals. The effect of cutting parameters on energy parameters was taken into account while extracting energy parameters of tool wear characteristic vector, this made

Xu Chuangwen; Liu Zhe; Luo Wencui

2009-01-01

289

Vibration Energy Harvesting for Disaster Asset Monitoring Using Active RFID Tags  

Microsoft Academic Search

This paper highlights the importance of energy harvesting in high-value asset monitoring applications involving use of active RFID tags. The paper begins by highlighting advantages of active tags including improved range and read rate in electromagnetically unfriendly environments. Although a battery can substantially improve performance, it limits maintenance-free operational life. Therefore, harvesting energy from sources such as vibration is shown

Abhiman Hande; Raj Bridgelall; Ben Zoghi

2010-01-01

290

AlN-based MEMS devices for vibrational energy harvesting applications  

Microsoft Academic Search

This paper presents a new AlN-based MEMS devices suitable for vibrational energy harvesting applications. Due to their particular shape and unlike traditional cantilever which efficiently harvest energy only if subjected to stimulus in the proper direction, the proposed devices have 3D generation capabilities solving the problem of device orientation and placement in real applications. Thanks to their particular shape, the

A. Bertacchini; S. Scorcioni; D. Dondi; L. Larcher; P. Pavan; M. T. Todaro; A. Campa; G. Caretto; S. Petroni; A. Passaseo; M. De Vittorio

2011-01-01

291

Accelerated simulation of tunable vibration energy harvesting systems using a linearised state-space technique  

Microsoft Academic Search

This paper proposes a linearised state-space tech- nique to accelerate the simulation of tunable vibration energy harvesting systems by at least two orders of magnitude. The paper provides evidence that currently available simulation tools are inadequate for simulating complete energy harvesting systems where prohibitive CPU times are encountered due to disparate time scales. In the proposed technique, the model of

Leran Wang; Tom J. Kazmierski; Bashir M. Al-Hashimi; Alex S. Weddell; Geoff V. Merrett; Ivo N. Ayala Garcia

2011-01-01

292

An automated design flow for vibration-based energy harvester systems  

Microsoft Academic Search

This paper proposes, for the first time, an automated energy harvester design flow which is based on a single HDL software platform that can be used to model, simulate, configure and optimise energy harvester systems. A demonstrator pro- totype incorporating an electromagnetic mechanical-vibration- based micro-generator and a limited number of library models has been developed and a design case study

Leran Wang; Tom J. Kazmierski; Bashir M. Al-hashimi; Stephen P. Beeby; Dibin Zhu

2009-01-01

293

Power and energy  

SciTech Connect

According to the author, in response to financial and competitive pressures, U.S. utilities have been proposing and consummating mergers on a scale not seen since the 1930s. The author discusses how such proposals have far-reaching consequences for U.S. transmission networks, and, along with concrete proposals for new federal clean air legislation, hint at structural changes in the utility industry. Competitive and environmental concerns are seen as having fostered technical advances, particularly in the harnessing of renewable- and alternative-energy sources and in the use of computers to monitor and control interconnected high-voltage transmission networks.

Zorpette, G

1990-01-01

294

Spectroscopic probes of vibrationally excited molecules at chemically significant energies  

SciTech Connect

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.

Rizzo, T.R.

1993-04-01

295

Energy Conservation in the Electric Power System.  

National Technical Information Service (NTIS)

The possibilities for energy conservation in the Norwegian electric power supply system are analysed. This power system is based exclusively on hydroelectric power and consists of water storage reservoirs, pipes and tunnels for water transport, power plan...

A. Killingtveit K. Tvinnereim

1983-01-01

296

Coupled piezoelectric-circuit FEA to study influence of a resistive load on power output of piezoelectric energy devices  

Microsoft Academic Search

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

Meiling Zhu; Emma Worthington; James Njuguna

2009-01-01

297

The potential energy surface and the highly excited vibrational band origins of the water molecule  

NASA Astrophysics Data System (ADS)

The potential energy surface for the electronic ground state of the water molecule is optimized by means of a variational procedure using the exact vibrational Hamiltonian in the bond length-bond angle coordinates. In the optimization, Jensen's potential energy function (J. Mol. Spectry. 133 (1989) 438) is taken as the starting point andthe recently observed band origins below 22000 cm -1 given by Rothman and co-workers (J. Quantum Spectry. Radiative Transfer 48 (1992) 469) are involved. The standard deviation of this fitting for the 70 vibrational levels is 1.171 cm -1.

Xie, Daiqian; Yan, Guosen

1996-01-01

298

Inducing bistability with local electret technology in a microcantilever based non-linear vibration energy harvester  

NASA Astrophysics Data System (ADS)

A micro-electro-mechanical system based vibration energy harvester is studied exploring the benefits of bistable non linear dynamics in terms of energy conversion. An electrostatic based approach to achieve bistability, which consists in the repulsive interaction between two electrets locally charged in both tip free ends of an atomic force microscope cantilever and a counter electrode, is experimentally demonstrated. A simple model allows the prediction of the measured dynamics of the system, which shows an optimal distance between the cantilever and the counter electrode in terms of the root mean square vibration response to a colored Gaussian excitation noise.

López-Suárez, M.; Agustí, J.; Torres, F.; Rurali, R.; Abadal, G.

2013-04-01

299

Direct energy flow measurement in magneto-sensitive vibration isolator systems  

NASA Astrophysics Data System (ADS)

The effectiveness of highly nonlinear, frequency, amplitude and magnetic field dependent magneto-sensitive natural rubber components applied in a vibration isolation system is experimentally investigated by measuring the energy flow into the foundation. The energy flow, including both force and velocity of the foundation, is a suitable measure of the effectiveness of a real vibration isolation system where the foundation is not perfectly rigid. The vibration isolation system in this study consists of a solid aluminium mass supported on four magneto-sensitive rubber components and is excited by an electro-dynamic shaker while applying various excitation signals, amplitudes and positions in the frequency range of 20-200 Hz and using magneto-sensitive components at zero-field and at magnetic saturation. The energy flow through the magneto-sensitive rubber isolators is directly measured by inserting a force transducer below each isolator and an accelerometer on the foundation close to each isolator. This investigation provides novel practical insights into the potential of using magneto-sensitive material isolators in noise and vibration control, including their advantages compared to traditional vibration isolators. Finally, nonlinear features of magneto-sensitive components are experimentally verified.

Alberdi-Muniain, A.; Gil-Negrete, N.; Kari, L.

2012-04-01

300

Time Transients of Roto-Vibrational Energy Distribution in Positive Column of Pulsed Nitrogen Discharge  

NASA Astrophysics Data System (ADS)

Time transients of energy stored in vibrational/rotational motion of molecular nitrogen in the ground electronic state were measured in a positive column of pulsed discharge. Discharge was operating at peak current densities up to 25 A/cm^2, pressures up to 6 Torr and pulse duration between 1.0 and 3.0 ?s . The measurements were done during the active discharge and in the afterglow. Coherent Anti-Stokes Raman Spectroscopy (CARS) in unstable-resonator spatially enhanced detection (USED) geometry was employed in all measurements. The 30 GHz line width of Nd-YAG laser set the limit on spectral resolution. The resolution was insufficient to observe single roto-vibrational lines. The energy stored in rotational motion was inferred from the width of vibrational bands. It is shown that initially energy is being transfer, primarily into vibrational levels above v=1, resulting in a highly non Boltzmann distribution. The redistribution between vibrational levels takes place within 100 ?s after the discharge pulse. The rotational temperature was as high as 4000 K and reached maximum values between 80 and 100 ?s after the discharge pulse.

Borysow, Jacek

1998-10-01

301

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

Microsoft Academic Search

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

Mickaël Lallart; Daniel Guyomar

2008-01-01

302

Second-order many-body perturbation expansions of vibrational Dyson self-energies.  

PubMed

Second-order many-body perturbation theories for anharmonic vibrational frequencies and zero-point energies of molecules are formulated, implemented, and tested. They solve the vibrational Dyson equation self-consistently by taking into account the frequency dependence of the Dyson self-energy in the diagonal approximation, which is expanded in a diagrammatic perturbation series up to second order. Three reference wave functions, all of which are diagrammatically size consistent, are considered: the harmonic approximation and diagrammatic vibrational self-consistent field (XVSCF) methods with and without the first-order Dyson geometry correction, i.e., XVSCF[n] and XVSCF(n), where n refers to the truncation rank of the Taylor-series potential energy surface. The corresponding second-order perturbation theories, XVH2(n), XVMP2[n], and XVMP2(n), are shown to be rigorously diagrammatically size consistent for both total energies and transition frequencies, yield accurate results (typically within a few cm(-1) at n = 4 for water and formaldehyde) for both quantities even in the presence of Fermi resonance, and have access to fundamentals, overtones, and combinations as well as their relative intensities as residues of the vibrational Green's functions. They are implemented into simple algorithms that require only force constants and frequencies of the reference methods (with no basis sets, quadrature, or matrix diagonalization at any stage of the calculation). The rules for enumerating and algebraically interpreting energy and self-energy diagrams are elucidated in detail. PMID:23883014

Hermes, Matthew R; Hirata, So

2013-07-21

303

Second-order many-body perturbation expansions of vibrational Dyson self-energies  

NASA Astrophysics Data System (ADS)

Second-order many-body perturbation theories for anharmonic vibrational frequencies and zero-point energies of molecules are formulated, implemented, and tested. They solve the vibrational Dyson equation self-consistently by taking into account the frequency dependence of the Dyson self-energy in the diagonal approximation, which is expanded in a diagrammatic perturbation series up to second order. Three reference wave functions, all of which are diagrammatically size consistent, are considered: the harmonic approximation and diagrammatic vibrational self-consistent field (XVSCF) methods with and without the first-order Dyson geometry correction, i.e., XVSCF[n] and XVSCF(n), where n refers to the truncation rank of the Taylor-series potential energy surface. The corresponding second-order perturbation theories, XVH2(n), XVMP2[n], and XVMP2(n), are shown to be rigorously diagrammatically size consistent for both total energies and transition frequencies, yield accurate results (typically within a few cm-1 at n = 4 for water and formaldehyde) for both quantities even in the presence of Fermi resonance, and have access to fundamentals, overtones, and combinations as well as their relative intensities as residues of the vibrational Green's functions. They are implemented into simple algorithms that require only force constants and frequencies of the reference methods (with no basis sets, quadrature, or matrix diagonalization at any stage of the calculation). The rules for enumerating and algebraically interpreting energy and self-energy diagrams are elucidated in detail.

Hermes, Matthew R.; Hirata, So

2013-07-01

304

Energy Industry Powers CTE Program  

ERIC Educational Resources Information Center

Michael Fields is a recent graduate of Buckeye Union High School in Buckeye, Arizona. Fields is enrolled in the Estrella Mountain Community College (EMCC) Get Into Energy program, which means he is well on his way to a promising career. Specializing in power plant technology, in two years he will earn a certificate that will all but guarantee a…

Khokhar, Amy

2012-01-01

305

Energy Industry Powers CTE Program  

ERIC Educational Resources Information Center

|Michael Fields is a recent graduate of Buckeye Union High School in Buckeye, Arizona. Fields is enrolled in the Estrella Mountain Community College (EMCC) Get Into Energy program, which means he is well on his way to a promising career. Specializing in power plant technology, in two years he will earn a certificate that will all but guarantee a…

Khokhar, Amy

2012-01-01

306

Diffusion Monte Carlo studies of low energy ro-vibrational states of CH 5 + and its deuterated isotopologues  

Microsoft Academic Search

A snapshot of the large amplitude motions of a rotating and vibrating CH 5 + molecule.&z.squf;&z.squf; Developed a method for evaluating J = 1 energies and wave functions for CH 5 + . Investigated implications of inversion symmetry in CH 5 + . Probed effects of deuteration on the ro-vibrational energies and wave functions.

Charlotte E. Hinkle; Andrew S. Petit; Anne B. McCoy

2011-01-01

307

Diffusion Monte Carlo studies of low energy ro-vibrational states of CH 5 + and its deuterated isotopologues  

NASA Astrophysics Data System (ADS)

A snapshot of the large amplitude motions of a rotating and vibrating CH 5 + molecule.&z.squf;&z.squf; Developed a method for evaluating J = 1 energies and wave functions for CH 5 + . Investigated implications of inversion symmetry in CH 5 + . Probed effects of deuteration on the ro-vibrational energies and wave functions.

Hinkle, Charlotte E.; Petit, Andrew S.; McCoy, Anne B.

2011-07-01

308

Iterative solutions with energy selected bases for highly excited vibrations of tetra-atomic molecules  

NASA Astrophysics Data System (ADS)

The use of energy selected bases (ESB) with iterative diagonalization of the Hamiltonian matrix is described for vibrations of tetra-atomic systems. The performance of the method is tested by computing vibrational states of HOOH below 10 000 cm-1 (1296 A+ symmetry states) and H2CO below 13 500 cm-1 (729 A1 symmetry states). For iterative solutions, we tested both the implicitly restarted Lanczos method (IRLM) and the standard (nonreorthogonalizing) Lanczos approach. Comparison with other contracted basis approach as well as direct product grid representation shows superior performance of the ESB/IRLM approach. Of the two systems, H2CO is found to be more challenging than HOOH since it has much stronger couplings among vibrational modes, which leads to a drastically larger primitive basis set. For H2CO we also discuss some interesting behavior of the molecule in the high internal energy regime.

Lee, Hee-Seung; Light, John C.

2004-03-01

309

V-V energy transfer from high vibrational levels of propynal  

SciTech Connect

Results on infrared multiphoton absorption in propynal in which changes in the vibrational populations of ..nu../sub 6/ (v = 1,2) and ..nu../sub 10/ (v = 1,2) pumped under molecular beam or fast flow conditions were observed and reported recently. By producing a vibrationally excited beam of propynal and allowing for subsequent collisions with added gas molecules, it was possible to study V-V energy transfer processes which occur on a time scale less than or equal to gas kinetic. Relative cross sections for energy transfer from high vibrational levels were measured directly for the first time using visible - IR double resonance in a molecular beam - gas experiment. The process can be described by the general equation, C/sub 3/H/sub 2/O (v > 1) + M ..-->.. C/sub 3/H/sub 2/O (v = 1) + M + ..delta..E.

Brenner, D M

1980-01-01

310

Tuning out vibrational levels in molecular electron energy-loss spectra  

NASA Astrophysics Data System (ADS)

The phenomenon whereby features associated with certain vibrational levels in molecular states of mixed electronic character disappear under specific scattering conditions in electron energy-loss spectra is investigated. In particular, using a combination of experimental measurements and coupled-channel calculations, anomalous vibrational intensities in the mixed valence-Rydberg 1?u?X1?g+ transition of N2 are explained. A single parameter, i.e., the ratio of the generalized electronic transition moments to the diabatic valence and Rydberg components of the mixed states, dependent on the experimental scattering conditions, is found to be essentially capable of describing all observed relative vibrational intensities, including the near disappearance of the b1?u(v=5) feature for momentum-transfer-squared values K2?0.3 a.u. This result highlights the interesting possibility of experimental control of molecular quantum-interference effects in electron energy-loss spectra, something that is not possible in optical spectra.

Heays, A. N.; Lewis, B. R.; Gibson, S. T.; Malone, C. P.; Johnson, P. V.; Kanik, I.; Khakoo, M. A.

2012-01-01

311

Low power interface IC's for electrostatic energy harvesting applications  

NASA Astrophysics Data System (ADS)

The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of interest where the storage capacitor can be optimized to produce almost 70% of the ideal power taken as the power harvested with synchronous converters when neglecting the power consumption associated with synchronizing control circuitry. Theoretical predictions are confirmed by measurements on an asynchronous EHC implemented with a macro-scale electrostatic converter prototype. Based on the preceding analysis, the design of a novel ultra low power electrostatic integrated energy harvesting circuit is proposed for efficient harvesting of mechanical energy. The fundamental challenges of designing reliable low power sensing circuits for charge constrained electrostatic energy harvesters with capacity to self power its controller and driver stages are addressed. Experimental results are presented for a controller design implemented in AMI 0.7muM high voltage CMOS process using a macro-scale electrostatic converter prototype. The EHC produces 1.126muW for a power investment of 417nW with combined conduction and controller losses of 450nW which is a 20-30% improvement compared to prior art on electrostatic EHCs operating under charge constrain. Inherently dual plate variable capacitors harvest energy only during half of the mechanical cycle with the other half unutilized for energy conversion. To harvest mechanical energy over the complete mechanical vibration cycle, a low power energy harvesting circuit (EHC) that performs charge constrained synchronous energy conversion on a tri-plate variable capacitor for maximizing energy conversion is proposed. The tri-plate macro electrostatic generator with capacitor variation of 405pF to 1.15nF and 405pF to 1.07nF on two complementary adjacent capacitors is fabricated and used in the characterization of the designed EHC. The integrated circuit fabricated in AMI 0.7muM high voltage CMOS process, produces a total output power of 497nW to a 10muF reservoir capacitor from a 98Hz vibration signal. In summary, the thesis lays out the theoretical and experimental foundation for overcoming the main challenges associated with the desi

Kempitiya, Asantha

312

Near-resonant vibration. -->. vibration energy transfer under single-collision conditions. [Propynal  

SciTech Connect

Energy transfer in single collisions of propynal (HC triple bond C-CHO) subsequent to ir multiphonon absorption (CO/sub 2/ laser) was studied. SiF/sub 4/, CH/sub 3/F, CCl/sub 4/, and CH/sub 4/ were added. (DLC)

Breener, D M

1981-01-01

313

Coriolis-induced vibrational energy transfer in D2CO-D2CO collisions - A classical perspective  

NASA Astrophysics Data System (ADS)

Recent experimental studies of vibrational energy transfer in D2CO-D2CO collisions have demonstrated extraordinarily high cross sections for an intramolecular V-V process in which a vibrational quantum is transferred between the two low-frequency modes nu4 and nu6. In this paper a purely classical description of the energy-transfer mechanism is put forward. It is argued that the energy transfer arises from a resonant interaction between the Coriolis-coupled vibrations and the nutation of an asymmetric top; this induces a slow flopping motion of the molecule's dipole moment (superimposed on end-over-end rotation) which is coupled to the vibrational dynamics. The torque on this dipole produced by a passing molecule can thus pump energy into the vibrations. Classical perturbation theory is used to obtain rough estimates of the energy-transfer cross sections, which agree reasonably well with the experimental values.

Parson, Robert

1989-08-01

314

Modeling and design of an electromagnetic vibration energy harvester and its dedicated energy extraction circuit  

Microsoft Academic Search

This work investigates the design of an electromagnetic generator including its energy extraction and conditioning circuit. The normalized model of an electromagnetic generator points out three dimensionless parameters, characteristic of the generator. The power harvested with the SMFE (Synchronized Magnetic Flux Extraction) circuit is theoretically calculated and compared to the power extracted with a conventional approach. Optimal parameters orders of

Emmanuelle Arroyo; Adrien Badel; Fabien Formosa

2012-01-01

315

Eggshell Cutter Using Ultrasonic Vibration  

NASA Astrophysics Data System (ADS)

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.

Miura, Hikaru

2003-05-01

316

MEMS Vibration Energy Harvesting Devices With Passive Resonance Frequency Adaptation Capability  

Microsoft Academic Search

Further advancement of ambient mechanical vibration energy harvesting depends on finding a simple yet efficient method of tuning the resonance frequency of the harvester to match the one dominant in the environment. We propose an innovative approach to achieve a completely passive, wideband adaptive system by employing mechanical nonlinear strain stiffening. We present analytical analysis of the underlying idea as

Marcin Marzencki; Maxime Defosseux; Skandar Basrour

2009-01-01

317

Density of low-energy vibrational states in a protein solution  

NASA Astrophysics Data System (ADS)

Electron paramagnetic resonance measurements on the aquo complex of sperm whale skeletal myoglobin in solution at T<4 K show that, at phonon energies around 20 cm-1, the density of vibrational states is that of a three-dimensional system.

Brill, A. S.; Fiamingo, F. G.; Hampton, D. A.; Levin, P. D.; Thorkildsen, R.

1985-04-01

318

Optimized Structure and Vibrational Properties by Error Affected Potential Energy Surfaces  

PubMed Central

The precise theoretical determination of the geometrical parameters of molecules at the minima of their potential energy surface and of the corresponding vibrational properties are of fundamental importance for the interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo techniques are correlated electronic structure methods promising for large molecules, which are intrinsically affected by stochastic errors on both energy and force calculations, making the mentioned calculations more challenging with respect to other more traditional quantum chemistry tools. To circumvent this drawback in the present work, we formulate the general problem of evaluating the molecular equilibrium structures, the harmonic frequencies, and the anharmonic coefficients of an error affected potential energy surface. The proposed approach, based on a multidimensional fitting procedure, is illustrated together with a critical evaluation of systematic and statistical errors. We observe that the use of forces instead of energies in the fitting procedure reduces the statistical uncertainty of the vibrational parameters by 1 order of magnitude. Preliminary results based on variational Monte Carlo calculations on the water molecule demonstrate the possibility to evaluate geometrical parameters and harmonic and anharmonic coefficients at this level of theory with an affordable computational cost and a small stochastic uncertainty (<0.07% for geometries and <0.7% for vibrational properties).

Zen, Andrea; Zhelyazov, Delyan; Guidoni, Leonardo

2013-01-01

319

Simulation of an Electrostatic Energy Harvester at Large Amplitude Narrow and Wide Band Vibrations  

Microsoft Academic Search

An electrostatic in-plane overlap varying energy harvester is modeled and simulated using a circuit simulator. Both linear and nonlinear models are investigated. The nonli- near model includes mechanical stoppers at the displacement extremes. Large amplitude excitation signals, both narrow and wide band, are used to emulate environmental vibrations. Non- linear behavior is significant at large displacement due to the impact

Lars Geir Whist Tvedt; Lars-cyril Julin Blystad; Einar Halvorsen

2008-01-01

320

FIRST STEPS IN THE DEVELOPMENT OF A SEMIACTIVE FRICTION DEVICE TO REDUCE VIBRATION BY ENERGY DISSIPATION  

Microsoft Academic Search

This paper presents the first steps undertaken in the development of a semi-active friction compact device which can be bonded to any light flexible structure. Vibration reduction is achieved by dissipating energy through dry friction contact surfaces. More specifically, actuator design and controller optimal configuration are investigated here. The device is designed to include piezoelectric (PZT) stack actuators which produce

Paulin Buaka; Patrice Masson; Philippe Micheau

321

Design Synthesis of Electromagnetic Vibration-Driven Energy Generators Using a Variational Formulation  

Microsoft Academic Search

This paper reports upon the design of electromag- netic vibration-driven energy generators using a variational for- mulation to derive the equation of motion of such generators, thereby gaining insight into the device physics. Using this ap- proach, the characteristics of the generator are analytically stud- ied, a newly developed optimization theory of the generator is derived, and a guide for

Emmanuel Bouendeu; Andreas Greiner; Patrick J. Smith; Jan G. Korvink

2011-01-01

322

Application of the generalized Euler series transformation for calculation of vibration-rotation energy levels of diatomic molecules  

NASA Astrophysics Data System (ADS)

The detailed spectroscope information about highly excited molecules and radicals such us as H+3, H2, HI, H2O, CH2 is needed for a number of applications in the field of laser physics, astrophysics and chemistry. Studies of highly excited molecular vibration-rotation states face several problems connected with slowly convergence or even divergences of perturbation expansions. The physical reason for a perturbation expansion divergence is the large amplitude motion and strong vibration-rotation coupling. In this case one needs to use the special method of series summation. There were a number of papers devoted to this problem: papers 1-10 in the reference list are only example of studies on this topic. The present report is aimed at the application of GET method (Generalized Euler Transformation) to the diatomic molecule. Energy levels of a diatomic molecule is usually represented as Dunham series on rotational J(J+1) and vibrational (V+1/2) quantum numbers (within the perturbation approach). However, perturbation theory is not applicable for highly excited vibration-rotation states because the perturbation expansion in this case becomes divergent. As a consequence one need to use special method for the series summation. The Generalized Euler Transformation (GET) is known to be efficient method for summing of slowly convergent series, it was already used for solving of several quantum problems Refs.13 and 14. In this report the results of Euler transformation of diatomic molecule Dunham series are presented. It is shown that Dunham power series can be represented of functional series that is equivalent to its partial summation. It is also shown that transformed series has the butter convergent properties, than the initial series.

Kruglova, T. V.

2004-01-01

323

ENergy and Power Evaluation Program  

SciTech Connect

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.

NONE

1996-11-01

324

Vibrational energy exchanges in H{sub 2} and D{sub 2} collisions; the effect of rotational coupling  

SciTech Connect

The importance of the Coriolis coupling term in vibration-to-translation (V-T/R) energy exchange in collisions between vibrational excited H{sub 2} and D{sub 2} molecules has been pointed out within a semiclassical {open_quotes}coupled state{close_quotes} method. According this model the quantum equations of motion for the vibrational amplitudes are solved numerically by expanding the total wave function in the basis of the centrifugally distorted Morse wave functions. It turns out that the inclusion of the centrifugal force in the quantum equations has a significant effect on the vibrational energy transfered during the collision and, in turn, on the V-T/R cross-sections. Furthermore, this effect critically depends both on the vibrational energy contents of the colliding molecules and the impact energy at which the collision takes place.

Cacciatore, M.; Caporusso, R.A.; Billing, G.D. [Univ. of Copenhagen (Denmark)

1992-12-01

325

Energy Storage Options for Space Power.  

National Technical Information Service (NTIS)

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, therma...

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

1985-01-01

326

H2 optimization of electricity-generating tuned mass dampers for simultaneous vibration control and energy harvesting  

NASA Astrophysics Data System (ADS)

The classic tuned mass damper (TMD) is a passive vibration control device composed of an auxiliary mass connected to a vibrating object with a spring and an energy-dissipative element. When its parameters are optimized, it can reduce the vibration effectively. Recently, the authors proposed simultaneous vibration control and energy harvesting from tall buildings by replacing the energy-dissipative element of the TMD with electromagnetic transducers, which is called electricity-generating TMD. However, the electromagnetic transducers and the energy harvesting circuit, the modeling of which is an essentially a RL circuit, will introduce extra dynamics into the system, which has significant influence on the vibration mitigation performance. This paper investigates the influence, by optimizing the parameters. We found that the electricity-generating TMD can provide better vibration mitigation performance than the classic TMD and similar performance as the three-element TMD while harvesting the vibration energy at the same time. This paper utilizes the H2 criterions, which is to minimize the root-mean-square vibration under random excitation. The optimization method is presented in this paper, as well as the concise closed-form solution of the optimal parameters. A case study is also given to illustrate the effectiveness, robustness of the electricity-generating TMD and the sensitivity to the parameter changes.

Cui, Wen; Tang, Xiudong; Zuo, Lei

2013-04-01

327

Converged quantum dynamics calculations of vibrational energies of CH4 and CH3D using an ab initio potential  

NASA Astrophysics Data System (ADS)

Exact variational calculations of vibrational energies of CH4 and CH3D are carried out using a two-layer Lanczos algorithm based on the ab initio potential energy surface of D. W. Schwenke and H. Partridge, Spectrochim. Acta, Part A 57, 887 (2001). The convergence of the calculated vibrational energies is discussed in detail. In addition, we report all well converged vibrational energy levels up to 6600 cm-1 for CH4, and those up to 5000 cm-1 for CH3D, respectively. These results clearly outperform previous theoretical calculations. And a comparison with experimental results available is also made.

Yu, Hua-Gen

2004-10-01

328

Converged quantum dynamics calculations of vibrational energies of CH4 and CH3D using an ab initio potential.  

PubMed

Exact variational calculations of vibrational energies of CH4 and CH3D are carried out using a two-layer Lanczos algorithm based on the ab initio potential energy surface of D. W. Schwenke and H. Partridge, Spectrochim. Acta, Part A 57, 887 (2001). The convergence of the calculated vibrational energies is discussed in detail. In addition, we report all well converged vibrational energy levels up to 6600 cm(-1) for CH4, and those up to 5000 cm(-1) for CH3D, respectively. These results clearly outperform previous theoretical calculations. And a comparison with experimental results available is also made. PMID:15446929

Yu, Hua-Gen

2004-10-01

329

Diamagnetic levitation for nonlinear vibration energy harvesting: Theoretical modeling and analysis  

NASA Astrophysics Data System (ADS)

This paper provides theoretical modeling and analysis of applying diamagnetic levitation for nonlinear vibration energy harvesting in detail by first identifying potential merits as well as limitations. Based on a magnetic dipole model, analytical analysis is conducted by providing simplified analytical expressions of restoring forces and electromagnetic damping which are then transformed into a hardening spring model and results in a Duffing equation with strong nonlinearity. In addition, constraints on physical geometry are discussed and derived in the view of practical energy harvester design. More importantly, the derivation and discussion extended to multi-well potential suggest that diamagnetic levitation may enable designing an energy harvester that subject to cross-well chaos with a compact volume and wideband responses. Without mechanical damping in any form, diamagnetic levitation may be considered as a promising mechanism for developing vibration energy harvesters with great performance, and the paper provides a technology push on the possibility.

Liu, Lei; Yuan, F. G.

2013-01-01

330

Collisional energy transfer in highly vibrationally excited H2CO (X 1A1)  

NASA Astrophysics Data System (ADS)

Collisional energy transfer in H2CO (X 1A1) is studied at an internal energy of 11,400/cm, where the vibrational density of states is estimated to be 0.42/cm. Measurements of the rates of collisional energy transfer at the rotational state-to-state level are presented. Energy transfer from the 6(1,5) parent level into the levels 3(1,2), 4(1,3), 5(1,4), 7(1,6), and 8(1,7) of the 2(4)4(4) vibrational state has been detected. Details of the experimental procedure, which employed stimulated-emission-pumping transient-absorption spectroscopy, are discussed.

Temps, F.; Halle, S.; Vaccaro, P. H.; Field, R. W.; Kinsey, J. L.

1987-08-01

331

High Power Pulse Energy System Concept.  

National Technical Information Service (NTIS)

New advances in capacitor technology create exciting opportunities in size and weight reduction for high-power, pulse energy systems having a broad range of applications. Characteristics of a proposed high power pulse energy system, formed by combining a ...

H. L. Lee G. Mason K. Kern

1988-01-01

332

Flow-induced vibration  

SciTech Connect

This book reports on dimensional analysis; ideal fluid models; vortex-induced vibration; galloping and flutter; instability of tube and cylinder arrays; vibrations induced by oscillating flow; vibration induced by turbulence and sound; damping of structures; sound induced by vortex shedding; vibrations of a pipe containing a fluid flow; indices. It covers the analysis of the vibrations of structures exposed to fluid flows; explores applications for offshore platforms and piping; wind-induced vibration of buildings, bridges, and towers; and acoustic and mechanical vibration of heat exchangers, power lines, and process ducting.

Blevins, R.D.

1990-01-01

333

Apparatus for generating seismic vibration energy in a borehole  

SciTech Connect

A signal generating apparatus is described for use in fluid-filled boreholes, comprising: a frame for suspension in the borehole; a tube having first and second ends and disposed in the frame a first acoustic energy source mounted in the first end to direct energy to a central point; a second acoustic energy source mounted in the second end to direct energy to the central point; an energy deflector plate disposed at 45 degrees to and along the axis of the tube central point at an equal angle to each means for energizing the first and second acoustic energy sources.

Benzing, W.M.

1986-12-30

334

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

Microsoft Academic Search

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

Arian Rahimi; Ozge Zorlu; Haluk Kulah; Ali Muhtaroglu

2010-01-01

335

Low-energy vibrational density of states of plasticized poly(methyl methacrylate)  

Microsoft Academic Search

The low-energy vibrational density of states (VDOS) of hydrogenated or deuterated poly(methyl methacrylate) (PMMA) plasticized by dibutyl phthalate (DBP) is determined by inelastic neutron scattering. From experiment, it is equal to the sum of VDOSs of the PMMA and DBP components. However, a partition of the total low-energy VDOS between PMMA and DBP was observed. Contrary to Raman scattering, neutron

L. Saviot; E. Duval; J. F. Jal; A. J. Dianoux; V. A. Bershtein; L. David; S. Etienne

2002-01-01

336

Exploring Energy, Power, and Transportation Technology.  

ERIC Educational Resources Information Center

|These teacher's materials for a seven-unit course were developed to help students develop technological literacy, career exploration, and problem-solving skills relative to the communication industries. The seven units include an overview of energy and power, principles of energy and power, power production and conversion, power transmission and…

Bowers, Donovan; Kellum, Mary

337

Measurement synchronization in the vibration diagnostic system of high power electric machines  

Microsoft Academic Search

The vibration measurement synchronization between wireless sensor nodes and with rotor revolution frequency of a supervised machine is necessary for diagnostic methods such as: operational modal analysis or operational shape deflection. This paper presents the review of existing methods for obtaining a discrete vibration signal whose sampling instants are synchronized with an angular position of the machine rotor. Moreover, the

Maciej Makowski; Piotr Pietrzak; B. Pe?kos?awski; Andrzej Napieralski

2010-01-01

338

The effects of whole-body vibration on muscle strength and power: a meta-analysis.  

PubMed

Exercise with whole-body vibration (WBV) is becoming popular as an alternative to conventional training or as supplementary training. However, despite increasing research efforts in this field, additive effects of WBV on muscle performance remain unclarified. In this review, we investigated the additive effects of long-term WBV on muscle strength and power. This meta-analysis was restricted to randomized controlled trials lasting for at least 5 weeks comparing exercise with and without WBV, or comparing only WBV exposure and control. Data from a total of 314 participants in 10 studies on knee extension muscle strength, and 249 participants in 7 studies on countermovement jump height were pooled using random-effect models. Meta-analysis showed significant additional effects of WBV on muscle strength (standardized mean difference [SMD]=0.76, 95% confidence interval [CI]=0.21-1.32; p=0.007) and countermovement jump (SMD=0.87, 95% CI=0.29-1.46; p=0.003). Based on these findings, we concluded that the use of WBV would lead to greater improvements in both knee extension muscle strength and countermovement jump than under identical conditions without WBV. PMID:23989260

Osawa, Y; Oguma, Y; Ishii, N

2013-09-01

339

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

Microsoft Academic Search

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

Meiling Zhu; Emma Worthington; Ashutosh Tiwari

2010-01-01

340

Elastic scattering, vibrational excitation, and attachment in low-energy electron- S F6 scattering: Experiment and effective range theory  

Microsoft Academic Search

Cross sections at low energies for vibrationally elastic and inelastic scattering, as well as electron attachment to SF6 , have been calculated using a multichannel effective range theory (ERT) with complex boundary conditions. The most active vibrational modes, the totally symmetric mode nu1 and the infrared active mode nu3 , have been included in the calculation. The ERT parameters were

Ilya I. Fabrikant; Hartmut Hotop; Michael Allan

2005-01-01

341

Effects of vibrational energy relaxation and reverse reaction on electron transfer kinetics and fluorescence line shapes in solution  

Microsoft Academic Search

The existing theoretical formulations of electron transfer reactions (ETR) neglect the effects of vibrational energy relaxation (VER) and do not include higher vibrational states in both the reactant and the product surfaces. Both of these aspects can be important for photo-induced electron transfer reactions, particularly for those which are in the Marcus inverted regime. In this article, a theoretical formulation

R. Aldrin Denny; Biman Bagchi; Paul F. Barbara

2001-01-01

342

Picosecond IR-UV pump-probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. I. Intramolecular vibrational energy redistribution of the OH and CH stretching vibrations of bare phenol  

NASA Astrophysics Data System (ADS)

The intramolecular vibrational energy redistribution (IVR) of the OH stretching vibration of jet-cooled phenol-h6 (C6H5OH) and phenol-d5 (C6D5OH) in the electronic ground state has been investigated by picosecond time-resolved IR-UV pump-probe spectroscopy. The OH stretching vibration of phenol was excited with a picosecond IR laser pulse, and the subsequent temporal evolutions of the initially excited level and the redistributed ones due to the IVR were observed by multiphoton ionization detection with a picosecond UV pulse. The IVR lifetime for the OH stretch vibration of phenol-h6 was determined to be 14 ps, while that of the OH stretch for phenol-d5 was found to be 80 ps. This remarkable change of the IVR rate constant upon the dueteration of the CH groups strongly suggests that the ``doorway states'' for the IVR from the OH level would be the vibrational states involving the CH stretching modes. We also investigated the IVR rate of the CH stretching vibration for phenol-h6. It was found that the IVR lifetime of the CH stretch is less than 5 ps. The fast IVR is described by the strong anharmonic resonance of the CH stretch with many other combinations or overtone bands.

Yamada, Yuji; Ebata, Takayuki; Kayano, Masakazu; Mikami, Naohiko

2004-04-01

343

Dynamic treatment of vibrational energy relaxation in a heterogeneous and fluctuating environment.  

PubMed

A computational approach to describe the energy relaxation of a high-frequency vibrational mode in a fluctuating heterogeneous environment is outlined. Extending previous work [H. Fujisaki, Y. Zhang, and J. E. Straub, J. Chem. Phys. 124, 144910 (2006)], second-order time-dependent perturbation theory is employed which includes the fluctuations of the parameters in the Hamiltonian within the vibrational adiabatic approximation. This means that the time-dependent vibrational frequencies along a molecular dynamics trajectory are obtained via a partial geometry optimization of the solute with fixed solvent and a subsequent normal mode calculation. Adopting the amide I mode of N-methylacetamide in heavy water as a test problem, it is shown that the inclusion of dynamic fluctuations may significantly change the vibrational energy relaxation. In particular, it is found that relaxation occurs in two phases, because for short times (approximately < 200 fs) the spectral density appears continuous due to the frequency-time uncertainty relation, while at longer times the discrete nature of the bath becomes apparent. Considering the excellent agreement between theory and experiment, it is speculated if this behavior can explain the experimentally obtained biphasic relaxation the amide I mode of N-methylacetamide. PMID:19045081

Fujisaki, Hiroshi; Stock, Gerhard

2008-10-01

344

Bottlenecks to vibrational energy flow in carbonyl sulfide: structures and mechanisms.  

PubMed

Finding the causes for the nonstatistical vibrational energy relaxation in the planar carbonyl sulfide (OCS) molecule is a longstanding problem in chemical physics: Not only is the relaxation incomplete long past the predicted statistical relaxation time but it also consists of a sequence of abrupt transitions between long-lived regions of localized energy modes. We report on the phase space bottlenecks responsible for this slow and uneven vibrational energy flow in this Hamiltonian system with three degrees of freedom. They belong to a particular class of two-dimensional invariant tori which are organized around elliptic periodic orbits. We relate the trapping and transition mechanisms with the linear stability of these structures. PMID:19405559

Paskauskas, R; Chandre, C; Uzer, T

2009-04-28

345

Vibrational subsystem analysis: A method for probing free energies and correlations in the harmonic limit  

PubMed Central

A new vibrational subsystem analysis (VSA) method is presented for coupling global motion to a local subsystem while including the inertial effects of the environment. The premise of the VSA method is a partitioning of a system into a smaller region of interest and a usually larger part referred to as environment. This method allows the investigation of local-global coupling, a more accurate estimation of vibrational free energy contribution for parts of a large system, and the elimination of the “tip effect” in elastic network model calculations. Additionally, the VSA method can be used as a probe of specific degrees of freedom that may contribute to free energy differences. The VSA approach can be employed in many ways, but it will likely be most useful for estimating activation free energies in QM?MM reaction path calculations. Four examples are presented to demonstrate the utility of this method.

Woodcock, H. Lee; Zheng, Wenjun; Ghysels, An; Shao, Yihan; Kong, Jing; Brooks, Bernard R.

2008-01-01

346

Vibrational subsystem analysis: A method for probing free energies and correlations in the harmonic limit  

NASA Astrophysics Data System (ADS)

A new vibrational subsystem analysis (VSA) method is presented for coupling global motion to a local subsystem while including the inertial effects of the environment. The premise of the VSA method is a partitioning of a system into a smaller region of interest and a usually larger part referred to as environment. This method allows the investigation of local-global coupling, a more accurate estimation of vibrational free energy contribution for parts of a large system, and the elimination of the ``tip effect'' in elastic network model calculations. Additionally, the VSA method can be used as a probe of specific degrees of freedom that may contribute to free energy differences. The VSA approach can be employed in many ways, but it will likely be most useful for estimating activation free energies in QM/MM reaction path calculations. Four examples are presented to demonstrate the utility of this method.

Woodcock, H. Lee; Zheng, Wenjun; Ghysels, An; Shao, Yihan; Kong, Jing; Brooks, Bernard R.

2008-12-01

347

Potential energy surface and vibrational band origins of the triatomic lithium cation  

NASA Astrophysics Data System (ADS)

The 104 point CISD Li +3 potential energy surface and its analytical representation is reported. The calculations predict the minimum energy geometry to be an equilateral triangle of side RLi?Li = 3.0 Å and of energy - 22.20506 E h. A fifth-order Morse—Dunham type analytical force field is used in the Carney—Porter normal co-ordinate vibrational Hamiltonian, the corresponding eigenvalue problem being solved variationally using a 560 configurational finite-element basis set. The predicted assignment of the vibrational band origins is in accord with that reported for H +3. Moreover, for 6Li +3 and 7Li +3 the lowest i.r. accessible band origin is the overline?0,1,±1 predicted to be at 243.6 and 226.0 cm -1 respectively.

Searles, Debra J.; Dunne, Simon J.; von Nagy-Felsobuki, Ellak I.

348

Static and free vibration analyses of continuously graded fiber-reinforced cylindrical shells using generalized power-law distribution  

Microsoft Academic Search

In this study, based on the three-dimensional theory of elasticity, static and free vibration characteristics of continuously\\u000a graded fiber-reinforced (CGFR) cylindrical shells are considered by making use of a generalized power-law distribution. In\\u000a the present formulation, the cylindrical shell is assumed to be made of an orthotropic material. The CGFR cylindrical shells\\u000a have a smooth variation of matrix volume fraction

B. Sobhani Aragh; M. H. Yas

2010-01-01

349

Fabrication of a vibration-driven electromagnetic energy harvester with integrated NdFeB\\/Ta multilayered micro-magnets  

Microsoft Academic Search

This paper describes the fabrication of MEMS-based electromagnetic energy harvesters for scavenging energy from the ambient vibration. The novel energy harvester is fabricated by bonding a vibrator with embedded micro-magnets and a stator with integrated microcoils. The micro-magnets are formed by using sputtering deposition of NdFeB\\/Ta multilayered magnetic films with a thickness of 10 µm and silicon molding techniques. High-aspect-ratio

Yonggang Jiang; Shingo Masaoka; Takayuki Fujita; Minoru Uehara; Tomohiko Toyonaga; Kouhei Fujii; Kohei Higuchi; Kazusuke Maenaka

2011-01-01

350

Modeling of magnetic vibrational energy harvesters using equivalent circuit representations  

Microsoft Academic Search

This paper develops and analyzes an equivalent circuit model of magnetic energy harvesters using reduced-order lumped element modeling (LEM) methods. This model is intended to enhance the design and analysis of a magnetic energy harvesting system by enabling direct physical insight into the system dynamics and simple circuit analysis techniques to extract all relevant performance parameters. Moreover, the model provides

Shuo Cheng; Naigang Wang; David P. Arnold

2007-01-01

351

Vibrational and collision energy effects on the reaction of CH3CHO+ with methanol  

NASA Astrophysics Data System (ADS)

Integral cross sections and product velocity distributions were measured for reaction of acetaldehyde cation with methanol over a center-of-mass collision energy range from 0.1 to 2.2 eV. Reactivity is dominated by exoergic proton transfer (PT), which is strongly suppressed by collision energy, and mildly suppressed by CH3CHO+ vibrational excitation. PT is complex-mediated at low energies, switching to a direct stripping mechanism at high energies. Of the two possible PT channels, it appears that transfer of the aldehyde proton dominates. Hydrogen abstraction (HA) is a minor channel at low collision energies, also complex-mediated. Abstraction is observed from both hydroxyl and methyl sites on methanol, and the two channels have different, and counterintuitive collision energy dependence. Despite being exoergic, with no barriers, the HA channel shows apparent threshold behavior, attributed to competition with the dominant PT channel. The competition indicates that different intermediate complexes must interconvert efficiently, at least for low collision energies. At low energies, HA is strongly enhanced by collision energy, while vibrational excitation has no effect. Finally, there is a minor product channel corresponding to methyl elimination (ME) from a complex. Despite a relatively complicated reaction coordinate, the ME channel shows substantial recoil energy release and an asymmetric velocity distribution. A series of ab initio and RRKM calculations were performed to help interpret the results.

Kim, Ho-Tae; Liu, Jianbo; Anderson, Scott L.

2001-10-01

352

Power Technologies Energy Data Book. Third Edition.  

National Technical Information Service (NTIS)

In 2002, the Energy Analysis Office of the National Renewable Energy Laboratory (NREL) developed the first version of the Power Technologies Energy Data Book for the Office of Power Technologies of the U.S. Department of Energy (DOE). The main purpose of ...

2005-01-01

353

Time Resolved Energy Transfer and Photodissociation of Vibrationally Excited Molecules.  

National Technical Information Service (NTIS)

These experiments use ultrafast laser spectroscopy to study reaction and photodissociation dynamics in solution, probing both photodissociation and intramolecular energy transfer. They have observed the photodissociation dynamics of methylhypochlorite (CH...

F. F. Crim

2007-01-01

354

Electromagnetic energy harvesting from vibrations of multiple frequencies  

Microsoft Academic Search

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

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

2009-01-01

355

Optimization and AMS Modeling for Design of an Electrostatic Vibration Energy Harvester's Conditioning Circuit with an Auto-Adaptive Process to the External Vibration Changes  

Microsoft Academic Search

Electrostatic transducers for vibration energy scavenging have been an object\\u000ato numerous studies, but are still facing major issues relating to their\\u000aconditioning circuit. One of the most popular ones uses a charge pump and a\\u000aflyback circuit based on a Buck DC-DC converter (Fig. 1). A commutation between\\u000athe energy accumulation in the charge pump and the recharge of

Dimitri Galayko; Philippe Basset; Ayyaz Mahmood Paracha

2008-01-01

356

Calculation of converged rovibrational energies and partition function for methane using vibrational-rotational configuration interaction.  

PubMed

The rovibration partition function of CH4 was calculated in the temperature range of 100-1000 K using well-converged energy levels that were calculated by vibrational-rotational configuration interaction using the Watson Hamiltonian for total angular momenta J = 0-50 and the MULTIMODE computer program. The configuration state functions are products of ground-state occupied and virtual modals obtained using the vibrational self-consistent field method. The Gilbert and Jordan potential energy surface was used for the calculations. The resulting partition function was used to test the harmonic oscillator approximation and the separable-rotation approximation. The harmonic oscillator, rigid-rotator approximation is in error by a factor of 2.3 at 300 K, but we also propose a separable-rotation approximation that is accurate within 2% from 100 to 1000 K. PMID:15260761

Chakraborty, Arindam; Truhlar, Donald G; Bowman, Joel M; Carter, Stuart

2004-08-01

357

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

Microsoft Academic Search

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

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

2012-01-01

358

Improved design of linear electromagnetic transducers for large-scale vibration energy harvesting  

Microsoft Academic Search

This paper presents the design and optimization of tubular Linear Electromagnetic Transducers (LETs) with applications to large-scale vibration energy harvesting, such as from vehicle suspensions, tall buildings or long bridges. Four types of LETs are considered and compared, namely, single-layer configuration using axial magnets, double-layer configuration using axial magnets, single-layer configuration using both axial and radial magnets, double-layer configuration using

Xiudong Tang; Lei Zuo; Teng Lin; Peisheng Zhang

2011-01-01

359

Interplay between vibrational energy transfer and excited state deactivation in DNA components.  

PubMed

Femtosecond laser spectroscopies are used to examine a thymine family of systems chosen to expose the interplay between excited state deactivation and two distinct vibrational energy transfer (VET) pathways: (i) VET from the base to the deoxyribose ring; (ii) VET between neighboring units in a dinucleotide. We find that relaxation in the ground electronic state accelerates markedly as the molecular sizes increase from the nucleobase to the dinucleotide. This behavior directly reflects growth in the density of vibrational quantum states on the substituent of the base. Excited state lifetimes are studied at temperatures ranging from 100 to 300 K to characterize the thermal fluctuations that connect the Franck-Condon geometries and the conical intersections leading back to the ground state. An Arrhenius analysis yields an approximate excited state energy barrier of 13 meV in the thymine dinucleotide. In addition, we find that the transfer of vibrational energy from the base to the substituent suppresses thermal fluctuations across this energy barrier. The possibility that the solvent viscosity imposes friction on the reaction coordinate is examined by comparing thymine and adenine systems. Experiments suggest that the solvent viscosity has little effect on barrier crossing dynamics in thymine because the conical intersection is accessed through relatively small out-of-plane atomic displacements. Overall, we conclude that the transfer of vibrational quanta from thymine to the deoxyribose ring couples significantly to the internal conversion rate, whereas the neighboring unit in the dinucleotide serves as a secondary heat bath. In natural DNA, it follows that (local) thermal fluctuations in the geometries of subunits involving the base and deoxyribose ring are most important to this subpicosecond relaxation process. PMID:22920964

West, Brantley A; Womick, Jordan M; Moran, Andrew M

2012-09-06

360

A nonlinear model for highly excited vibrational energy levels of silane  

Microsoft Academic Search

The highly excited vibrational energy levels of SiH stretches of silane SiH4 in the electronic ground state are calculated using a three-parameter nonlinear model, i.e., the quantized discrete self-trapping equation. The obtained results are in good agreements with the experimental data and with those obtained from local mode calculations of others. We note that SiH4 molecule is a typical molecule

Chen Xiang-rong; Cheng Yan; Luo Jun; Gou Qing-quan; Pang Xiao-feng

1999-01-01

361

Calculations of stretching vibrational energy levels of the CH3I molecule by a nonlinear model  

Microsoft Academic Search

A nonlinear model, i.e. the quantized discrete self-trapping equation, is applied to calculate the highly excited CH stretching vibrational energy levels of the CH3I molecule in the liquid phase at the electronic ground state up to n=8. The obtained results agree well with the experimental data and with those obtained from local mode model calculations. We note that the dominant

Jun Zhu; Qing-quan Gou

2001-01-01

362

The Effect of Vibrational Energy on the Isomerization Reaction of Trans-Stilbene in the Condensed Phase  

NASA Astrophysics Data System (ADS)

We study the effect of vibrational energy on the isomerization reaction of trans-stilbene in deuterated chloroform. We first excite a ground-state C-H stretch overtone or a stretch-bend combination and allow vibrational relaxation to occur within the molecule before photoinitiating the excited-state isomerization with an ultraviolet photon. Once the stilbene molecule is on the excited state, we monitor the isomerization dynamics via broadband transient absorption spectroscopy. We measure an excited-state lifetime of 55 ± 9 ps when exciting through the C-H stretch overtone and a lifetime of 56 ± 7 ps for excitation through the stretch-bend combination. The trans-stilbene excited-state lifetime after single photon vertical excitation is 52 ± 6 ps with the total added energy being the same for all measurements. Unlike in gas phase studies, where vibrational motion can change the outcome of a chemical reaction, there is no observed difference in the reaction dynamics when exciting this condensed phase system with a single photon versus exciting through a ground-state vibrational mode. Interactions with the solvent cause fast vibrational relaxation on the excited state, though the insensitivity of the rate to vibrational energy may also be due to excess vibrational energy not being promptly partitioned into modes along the isomerization coordinate.

Briney, Kristin A.; Herman, Leslie V.; Boucher, Dave S.; Crim, F. Fleming

2010-06-01

363

Real-time condition monitoring of thermal power plants feed-pumps by rolling bearings supports vibration  

NASA Astrophysics Data System (ADS)

The report addresses the real-time condition monitoring of technical state and automatic diagnosis of auxiliary equipment for bearings supports vibration, for example, control of the feed-pump operating modes of thermal power stations. The causes that lead to premature birth and development of defects in rolling bearings are identified and the development of activities ensuring safe and continuous operation of the auxiliary equipment of thermal power stations is carried out. Collection and analysis of vibration parameters of pumping units during their operation at the operating modes of the technological process are realized by means of real-time technical condition monitoring. Spectral analysis of vibration parameters of one of the pumps showed the presence of frequency components, which mark violations in the operating practices of the pump, the imbalance development and, as a consequence, the development of defects in the bearings by long-term operation of the unit. Timely warning of the personnel on the operation of the unit with the "INTOLERABLE" technical state and automatic warning issuance of the need to change the technological process allowed to recover the estimated pump operation mode in due time and prevent further development of defects in equipment.

Kostyukov, V. N.; Tarasov, E. V.

2012-05-01

364

Picosecond IR-UV pump-probe spectroscopic study on the intramolecular vibrational energy redistribution of NH2 and CH stretching vibrations of jet-cooled aniline  

NASA Astrophysics Data System (ADS)

Intramolecular vibrational energy redistribution (IVR) of the NH2 symmetric and asymmetric stretching vibrations of jet-cooled aniline has been investigated by picosecond time-resolved IR-UV pump-probe spectroscopy. A picosecond IR laser pulse excited the NH2 symmetric or asymmetric stretching vibration of aniline in the electronic ground state and the subsequent time evolutions of the excited level as well as redistributed levels were observed by a picosecond UV pulse. The IVR lifetimes for symmetric and asymmetric stretches were obtained to be 18 and 34 ps, respectively. In addition, we obtained the direct evidence that IVR proceeds via two-step bath states; that is, the NH2 stretch energy first flows into the doorway state and the energy is further dissipated into dense bath states. The rate constants of the second step were estimated to be comparable to or slower than those of the first step IVR. The relaxation behavior was compared with that of IVR of the OH stretching vibration of phenol [Y. Yamada, T. Ebata, M. Kayano, and M. Mikami J. Chem. Phys. 120, 7400 (2004)]. We found that the second step IVR process of aniline is much slower than that of phenol, suggesting a large difference of the ``doorway state<-->the dense bath states'' anharmonic coupling strength between the two molecules. We also observed IVR of the CH stretching vibrations, which showed much faster IVR behavior than that of the NH2 stretches. The fast relaxation is described by the interference effect, which is caused by the coherent excitation of the quasistationary states.

Yamada, Yuji; Okano, Jun-Ichi; Mikami, Naohiko; Ebata, Takayuki

2005-09-01

365

Power Composites: Structural Materials that Generate and Store Electrical Energy.  

National Technical Information Service (NTIS)

We describe progress in the development of a synthetic multifunctional material: namely a fiber composite with both power and structural function. The structural composite contains batteries encased in piezoelectric tubes. When the structure vibrates the ...

D. A. Shockey S. C. Ventura S. C. Narang J. W. Simons B. C. Bourne

2005-01-01

366

Intermolecular Vibration-to-Vibration Energy Transfer in HF/DF(v=1) + HF/DF(v=1) yields HF/DF(v=0) + HF/DF(v=2) through the Formation of Dimers.  

National Technical Information Service (NTIS)

A theory of vibration-to-vibration energy transfer is developed for HF/DF(V=1) + HF/DF(V=1) yeilds HF/DF(V=0) + HF/DF(V=2) based on the model of dimer formation. This model is shown to be primarily responsible for the energy transfer below 500 K where a s...

H. K. Shin

1974-01-01

367

Study on optical attenuation performance of special stock power optical cable based on a wind induced vibration environment in laboratory  

NASA Astrophysics Data System (ADS)

For the purpose of 10G communication system upgrade for Guangdong Power Grid, laboratory simulation tests on dynamic and temperature cycle are performed for the reserved cables (stock optical cables) of existing 2.5G special optical cable lines that have operated for ten years, in order to verify the possibility of optical cable to be upgraded to a 10G transmission level and evaluate the degradation level of optical cables. This paper points out the necessity of laboratory test on attenuation performance in a wind-induced vibration environment, describes the test methods thereof, summarizes and analyzes a variety of optical attenuation performance data, and finds that the attenuation performance of current OPGW, ADSS, ADL optical fiber lines in wind-induced vibration environment meets the industry standards.

Li, Jie; Zhao, Ziyuan

2010-08-01

368

A Sigma–Delta Controlled Power Converter for Energy Harvesting Applications  

Microsoft Academic Search

\\u000a This work proposes an autonomous energy scavenger battery-free switching power supply. A piezoelectric transducer is used\\u000a to get electric energy from a mechanical vibrating source. Piezoelectric device has been modelled by means of its equivalent\\u000a electric resonant model. All system has been designed and then simulated at system level by means of SystemC-WMS environment.\\u000a The device make use of a

Rocco d’Aparo; Simone Orcioni; Massimo Conti

369

Vibrational exchange in high-energy linear collisions  

SciTech Connect

Over a wide interval for the interval for the energy of relative motion, the authors have considered the problems of linear collision of a classical oscillator (anharmonic in the general case) with a structureless particle for an arbitrary mass ratio, and the collision of two classical harmonic oscillators with close frequencies. Results of the analytical solutions in the adiabatic and the impulse limits are given in comparison with the results of the corresponding numerical calculations.

Skrebkov, O.V.; Smirnov, A.L.

1985-09-01

370

Vibrational energy scavenging with Si technology electromagnetic inertial microgenerators  

Microsoft Academic Search

In this work, we present the design and optimization of an electromagnetic inertial microgenerator for energy scavenging applications,\\u000a compatible with Si technology. It consists of a fixed micromachined coil and a movable magnet (inertial mass) mounted on a\\u000a resonant structure (Kapton® membrane). The modeling of the device, based on a velocity damped resonator, has allowed to make a quantitative analysis

Christophe Serre; Alejandro Pérez-Rodríguez; Nuria Fondevilla; Joan Ramon Morante; Josep Montserrat; Jaume Esteve

2007-01-01

371

Vibrational-Rotational Energy Distributions in the Reaction O- + D2 ? OD + D-  

NASA Astrophysics Data System (ADS)

The D+ transfer reaction between O- (2P) and D2 to form OD and D- was studied using the crossed molecular beam technique at collision energies of 1.55 and 1.95 eV. The reaction appears to proceed by a direct mechanism through large impact parameters. At both collision energies, more that 70% of the excess energy is partitioned into product translation. At the lower collision energy, the OD products are formed in the ground vibrational state with a bimodal rotational energy distribution. At the higher collision energy, both v' = 0 and 1 products are formed; ground vibrational state products have a mean rotational energy of 0.05 eV, corresponding to J' ? 6. In contrast, OD products formed in v' = 1 are formed with significant rotational excitation, with the most probable J' ? 15. The bimodal rotational distribution is rationalized in terms of trajectories that sample two potential surfaces coupled by a conical intersection in the vicinity of the [O···DD]- intermediate that correlate to (OD-,D) or (OD,D-) products.

Li, Yue; Liu, Li; Farrar, James M.

2009-10-01

372

Energy storage systems for advanced power applications  

Microsoft Academic Search

While energy storage technologies do not represent energy sources, they provide valuable added benefits to improve stability power quality, and reliability of supply. Battery technologies have improved significantly in order to meet the challenges of practical electric vehicles and utility applications. Flywheel technologies are now used in advanced nonpolluting uninterruptible power supplies. Advanced capacitors are being considered as energy storage

PAULO F. RIBEIRO; BRIAN K. JOHNSON; MARIESA L. CROW; AYSEN ARSOY; YILU LIU

2001-01-01

373

Potential energy, relaxation, vibrational dynamics and the boson peak, of hyperquenched glasses  

NASA Astrophysics Data System (ADS)

We describe a combination of laboratory and simulation studies that give quantitative information on the energy landscape for glass-forming liquids. Both types of study focus on the idea of suddenly extracting the thermal energy, so that the system obtained for subsequent study has the structure, and hence potential energy, of a liquid at a much higher temperature than the normal glass temperature Tg. One type of study gives information on the energy that can be trapped in experimental glasses by hyperquenching, relative to the normal glass, and on the magnitude of barriers separating basins of attraction on the landscape. Stepwise annealing studies also give information on the matter of energy heterogeneity and the question of 'nanogranularity' in liquids near Tg. The other type of study gives information on the vibrational properties of a system confined to a given basin, and particularly on how that vibrational structure changes with the state of configurational excitation of the liquid. A feature in the low frequency ('boson peak') region of the density of vibrational states of the normal glass becomes much stronger in the hyperquenched glass. Qualitatively similar observations are made on heating fragile glass-formers into the supercooled and stable liquid states. The vibrational dynamics findings are supported and elucidated by constant pressure molecular dynamics/normal mode MD/NM simulations/analysis of the densities of states of different inherent structures of a model fragile liquid (orthoterphenyl (OTP) in the Lewis-Wahnstrom approximation). These show that, when the temperature is raised at constant pressure, the total density of states changes in a manner that can be well represented by a two-Gaussian 'excitation across the centroid', leaving a third and major Gaussian component unchanging. The low frequency Gaussian component, which grows with increasing temperature, has a constant peak frequency of 18 cm-1 and is identified with the Boson peak. It is suggested that the latter can serve as a signature for configurational excitations of the ideal glass structure, i.e. the topologically diverse defects of the glassy solid state. The excess vibrational heat capacity associated with this generation of low frequency modes with structural excitation is shown to be responsible for about 60% of the jump in heat capacity at Tg, most of the remainder coming from configurational excitation.

Angell, C. Austen; Yue, Yuanzheng; Wang, Li-Min; Copley, John R. D.; Borick, Steve; Mossa, Stefano

2003-03-01

374

Power management in energy harvesting sensor networks  

Microsoft Academic Search

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

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

2007-01-01

375

Energy analysis of the Solar Power Satellite  

Microsoft Academic Search

The energy requirements to build and operate the proposed Solar Power Satellite are evaluated and compared with the energy it produces. Because the technology is so speculative, uncertainty is explicitly accounted for. For a proposed 10-gigawatt satellite system, the energy ratio, defined as the electrical energy produced divided by the primary nonrenewable energy required over the lifetime of the system,

R. A. Herendeen; T. Kary; J. Rebitzer

1979-01-01

376

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

SciTech Connect

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.

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

1992-04-01

377

Power shock: The next energy revolution  

SciTech Connect

Most experts seem to think that our decades-old oil- and coal-based energy systems will barely change. Developments around the world are already proving them wrong, however. We may soon witness the most dramatic changes in the world energy economy in a hundred years. This article discusses the power shift of the future from coal and oil fueled electric power to energy sources of the future such as wind power, photovoltaics, and solar heating.

Flavin, C.

1996-01-01

378

Study on boring hardened materials dryly by ultrasonic vibration cutter  

Microsoft Academic Search

It has been one of the difficulties that high-precision hole on hardened materials is machined. The supersonic vibration boring acoustic system in the lathe in which supersonic wave energy is applied on tool is introduced to create pulse power on the cutting process. The separation vibration cutting is achieved by the pulse force. The comparative tests on boring accuracy and

Jiangzhong Zhang; Heng Zhang; Yue Zhang

2010-01-01

379

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

NASA Astrophysics Data System (ADS)

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).

Rossi, Mariana; Blum, Volker; Scheffler, Matthias

2012-02-01

380

Unified energy conversion, power systems and power electronics lab  

Microsoft Academic Search

This paper introduces an unified laboratory consisting of power systems, power electronics and energy conversions at Oklahoma State University-Tulsa. It presents more on digital data acquisition (DAQ), and virtual instrumentation (VI), the base of our unified lab. The general design of lab setup is described here, and unique designs of front panels and motor mount are discussed in detail. Some

Seungwon An; Swakshar Ray; Thomas W. Gedra

2002-01-01

381

Energy trapping in power transmission through a circular cylindrical elastic shell by finite piezoelectric transducers.  

PubMed

We study the transmission of electric energy through a circular cylindrical elastic shell by acoustic wave propagation and piezoelectric transducers. Our mechanics model consists of a circular cylindrical elastic shell with finite piezoelectric patches on both sides of the shell. A theoretical analysis using the equations of elasticity and piezoelectricity is performed. A trigonometric series solution is obtained. Output voltage and transmitted power are calculated. Confinement and localization of the vibration energy (energy trapping) is studied which can only be understood from analyzing finite transducers. It is shown that when thickness-twist mode is used the structure shows energy trapping with which the vibration can be confined to the transducer region. It is also shown that energy trapping is sensitive to the geometric and physical parameters of the structure. PMID:18499207

Yang, Z T; Guo, S H

2008-04-12

382

Energy function analysis for power system stability  

Microsoft Academic Search

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.

M. A. Pai

1989-01-01

383

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

NASA Astrophysics Data System (ADS)

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.

Wolfsteiner, Peter; Breuer, Werner

2013-10-01

384

VIBRATION CONTROL OF SHIP STRUCTURES  

Microsoft Academic Search

Two control approaches are presented in this paper for the vibration control of ship structures. One aims to control vibration energy transmission from vibrating machinery to a ship structure by modifyin g the input mobility of the local supporting structure. A nother aims to control vibration energy propagation in the ship structure by introducing irregularities to the ring frame locations.

Tian Ran Lin; Chris Mechefske

385

Calculation of the interaction potential energy curve and vibrational levels for the a3?u+ state of Li27 molecule  

NASA Astrophysics Data System (ADS)

We solve the Schrödinger equation with the improved expression of the Manning–Rosen empirical potential energy model. The rotation-vibrational energy spectra and the unnormalized radial wave functions have been obtained. The interaction potential energy curve for the a3?u+ state of Li27 molecule is modeled by employing Manning–Rosen potential model. Favorable agreement for the Manning–Rosen potential is found in comparing with ab initio data. The vibrational energy levels predicted by using the Manning–Rosen potential for the a3?u+ state of Li27 are in good agreement with the RKR data and ab initio determinations.

Liu, Jian-Yi; Zhang, Guang-Dong; Jia, Chun-Sheng

2013-09-01

386

Vibration energy harvesting based on integrated piezoelectric components operating in different modes.  

PubMed

To increase the vibration energy-harvesting capability of the piezoelectric generator based on a cantilever beam, we have proposed a piezoelectric generator that not only uses the strain change of piezoelectric components bonded on a cantilever beam, but also employs the weights at the tip of the cantilever beam to hit piezoelectric components located on the 2 sides of weights. A prototype of the piezoelectric generator has been fabricated and its characteristics have been measured and analyzed. The experimental results show that the piezoelectric components operating in the hit mode can substantially enhance the energy harvesting of the piezoelectric generator on a cantilever beam. Two methods are used and compared in the management of rectified output voltages from different groups of piezoelectric components. In one of them, the DC voltages from rectifiers are connected in series, and then the total DC voltage is applied to a capacitor. In another connection, the DC voltage from each group is applied to different capacitors. It is found that 22.3% of the harvested energy is wasted due to the series connection. The total output electric energy of our piezoelectric generator at nonresonance could be up to 43 nJ for one vibration excitation applied by spring, with initial vibration amplitude (0-p) of 18 mm and frequency of 18.5 Hz, when the rectified voltages from different groups of piezoelectric components are connected to their individual capacitors. In addition, the motion and impact of the weights at the tip of the cantilever beam are theoretically analyzed, which well explains the experimental phenomena and suggests the measures to improve the generator. PMID:20178904

Hu, Junhui; Jong, Januar; Zhao, Chunsheng

2010-01-01

387

State-to-state spin-orbit and rotational energy transfer of very highly vibrationally excited nitric oxide  

NASA Astrophysics Data System (ADS)

The rotational and spin-orbit energy transfer in very highly vibrationally excited NO was investigated by the PUMP-DUMP-PROBE method. The vibrational influence on the rotational and spin-orbit energy transfer dynamics is evaluated by comparing the results with previous measurements for v = 2. Total depopulation rate constants for individual rovibrational states are found to be very similar for v = 2, 8, and 19; state-to-state rotational energy transfer rate constants could be compared for v = 8 and 19, and only small differences were found. The results suggest that vibrational energy has little effect on the rotational and spin-orbit energy transfer dynamics for NO-NO collisions.

Yang, Xueming; Wodtke, Alec M.

1992-04-01

388

The design, fabrication and evaluation of a MEMS PZT cantilever with an integrated Si proof mass for vibration energy harvesting  

Microsoft Academic Search

A microelectromechanical system (MEMS) piezoelectric energy harvesting device, a unimorph PZT cantilever with an integrated Si proof mass, was designed for low vibration frequency and high vibration amplitude environment. Pt\\/PZT\\/Pt\\/Ti\\/SiO2 multilayered films were deposited on a Si substrate and then the cantilever was patterned and released by inductively coupled plasma reactive ion etching. The fabricated device, with a beam dimension

Dongna Shen; Jung-Hyun Park; Jyoti Ajitsaria; Song-Yul Choe; Howard C. Wikle III; Dong-Joo Kim

2008-01-01

389

Unified power engineering laboratory for electromechanical energy  

Microsoft Academic Search

Summary form only given. This paper introduces a unified power engineering laboratory capable of various experiments for power systems, power electronics and electromechanical energy conversion. It presents a flexible hardware setup, data acquisition (DAQ), and virtual instrumentation (VI), the base of our unified lab. Some features of virtual instrumentation are shown with real-time phasor diagrams, sequence component analysis, and spectral

T. Gedra; Seungwon An

2004-01-01

390

Renewable Energy. The Power to Choose.  

ERIC Educational Resources Information Center

|This book, consisting of 13 chapters, charts the progress made in renewable energy in recent years and outlines renewable energy's prospects. Areas addressed include: energy at the crossroads (discussing oil, gas, coal, nuclear power, and the conservation revolution); solar building design; solar collection; sunlight to electricity; wood; energy

Deudney, Daniel; Flavin, Christopher

391

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

NASA Astrophysics Data System (ADS)

Numerous experimental and theoretical studies have established that intramolecular vibrational energy redistribution in isolated molecules has a hierarchical 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 correlation, 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. In this work we investigate the usefulness of the correlator in understanding the classical-quantum correspondence of effective spectroscopic Hamiltonians. 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 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.

Keshavamurthy, Srihari; Cerruti, Nicholas R.; Tomsovic, Steven

2002-09-01

392

Optimal Power Flow of Multiple Energy Carriers  

Microsoft Academic Search

This paper presents an approach for combined optimization of coupled power flows of different energy infrastructures such as electricity, gas, and district heating systems. A steady state power flow model is presented that includes conversion and transmission of an arbitrary number of energy carriers. The couplings between the different infrastructures are explicitly taken into account based on the new concept

Martin Geidl; Göran Andersson

2007-01-01

393

Mode-specific intermolecular vibrational energy transfer. II. Deuterated water and potassium selenocyanate mixture  

NASA Astrophysics Data System (ADS)

Vibrational energy transfer from the first excited state (2635 cm-1) of the O-D stretch of deuterated water (D2O) to the 0-1 transition (2075 cm-1) of the CN stretch of potassium selenocyanate (KSeCN) in their 2.5:1 liquid mixture was observed with a multiple-mode two dimensional infrared spectroscopic technique. Despite the big energy mismatch (560 cm-1) between the two modes, the transfer is still very efficient with a time constant of 20 ps. The efficient energy transfer is probably because of the large excitation coupling between the two modes. The coupling is experimentally determined to be 176 cm-1. An approximate analytical equation derived from the Landau-Teller formula is applied to calculate the energy transfer rate with all parameters experimentally determined. The calculation results are qualitatively consistent with the experimental data.

Bian, Hongtao; Wen, Xiewen; Li, Jiebo; Zheng, Junrong

2010-07-01

394

Accurate potential energy curve for B2. Ab initio elucidation of the experimentally elusive ground state rotation-vibration spectrum.  

PubMed

The electron-deficient diatomic boron molecule has long puzzled scientists. As yet, the complete set of bound vibrational energy levels is far from being known, experimentally as well as theoretically. In the present ab initio study, all rotational-vibrational levels of the X (3)?(g)(-) ground state are determined up to the dissociation limit with near-spectroscopic accuracy (<10 cm(-1)). Two complete sets of bound vibrational levels for the (11)B(2) and (11)B-(10)B isotopomers, containing 38 and 37 levels, respectively, are reported. The results are based on a highly accurate potential energy curve, which also includes relativistic effects. The calculated set of all vibrational levels of the (11)B(2) isotopomer is compared with the few results derived from experiment [Bredohl, H.; Dubois, I.; and Nzohabonayo, P. J. Mol. Spectrosc. 1982, 93, 281; Bredohl, H.; Dubois, I.; and Melen, F. J. Mol. Spectrosc. 1987, 121, 128]. Theory agrees with experiment within 4.5 cm(-1) on average for the four vibrational level spacings that are so far known empirically. In addition, the present theoretical analysis suggests, however, that the transitions from higher electronic states to the ground state vibrational levels v = 12-15 deserve to be reanalyzed. Whereas previous experimental investigators considered them to originate from the v' = 0 vibrational level of the upper state (2)(3)?(u)(-), the present results make it likely that these transitions originate from a different upper state, namely the v' = 16 or the v' = 17 vibrational level of the (1)(3)?(u)(-) state. The ground state dissociation energy D(0) is predicted to be 23164 cm(-1). PMID:22175225

Bytautas, Laimutis; Matsunaga, Nikita; Scuseria, Gustavo E; Ruedenberg, Klaus

2012-02-09

395

Ab initio study of vibrational excitation of HF by low energy electrons  

SciTech Connect

Fixed-nuclei, static-exchange calculations have been performed to study the vibrational-rotational excitation of HF by electrons from threshold to 5 eV. Our calculated, R-dependent K-matrix elements in /sup 2/..sigma../sup +/, /sup 2/Pi, and /sup 2/..delta.. symmetry are combined with exact point-dipole and laboratory-frame first-Born-approximation results for higher symmetries to obtain converged, integrated cross sections. The calculations show strong threshold peaks which are related to the dependence of the /sup 2/..sigma../sup +/ K-matrix elements on internuclear distance at small scattering energies.

Rescigno, T.N.; Orel, A.E.; Hazi, A.U.; McKoy, B.V.

1982-07-01

396

Compact inductive energy storage pulse power system.  

PubMed

An inductive energy storage pulse power system is being developed in BARC, India. Simple, compact, and robust opening switches, capable of generating hundreds of kV, are key elements in the development of inductive energy storage pulsed power sources. It employs an inductive energy storage and opening switch power conditioning techniques with high energy density capacitors as the primary energy store. The energy stored in the capacitor bank is transferred to an air cored storage inductor in 5.5 ?s through wire fuses. By optimizing the exploding wire parameters, a compact, robust, high voltage pulse power system, capable of generating reproducibly 240 kV, is developed. This paper presents the full details of the system along with the experimental data. PMID:22667637

K, Senthil; Mitra, S; Roy, Amitava; Sharma, Archana; Chakravarthy, D P

2012-05-01

397

Compact inductive energy storage pulse power system  

NASA Astrophysics Data System (ADS)

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.

K, Senthil; Mitra, S.; Roy, Amitava; Sharma, Archana; Chakravarthy, D. P.

2012-05-01

398

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

SciTech Connect

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.

Carter, S.; Bowman, J.M.

2000-03-23

399

Artificial piezoelectric grass for energy harvesting from turbulence-induced vibration  

NASA Astrophysics Data System (ADS)

The primary objective of this research is to develop a deploy-and-forget energy harvesting device for use in low-velocity, highly turbulent fluid flow environments i.e. streams or ventilation systems. The work presented here focuses on a novel, lightweight, highly robust, energy harvester design referred to as piezoelectric grass. This biologically inspired design consists of an array of cantilevers, each constructed with piezoelectric material. When exposed to proper turbulent flow conditions, these cantilevers experience vigorous vibrations. Preliminary results have shown that a small array of piezoelectric grass was able to produce up to 1.0 mW per cantilever in high-intensity turbulent flow having a mean velocity of 11.5 m s-1. According to the literature, this is among the highest output achieved using similar harvesting methods. A distributed parameter model for energy harvesting from turbulence-induced vibration will be introduced and experimentally validated. This model is generalized for the case of a single cantilever in turbulent cross-flow. Two high-sensitivity pressure probes were needed to perform spectral measurements within various turbulent flows. The design and performance of these probes along with calibration and measurement techniques will be discussed.

Hobeck, J. D.; Inman, D. J.

2012-10-01

400

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

Microsoft Academic Search

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

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

2004-01-01

401

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

SciTech Connect

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.

Rizzo, T.R.

1992-03-01

402

Stopping power for low-energy protons  

Microsoft Academic Search

The stopping power and straggling of energy loss for protons of initial energies 418, 340 and 303 keV have been studied in ethylene, propylene, styrene and their polymers. Employing the inverse stopping power functions, cross sections have been obtained in the energy range 20-400 keV. The existence of a phase effect has been clearly demonstrated. The theoretical stopping cross section

A. K. M. M. Haque; A. Mohammadi; H. Nikjoo

1989-01-01

403

Linear and nonlinear electromagnetic coupling models in vibration-based energy harvesting  

NASA Astrophysics Data System (ADS)

This paper investigates the response of an energy harvester that uses electromagnetic induction to convert ambient vibration into electrical energy. A unique aspect of the present study is the comparison of the system's response behavior when either a linear or a physically motivated form of nonlinear coupling is applied. The motivating hypothesis for this work was that nonlinear coupling could be used to improve the performance of an energy harvester by broadening its frequency response. Combined theoretical and numerical studies investigate the harvester's response for both single and multi-frequency base excitation. Our investigations unveil regions in the parameter space where nonlinear coupling is better than linear coupling and regions where the opposite is true. The meaningful conclusion is that nonlinear coupling can sometimes be detrimental, but it can also be beneficial if properly designed into the system.

Owens, Benjamin A. M.; Mann, Brian P.

2012-02-01

404

Designing maximum power output into piezoelectric energy harvesters  

NASA Astrophysics Data System (ADS)

Energy harvesting from vibrational sources has been the focus of extensive research in the last decade, but fundamental questions remain concerning the design of these harvesters. We consider a piezoelectric bimorph energy harvester and seek to translate design requirements, such as mass and target natural frequency, into beam dimensions that maximize power output. Our method centers around optimizing the thickness of the piezoelectric layers of a beam relative to the total beam thickness, otherwise known as the thickness ratio. This method uses approximations for the fundamental frequency and mode shape. This allows for the development of algebraic expressions for the modal parameters required for the prediction of power output. The resulting expression for power is fully defined by the fixed system level requirements and the only unknown parameters, the piezoelectric thickness ratio and the damping ratio. We show in an example case that, for typical damping ratio values, the ideal thickness ratio is not significantly affected by changes in the damping ratio. As such, the method requires a simple sweep of the thickness ratio in order to determine the beam design which maximizes the power. We develop the design method for both systems where the piezoelectric material is continuous and where the thickness is selected from a discrete set of values. Because our method produces a single algebraic expression for the power, the resulting beam design can be developed extremely quickly from a set of design requirements, and thus does not require optimization algorithms. We also show that our design method achieves more power output and requires less piezoelectric material than an approach which maximizes the coupling coefficient.

Shafer, Michael W.; Bryant, Matthew; Garcia, Ephrahim

2012-08-01

405

Energy extraction from a low Reynolds-number-flow using vortex-induced vibrations and optimal control  

Microsoft Academic Search

The present work investigates the dynamics of a spring-mounted circular cylinder by focusing on the amount of energy that can be extracted from the flow when an appropriate forcing is applied, which is of practical interest when vortex-induced vibrations are thought to be used for energy production. The analysis relies on an asymptotic model developed at low Reynolds numbers, herein

Philippe Meliga; Jean-Marc Chomaz

2010-01-01

406

Collision time-correlation functions in the semiclassical limit. II. Vibrational-rotational energy transfer in molecule-molecule collisions  

Microsoft Academic Search

A semiclassical limit of collisional time-correlation functions is applied to energy transfer in collisions between two molecules. The internal degrees of freedom (vibration and rotation) are treated quantum mechanically while the relative motion is described by classical trajectories for fixed molecular orientations. Hence the theory is well-suited to the analysis of energy and angular distributions in collisions governed by general

Eduardo Vilallonga; David A. Micha

1987-01-01

407

Calculation of highly excited vibrational energy levels of CH3CN molecule by non-linear quantum theory  

Microsoft Academic Search

A three-parameter nonlinear dynamical model, i.e., the quantized discrete self-trapping equation, was used to calculate the highly excited CH stretching vibrational energy levels of liquid phase CH3CN molecule in the electronic ground state up to n=7. The calculated results show that the experimental energy levels can be well described by the model.

Zhu Jun; Gou Qing-quan

1999-01-01

408

On the self-powering of SHM techniques using seismic energy harvesting  

NASA Astrophysics Data System (ADS)

Growing demands in self-powered, wireless Structural Health Monitoring (SHM) systems has placed a particular attention on energy harvesting products. While most of works done in this domain considered directly coupled active materials, it may be preferential to use seismic (or indirect-coupled) harvesters for maintenance issues. With a seismic type harvester, a model considering constant vibration magnitude excitation is no longer valid as electrical energy extraction from mechanical vibration leads to a reduction of the vibration magnitude of the harvester because of electromechanical coupling effect. This paper extends a Single Degree of Freedom (SDOF) model with a constant force or acceleration excitation to a Two Degree of Freedom (TDOF) approach to describe the tradeoff between the damping effect on the host structure and the harvested power due to the mechanical to mechanical coupling effect. When the harvester mass to host structure mass ratio is around 10-3, the maximal power is obtained and the host structure has then a sudden displacement reduction due to the strong mechanical to mechanical coupling. Its application to self-powered SHM will be also introduced in the paper.

Wu, Yi-Chieh; Lallart, Mickaël.; Yan, Linjuan; Guyomar, Daniel; Richard, Claude

2013-04-01

409

Teachers Environmental Resource Unit: Energy and Power.  

ERIC Educational Resources Information Center

Problems associated with energy production and power are studied in this teacher's guide to better understand the impact of man's energy production on the environment, how he consumes energy, and in what quantities. The resource unit is intended to provide the teacher with basic information that will aid classroom review of these problems. Topics…

Bemiss, Clair W.

410

Power Electronics in Renewable Energy Systems  

Microsoft Academic Search

The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should also be set up. Deregulation

F. Blaabjerg; F. Iov; R. Teodorescu; Z. Chen

2006-01-01

411

Teachers Environmental Resource Unit: Energy and Power.  

ERIC Educational Resources Information Center

|Problems associated with energy production and power are studied in this teacher's guide to better understand the impact of man's energy production on the environment, how he consumes energy, and in what quantities. The resource unit is intended to provide the teacher with basic information that will aid classroom review of these problems. Topics…

Bemiss, Clair W.

412

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

PubMed

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

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

2008-05-28

413

Energy analysis of the solar power satellite.  

PubMed

The energy requirements to build and operate the proposed Solar Power Satellite are evaluated and compared with the energy it produces. Because the technology is so speculative, uncertainty is explicitly accounted for. For a proposed 10-gigawatt satellite system, the energy ratio, defined as the electrical energy produced divided by the primary nonrenewable energy required over the lifetime of the system, is of order 2, where a ratio of 1 indicates the energy breakeven point. This is significantly below the energy ratio of today's electricity technologies such as light-water nuclear or coal-fired electric plants. PMID:17758765

Herendeen, R A; Kary, T; Rebitzer, J

1979-08-01

414

Electrodynamic vibrators  

Microsoft Academic Search

The present work describes current electrodynamic vibrators and vibration rigs for investigating materials, structural elements, machine parts, and certain biological objects subjected to vibrations and large accelerations. Methods of increasing the thrusting force and amplitude of oscillations in electrodynamic vibrators are discussed along with broadening of the frequency range. The characteristics of commercial vibrators are examined. Ways of preventing vibrations

M. D. Genkin; A. M. Rusakov; V. V. Iablonskii

1975-01-01

415

Design and testing of piezoelectric energy harvester for powering wireless sensors of electric line monitoring system  

NASA Astrophysics Data System (ADS)

Scavenging electromagnetic and vibration energy from environments is an attractive technique for powering wireless sensors in a wireless sensor network. This paper reports our design and testing results on the electric output performance of a piezoelectric energy harvesting device, which consists of cantilever beams, magnetoelectric (ME) transducers, and permanent magnets. The geometric parameters of the device are based on an optimization design with a targeted resonant frequency of 50 Hz. Experimental results show that an output voltage of 56.1 V and an average power of 0.24 mW are achieved responding to a current of 3 A at 50 Hz. Remarkably, this power is a very encouraging power figure that gives the prospect of being able to power a wide range of wireless sensors in an electric line monitoring system.

Qiu, Jing; Wen, Yumei; Li, Ping; Yang, Jin

2012-04-01

416

Composed vibration pulses for ultrasound vibrometry  

Microsoft Academic Search

Composed vibration pulses are developed to generate ultrasound radiation force for stimulating vibrations in a tissue region with preferred spectral distributions and increasing specific vibration harmonics when the peak radiation power is limited. The new vibration sequence has multiple pulses in one fundamental period of the vibration. The pulses are sparsely sampled from an orthogonal frequency wave composed of several

Yi Zheng; Aiping Yao; Yu Liu; Ke Chen; Shigao Chen; Matthew W. Urban; James F. Greenleaf

2010-01-01

417

State and species selective energy flow in gas ensembles containing vibrationally excited O2  

NASA Astrophysics Data System (ADS)

State-to-state, collision-induced, energy transfer is followed to equilibrium through sequences of collision cycles in gas ensembles containing vibrationally excited oxygen molecules (v = 8 and 1) in several different atomic and molecular bath gases. Quantum state distributions for each of the constituent species are available at each stage of the ensemble's evolution and enable the dominant energy exchange mechanisms to be identified. Equilibration is generally a complex process that evolves through several phases of inter- and intra-molecular events, each with their characteristic response rate to collisions. The results suggest that single quantum state population loss rate constants, however precisely determined, may miss key features of the overall equilibration process.

McCaffery, Anthony J.

2012-10-01

418

Power and Energy Strategy White Paper.  

National Technical Information Service (NTIS)

Power and energy grow ever more important to our military capabilities; they enable every system that supports Soldier and unit performance, from mobility and weapons systems to surveillance and communications -- not to mention simple heating and cooling....

P. Schihl P. E. Roege R. Kirker

2010-01-01

419

Teaching About Energy: Power of a Student  

NSDL National Science Digital Library

This student activity is designed to help students understand the concept of power. The energy required to climb stairs, and the rate at which students can do this, illustrates this concept. The energy requirements for other common activities are given to help students calculate their energy needs. Included are notes for instructors wishing to use this material. This activity is part of a PTRA manual on Energy.

Roeder, John

2006-01-17

420

Energy storage for hybrid remote power systems.  

National Technical Information Service (NTIS)

Energy storage can be a cost-effective component of hybrid remote power systems. Storage serves the special role of taking advantage of intermittent renewable power sources. Traditionally this role has been played by lead-acid batteries, which have high l...

W. Isherwood

1998-01-01

421

Direct energy conversion for fusion power  

Microsoft Academic Search

The potential importance of direct energy conversion to the long-term development of fusion power is discussed with stress on the possibility of alleviating waste heat problems. This is envisioned to be crucial for any central power station in the 21st century. Two approaches, direct collection and magnetic expansion, are reviewed. While other techniques may be possible, none have received sufficient

G. H. Miley

1980-01-01

422

Energy Decisions: Is Solar Power the Solution?  

ERIC Educational Resources Information Center

|People around the world are concerned about affordable energy. It is needed to power the global economy. Petroleum-based transportation and coal-fired power plants are economic prime movers fueling the global economy, but coal and gasoline are also the leading sources of air pollution. Both of these sources produce greenhouse gases and toxins.…

Childress, Vincent W.

2011-01-01

423

Power Technologies Energy Data Book - Fourth Edition  

SciTech Connect

This report, prepared by NREL's Strategic Energy Analysis Center, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, and conversion factors.

Aabakken, J.

2006-08-01

424

The chemical bond in external electric fields: Energies, geometries, and vibrational Stark shifts of diatomic molecules  

NASA Astrophysics Data System (ADS)

It is shown that the response of molecular properties of diatomics such as the total energy, the bond length, and the vibrational Stark shift to an external homogenous electric field (EF) can be predicted from field-free observable properties such as the equilibrium bond length, the bond dissociation energy, the polarizability and dipole moment functions, and the vibrational frequency. Delley [J. Mol. Struct.: THEOCHEM 434, 229 (1998)] suggested to approximate the potential energy surface under an EF by a Morse function augmented with a EF term proportional to the internuclear separation. In this work, this term is replaced by the expression of the field-induced energy change which yields a field-perturbed Morse potential that tends to a constant asymptotic limit when the EF term itself become proportional to the sum of the polarizabilities of the separated atoms. The model is validated by comparison with direct calculations on nine diatomics, five homo-nuclear (H2, N2, O2, F2, and Cl2) and four hetero-nuclear (HF, HCl, CO, and NO), covering a range and combinations of dipole moments and polarizabilities. Calculations were conducted at the quadratic configuration interaction with single and double excitations (QCISD) and density functional theory (DFT)-B3LYP levels of theory using the 6-311++G(3df,2pd) basis set. All results agree closely at the two levels of theory except for the Stark effect of NO which is not correctly predicted by QCISD calculations as further calculations, including at the coupled cluster with single and double excitation (CCSD) level of theory, demonstrate.

Sowlati-Hashjin, Shahin; Matta, Chérif F.

2013-10-01

425

A New Design for Vibration-Based Electromagnetic Energy Harvesting Systems Using Coil Inductance of Microgenerator  

Microsoft Academic Search

In this paper, a new design methodology for low- voltage electromagnetic energy harvesting systems consisting of a microgenerator and power processing circuit is introduced. In the first section of this paper, a simple topology for a resonance-based electromagnetic generator is presented. The microgenerator is capable of producing a voltage of a few hundred millivolts. Since traditional two-stage power conversion schemes

Rohan Dayal; Suman Dwari; Leila Parsa

2011-01-01

426

Self-timed circuits for energy harvesting AC power supplies  

Microsoft Academic Search

The recent explosion in capability of embedded and portable electronics has not been matched by battery technology. The slow growth of battery energy density has limited device lifetime and added weight and volume. Passive energy harvesting from vibration has potentially wide application in wearable and embedded sensors to complement or replace batteries. We propose increasing energy harvesting efficiency by eliminating

Jeff Siebert; Jamie Collier; Rajeevan Amirtharajah

2005-01-01

427

Increasing Power and Energy in Amonix CPV Solar Power Plants  

Microsoft Academic Search

Large-scale concentration photovoltaic (CPV) power plants deliver the high energy production and low electricity cost that will allow photovoltaics to become a substantial portion of the electrical grid. High concentration minimizes the semiconductor material costs, while tracking delivers higher capacity factors and provides a better match to demand. In order to prove the net cost benefits, however, annual deployments must

Geoffrey S. Kinsey; Aditya Nayak; Mingguo Liu; Vahan Garboushian

2011-01-01

428

Increasing power and energy in Amonix solar power plants  

Microsoft Academic Search

Large-scale CPV power plants are expected to deliver the high energy production and low electricity cost that will allow PV to become a substantial portion of the electrical grid supply. High concentration minimizes the semiconductor material costs. Dual-axis tracking delivers higher capacity factors and provides a better match to electricity demand. In order to prove the net cost benefits, however,

Geoffrey S Kinsey; Aditya Nayak; Mingguo Liu; Vahan Garboushian

2011-01-01

429

Picosecond IR-UV pump-probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. II. Intracluster vibrational energy redistribution of the OH stretching vibration of hydrogen-bonded clusters  

NASA Astrophysics Data System (ADS)

A picosecond time-resolved IR-UV pump-probe spectroscopic study has been carried out for investigating the intracluster vibrational energy redistribution (IVR) and subsequent dissociation of hydrogen-bonded clusters of phenol (C6H5OH) and partially deuterated phenol (C6D5OH, phenol-d5) with various solvent molecules. The H-bonded OH stretching vibration was pumped by a picosecond IR pulse, and the transient S1-S0 UV spectra from the pumped level as well as the redistributed levels were observed with a picosecond UV laser. Two types of hydrogen-bonded clusters were investigated with respect to the effect of the H-bonding strength on the energy flow process: the first is of a strong ``?-type H-bond'' such as phenol-(dimethyl ether)n=1 and phenol dimer, and the second is phenol-(ethylene)n=1 having a weak ``?-type H-bond.'' It was found that the population of the IR-pumped OH level exhibits a single-exponential decay, whose rate increases with the H-bond strength. On the other hand, the transient UV spectrum due to the redistributed levels showed a different time evolutions at different monitoring UV frequency. From an analysis of the time profiles of the transient UV spectra, the following three-step scheme has been proposed for describing the energy flow starting from the IVR of the initially excited H-bonded OH stretching level to the dissociation of the H bond. (1) The intramolecular vibrational energy redistribution takes place within the phenolic site, preparing a hot phenol. (2) The energy flows from the hot phenol to the intermolecular vibrational modes of the cluster. (3) Finally, the hydrogen bond dissociates. Among the three steps, the rate constant of the first step was strongly dependent on the H-bond strength, while the rate constants of the other two steps were almost independent of the H-bond strength. For the dissociation of the hydrogen bond, the observed rate constants were compared with those calculated by the Rice, Ramsperger, Kassel, and Marcus model. The result suggests that dissociation of the hydrogen bond takes place much faster than complete energy randomization within the clusters.

Kayano, Masakazu; Ebata, Takayuki; Yamada, Yuji; Mikami, Naohiko

2004-04-01

430

Feasibility of energy harvesting for powering wireless sensors in transportation infrastructure applications  

NASA Astrophysics Data System (ADS)

In recent years, wireless sensors technologies are attracted many researchers in the field of structural health monitoring (SHM) of civil, mechanical and aerospace systems. Another potential application of wireless sensors is in the Vehicle-Infrastructure Integration (VII) which is an initiative by the U.S. Department of Transportation to improve road safety and reduce congestion, through as part of its Intelligent Transportation System program. However, fundamental issues remain unresolved before a broad application of the wireless SHM or VII sensor network concept is the question of sustainable power source for each independent sensor mounted on infrastructures. With a vast number of sensors nodes/networks in the infrastructure, connecting them to the grid power source is simply uneconomical in the era of wireless technology. The other option, which is providing power to each sensor from battery sources, has its own setbacks, as batteries can only provide power for a limited period, have to be replaced periodically (often difficult and costly), and their disposal creates environmental hazard. This study addresses the feasibility of energy harvesting from the ambient vibration of transportation infrastructures to power wireless sensors. Based on the vibration responses from simulation and field tests, vehicle induced vibrations on bridge and pavement were obtained and the theoretical power output from such vibration sources were computed. The expected results from this study will be demonstrated by avoiding complex wiring to the sensors by which the associated cost of wiring and batteries will be significantly reduced, and at the same time the technology can easily be deployed, meaning it is one step forward in improving the SHM and VII applications.

Ashebo, Demeke Beyene; Tan, Chin An; Wang, Jun; Li, Gang

2008-04-01

431

Coal and nuclear power: Illinois' energy future  

SciTech Connect

This conference was sponsored by the Energy Resources Center, University of Illinois at Chicago; the US Department of Energy; the Illinois Energy Resources Commission; and the Illinois Department of Energy and Natural Resources. The theme for the conference, Coal and Nuclear Power: Illinois' Energy Future, was based on two major observations: (1) Illinois has the largest reserves of bituminous coal of any state and is surpassed in total reserves only by North Dakota, and Montana; and (2) Illinois has made a heavy commitment to the use of nuclear power as a source of electrical power generation. Currently, nuclear power represents 30% of the electrical energy produced in the State. The primary objective of the 1982 conference was to review these two energy sources in view of the current energy policy of the Reagan Administration, and to examine the impact these policies have on the Midwest energy scene. The conference dealt with issues unique to Illinois as well as those facing the entire nation. A separate abstract was prepared for each of the 30 individual presentations.

Not Available

1982-01-01

432

Theoretical equilibrium geometry, vibrational frequencies and the first electronic transition energy of HCC  

NASA Astrophysics Data System (ADS)

Ab initio calculations with the 6-311 G** basis set and all single and double excitations in the CI treatment have been carried out to determine the structure of the HCC radical. The theoretical geometry of R(CC) = 1·209, r(CH) = 1·067 Å (or 1·205 and 1·063, respectively, if corrected for residual errors) is in excellent accordance with the experimental rotational constant. The calculated harmonic vibrational frequencies are v1 ? 3450, v2 ? 540 and v3 ? 2040 cm-1. An extremely low energy around 2000 cm-1 is obtained for the first electronic transition A2II ? X 2?. Results for the excited state are also given. The theoretical vibrational frequencies, with all possible errors taken into account, are inconsistent with the accepted interpretations of the few experimental results. It is shown, however, that a complete reinterpretation of the spectroscopic observations is possible, by which the present calculations fit with the recent gas phase infrared laser spectroscopic data but remain in definite contradiction with the infrared matrix results.

Fogarasi, Géza; Boggs, James E.; Pulay, Péter

433

Vibrational energy relaxation of liquid aryl-halides X-C6H5 (X = F, Cl, Br, I).  

PubMed

Anti-Stokes Raman spectroscopy was used to probe vibrational energy dynamics in liquid ambient-temperature aryl-halides, X-Ph (X = F, Cl, Br, I; -Ph = C(6)H(5)), following IR excitation of a 3068 cm(-1) CH-stretching transition. Five ring vibrations and two substituent-dependent vibrations were monitored in each aryl-halide. Overall, the vibrational relaxation (VR) lifetimes in aryl-halides were shorter than those in normal benzene (H-Ph). The aryl-halide CH-stretch lifetimes increased in the order F, Cl, Br, I, ranging from 2.5 to 3.4 ps, compared with 6.2 ps in H-Ph. The aryl-halide energy transfer processes were similar overall with four exceptions. Three of the four exceptions could be explained as a result of faster VR of midrange vibrations (1000-1600 cm(-1)) in the heavier aryl-halides. The fourth appeared to result from a coincidental resonance in chlorobenzene that does not occur in the other aryl-halides. Among the aryl-halides, the decay of CH-stretching excitations (?3070 cm(-1)) was slower in the heavier species, but the decay of midrange vibrations was faster in the heavier species. This seeming contradiction could be explained if VR depended primarily on the density of states (DOS) of the lower tiers of vibrational excitations. The DOS for the first few (1-4) tiers is similar for all aryl-halides in the CH-stretch region, but DOS increases with increasing halide mass in the midrange region. PMID:20839814

Pein, Brandt C; Seong, Nak-Hyun; Dlott, Dana D

2010-10-01

434

Unified power engineering laboratory for electromechanical energy conversion, power electronics, and power systems  

Microsoft Academic Search

This paper introduces a unified power engineering laboratory capable of various experiments for power systems, power electronics, and electromechanical energy conversion. It presents a flexible hardware setup, data acquisition (DAQ), and virtual instrumentation (VI). Some features of virtual instrumentation are shown with real-time phasor diagrams, sequence component analysis, and spectral analysis of AC data. We describe the general design of

Thomas W. Gedra; Seungwon An; Q. H. Arsalan; S. Ray

2004-01-01

435

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

SciTech Connect

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.

Marks, S.

1981-08-01

436

Quantum dynamics of intramolecular vibrational energy redistribution for initally excited CC ring modes in 30-mode benzene  

Microsoft Academic Search

Energy flow from four CC ring-mode bright states (A1g , B2u , E1u , and E2g ) was examined for the CC(v=2) overtone. The A1g normal mode exhibits completely reversible intramolecular vibrational energy redistribution (IVR) over the course of the dynamics (9.6 ps); energy flow out of the initially excited mode is less complete but less reversible for the B2u

Todd J. Minehardt; Robert E. Wyatt

1999-01-01

437

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

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,

Meiling Zhu; Emma Worthington; James Njuguna

2009-01-01

438

Fluid Power Systems. Energy Technology Series.  

ERIC Educational Resources Information Center

|This course in fluid power systems is one of 16 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in company-sponsored…

Center for Occupational Research and Development, Inc., Waco, TX.

439

Power law scaling for rotational energy transfer  

Microsoft Academic Search

We have applied a new scaling law to several sets of rotational energy transfer cross sections. The new law asserts that the square of the T-matrix depends on the amount of energy transferred as a power law. Two different kinds of angular momentum statistics are assumed, one corresponding to mj being conserved and the other corresponding to mj being completely

David E. Pritchard; Neil Smith; Richard D. Driver; Timothy A. Brunner

1979-01-01

440

Power conditioning system for energy sources  

DOEpatents

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.

Mazumder, Sudip K. (Chicago, IL); Burra, Rajni K. (Chicago, IL); Acharya, Kaustuva (Chicago, IL)

2008-05-13

441

Breezy Power: From Wind to Energy  

ERIC Educational Resources Information Center

|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…

Claymier, Bob

2009-01-01

442

Nuclear power, coal, and energy conservation  

Microsoft Academic Search

A programming model is used to explore options by which the U.S. may realistically move from its dependence on oil and gas to a more diversified energy economy based on nuclear power and\\/or coal. Supply options considered are: direct combustion of coal; conversion of coal to synthetic fuels; petroleum, natural gas, and oil shale resources; nuclear energy from light water

P. L. Auer; A. S. Manne; O. S. Yu

1976-01-01

443

Powerful low-frequency vibrators and outlooks of their application at monitoring of engineering constructions and at solving other problems of active seismology  

SciTech Connect

In the past two decades, active seismology studies in Russia have made use of powerful (40- and 100-ton) low-frequency vibrators. These sources create a force amplitude of up to 100 tons and function in the 1.5-3, 3-6 and 5-10 Hz frequency bands. The mobile versions of the vibrator have a force amplitude of 40 tons and a 6-12 Hz frequency band. Registration distances for the 100 ton vibrator are as large as 350 km, enabling the refracted waves to penetrate down to 50 km depths. Vibrator operation sessions are highly repeatable, having distinct ''summer'' or ''winter'' spectral patterns. A long profile of seismic records allows estimating of fault zone depths using changes in recorded spectra. Other applications include deep seismic profiling, seismic hazard mapping, structural testing, stress induced anisotropy studies, seismic station calibration, and large-structure integrity testing. In more detail, these questions are discussed in reports of our colleagues from Novosibirsk. This report is devoted mainly to powerful low-frequency vibrators, their theoretical description and design. Besides, problems of vibroseismic monitoring of engineering constructions are briefly elucidated.

Alekseev, A. S.; Chichinin, I. S.; Korneev, V. A.; Komissarov, V. V.; Seleznev, V. S.; Emanov, A. F.

2004-06-11

444

Time-dependent perturbation theory for vibrational energy relaxation and dephasing in peptides and proteins.  

PubMed

Without invoking the Markov approximation, we derive formulas for vibrational energy relaxation (VER) and dephasing for an anharmonic system oscillator using a time-dependent perturbation theory. The system-bath Hamiltonian contains more than the third order coupling terms since we take a normal mode picture as a zeroth order approximation. When we invoke the Markov approximation, our theory reduces to the Maradudin-Fein formula which is used to describe the VER properties of glass and proteins. When the system anharmonicity and the renormalization effect due to the environment vanishes, our formulas reduce to those derived by and Mikami and Okazaki [J. Chem. Phys. 121, 10052 (2004)] invoking the path-integral influence functional method with the second order cumulant expansion. We apply our formulas to VER of the amide I mode of a small amino-acid like molecule, N-methylacetamide, in heavy water. PMID:16626248

Fujisaki, Hiroshi; Zhang, Yong; Straub, John E

2006-04-14

445

High resolution electron energy loss studies of surface vibrations. Progress report, June 1, 1991--May 1, 1992  

SciTech Connect

New experimental studies of surface vibrational properties of materials with high-resolution electron energy loss spectroscopy (EELS) are reported. This document summarizes recent progress on surface phonon dispersion measurements on copper (001); silver (001) and (111); oxygen adsorption on ultrathin films of cobalt and nickel; aluminum on silicon (111); and copper-oxide based superconductors.

Kesmodel, L.L.