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1

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY  

E-print Network

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING and magneticand magnetic field.field. Piezoelectric Materials as Smart Material- Among the all smart materials, piezoelectric materials are of great interest, as they are commonly used as sensors, actuators and memory

Ervin, Elizabeth K.

2

Piezoelectric capacitive power generator from vibration energy  

NASA Astrophysics Data System (ADS)

A vibration-powered micro-power-generator has been presented in this paper, which has integrated two different energy harvesting mechanisms, e.g., Capacitive and Piezoelectric Mechanisms. The periodic vibration of the mass on movable electrode causes the variation of the capacitance, and the strain in the piezoelectric film. These two mechanisms can harvest the vibration energy and generate current in the output circuit. By using two different metals with large difference in working function as the two electrodes of the capacitor, our design, the combination of these two different scavenge mechanisms, can overcome the dependence of the traditional capacitive converter on the separate voltage source and improve the efficiency of power conversion. The volume of the designed device is less than 0.8 cm 3. The simulated results reveal that this energy converter can provide an average output power of 82.21?W at an external vibration with a frequency of 111.4 Hz and amplitude of 0.2g.

Zhang, Yangjian; Li, Lin; San, Haisheng; Chen, Xuyuan

2008-03-01

3

An energy-adaptive MPPT power management unit for micro-power vibration energy harvesting  

Microsoft Academic Search

A batteryless power management unit (PMU) that manages harvested low-level vibration energy from a piezoelectric device for a wireless sensor node is presented. An energy-adaptive maximum power point tracking (EA-MPPT) scheme is proposed that allows the PMU to activate different operation modes according to the available power level. The harvested energy is processed by an ac-dc voltage doubler followed by

Jun Yi; Feng Su; Yat-hei Lam; Wing-hung Ki; Chi-ying Tsui

2008-01-01

4

A comparison of power output from linear and nonlinear kinetic energy harvesters using real vibration data  

NASA Astrophysics Data System (ADS)

The design of vibration energy harvesters (VEHs) is highly dependent upon the characteristics of the environmental vibrations present in the intended application. VEHs can be linear resonant systems tuned to particular frequencies or nonlinear systems with either bistable operation or a Duffing-type response. This paper provides detailed vibration data from a range of applications, which has been made freely available for download through the Energy Harvesting Network’s online data repository. In particular, this research shows that simulation is essential in designing and selecting the most suitable vibration energy harvester for particular applications. This is illustrated through C-based simulations of different types of VEHs, using real vibration data from a diesel ferry engine, a combined heat and power pump, a petrol car engine and a helicopter. The analysis shows that a bistable energy harvester only has a higher output power than a linear or Duffing-type nonlinear energy harvester with the same Q-factor when it is subjected to white noise vibration. The analysis also indicates that piezoelectric transduction mechanisms are more suitable for bistable energy harvesters than electromagnetic transduction. Furthermore, the linear energy harvester has a higher output power compared to the Duffing-type nonlinear energy harvester with the same Q factor in most cases. The Duffing-type nonlinear energy harvester can generate more power than the linear energy harvester only when it is excited at vibrations with multiple peaks and the frequencies of these peaks are within its bandwidth. Through these new observations, this paper illustrates the importance of simulation in the design of energy harvesting systems, with particular emphasis on the need to incorporate real vibration data.

Beeby, Stephen P.; Wang, Leran; Zhu, Dibin; Weddell, Alex S.; Merrett, Geoff V.; Stark, Bernard; Szarka, Gyorgy; Al-Hashimi, Bashir M.

2013-07-01

5

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

6

A self-powered sensor module using vibration-based energy generation for ubiquitous systems  

Microsoft Academic Search

A new architecture for ubiquitous sensor modules using vibration-based energy generation is proposed and the CMOS implementation of the proposed architecture is presented. The sensor module only scavenges vibration-based energy as energy source by using piezoelectric element to realize no batteries operation. The sensor module is used to supervise the vibration of machines and transfer the vibration signal discontinuously. Based

Jun Pan; Baocheng Xue; Y. Inoue

2005-01-01

7

A vibration-based MEMS piezoelectric energy harvester and power conditioning circuit.  

PubMed

This paper presents a micro-electro-mechanical system (MEMS) piezoelectric power generator array for vibration energy harvesting. A complete design flow of the vibration-based energy harvester using the finite element method (FEM) is proposed. The modal analysis is selected to calculate the resonant frequency of the harvester, and harmonic analysis is performed to investigate the influence of the geometric parameters on the output voltage. Based on simulation results, a MEMS Pb(Zr,Ti)O3 (PZT) cantilever array with an integrated large Si proof mass is designed and fabricated to improve output voltage and power. Test results show that the fabricated generator, with five cantilever beams (with unit dimensions of about 3 × 2.4 × 0.05 mm3) and an individual integrated Si mass dimension of about 8 × 12.4 × 0.5 mm3, produces a output power of 66.75 ?W, or a power density of 5.19 ?W?mm-3?g-2 with an optimal resistive load of 220 k? from 5 m/s2 vibration acceleration at its resonant frequency of 234.5 Hz. In view of high internal impedance characteristic of the PZT generator, an efficient autonomous power conditioning circuit, with the function of impedance matching, energy storage and voltage regulation, is then presented, finding that the efficiency of the energy storage is greatly improved and up to 64.95%. The proposed self-supplied energy generator with power conditioning circuit could provide a very promising complete power supply solution for wireless sensor node loads. PMID:24556670

Yu, Hua; Zhou, Jielin; Deng, Licheng; Wen, Zhiyu

2014-01-01

8

Self-Powered Kinetic Energy Harvesters for Seek-Induced Vibrations in Hard Disk Drives  

NASA Astrophysics Data System (ADS)

Energy harvesters with battery charging circuitry, which collect wasted kinetic energy from a magnetic disk drive's rotary actuator seek operations and flexible cable vibrations, are proposed, prototyped and presented in this paper. Depending on a disk drive's form factor and seek format, it is suggested by the present study that the harvested energy can be optimized by tuning the harvester's natural frequencies to major frequency content in the rotary actuator's excitation. It is demonstrated in this study that with prototype energy harvester systems, one can easily light up a regular LED. The work presented in this paper has implications in energy saving and recycling wasted mechanical energy for other low-power electronic applications in magnetic disk drive storage devices.

Chang, Jen-Yuan (James; Gutierrez, Mike

9

Downhole vibration sensing by vibration energy harvesting  

E-print Network

This thesis outlines the design of a prototype electromagnetic induction vibration energy harvesting device for use in a downhole environment. First order models of the necessary components for a generic vibration energy ...

Trimble, A. Zachary

2007-01-01

10

Multi-modal vibration based MEMS energy harvesters for ultra-low power wireless functional nodes  

NASA Astrophysics Data System (ADS)

The aim of this contribution is to report and discuss a preliminary study and rough optimization of a novel concept of MEMS device for vibration energy harvesting, based on a multi-modal dynamic behavior. The circular-shaped device features Four-Leaf Clover-like (FLC) double spring-mass cascaded systems, kept constrained to the surrounding frame by means of four straight beams. The combination of flexural bending behavior of the slender beams plus deformable parts of the petals enable to populate the desired vibration frequency range with a number of resonant modes, and improve the energy conversion capability of the micro-transducer. The harvester device, conceived for piezoelectric mechanical into electric energy conversion, is intended to sense environmental vibrations and, thereby, its geometry is optimized to have a large concentration of resonant modes in a frequency range below 5-10 kHz. The results of FEM (Finite Element Method) based analysis performed in ANSYSTM Workbench are reported, both concerning modal and harmonic response, providing important indications related to the device geometry optimization. The analysis reported in this work is limited to the sole mechanical modeling of the proposed MEMS harvester device concept. Future developments of the study will encompass the inclusion of piezoelectric conversion in the FEM simulations, in order to have indications of the actual power levels achievable with the proposed harvester concept. Furthermore, the results of the FEM studies here discussed, will be validated against experimental data, as soon as the MEMS resonator specimens, currently under fabrication, are ready for testing.

Iannacci, J.; Gottardi, M.; Serra, E.; Di Criscienzo, R.; Borrielli, A.; Bonaldi, M.

2013-05-01

11

Vibration Testing of Stirling Power Convertors  

NASA Technical Reports Server (NTRS)

The NASA John H. Glenn Research Center (GRC) and the U.S. Department of Energy (DOE) are currently developing a high efficient, long life, free piston Stirling convertor for use as an advanced spacecraft power system for future NASA missions. As part of this development, a Stirling Technology Demonstrator Convertor (TDC), developed by Stirling Technology Company (STC) for DOE, was vibration tested at GRC s Structural Dynamics Laboratory (SDU7735) in November- December 1999. This testing demonstrated that the Stirling TDC is able to withstand the harsh random vibration (20 to 2000 Hertz) seen during a typical spacecraft launch and survive with no structural damage or functional power performance degradation, thereby enabling its usage in future spacecraft power systems. The Stirling Vibration Test Team at NASA GRC and STC personnel conducted tests on a single 55 electric watt TDC. The purpose was to characterize the TDC s structural response to vibration and determine if the TDC could survive the vibration criteria established by the Jet Propulsion Laboratory (JPL) for launch environments. The TDC was operated at full-stroke and full power conditions during the vibration testing. The TDC was tested in two orientations, with the direction of vibration parallel and perpendicular to the TDC s moving components (displacer and piston). The TDC successfully passed a series of sine and random vibration tests. The most severe test was a 12.3 Grms random vibration test (peak vibration level of 0.2 g2/Hz from 50 to 250 Hertz) with test durations of 3 minutes per axis. The random vibration test levels were chosen to simulate, with margin, the maximum anticipated launch vibration conditions. As a result of this very successful vibration testing and successful evaluations in other key technical readiness areas, the Stirling power system is now considered a viable technology for future application for NASA spacecraft missions. Possible usage of the Stirling power system would be to supply on- board electric spacecraft power for future NASA Deep-Space Missions, performing as an attractive alternative to Radioisotope Thermoelectric Generators (RTG). Usage of the Stirling technology is also being considered as the electric power source for future Mars rovers, whose mission profiles may exclude the use of photovoltaic power systems (such as exploring at high Martian latitudes or for missions of lengthy durations). GRC s Thermo-Mechanical Systems Branch (5490) provides Stirling technology expertise under a Space Act Agreement with the DOE. Additional vibration testing, by GRC s Structural Systems Dynamics Branch (7733, is planned to continue to demonstrate the Stirling power system s vibration capability as its technology and flight system designs progress.

Hughes, Bill; Goodnight, Thomas; McNelis, Mark E.; Suarez, Vicente J.; Schreiber, Jeff; Samorezov, Sergey

2003-01-01

12

Harvesting energy from non-ideal vibrations  

E-print Network

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

Chang, Samuel C

2013-01-01

13

A three-dimensional electret-based micro power generator for low-level ambient vibrational energy harvesting  

NASA Astrophysics Data System (ADS)

A novel three-dimensional (3D) electret-based micro power generator with multiple vibration modes has been developed, which is capable of converting low-level ambient kinetic energy to electrical energy. The device is based on a rotational symmetrical resonator which consists of a movable disc-shaped seismic mass suspended by three sets of spiral springs. Experimental analysis shows that the proposed generator operates at an out-of-plane direction at mode I of 66 Hz and two in-plane directions at mode II of 75 Hz and mode III of 78.5 Hz with a phase difference of about 90°. A corona localized charging method is also proposed that employs a shadow mask and multiple discharge needles for the production of micro-sized electret array. From tests conducted at an acceleration of 0.05 g, the prototype can generate a maximum power of 4.8 nW, 0.67 nW and 1.2 nW at vibration modes of I, II and III, respectively. These values correspond to the normalized power densities of 16 µW cm-3 g-2, 2.2 µW cm-3 g-2 and 4 µW cm-3 g-2, respectively. The results show that the generator can potentially offer an intriguing alternative for scavenging low-level ambient energy from 3D vibration sources.

Tao, Kai; Liu, Shuwei; Woh Lye, Sun; Miao, Jianmin; Hu, Xiao

2014-06-01

14

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

15

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

16

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

PubMed

We fabricated dual-beam cantilevers on the microelectromechanical system (MEMS) scale with an integrated Si proof mass. A Pb(Zr,Ti)O3 (PZT) cantilever was designed as a mechanical vibration energy-harvesting system for low power applications. The resonant frequency of the multilayer composition cantilevers were simulated using the finite element method (FEM) with parametric analysis carried out in the design process. According to simulations, the resonant frequency, voltage, and average power of a dual-beam cantilever was 69.1 Hz, 113.9 mV, and 0.303 microW, respectively, at optimal resistance and 0.5 g (gravitational acceleration, m/s2). Based on these data, we subsequently fabricated cantilever devices using dual-beam cantilevers. The harvested power density of the dual-beam cantilever compared favorably with the simulation. Experiments revealed the resonant frequency, voltage, and average power density to be 78.7 Hz, 118.5 mV, and 0.34 microW, respectively. The error between the measured and simulated results was about 10%. The maximum average power and power density of the fabricated dual-beam cantilever at 1 g were 0.803 microW and 1322.80 microW cm(-3), respectively. Furthermore, the possibility of a MEMS-scale power source for energy conversion experiments was also tested. PMID:24266167

Kim, Moonkeun; Lee, Sang-Kyun; Yang, Yil Suk; Jeong, Jaehwa; Min, Nam Ki; Kwon, Kwang-Ho

2013-12-01

17

Stochastic quantification of the electric power generated by a piezoelectric energy harvester using a time-frequency analysis under non-stationary random vibrations  

NASA Astrophysics Data System (ADS)

Vibration energy, which is widely available, can be converted into electric energy using a piezoelectric energy harvester that generates alternating current in response to applied mechanical strain. For the last decade, there has been a strong surge of interest in developing an electromechanically-coupled analytical model of a piezoelectric energy harvester. Such a model is of great importance to enable understanding of the first principle of the piezoelectric transduction and to quantify harvestable electric power under a given vibration condition. However, existing analytical models that operate under an assumption of deterministic excitations cannot deal with the random nature present in realistic vibrations, even though this randomness considerably affects the variation in harvestable electric power. Furthermore, even when random vibrations are taken into account, existing stochastic analytical models can only be applied to stationary excitations, such as in the case of white Gaussian noise. This paper thus proposes a three-step framework for stochastic quantification of the electric power generated by a piezoelectric energy harvester under non-stationary random vibrations. First, we propose estimation of the time-varying power spectral density (PSD) of the input non-stationary random vibration using a statistical time-frequency analysis. The second step is to employ an existing electromechanical model as the linear operator for calculating the output voltage response. The final step is to estimate the time-varying PSD of the output voltage response. Following this three-step process, the expected electric power can be estimated from the autocorrelation function which is the inverse Fourier transform of the time-varying PSD of the output voltage response. The merits of the proposed framework are two-fold in that it enables: (i) quantification of the time-varying electric power generated under non-stationary random vibrations and (ii) consideration of the randomness in the design process of the energy harvester. Four case studies are used to demonstrate the effectiveness of the proposed framework.

Yoon, Heonjun; Youn, Byeng D.

2014-04-01

18

Vibration energy harvester optimization using artificial intelligence  

NASA Astrophysics Data System (ADS)

This paper deals with an optimization study of a vibration energy harvester. This harvester can be used as autonomous source of electrical energy for remote or wireless applications, which are placed in environment excited by ambient mechanical vibrations. The ambient energy of vibrations is usually on very low level but the harvester can be used as alternative source of energy for electronic devices with an expected low level of power consumption of several mW. The optimized design of the vibration energy harvester was based on previous development and the sensitivity of harvester design was improved for effective harvesting from mechanical vibrations in aeronautic applications. The vibration energy harvester is a mechatronic system which generates electrical energy from ambient vibrations due to precision tuning up generator parameters. The optimization study for maximization of harvested power or minimization of volume and weight are the main goals of our development. The optimization study of such complex device is complicated therefore artificial intelligence methods can be used for tuning up optimal harvester parameters.

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

2011-06-01

19

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

20

Extremely low-loss rectification methodology for low-power vibration energy harvesters  

NASA Astrophysics Data System (ADS)

Because of its promise for the generation of wireless systems, energy harvesting technology using smart materials is the focus of significant reported effort. Various techniques and methodologies for increasing power extraction have been tested. One of the key issues with the existing techniques is the use of diodes in the harvesting circuits with a typical voltage drop of 0.7 V. Since most of the smart materials, and other transducers, do not produce large voltage outputs, this voltage drop becomes significant in most applications. Hence, there is a need for designing a rectification method that can convert AC to DC with minimal losses. This paper describes a new mechanical rectification scheme, designed using reed switches, in a full-bridge configuration that shows the capability of working with signals from millivolts to a few hundred volts with extremely low losses. The methodology has been tested for piezoelectric energy harvesters undergoing mechanical excitation.

Tiwari, R.; Ryoo, K.; Schlichting, A.; Garcia, E.

2013-06-01

21

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

22

MEMS for vibration energy harvesting  

NASA Astrophysics Data System (ADS)

In this paper, a capacitive vibration-to-electrical energy harvester was designed. An integrated process flow for fabricating the designed capacitive harvester is presented. For overcoming the disadvantage of depending on external power source in capacitive energy harvester, two parallel electrodes with different work functions are used as the two electrodes of the capacitor to generate a build-in voltage for initially charging the capacitor. The device is a sandwich structure of silicon layer in two glass layers with area of about 1 cm2. The silicon structure is fabricated by using silicon-on-insulator (SOI) wafer. The glass wafers are anodic bonded on to both sides of the SOI wafer to create a vacuum sealed package.

Li, Lin; Zhang, Yangjian; San, Haisheng; Guo, Yinbiao; Chen, Xuyuan

2008-03-01

23

Piezoelectric energy harvesting from traffic-induced bridge vibrations  

E-print Network

for self powered health monitoring sensor nodes. As traffic-induced bridge vibrations are low frequencyPiezoelectric energy harvesting from traffic-induced bridge vibrations MichaĀØel Peigney1 harvesting of traffic-induced vibrations in bridges. Using a pre-stressed concrete highway bridge as a case

Paris-Sud XI, UniversitƩ de

24

On energy harvesting from ambient vibration  

NASA Astrophysics Data System (ADS)

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 analysed in detail. The amplitude of the seismic mass is limited in any practical device and this, together with the magnitude and frequency of the excitation define the maximum power that can be extracted from the environment. The overall damping coefficient (part of which is mechanical) is associated with the harvesting and dissipation of energy and also the transfer of energy from the vibrating base into the system. It is shown that net energy flow from the base through the damper is positive (negative) for ?>?n (?power than it dissipates and is neutral, at best, when ?/?n??. Maximum power is delivered to an electrical load when its resistance is equal to the sum of the coil internal resistance and the electrical analogue of the mechanical damping coefficient, which differs from what has been claimed. A highly damped system has the advantage of harvesting energy over a wider band of excitation frequencies on either side of the natural frequency, is smaller, but will harvest marginally less power. One possible strategy for variable amplitude excitation is proposed.

Stephen, N. G.

2006-05-01

25

Harvesting Vibrational Energy Using Material Work Functions  

NASA Astrophysics Data System (ADS)

Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications.

Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

2014-10-01

26

Harvesting vibrational energy using material work functions.  

PubMed

Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications. PMID:25348004

Varpula, Aapo; Laakso, Sampo J; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

2014-01-01

27

Harvesting Vibrational Energy Using Material Work Functions  

PubMed Central

Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications. PMID:25348004

Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

2014-01-01

28

Energy harvesting from wind-induced vibration of suspension bridges  

E-print Network

Recently, an extensive amount of research has been focused on energy harvesting from structural vibration sources for wireless self-powered microsystem applications. One method of energy harvesting is using electromagnetic ...

Shi, Miao, M. Eng. Massachusetts Institute of Technology

2013-01-01

29

Estimation of vibration power absorption density in human fingers.  

PubMed

The absorption of hand-transmitted vibration energy may be an etiological factor in vibration-induced disorders. The vibration power absorption density (VPAD) may be a better measure of energy than the total power absorption of the hand-arm system. The objectives of the present study are to develop a method to estimate the average absorption density in the fingers and to investigate its basic characteristics. Ten healthy male subjects were used in this study. The biodynamic response of the fingers in a power grip subjected to a broad-band random excitation was measured under three grip forces (15, 30, 50 N) and three push forces (35, 45, 50 N). The response was used to estimate the total finger energy absorption. The response, together with the finger volume, was also used to estimate the amount of tissue effectively involved in the absorption. Then, the average VPAD under constant-acceleration, constant-power density, constant-velocity vibration spectra, and 20 tool vibration spectra were calculated. The correlations between the VPAD and the unweighted and weighted accelerations (ISO 5349-1, 2001) were also examined. The VPAD depends on both the characteristics of the vibration spectrum and the biodynamic response of the finger-hand-arm system. The biodynamic response generally plays a more important role in determining the VPAD in the middle frequency range (31.5-400 Hz) than those at the low and high ends. The applied force significantly affected the VPAD. The finger VPAD was highly correlated to the unweighted acceleration. The average VPAD can be determined using the proposed experimental method. It can serve as an alternative tool to quantify the severity of the vibration exposure for studying vibration-induced finger disorders. PMID:16248315

Dong, Ren G; Wu, John Z; Welcome, Daniel E; McDowell, Thomas W

2005-10-01

30

HIGH-VOLTAGE LOW POWER ANALOGUE-TO-DIGITAL CONVERSION FOR ADAPTIVE ARCHITECTURES OF CAPACITIVE VIBRATION ENERGY  

E-print Network

, and alternative energy sources are needed. Extracting the power from the ambient energy sources such as light-AMS, calibration, MEMS. INTRODUCTION The energy capacity, as well as lifetime of the existing sources is limited source converts the mechanical energy to electrical energy using an electrostatic transducer, which

Boyer, Edmond

31

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

32

Modeling and design of a MEMS piezoelectric vibration energy harvester  

E-print Network

The modeling and design of MEMS-scale piezoelectric-based vibration energy harvesters (MPVEH) are presented. The work is motivated by the need for pervasive and limitless power for wireless sensor nodes that have application ...

Du Toit, Noėl Eduard

2005-01-01

33

Vibration analysis of small power transformer  

Microsoft Academic Search

Purpose – The purpose of this paper is to present a methodology of identification and calculating vibrations of power transformers caused by magnetostriction. Design\\/methodology\\/approach – All calculations are based on finite element approach. Electromagnetic model uses 2D time stepping solution in nonlinear continuum of the core accompanied with equivalent representation of overlapping areas. Structural model is 3D with special representation

Witold Kubiak; Pawel Witczak

2010-01-01

34

Electrostatic vibration-to-electric energy conversion  

E-print Network

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

Mur Miranda, José Oscar, 1972-

2004-01-01

35

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.

2008-03-01

36

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

37

Piezoelectric Power Requirements for Active Vibration Control  

NASA Technical Reports Server (NTRS)

This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material non- linearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined.

Brennan, Matthew C.; McGowan, Anna-Maria Rivas

1997-01-01

38

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

NASA Technical Reports Server (NTRS)

Stirling Technology Company (STC), as part of a Small Business Innovation Research contract Phase II with the NASA Glenn Research Center at Lewis Field, is developing an Adaptive Vibration Reduction System (AVRS) that will effectively eliminate vibrations for the Stirling radioisotope power system. The AVRS will reduce vibration levels for two synchronized, opposed Stirling converters by a factor of 10 or more under normal operating conditions. Even more importantly, the AVRS will be adaptive and will be able to adjust to any changing converter conditions over the course of a mission. The Stirling converter is being developed by NASA and the Department of Energy (DOE) as a high-efficiency option for a radioisotope power system to provide onboard electric power for NASA deep space missions. The high Stirling efficiency of over 25 percent for this application will reduce the required amount of isotope by more than a factor of 3 in comparison to the current radioisotope thermoelectric generators (RTG s). Stirling is the most developed converter option of the advanced power technologies under consideration.

Thieme, Lanny G.

2000-01-01

39

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

40

Energy transfer of highly vibrationally excited naphthalene. II. Vibrational energy dependence and isotope and mass effects  

Microsoft Academic Search

The vibrational energy dependence, H and D atom isotope effects, and the mass effects in the energy transfer between rare gas atoms and highly vibrationally excited naphthalene in the triplet state were investigated using crossed-beam\\/time-sliced velocity-map ion imaging at various translational collision energies. Increase of vibrational energy from 16 194 to 18 922 cm?1 does not make a significant difference

Chen-Lin Liu; Hsu Chen Hsu; Yuan Chin Hsu; Chi-Kung Ni

2008-01-01

41

Energy transfer of highly vibrationally excited naphthalene. II. Vibrational energy dependence and isotope and mass effects  

Microsoft Academic Search

The vibrational energy dependence, H and D atom isotope effects, and the mass effects in the energy transfer between rare gas atoms and highly vibrationally excited naphthalene in the triplet state were investigated using crossed-beam\\/time-sliced velocity-map ion imaging at various translational collision energies. Increase of vibrational energy from 16 194 to 18 922 cm-1 does not make a significant difference

Chen-Lin Liu; Hsu Chen Hsu; Yuan Chin Hsu; Chi-Kung Ni

2008-01-01

42

Piezoelectric energy harvesting from hybrid vibrations  

NASA Astrophysics Data System (ADS)

The concept of harvesting energy from ambient and galloping vibrations of a bluff body with a triangular cross-section geometry is investigated. A piezoelectric transducer is attached to the transverse degree of freedom of the body in order to convert these vibrations to electrical energy. A coupled nonlinear distributed-parameter model is developed that takes into consideration the galloping force and moment nonlinearities and the base excitation effects. The aerodynamic loads are modeled using the quasi-steady approximation. Linear analysis is performed to determine the effects of the electrical load resistance and wind speed on the global damping and frequency of the harvester as well as on the onset of instability. Then, nonlinear analysis is performed to investigate the impact of the base acceleration, wind speed, and electrical load resistance on the performance of the harvester and the associated nonlinear phenomena that take place. The results show that, depending on the interaction between the base and galloping excitations, and the considered values of the wind speed, base acceleration, and electrical load resistance, different nonlinear phenomena arise while others disappear. Short- and open-circuit configurations for different wind speeds and base accelerations are assessed. The results show that the maximum levels of harvested power are accompanied by a minimum transverse displacement when varying the electrical load resistance.

Yan, Zhimiao; Abdelkefi, Abdessattar; Hajj, Muhammad R.

2014-02-01

43

Vibration power generator for a linear MR damper  

NASA Astrophysics Data System (ADS)

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

Sapi?ski, Bogdan

2010-10-01

44

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

E-print Network

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

Kumar, Ratnesh

45

Piezoelectric energy harvesting from traffic-induced bridge vibrations  

NASA Astrophysics Data System (ADS)

This paper focuses on energy harvesting from traffic-induced vibrations in bridges. Using a pre-stressed concrete highway bridge as a case study, in situ vibration measurements are presented and analysed. From these results, a prototype of a cantilever piezoelectric harvester is designed, tested and modelled. Even though the considered bridge vibrations are characterized by small amplitude and a low frequency (i.e. below 15 Hz), it is shown that mean power of the order of 0.03 mW can be produced, with a controlled voltage between 1.8 and 3.6 V. A simple model is proposed for theoretical prediction of the delivered power in terms of traffic intensity. This model shows good agreement with the experimental results and leads to a simple but effective design rule for piezoelectric harvesters to be used on bridges.

Peigney, Michaėl; Siegert, Dominique

2013-09-01

46

Multi-link piezoelectric structure for vibration energy harvesting  

NASA Astrophysics Data System (ADS)

Work in piezoelectric vibration energy harvesting has typically focused on single member cantilevered structures with transverse tip displacement at a known frequency, taking advantage of the optimal coupling characteristics of piezoceramics in the 3-1 bending mode. Multi-member designs could be advantageous in delivering power to a load in environments with random or wide-band vibrations. The design presented in this work consists of two hinged piezoceramic (PZT-5A) beams x-poled for series operation. Each beam measures 31.8mm x 12.7mm x 0.38mm and consists of two layers of nickel-plated piezoceramic adhered to a brass center shim. The hinge device consists of two custom-machined aluminum attachments epoxied to the end of a beam and connected using a 1.59mm diameter alloy steel dowel. A stainless steel torsion spring is placed over the pin and attached to the aluminum body to provide a restoring torque when under rotation. The design is modeled using the piezoelectric constitutive equations to solve for voltage and power for a set of electromechanical boundary conditions. Experimental measurements on the design are achieved by bolting one end of the structure to a vibration shaker and fixing the other to a rigid framework of industrial aluminum framing material. For a given frequency of vibration, power output of the structure can be obtained by measuring voltage drop across a resistive load.

Aryanpur, Rameen M.; White, Robert D.

2012-04-01

47

Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester  

PubMed Central

Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM) applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA) was used as an initial tool to compare the three geometries' stiffness (K), output open-circuit voltage (Vave), and average normal strain in the piezoelectric transducer (?ave) that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3), has a maximum power output of 2.05 mW (H = 29.29 ?J/cycle). PMID:24366177

Kubba, Ali E.; Jiang, Kyle

2014-01-01

48

Analysis of Energy Harvesting for Vibration-Motivated Wireless Sensor Networks  

E-print Network

techno- logical advances have fueled the development of a tiny, low- cost, and low-power node which in such as bridges, buildings, dams, ships, aircrafts, etc. Each node equipped with a vibration detecting card can inherent pros and cons. When vibrations are a dominant source of energy and solar light is not always

Lim, Sunho

49

Converged vibrational energy levels and quantum mechanical vibrational partition function of ethane  

E-print Network

Converged vibrational energy levels and quantum mechanical vibrational partition function of ethane a combined valence-bond mo- lecular mechanics CVBMM potential energy surface.26 The calculations are carried function of ethane is calculated in the temperature range of 200Ā­600 K using well-converged energy levels

Truhlar, Donald G

50

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

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

2005-01-01

51

Multistable chain for ocean wave vibration energy harvesting  

NASA Astrophysics Data System (ADS)

The heaving of ocean waves is a largely untapped, renewable kinetic energy resource. Conversion of this energy into electrical power could integrate with solar technologies to provide for round-the-clock, portable, and mobile energy supplies usable in a wide variety of marine environments. However, the direct drive conversion methodology of gridintegrated wave energy converters does not efficiently scale down to smaller, portable architectures. This research develops an alternative power conversion approach to harness the extraordinarily large heaving displacements and long oscillation periods as an excitation source for an extendible vibration energy harvesting chain. Building upon related research findings and engineering insights, the proposed system joins together a series of dynamic cells through bistable interfaces. Individual impulse events are generated as the inertial mass of each cell is pulled across a region of negative stiffness to induce local snap through dynamics; the oscillating magnetic inertial mass then generates current in a coil which is connected to energy harvesting circuitry. It is shown that linking the cells into a chain transmits impulses through the system leading to cascades of vibration and enhancement of electrical energy conversion from each impulse event. This paper describes the development of the multistable chain and ways in which realistic design challenges were addressed. Numerical modeling and corresponding experiments demonstrate the response of the chain due to slow and large amplitude input motion. Lastly, experimental studies give evidence that energy conversion efficiency of the chain for wave energy conversion is much higher than using an equal number of cells without connections.

Harne, R. L.; Schoemaker, M. E.; Wang, K. W.

2014-03-01

52

Resonant vibrational energy transfer in ice Ih  

NASA Astrophysics Data System (ADS)

Fascinating anisotropy decay experiments have recently been performed on H2O ice Ih by Timmer and Bakker [R. L. A. Timmer, and H. J. Bakker, J. Phys. Chem. A 114, 4148 (2010)]. The very fast decay (on the order of 100 fs) is indicative of resonant energy transfer between OH stretches on different molecules. Isotope dilution experiments with deuterium show a dramatic dependence on the hydrogen mole fraction, which confirms the energy transfer picture. Timmer and Bakker have interpreted the experiments with a Förster incoherent hopping model, finding that energy transfer within the first solvation shell dominates the relaxation process. We have developed a microscopic theory of vibrational spectroscopy of water and ice, and herein we use this theory to calculate the anisotropy decay in ice as a function of hydrogen mole fraction. We obtain very good agreement with experiment. Interpretation of our results shows that four nearest-neighbor acceptors dominate the energy transfer, and that while the incoherent hopping picture is qualitatively correct, vibrational energy transport is partially coherent on the relevant timescale.

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

2014-06-01

53

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

54

Vibration-Based MEMS Piezoelectric Energy Harvester (VMPEH) Modeling and Analysis for Green Energy Source  

Microsoft Academic Search

The wireless sensor network market is growing quickly yet is limited by existing short lifetime batteries. Providing a green, virtually infinite alternative power source to traditional energy sources will significantly expand applications for WSNs and other technologies, the use of piezoelectric materials to capitalize on the ambient vibrations surrounding a system is one method that has seen a dramatic rise

Salem Saadon; Othman Sidek

2011-01-01

55

Ambient vibration-based MEMS piezoelectric energy harvester for green energy source  

Microsoft Academic Search

The wireless sensor network (WSN) market is growing quickly yet is limited by existing short lifetime batteries. Providing a green, virtually infinite alternative power source to traditional energy sources will significantly expand applications for WSNs and other technologies, the use of piezoelectric materials to capitalize on the ambient vibrations surrounding a system is one method that has seen a dramatic

Salem Saadon; Othman Sidek

2011-01-01

56

Stresa, Italy, 26-28 April 2006 VIBRATIONAL ENERGY SCAVENGING WITH SI TECHNOLOGY  

E-print Network

Stresa, Italy, 26-28 April 2006 VIBRATIONAL ENERGY SCAVENGING WITH SI TECHNOLOGY ELECTROMAGNETIC present the design and optimization of an electromagnetic inertial microgenerator for energy scavenging of the devices, the power consumption have considerably decreased, allowing to consider powering alternatives

Boyer, Edmond

57

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

58

Membrane-type vibrational energy harvester based on a multi-layered piezoelectric membrane  

NASA Astrophysics Data System (ADS)

In this study, we fabricated a membrane-type vibrational energy harvester by using a conventional micro-electro-mechanical (MEMS) method. The membrane-type vibrational energy harvester consists of a multi-layered diaphragm for stable and flexible vibration, a piezoelectric ZnO film for responding to the vibrational energy and for generating electric power, and a vibrator connected to the bottom of multi-layered diaphragm for enhancing the vibrational displacement of the diaphragm. First, we characterized the quality of a ZnO film through scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD), which showed a preferred c-axis orientation, a hexagonal rod shape and a quite smooth surface. After the membrane-type vibrational energy harvester had been fabricated, we integrated it into a printing circuit board to realize piezoelectric generation and confirm its performance. Finally, under vibrational motion, we obtained a useful output voltage of 400 mV, and we estimated that the energy harvester generated an actual output voltage of about 200 uV.

Yoo, Seunghwan; Kim, Jonghun; Park, Suk-in; Jang, Cheol-Yong; Jeong, Hakgeun

2014-03-01

59

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

60

Study of vibrational energy transfer at a liquid tin surface  

NASA Astrophysics Data System (ADS)

Single collision vibrational energy transfer for a canonical ensemble (T=300K) of cyclobutene molecules at a liquid tin surface was studied at temperatures from 500K to 775K. Transport above the reaction threshold for isomerization to butadiene was used as the criterion for efficiency of vibrational energy accommodation. The surface was found to function as a strong collider below 550 K. Experiments both above and below the freezing point revealed no discontinuity in the vibrational accommodation efficiency.

Nilsson, W. B.; Rabinovitch, B. S.

1984-08-01

61

MEMS DC\\/DC converter for 1D and 2D vibration-to-electricity power conversion  

Microsoft Academic Search

This paper presents a working silicon-based MEMS electrostatic transducer for harvesting and converting the energy of vibrations into electrical energy. The transducer is fabricated in a batch silicon-on-glass process. Two designs, for 1D and 2D vibrations, are addressed. The 1D harvester demonstrates between 60 and 100 nW of mechanical-to-electrical power conversion at 250 Hz when implemented in a classical DC\\/DC

A. Mahmood Paracha; P. Basset; D. Galayko; A. Dudka; F. Marty; T. Bourouina

2009-01-01

62

On the role of dielectric friction in vibrational energy relaxation  

NASA Astrophysics Data System (ADS)

The phrase ``dielectric friction'' tends to bring to mind the drag force exerted by a polar liquid on some translating ion or rotating dipolar molecule, but the underlying idea is far more general. Any relaxation process taking place in a polar environment, including those involving solvation and vibrational relaxation, has the potential to be strongly affected by the special dynamics associated with Coulombic forces. Indeed, there is considerable evidence that vibrational energy relaxation is noticeably accelerated in hydrogen-bonding solvents. What is less clear is precisely how electrostatic forces achieve the accelerations they do and to what extent this phenomenon relies on specifically protic solvents. We explore this issue in this paper by using classical molecular dynamics to study the vibrational population relaxation of diatomic solutes with varying levels of polarity dissolved in both dipolar and nondipolar aprotic solvents. We find that the conventional analysis based on partitioning the force autocorrelation function can be usefully extended by adapting an instantaneous perspective; distinguishing between the purely equilibrium effects of the instantaneous liquid structure surrounding a solute and the solely nonequilibrium effects of the relaxation dynamics launched from those initial conditions. Once one removes the powerful influence of electrostatic forces on the liquid structure, either by simple normalization or by looking at the ``force-velocity'' autocorrelation function, the subsequent dynamics (and therefore the mechanism) of the relaxation is revealed to be dominated by short-ranged repulsive forces, even under the most polar circumstances. The main rate-enhancing effect of Coulombic forces seems to be an equilibrium electrostriction: The solvent is simply ordered around the solute in such a way as to amplify the repulsive forces. At least in our examples, the slowly varying character of Colombic forces actually makes them quite ineffective at any kind of direct promotion of vibrational energy relaxation.

Ladanyi, Branka M.; Stratt, Richard M.

1999-08-01

63

Vibrational energy redistribution in glyoxal following internal conversion  

E-print Network

pumped excitation/ detection vacuum chamber is attached. Inside the cross is the beam source, whichVibrational energy redistribution in glyoxal following internal conversion R. Naaman,a) D. M 4 June 1979; accepted 10 August 1979) The vibrational redistribution of energy following internal

Zare, Richard N.

64

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

2014-01-01

65

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

PubMed

To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%. PMID:24854054

Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

2014-01-01

66

Accurate Measurement of Velocity and Acceleration of Seismic Vibrations near Nuclear Power Plants  

NASA Astrophysics Data System (ADS)

In spite of all prerequisite geological study based precautions, the sites of nuclear power plants are also susceptible to seismic vibrations and their consequent effects. The effect of the ongoing nuclear tragedy in Japan caused by an earthquake and its consequent tsunami on March 11, 2011 is currently beyond contemplations. It has led to a rethinking on nuclear power stations by various governments around the world. Therefore, the prediction of location and time of large earthquakes has regained a great importance. The earth crust is made up of several wide, thin and rigid plates like blocks which are in constant motion with respect to each other. A series of vibrations on the earth surface are produced by the generation of elastic seismic waves due to sudden rupture within the plates during the release of accumulated strain energy. The range of frequency of seismic vibrations is from 0 to 10 Hz. However, there appears a large variation in magnitude, velocity and acceleration of these vibrations. The response of existing or conventional methods of measurement of seismic vibrations is very slow, which is of the order of tens of seconds. A systematic and high resolution measurement of velocity and acceleration of these vibrations are useful to interpret the pattern of waves and their anomalies more accurately, which are useful for the prediction of an earthquake. In the proposed work, a fast rotating magnetic field (RMF) is used to measure the velocity and acceleration of seismic vibrations in the millisecond range. The broad spectrum of pulses within one second range, measured by proposed method, gives all possible values of instantaneous velocity and instantaneous acceleration of the seismic vibrations. The spectrum of pulses in millisecond range becomes available which is useful to measure the pattern of fore shocks to predict the time and location of large earthquakes more accurately. Moreover, instead of average, the peak values of these quantities are helpful in proper design of earthquake resistant nuclear power plants, buildings and structures. The proposed measurement scheme is successfully tested with a microprocessor based rocking vibration arrangement and the overall performance is recorded at dynamic conditions.

Arif, Syed Javed; Imdadullah; Asghar, Mohammad Syed Jamil

67

Power management circuit for resonant energy harvesters  

NASA Astrophysics Data System (ADS)

This paper deals with the design of the power management circuit for the vibration generator developed in the frame of the European WISE project and its testing in the connection with the generator and the dynamic load simulating the real load. This generator is used as an autonomous energy source for wireless sensor applications. It can be used for example in the aeronautic, automotive and many other applications. The generator output power analysis was based on the vibration spectrum measured on the helicopter engine, provided by the consortium EADS, EUROCOPTER, DASSAULT AVIATION - 6.RP -WIreless SEnsing (WISE) project. This spectrum shows very unstable vibration levels. It was done the statistical analysis of these vibration levels and it was shown that there is a need of the power management circuit, which can provide a stable output voltage for the supplied circuit and if there is a need it can store an immediately unusable generated energy. The generator can't be used as the only energy source for the sensor circuit, because there are not any vibrations when for example a motor is stopped. In these periods and in the time of low vibration levels the circuit must be supplied from battery. The power management circuit described in this paper fulfills these requirements. It has two power inputs - the battery and the generator. It can switch between them at certain defined generator output levels by the threshold detector. Also when there is too much of the generated power, it can store the extra energy in the storage for the later usage. The storage device is the advanced capacitor. The advanced capacitor is a device containing three capacitors. These capacitors are connected (and charged) sequentially so the increasing capacity is provided. The developed power management was tested in the connection with the real vibration generator raised by stable vibration levels and the dynamic load simulating the real sensor in the main operation stages - sampling and data transmitting. It was shown that the generator with output power of 8mW@0,3GRMS with generator weight of 140g together with the described power management circuit can save about 50% of battery energy with the mentioned vibration spectrum. The generator used for the testing was improved, so it is more sensitive and also the sensor power requirements were decreased, so now it can be saved up to 100% battery energy during the generator operation. Also the power management circuit is still refined.

Jirku, Tomas; Steinbauer, Miloslav; Kluge, Martin

2009-05-01

68

Vibrational energy transfer in shocked molecular crystals.  

PubMed

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

Hooper, Joe

2010-01-01

69

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

70

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

71

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

72

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

73

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

E-print Network

In general, vibration energy harvesting is the scavenging of ambient vibration by transduction of mechanical kinetic energy into electrical energy. Many mechanical or electro-mechanical systems produce mechanical vibrations. ...

Trimble, A. Zachary

2011-01-01

74

Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.  

PubMed

Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. PMID:24246149

Saffar, Saber; Abdullah, Amir

2014-03-01

75

Magnetic induction systems to harvest energy from mechanical vibrations  

E-print Network

This thesis documents the design process for magnetic induction systems to harvest energy from mechanical vibrations. Two styles of magnetic induction systems - magnet-through-coil and magnet-across-coils - were analyzed. ...

Jonnalagadda, Aparna S

2007-01-01

76

Vibration Isolation of a Locomotive Mounted Energy Storage Flywheel  

E-print Network

Utilizing flywheels to store and reuse energy from regenerative braking on locomotives is a new technology being developed in the Vibration Control and Electromechanics Lab at Texas A&M. This thesis focuses on the motion analysis of a locomotive...

Zhang, Xiaohua

2011-02-22

77

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

78

Comprehensive Vibration Assessment Program (CAP) performed Yonggwang Nuclear Power Plant Unit 4 (YGN 4) order verify structural integrity reactor internals flow induced vibrations prior commercial operation.  

EPA Pesticide Factsheets

Search instead for Comprehensive Vibration Assessment Program (CAP) performed Yonggwang Nuclear Power Plant Unit 4 (YGN 4) order verify structural integrity reactor internals flow induced vibrations prior commercial operation. ?

79

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

80

Non-Linear Vibration of Power Transmission Belts  

NASA Astrophysics Data System (ADS)

Non-linear vibration of a prototypical power transmission belt system, which is excited by pulleys having slight eccentricity, is investigated through experimental and analytical methods. Laboratory measurements demonstrate the role of non-linearity in setting the belt's response, particularly in the near-resonance region, and at high running speeds. The belt is coated with a retroreflective medium so as to improve displacement and velocity measurements made through non-contact laser interferometry. A frequency crossing diagram relates the belt's speed-dependent excitation and natural frequencies, and is shown to be useful for identifying those speeds at which resonance is expected. Distinctive jump and hysteresis phenomena in the near-resonant response are observed experimentally, and are also studied with a model that includes non-linear stretching of the belt. In that regard, a modal perturbation solution is developed in the context of the asymptotic method of Krylov, Bogoliubov and Mitropolsky for a general, continuous, non-autonomous, gyroscopic system with weakly non-linear stiffness. The solution is subsequently specialized to the belt vibration problem at hand. Near- and exact-resonant response amplitudes are predicted by the perturbation method, and they are compared with those obtained by laboratory tests and by direct numerical simulation of the non-linear model.

Moon, J.; Wickert, J. A.

1997-03-01

81

Energy-based comparison of various controllers for vibration suppression using piezoceramics  

NASA Astrophysics Data System (ADS)

The large-scale and light-weight design trend in aircraft and spacecraft results in extremely flexible structures with lowfrequency vibration modes. Suppression of undesired vibrations in such flexible structures with limited energy is becoming an important design problem to develop energy-autonomous controllers powered using the harvested ambient energy. The objective of this paper is to compare different control laws to suppress low-frequency vibrations using the minimum actuation energy for the same system and under the same design constraint (identical settling time for free vibrations). The vibration suppression performance of four active control systems as well as their hybrid versions employing a switching technique are presented and compared. The control systems compared here are a Positive Position Feedback (PPF) controller, a Proportional Integral Derivative (PID) controller, a nonlinear controller (with a second-order nonlinear term multiplying the position and velocity feedback to create variable damping), a Linear Quadratic Regulator (LQR) controller and their hybrid versions integrating a bang-bang control law (on-off control) with each of these controllers. Experimental results are presented for a thin cantilevered beam with a piezoceramic transducer controlled by these eight controllers with a focus on the fundamental vibration mode under transverse free vibrations and the control energy requirements are compared. Experiments results reveal that all the controllers reduce the vibration settling time to 0.85s as a design constraint (which is 92.3% of the open-loop settling time: 10.9s). The average actuation power input provided to the piezoceramic transducer in each case is obtained for the time current and voltage measurements until the settling time. Comparisons show that the switching technology reduces significant actuation power requirement, so that all the hybrid control systems require much less power than their conventional versions. Especially, the hybrid bang-bang-nonlinear controller requires 67% less power than the conventional nonlinear controller. In order to verify this statement, the actuation current is theoretically calculated through piezo-capacitance using voltage measurements to check out the average power estimation. The theoretical checking out provides the same results with slightly error, which can be explained by measurement errors.

Wang, Ya; Inman, Daniel J.

2011-03-01

82

Spectroscopic probes of vibrationally excited molecules at chemically significant energies  

SciTech Connect

This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

Rizzo, T.R. [Univ. of Rochester, NY (United States)

1993-12-01

83

Damping of flexural vibrations in rectangular plates by slots of power-law profile  

E-print Network

investigations are described: the effect of power-law tapered slots on vibration damping in steel and composite method of damping flexural vibrations, which is comparable with the method using power-law wedges Eleven samples were designed for this investigation; six of which were manufactured from 5 mm thick hot

Paris-Sud XI, UniversitƩ de

84

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

NASA Astrophysics Data System (ADS)

Water clustering and connectivity around lipid bilayers strongly influences the properties of membranes and is important for functions such as proton and ion transport. Vibrational anisotropic pump-probe spectroscopy is a powerful tool for understanding such clustering, as the measured anisotropy depends upon the time-scale and degree of intra- and intermolecular vibrational energy transfer. In this article, we use molecular dynamics simulations and theoretical vibrational spectroscopy to help interpret recent experimental measurements of the anisotropy of water in lipid multi-bilayers as a function of both lipid hydration level and isotopic substitution. Our calculations are in satisfactory agreement with the experiments of Piatkowski, Heij, and Bakker, and from our simulations we can directly probe water clustering and connectivity. We find that at low hydration levels, many water molecules are in fact isolated, although up to 70% of hydration water forms small water clusters or chains. At intermediate hydration levels, water forms a wide range of cluster sizes, while at higher hydration levels, the majority of water molecules are part of a large, percolating water cluster. Therefore, the size, number, and nature of water clusters are strongly dependent on lipid hydration level, and the measured anisotropy reflects this through its dependence on intermolecular energy transfer.

Gruenbaum, S. M.; Skinner, J. L.

2013-11-01

85

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

NASA Astrophysics Data System (ADS)

Quantum scattering calculations are reported for state-to-state vibrational relaxation and reactive scattering in O + OH(v = 2 - 3, j = 0) collisions on the electronically adiabatic ground state 2A'' potential energy surface of the HO2 molecule. The time-independent Schrödinger equation in hyperspherical coordinates is solved to determine energy dependent probabilities and cross sections over collision energies ranging from ultracold to 0.35 eV and for total angular momentum quantum number J = 0. A J-shifting approximation is then used to compute initial state selected reactive rate coefficients in the temperature range T = 1 - 400 K. Results are found to be in reasonable agreement with available quasiclassical trajectory calculations. Results indicate that rate coefficients for O2 formation increase with increasing the OH vibrational level except at low and ultralow temperatures where OH(v = 0) exhibits a slightly different trend. It is found that vibrational relaxation of OH in v = 2 and v = 3 vibrational levels is dominated by a multi-quantum process.

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

2013-11-01

86

Energy transfer of highly vibrationally excited naphthalene. I. Translational collision energy dependence  

Microsoft Academic Search

Energy transfer between highly vibrationally excited naphthalene and Kr atom in a series of translational collision energies (108–847 cm?1) was studied separately using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. Highly vibrationally excited naphthalene in the triplet state (vibrational energy: 16 194 cm?1; electronic energy: 21 400 cm?1) was formed via the rapid intersystem crossing of

Chen-Lin Liu; Hsu Chen Hsu; Yuan Chin Hsu; Chi-Kung Ni

2007-01-01

87

Energy transfer of highly vibrationally excited naphthalene. I. Translational collision energy dependence  

Microsoft Academic Search

Energy transfer between highly vibrationally excited naphthalene and Kr atom in a series of translational collision energies (108-847 cm-1) was studied separately using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. Highly vibrationally excited naphthalene in the triplet state (vibrational energy: 16 194 cm-1 electronic energy: 21 400 cm-1) was formed via the rapid intersystem crossing of

Chen-Lin Liu; Hsu Chen Hsu; Yuan Chin Hsu; Chi-Kung Ni

2007-01-01

88

Flow-control-induced vibrations for power generation using pulsed plasma actuators  

NASA Astrophysics Data System (ADS)

This paper describes flow-control-induced vibrations using pulsed dielectric barrier discharge plasma actuators, in which boundary layer separation on a structure is actively controlled to produce periodic loads that lead to its vibration. The concept is intended for energy generation and is demonstrated experimentally using a one-degree-of-freedom pivoted cylindrical body mounted vertically within a blow-down wind tunnel. Subcritical Reynolds numbers, less than 105, were considered where typical shedding frequencies were several times larger than the system natural frequency. Static deflection experiments were performed to determine the maximum imposed aerodynamic loads as a function of control parameters and these were complemented with flow-field measurements. Periodic loading of the cylinder was achieved by periodic modulation of the actuator. Large amplitude oscillations were observed when the modulation frequency was close to the system natural frequency. In contrast to natural vortex induced vibration, the large amplitude oscillations were achieved by alternating dynamic separation and attachment of the boundary layer. Estimation of the transient loads was performed using a system identification technique and the power generated by the system was estimated on the basis of a piecewise linear model. Peak estimated power coefficients were relatively small (0.042) but can be improved by increasing the lateral force coefficients and by proportionately increasing the system's physical size.

Greenblatt, David; Treizer, Alexander; Eidelman, Alexander; Mueller-Vahl, Hanns

2012-10-01

89

Design of energy harvesting systems for harnessing vibrational motion from human and vehicular motion  

NASA Astrophysics Data System (ADS)

In much of the vibration-based energy harvesting literature, devices are modeled, designed, and tested for dissipating energy across a resistive load at a single base excitation frequency. This paper presents several practical scenarios germane to tracking, sensing, and wireless communication on humans and land vehicles. Measured vibrational data from these platforms are used to provide a time-varying, broadband input to the energy harvesting system. Optimal power considerations are given for several circuit topologies, including a passive rectifier circuit and active, switching methods. Under various size and mass constraints, the optimal design is presented for two scenarios: walking and idling a car. The frequency response functions are given alongside time histories of the power harvested using the experimental base accelerations recorded. The issues involved in designing an energy harvester for practical (i.e. timevarying, non-sinusoidal) applications are discussed.

Wickenheiser, Adam; Garcia, Ephrahim

2010-04-01

90

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

91

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

92

An auto-parametrically excited vibration energy harvester  

E-print Network

resonance. The authors however, have previously demonstrated an alter- native: parametric resonance at both macro-scale [16, 17] and MEMS scale [18, 19], outperforming the same device driven into direct resonance by over an order of magnitude in power output... compromises the absolute power output attainable, the piezoceramic still acts as a viable vibration sensor to achieve qualitative characterisation and a relative quantitative comparison when the prototype is driven into direct and parametric resonance. Results...

Jia, Yu; Seshia, Ashwin A.

2014-01-01

93

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

2011-04-01

94

A two-dimensional broadband vibration energy harvester using magnetoelectric transducer  

SciTech Connect

In this study, a magnetoelectric vibration energy harvester was demonstrated, which aims at addressing the limitations of the existing approaches in single dimensional operation with narrow working bandwidth. A circular cross-section cantilever rod, not a conventional thin cantilever beam, was adopted to extract vibration energy in arbitrary in-plane motion directions. The magnetic interaction not only resulted in a nonlinear motion of the rod with increased frequency bandwidth, but also contributed to a multi-mode motion to exhibit double power peaks. In energy harvesting with in-plane directions, it showed a maximum bandwidth of 4.4?Hz and power of 0.59?mW, with acceleration of 0.6?g (with g?=?9.8?m?s{sup ?2})

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

2013-12-09

95

Piezoelectric Power Scavenging of Mechanical Vibration and R H Middleton  

E-print Network

be present. If successfully harvested, this energy could be used to eliminate batteries in wireless sensors of the model, prototype of the power scavenging circuit, experimental results and its future perspectives for portable electronics and wireless sensors is growing rapidly. Because these devices are portable

Duffy, Ken

96

Minimization of the vibration energy of thin-plate structures and the application to the reduction of gearbox vibration  

NASA Technical Reports Server (NTRS)

While the vibration analysis of gear systems has been developed, a systematic approach to the reduction of gearbox vibration has been lacking. The technique of reducing vibration by shifting natural frequencies is proposed here for gearboxes and other thin-plate structures using the theories of finite elements, modal analysis, and optimization. A triangular shell element with 18 degrees of freedom is developed for structural and dynamic analysis. To optimize, the overall vibration energy is adopted as the objective function to be minimized at the excitation frequency by varying the design variable (element thickness) under the constraint of overall constant weight. Modal analysis is used to determine the sensitivity of the vibration energy as a function of the eigenvalues and eigenvectors. The optimum design is found by the gradient projection method and a unidimensional search procedure. By applying the computer code to design problems for beams and plates, it was verified that the proposed method is effective in reducing vibration energy. The computer code is also applied to redesign the NASA Lewis gear noise rig test gearbox housing. As one example, only the shape of the top plate is varied, and the vibration energy levels of all the surfaces are reduced, yielding an overall reduction of 1/5 compared to the initial design. As a second example, the shapes of the top and two side plates are varied to yield an overall reduction in vibration energy of 1/30.

Inoue, Katsumi; Krantz, Timothy L.

1995-01-01

97

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

NASA Technical Reports Server (NTRS)

While the vibration analysis of gear systems has been developed, a systematic approach to the reduction of gearbox vibration has been lacking. The technique of reducing vibration by shifting natural frequencies is proposed here for gearboxes and other thin-plate structures using the theories of finite elements, modal analysis, and optimization. A triangular shell element with 18 degrees of freedom is developed for structural and dynamic analysis. To optimize, the overall vibration energy is adopted as the objective function to be minimized at the excitation frequency by varying the design variable (element thickness) under the constraint of overall constant weight. Modal analysis is used to determine the sensitivity of the vibration energy as a function of the eigenvalues and eigenvectors. The optimum design is found by the gradient projection method and a unidimensional search procedure. By applying the computer code to design problems for beams and plates, it was verified that the proposed method is effective in reducing vibration energy. The computer code is also applied to redesign the NASA Lewis gear noise rig test gearbox housing. As one example, only the shape of the top plate is varied, and the vibration energy levels of all the surfaces are reduced, yielding an overall reduction of 1/5 compared to the initial design. As a second example, the shapes of the top and two side plates are varied to yield an overall reduction in vibration energy of 1/30.

Inoue, Katsumi; Krantz, Timothy L.

1995-01-01

98

Comparison of vibrational conductivity and radiative energy transfer methods  

E-print Network

of the wideband response of built-up stuctures subjected to high frequency vibrational excitation. The first], plates [7, 8] and built-up structures [9]. In the field of acoustics, the so-called radiosity method [10 of the repartition of energy in built-up structures. Both methods are also based on analogies with some equations

Paris-Sud XI, UniversitƩ de

99

Experimental Vibrational Zero-Point Energies: Diatomic Molecules  

Microsoft Academic Search

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

Karl K. Irikura

2007-01-01

100

Skyrmion vibrational energies with a generalized mass term  

E-print Network

We study various properties of a one parameter mass term for the Skyrme model, originating from the works of Kopeliovich, Piette and Zakrzewski, through the use of axially symmetric solutions obtained numerically by simulated-annealing. These solutions allow us to observe asymptotic behaviors of the B=2 binding energies that differ to those previously obtained. We also decipher the characteristics of three distinct vibrational modes that appear as eigenstates of the vibrational Hamiltonian. This analysis further examine the assertion that the one parameter mass term offers a better account of baryonic matter than the traditional mass term.

Merlin C. Davies; Luc Marleau

2009-04-21

101

Minimization of the vibration energy of thin-plate structure  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

102

Vibrational zero point energy for H-doped silicon  

NASA Astrophysics Data System (ADS)

Most of the studies addressed to computations of hydrogen parameters in semiconductor systems, such as silicon, are performed at zero temperature T = 0 K and do not account for contribution of vibrational zero point energy (ZPE). For light weight atoms such as hydrogen (H), however, magnitude of this parameter might be not negligible. This Letter is devoted to clarify the importance of accounting the zero-point vibrations when analyzing hydrogen behavior in silicon and its effect on silicon electronic properties. For this, we estimate the ZPE for different locations and charge states of H in Si. We show that the main contribution to the ZPE is coming from vibrations along the Si-H bonds whereas contributions from other Si atoms apart from the direct Si-H bonds play no role. It is demonstrated that accounting the ZPE reduces the hydrogen formation energy by ?0.17 eV meaning that neglecting ZPE at low temperatures one can underestimate hydrogen solubility by few orders of magnitude. In contrast, the effect of the ZPE on the ionization energy of H in Si is negligible. The results can have important implications for characterization of vibrational properties of Si by inelastic neutron scattering, as well as for theoretical estimations of H concentration in Si.

Karazhanov, S. Zh.; Ganchenkova, M.; Marstein, E. S.

2014-05-01

103

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

104

A non-resonant, frequency up-converted electromagnetic energy harvester from human-body-induced vibration for hand-held smart system applications  

NASA Astrophysics Data System (ADS)

We present a non-resonant, frequency up-converted electromagnetic energy harvester that generates significant power from human-body-induced vibration, e.g., hand-shaking. Upon excitation, a freely movable non-magnetic ball within a cylinder periodically hits two magnets suspended on two helical compression springs located at either ends of the cylinder, allowing those to vibrate with higher frequencies. The device parameters have been designed based on the characteristics of human hand-shaking vibration. A prototype has been developed and tested both by vibration exciter (for non-resonance test) and by manual hand-shaking. The fabricated device generated 110 ?W average power with 15.4 ?W cm-3 average power density, while the energy harvester was mounted on a smart phone and was hand-shaken, indicating its ability in powering portable hand-held smart devices from low frequency (<5 Hz) vibrations.

Halim, Miah A.; Park, Jae Y.

2014-03-01

105

Liquid-encapsulated energy harvester for low frequency vibrations  

Microsoft Academic Search

This paper presents the design, fabrication, and testing of prototype liquid-encapsulated energy harvester (LEEH) using PVDF electrets. Unlike harvesters reported in previous literature, this LEEH uses flowing liquid rather than resonating structures to induce variable capacitance, thus is more suitable for low frequency vibration energy harvesting. Manufactured prototypes with three different types of liquid (N-methyl-2pyrrolidone, N, N-Dimethylformamide, and glycerin) are

L. Bu; X. M. Wu; X. H. Wang; L. T. Liu

2011-01-01

106

A Branched Beam-Based Vibration Energy Harvester  

NASA Astrophysics Data System (ADS)

In this paper, a strategy to utilize a branched beam system to improve the frequency response characteristic of vibration energy harvesting is demonstrated. A basic unit of the device consists of several branch beams with proof mass at their ends and one main cantilever beam with a piezoelectric component at its root and proof mass at its end. The device can utilize the resonance of the branch beams and main beam to generate multiple output voltage peaks, providing a better frequency response characteristic than that of the conventional piezoelectric vibration energy harvester. Multiple branch structure and multiple basic units with similar structures can be connected to generate more output voltage peaks in the frequency response characteristic. Only one piezoelectric component is needed in the device, which makes it competitive in the management of harvested electric energy.

Zhang, Guangcheng; Hu, Junhui

2014-09-01

107

A Branched Beam-Based Vibration Energy Harvester  

NASA Astrophysics Data System (ADS)

In this paper, a strategy to utilize a branched beam system to improve the frequency response characteristic of vibration energy harvesting is demonstrated. A basic unit of the device consists of several branch beams with proof mass at their ends and one main cantilever beam with a piezoelectric component at its root and proof mass at its end. The device can utilize the resonance of the branch beams and main beam to generate multiple output voltage peaks, providing a better frequency response characteristic than that of the conventional piezoelectric vibration energy harvester. Multiple branch structure and multiple basic units with similar structures can be connected to generate more output voltage peaks in the frequency response characteristic. Only one piezoelectric component is needed in the device, which makes it competitive in the management of harvested electric energy.

Zhang, Guangcheng; Hu, Junhui

2014-11-01

108

IEEE Power and Energy  

NSDL National Science Digital Library

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

2003-01-01

109

Calculation of vibrational zero-point energy  

Microsoft Academic Search

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

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

2001-01-01

110

A review of vibration problems in power station boiler feed pumps  

NASA Technical Reports Server (NTRS)

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

111

Determination of stepsize parameters for intermolecular vibrational energy transfer  

SciTech Connect

The understanding of intermolecular vibrational energy transfer (IVET) is important since it is involved in any mechanism in which internal energy is added or removed from molecules. The database for the details of IVET for highly excited polyatomic molecules is inadequate and must be expanded. The overall objectives of this project are: (1) to determine the dependence of energy relaxation on excitation energy and on the molecular complexity of substrate and deactivator, (2) to assess the importance of intermolecular attractions on IVET, (3) to obtain more detailed information on the energy distribution after collision, and (4) to evaluate the importance of IVET on high temperature unimolecular reactions. The first three objectives are being met by experimentally measuring the time evolution of the average energy of the vibrationally excited species (hydro- and fluoro- carbons excited by a pulsed CO{sub 2} laser) and the average energy transferred into relative translation via time resolved IR spectrometry, interferometry and optoacoustic techniques. Trajectory calculations simulating IVET are being performed for model substrate/deactivator pairs to provide additional details and insight on the critical parameters. Our calculations for high temperature unimolecular reactions indicate that IVET effects are significant and must be correctly taken into account. 9 refs., 3 figs., 6 tabs.

Tardy, D.C.

1989-06-01

112

The fabrication of vibration energy harvester arrays based on AlN piezoelectric film  

NASA Astrophysics Data System (ADS)

The fabrication and measurement results of the vibration energy harvester arrays based on the piezoelectric aluminum nitride (AlN) film are presented. The structure design and fabrication process of the device are introduced. The key material, the AlN film with crystal orientation (002), was deposited by pulsed-DC magnetron sputtering and characterized by X-ray diffraction (XRD). The resonant frequency, power out, and the open circuit voltage of the device are detected. The optimized load of 80 k? and a remarkable maximum power out of 30.4 ?W are obtained when the acceleration of 0.9g (g is standard gravity acceleration) is applied.

Zhengguo, Shang; Dongling, Li; Zhiyu, Wen; Xingqiang, Zhao

2013-11-01

113

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

SciTech Connect

The physics of vibrational kinetics in nitrogen-containing plasma produced by collisions with electrons is studied on the basis of recently derived cross sections and rate coefficients for the resonant vibrational-excitation by electron-impact. The temporal relaxation of the vibrational energy and of the vibrational distribution function is analyzed in a state-to-state approach. The electron and vibrational temperatures are varied in the range [0-50 000] K. Conclusions are drawn with respect to the derivation of reduced models and to the accuracy of a relaxation time formalism. An analytical fit of the vibrational relaxation time is given.

Laporta, V. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 70125 Bari (Italy); Bruno, D. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, 70125 Bari (Italy)

2013-03-14

114

Modeling nonlinear random vibration: Implication of the energy conservation law  

E-print Network

Nonlinear random vibration under excitations of both Gaussian and Poisson white noises is considered. The model is based on stochastic differential equations, and the corresponding stochastic integrals are defined in such a way that the energy conservation law is satisfied. It is shown that Stratonovich integral and Di Paola-Falsone integral should be used for excitations of Gaussian and Poisson white noises, respectively, in order for the model to satisfy the underlining physical laws (e.g., energy conservation). Numerical examples are presented to illustrate the theoretical results.

Xu Sun; Jinqiao Duan; Xiaofan Li

2012-06-18

115

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

116

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

PubMed

Conversion of ambient vibrational energy into electric power has been the impetus of much modern research. The traditional analysis has focused on absolute electrical power output from the harvesting devices and efficiency defined as the convertibility of an infinite resource of vibration excitation into power. This perspective has limited extensibility when applying resonant harvesters to host resonant structures when the inertial influence of the harvester is more significant. Instead, this work pursues a fundamental understanding of the coupled dynamics of a main mass-spring-damper system to which an electromagnetic or piezoelectric mass-spring-damper is attached. The governing equations are derived, a metric of efficiency is presented, and analysis is undertaken. It is found that electromagnetic energy harvesting efficiency and maximum power output is limited by the strength of the coupling such that no split system resonances are induced for a given mass ratio. For piezoelectric harvesters, only the coupling strength and certain design requirements dictate maximum power and efficiency achievable. Since the harvesting circuitry must "follow" the split resonances as the piezoelectric harvesters become more massive, the optimum design of piezoelectric harvesters appears to be more involved than for electromagnetic devices. PMID:22779465

Harne, Ryan L

2012-07-01

117

Repulsively driven frequency-increased-generators for durable energy harvesting from ultra-low frequency vibration.  

PubMed

An electromagnetic kinetic energy harvester has been developed, which can convert ultra-low-frequency motion and vibration energy into electrical power. This harvester employs a two-stage vibratory structure to collect low-frequency kinetic energy and effectively transfer it into electric power by using a pair of high-frequency resonant generators. Non-contact magnetic repulsive force is herein utilized for the 1st-stage sliding vibrator to drive the 2nd-stage resonators into frequency-up-conversion resonance. The non-contact actuation is helpful for durable and long-life working of the device. The prototyped device is fabricated and the design is well confirmed by experimental test. The harvester can be well operated at the frequency as low as 0.25 Hz. Under driving acceleration of 1 g at 0.5 Hz, the miniaturized harvester can generate a peak power of 4.42 mW and an average power of 158 ?W. PMID:24784650

Tang, Qiaochu; Yang, Yongliang; Li, Xinxin

2014-04-01

118

Repulsively driven frequency-increased-generators for durable energy harvesting from ultra-low frequency vibration  

NASA Astrophysics Data System (ADS)

An electromagnetic kinetic energy harvester has been developed, which can convert ultra-low-frequency motion and vibration energy into electrical power. This harvester employs a two-stage vibratory structure to collect low-frequency kinetic energy and effectively transfer it into electric power by using a pair of high-frequency resonant generators. Non-contact magnetic repulsive force is herein utilized for the 1st-stage sliding vibrator to drive the 2nd-stage resonators into frequency-up-conversion resonance. The non-contact actuation is helpful for durable and long-life working of the device. The prototyped device is fabricated and the design is well confirmed by experimental test. The harvester can be well operated at the frequency as low as 0.25 Hz. Under driving acceleration of 1 g at 0.5 Hz, the miniaturized harvester can generate a peak power of 4.42 mW and an average power of 158 ?W.

Tang, Qiaochu; Yang, Yongliang; Li, Xinxin

2014-04-01

119

Semiclassical wave packet study of V-V energy transfer in highly vibrationally excited CO molecules  

Microsoft Academic Search

Application of a semiclassical wave packet approach to the study of vibrational energy transfer in collision between highly vibrationally excited diatomic molecules is discussed. The method uses a quantum mechanical description based on the solution to the time-dependent Schrödinger equation to describe the vibrational motions and a classical mechanical treatment for the rotational and translational motions. The quantum and classical

N. Balakrishnan; G. D. Billing

1996-01-01

120

ESTIMATING DAMPING PARAMETERS IN MULTI-DEGREE-OF-FREEDOM VIBRATION SYSTEMS BY BALANCING ENERGY0  

E-print Network

of Vibration and Acoustics, 131 (4) 041005, 2009 Measurement of damping forces, such as dry frictionESTIMATING DAMPING PARAMETERS IN MULTI-DEGREE-OF-FREEDOM VIBRATION SYSTEMS BY BALANCING ENERGY0 B@egr.msu.edu ABSTRACT A method of estimating damping parameters for multi- degree-of-freedom vibration systems

Feeny, Brian

121

Modeling and Tuning for Vibration Energy Harvesting using a Piezoelectric Bimorph  

NASA Astrophysics Data System (ADS)

With the development of wireless sensors and other devices, the need for continuous power supply with high reliability is growing ever more. The traditional battery power supply has the disadvantage of limited duration of continuous power supply capability so that replacement for new batteries has to be done regularly. This can be quite inconvenient and sometimes quite difficult especially when the sensors are located in places not easily accessible such as the inside of a machine or wild field. This situation stimulates the development of renewable power supply which can harvest energy from the environment. The use of piezoelectric materials to converting environment vibration to electrical energy is one of the alternatives of which a broad range of research has been done by many researchers, focusing on different issues. The improvement of efficiency is one of the most important issues in vibration based energy harvesting. For this purpose different methods are devised and more accurate modeling of coupled piezoelectric mechanical systems is investigated. In the current paper, the research is focused on improving voltage generation of a piezoelectric bimorph on a vibration beam, as well as the analytical modeling of the same system. Also an initial study is conducted on the characteristics of the vibration of Zinc oxide (ZnO) nanowire, which is a promising material for its coupled semiconducting and piezoelectric properties. The effect on the voltage generation by different placement of the piezoelectric bimorph on the vibrating beam is investigated. The relation between the voltage output and the curvature is derived which is used to explain the effect of placement on voltage generation. The effect of adding a lumped mass on the modal frequencies of the beam and on the curvature distribution is investigated. The increased voltage output from the piezoelectric bimorph by using appropriately selected mass is proved analytically and also verified by experiment. For the modeling of piezoelectric generator, different methods are employed to modeling the coupled dynamics of a piezoelectric bimorph on a vibrating beam as well as a simple piezoelectric bimorph cantilever. The modeling of piezoelectric bimorph as an alternative current (AC) source with internal capacitance and resistance is used to analyze a piezoelectric bimorph cantilever and to calculate the optimal external load resistance for maximal power output. The couple dynamics method based on Hamilton's Principle is applied in the modeling of the piezoelectric bimorph on a vibrating beam. Impulse response experiment shows this method has a better estimation of the experimental results than the curvature model. The coupled dynamics model is also applied to piezoelectric bimorph cantilever and the external load resistance is also determined by this to maximize the power output. The finite element equations for the piezoelectric materials in the element domain are theoretically derived. The procedure of modeling a piezoelectric on a vibrating beam is demonstrated base on the package of ANSYS. The frequency response of ZnO nanowires with different dimensions is derived analytically for ambient mediums with different damping ratios. With help from nano research lab of Dr. Yong Zhu and the student Feng Xu, an experiment is conducted which indentifies the first modal frequency of ZnO nanowires with different dimensions. The experimental modal frequencies are compared with the numerical results. The influence of the thickness of deposit on the modal frequency is also investigated by finite element modeling.

Cao, Yongqing

122

Field Telemetry of Blade-rotor Coupled Torsional Vibration at Matuura Power Station Number 1 Unit  

NASA Technical Reports Server (NTRS)

The quasi-modal reduction technique and finite element model (FEM) were used to construct an analytical model for the blade-rotor coupled torsional vibration of a steam turbine generator of the Matuura Power Station. A single rotor test was executed in order to evaluate umbrella vibration characteristics. Based on the single rotor test results and the quasi-modal procedure, the total rotor system was analyzed to predict coupled torsional frequencies. Finally, field measurement of the vibration of the last stage buckets was made, which confirmed that the double synchronous resonance was 124.2 Hz, meaning that the machine can be safely operated. The measured eigen values are very close to the predicted value. The single rotor test and this analytical procedure thus proved to be a valid technique to estimate coupled torsional vibration.

Isii, Kuniyoshi; Murakami, Hideaki; Otawara, Yasuhiko; Okabe, Akira

1991-01-01

123

Electronic resonance with anticorrelated pigment vibrations drives photosynthetic energy transfer outside the adiabatic framework  

PubMed Central

The delocalized, anticorrelated component of pigment vibrations can drive nonadiabatic electronic energy transfer in photosynthetic light-harvesting antennas. In femtosecond experiments, this energy transfer mechanism leads to excitation of delocalized, anticorrelated vibrational wavepackets on the ground electronic state that exhibit not only 2D spectroscopic signatures attributed to electronic coherence and oscillatory quantum energy transport but also a cross-peak asymmetry not previously explained by theory. A number of antennas have electronic energy gaps matching a pigment vibrational frequency with a small vibrational coordinate change on electronic excitation. Such photosynthetic energy transfer steps resemble molecular internal conversion through a nested intermolecular funnel. PMID:23267114

Tiwari, Vivek; Peters, William K.; Jonas, David M.

2013-01-01

124

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

PubMed

An unstable mechanical structure that can self-balance when perturbed is a superior choice for vibration energy harvesting and vibration detection. In this work, a suspended 3D spiral structure is integrated with a triboelectric nanogenerator (TENG) for energy harvesting and sensor applications. The newly designed vertical contact-separation mode TENG has a wide working bandwidth of 30 Hz in low-frequency range with a maximum output power density of 2.76 W/m(2) on a load of 6 M?. The position of an in-plane vibration source was identified by placing TENGs at multiple positions as multichannel, self-powered active sensors, and the location of the vibration source was determined with an error less than 6%. The magnitude of the vibration is also measured by the output voltage and current signal of the TENG. By integrating the TENG inside a buoy ball, wave energy harvesting at water surface has been demonstrated and used for lighting illumination light, which shows great potential applications in marine science and environmental/infrastructure monitoring. PMID:24168315

Hu, Youfan; Yang, Jin; Jing, Qingshen; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin

2013-11-26

125

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

PubMed Central

The simulation results for electromagnetic energy harvesters (EMEHs) under broad band stationary Gaussian random excitations indicate the importance of both a high transformation factor and a high mechanical quality factor to achieve favourable mean power, mean square load voltage, and output spectral density. The optimum load is different for random vibrations and for sinusoidal vibration. Reducing the total damping ratio under band-limited random excitation yields a higher mean square load voltage. Reduced bandwidth resulting from decreased mechanical damping can be compensated by increasing the electrical damping (transformation factor) leading to a higher mean square load voltage and power. Nonlinear EMEHs with a Duffing spring and with linear plus cubic damping are modeled using the method of statistical linearization. These nonlinear EMEHs exhibit approximately linear behaviour under low levels of broadband stationary Gaussian random vibration; however, at higher levels of such excitation the central (resonant) frequency of the spectral density of the output voltage shifts due to the increased nonlinear stiffness and the bandwidth broadens slightly. Nonlinear EMEHs exhibit lower maximum output voltage and central frequency of the spectral density with nonlinear damping compared to linear damping. Stronger nonlinear damping yields broader bandwidths at stable resonant frequency. PMID:24605063

Sassani, Farrokh

2014-01-01

126

Electrostatic vibration energy harvester with combined effect of electrical nonlinearities and mechanical impact  

NASA Astrophysics Data System (ADS)

This paper presents an advanced study including the design, characterization and theoretical analysis of a capacitive vibration energy harvester. Although based on a resonant electromechanical device, it is intended for operation in a wide frequency band due to the combination of stop-end effects and a strong biasing electrical field. The electrostatic transducer has an interdigited comb geometry with in-plane motion, and is obtained through a simple batch process using two masks. A continuous conditioning circuit is used for the characterization of the transducer. A nonlinear model of the coupled system ‘transduce-conditioning circuit’ is presented and analyzed employing two different semi-analytical techniques together with precise numerical modelling. Experimental results are in good agreement with results obtained from numerical modelling. With the 1 g amplitude of harmonic external acceleration at atmospheric pressure, the system transducer-conditioning circuit has a half-power bandwidth of more than 30% and converts more than 2 µW of the power of input mechanical vibrations over the range of 140 and 160 Hz. The harvester has also been characterized under stochastic noise-like input vibrations.

Basset, P.; Galayko, D.; Cottone, F.; Guillemet, R.; Blokhina, E.; Marty, F.; Bourouina, T.

2014-03-01

127

Effects of acute upper-body vibration on strength and power variables in climbers.  

PubMed

Whole-body vibration training has recently received a lot of attention with reported enhancements of strength and power qualities in athletes. This study investigated whether upper-body vibration would be able to augment muscular attributes for climbing performance. Twelve healthy active climbers volunteered for the study. All participants underwent 3 treatments--arm cranking (AC), upper-body vibration (UBV), and non-UBV (NUBV)--in a balanced random order, conducted on separate days. Upper-body vibration was generated via a commercialized electric-powered dumbbell with a rotating axis that delivered oscillatory movements to the shoulders and arms. The UBV treatment consisted of performing 5 upper-body exercises for a total duration of 5 minutes. The UBV frequency was set at 26 Hz, amplitude 3 mm. For the NUBV treatment, the participants performed the exact exercises and time constraints as UBV; however, the vibration dumbbell was set at 0 Hz and 0 mm amplitude. The third treatment consisted of AC, which was performed at 75 k.min(-1) for 5 minutes. Pre- and postmuscular performance measures of medicine ball throw, hand grip strength, and a specific climbing maneuver were performed after each treatment. There were no significant treatment differences on medicine ball throw, hand grip strength, and the specific climbing maneuver. Acute UBV exposure did not demonstrate the expected potential neuromuscular enhancements on the climbing performance tests selected for this study. PMID:17530943

Cochrane, Darryl J; Hawke, Emma J

2007-05-01

128

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

129

Solvent-side observation on vibrational energy transfer by transient grating spectroscopy: Bridged azulene-anthracene  

E-print Network

Transient grating acoustic spectroscopy has been applied to studies on the vibrational energy relaxation process of the electronic ground state of azulene, two 1-alkylazulenes, and five bridged azulene-anthracenes in three different solvents: 1,1,1-trichloro-1,2,2-trifluoroethane, acetonitrile, and xenon. The solute molecule was vibrationally excited by the photo-excitation of the auzlenyl group to the S1 state through the fast internal conversion, and the rate of solvent thermalization due to the vibrational energy relaxation was determined. The thermalization rates for 1-alkylazulenes and bridged azulene-anthracenes were faster than that of azulene. Based on the results of the thermalization rates of 1-alkylazulenes, we concluded that the acceleration of the energy dissipation from the azulenyl group induced the faster energy dissipation from the solute to the solvent. The vibrational normal mode analysis suggests that the density of the vibrational modes and anharmonic coupling between the vibrational mode...

Fujiwara, Hiroki

2014-01-01

130

A low frequency MEMS vibration sensor for low power missile health monitoring  

NASA Astrophysics Data System (ADS)

This paper addresses the design, fabrication and characterization of a first-generation, low frequency MEMS vibration sensor. The sensor is designed specifically for applications requiring extremely low power vibration detection at only targeted frequencies. For development, lumped element and finite element modeling was performed, driving the design towards a realizable geometry that addresses the targeted performance specs. The sensors were microfabricated using conventional surface micromachining, sol-gel PZT (lead zirconate titanate) thin films, and bulk silicon etching techniques. The completed sensors were then characterized to determine electrical, mechanical and piezoelectric properties at the material and device level. Results demonstrate functional operation with performance close to predicted specifications.

Horowitz, S. B.; Allen, M. S.; Fox, J. R.; Cortes, J. P.; Barkett, L.; Mathias, A. D.; Hernandez, C.; Martin, A. C.; Sanghadasa, M.; Marotta, S.

131

Virginia Power's alternative energy study  

Microsoft Academic Search

In June 1981, the management of Virginia Electric and Power Company (now Virginia Power, or the Power Company) appointed a committee to formulate a study of conventional and alternative energy sources to meet future growth in electric power demand in a least-cost manner. This Committee on Conventional and Alternative Energy Sources recommended several energy alternatives for evaluation. The alternatives for

1986-01-01

132

Note: A cubic electromagnetic harvester that convert vibration energy from all directions.  

PubMed

We investigate the output performance of a cubic harvester which can scavenge low-frequency vibration energy from all directions. By adjusting the size and shape of the inside magnets, higher induced voltages and output power can be achieved. The optimal magnet is found to be cubic shape with the length of 6.35 mm (25.6% volume ratio), which can generate 4.27 mV root mean square voltage and 2.45 ?W average power at the frequency of 28.86 Hz and acceleration of 1.17 g. The device is also demonstrated as a self-powered tilt sensor by measuring induced voltages at different tilt angles. PMID:25085194

Han, Mengdi; Qiu, Guolin; Liu, Wen; Meng, Bo; Zhang, Xiao-Sheng; Zhang, Haixia

2014-07-01

133

Note: A cubic electromagnetic harvester that convert vibration energy from all directions  

NASA Astrophysics Data System (ADS)

We investigate the output performance of a cubic harvester which can scavenge low-frequency vibration energy from all directions. By adjusting the size and shape of the inside magnets, higher induced voltages and output power can be achieved. The optimal magnet is found to be cubic shape with the length of 6.35 mm (25.6% volume ratio), which can generate 4.27 mV root mean square voltage and 2.45 ?W average power at the frequency of 28.86 Hz and acceleration of 1.17 g. The device is also demonstrated as a self-powered tilt sensor by measuring induced voltages at different tilt angles.

Han, Mengdi; Qiu, Guolin; Liu, Wen; Meng, Bo; Zhang, Xiao-Sheng; Zhang, Haixia

2014-07-01

134

A micromachined low-frequency piezoelectric harvester for vibration and wind energy scavenging  

NASA Astrophysics Data System (ADS)

To efficiently scavenge ambient vibration energy and wind energy at the same time, a low-frequency piezoelectric harvester was designed, fabricated and tested. A lumped-parameter model of the cantilevered piezoelectric energy harvester with a proof mass was established and the closed-form expressions of voltage and power on a resistance load under base acceleration excitation were derived. After effects of the lengths of the proof mass and electrodes on output power were analyzed, a MEMS harvester was optimally designed. By using aluminum nitride as piezoelectric layer, a MEMS energy harvester was fabricated with bulk micromachining process. Experimental results show that the open-circuit frequency of the MEMS harvester is about 134.8 Hz and the matched resistance is about 410 k?. Under the harmonic acceleration excitation of ±0.1 g, the maximum output power is about 1.85 µW, with the normalized power density of about 6.3 mW cm-3 g-2. The critical wind speed of the device is between 12.7 and 13.2 m s-1 when the wind direction is from the proof mass to the fixed end of the cantilever. The maximum output power under 16.3 m s-1 wind is about 2.27 µW.

He, Xuefeng; Shang, Zhengguo; Cheng, Yaoqing; Zhu, You

2013-12-01

135

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

136

Time averaging the semiclassical initial value representation for the calculation of vibrational energy levels  

E-print Network

, particularly so for the calculation of spectral densities from which vibrational energy levels canTime averaging the semiclassical initial value representation for the calculation of vibrational energy levels Alexey L. Kaledin and William H. Millera) Department of Chemistry and Kenneth S. Pitzer

Miller, William H.

137

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

E-print Network

FRONTIERS ARTICLE Imaging bond breaking and vibrational energy transfer in small water containing of state-to-state vibrational pre- dissociation (VP) dynamics of small hydrogen bonded (H-bonded) clusters (REMPI) are used to determine accurate bond dissociation energies (D0) of (H2O)2, (H2O)3, HClĀ­H2O and NH3

Reisler, Hanna

138

Mobile remote control application for power generators vibration monitoring  

Microsoft Academic Search

Mobile applications and devices are one of the fasted developing computer technologies now days. Mobile devices, such as smartphons, are not used for communication only but also for remote data access and exchange. In this article mobile application for remote monitoring of power generators condition is discussed. Application was run on Symbian OS based cell phones and was developed using

P. Podsiadly; B. Swiercz; S. Wroblewski

2009-01-01

139

Vibrational Energy Relaxation of "Tailored" Hemes in Myoglobin Following Ligand Photolysis Supports Energy Funneling Mechanism of Heme "Cooling"  

E-print Network

Energy Funneling Mechanism of Heme "Cooling" Lintao Bu and John E. Straub* Department of Chemistry and mechanisms of vibrational energy transfer is an essential component of a complete understandingVibrational Energy Relaxation of "Tailored" Hemes in Myoglobin Following Ligand Photolysis Supports

Straub, John E.

140

[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

141

VIBRATING RF MEMS FOR LOW POWER WIRELESS COMMUNICATIONS  

Microsoft Academic Search

Micromechanical communication circuits fab- ricated via IC-compatible MEMS technologies and capable of low-loss filtering, mixing, switching, and frequency generation, are described with the intent to miniaturize wire- less transceivers. Possible transceiver front-end architectures are then presented that use these micromechanical circuits in large quantities to substantially reduce power consumption. Tech- nologies that integrate MEMS and transistor circuits into single-chip systems

Clark T.-C. Nguyen

142

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

143

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

E-print Network

Past research in vibration energy harvesting has focused on the use of variable capacitors, magnets, or piezoelectric materials as the basis of energy transduction. How- ever, few of these studies have explored the detailed ...

Yen, Bernard Chih-Hsun, 1981-

2005-01-01

144

Energy transfer of highly vibrationally excited naphthalene: Collisions with CHF3, CF4, and Kr  

NASA Astrophysics Data System (ADS)

Energy transfer of highly vibrationally excited naphthalene in the triplet state in collisions with CHF3, CF4, and Kr was studied using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. Highly vibrationally excited naphthalene (2.0 eV vibrational energy) was formed via the rapid intersystem crossing of naphthalene initially excited to the S2 state by 266 nm photons. The shapes of the collisional energy-transfer probability density functions were measured directly from the scattering results of highly vibrationally excited naphthalene. In comparison to Kr atoms, the energy transfer in collisions between CHF3 and naphthalene shows more forward scatterings, larger cross section for vibrational to translational (V --> T) energy transfer, smaller cross section for translational to vibrational and rotational (T --> VR) energy transfer, and more energy transferred from vibration to translation, especially in the range -?Ed = -100 to -800 cm-1. On the other hand, the difference of energy transfer properties between collisional partners Kr and CF4 is small. The enhancement of the V --> T energy transfer in collisions with CHF3 is attributed to the large attractive interaction between naphthalene and CHF3 (1-3 kcal/mol).

Chen Hsu, Hsu; Tsai, Ming-Tsang; Dyakov, Yuri A.; Ni, Chi-Kung

2011-08-01

145

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

Microsoft Academic Search

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

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

2000-01-01

146

Global Nonlinear Analysis of Piezoelectric Energy Harvesting from Ambient and Aeroelastic Vibrations  

NASA Astrophysics Data System (ADS)

Converting vibrations to a usable form of energy has been the topic of many recent investigations. The ultimate goal is to convert ambient or aeroelastic vibrations to operate low-power consumption devices, such as microelectromechanical systems, heath monitoring sensors, wireless sensors or replacing small batteries that have a finite life span or would require hard and expensive maintenance. The transduction mechanisms used for transforming vibrations to electric power include: electromagnetic, electrostatic, and piezoelectric mechanisms. Because it can be used to harvest energy over a wide range of frequencies and because of its ease of application, the piezoelectric option has attracted significant interest. In this work, we investigate the performance of different types of piezoelectric energy harvesters. The objective is to design and enhance the performance of these harvesters. To this end, distributed-parameter and phenomenological models of these harvesters are developed. Global analysis of these models is then performed using modern methods of nonlinear dynamics. In the first part of this Dissertation, global nonlinear distributed-parameter models for piezoelectric energy harvesters under direct and parametric excitations are developed. The method of multiple scales is then used to derive nonlinear forms of the governing equations and associated boundary conditions, which are used to evaluate their performance and determine the effects of the nonlinear piezoelectric coefficients on their behavior in terms of softening or hardening. In the second part, we assess the influence of the linear and nonlinear parameters on the dynamic behavior of a wing-based piezoaeroelastic energy harvester. The system is composed of a rigid airfoil that is constrained to pitch and plunge and supported by linear and nonlinear torsional and flexural springs with a piezoelectric coupling attached to the plunge degree of freedom. Linear analysis is performed to determine the effects of the linear spring coefficients and electrical load resistance on the flutter speed. Then, the normal form of the Hopf bifurcation ( utter) is derived to characterize the type of instability and determine the effects of the aerodynamic nonlinearities and the nonlinear coefficients of the springs on the system's stability near the bifurcation. This is useful to characterize the effects of different parameters on the system's output and ensure that subcritical or "catastrophic" bifurcation does not take place. Both linear and nonlinear analyses are then used to design and enhance the performance of these harvesters. In the last part, the concept of energy harvesting from vortex-induced vibrations of a circular cylinder is investigated. The power levels that can be generated from these vibrations and the variations of these levels with the freestream velocity are determined. A mathematical model that accounts for the coupled lift force, cylinder motion and generated voltage is presented. Linear analysis of the electromechanical model is performed to determine the effects of the electrical load resistance on the natural frequency of the rigid cylinder and the onset of the synchronization region. The impacts of the nonlinearities on the cylinder's response and energy harvesting are then investigated.

Abdelkefi, Abdessattar

147

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

Microsoft Academic Search

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

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

148

A distributed parameter electromechanical and statistical model for energy harvesting from turbulence-induced vibration  

NASA Astrophysics Data System (ADS)

Extensive research has been done on the topics of both turbulence-induced vibration and vibration based energy harvesting; however, little effort has been put into bringing these two topics together. Preliminary experimental studies have shown that piezoelectric structures excited by turbulent flow can produce significant amounts of useful power. This research could serve to benefit applications such as powering remote, self-sustained sensors in small rivers or air ventilation systems where turbulent fluid flow is a primary source of ambient energy. A novel solution for harvesting energy in these unpredictable fluid flow environments was explored by the authors in previous work, and a harvester prototype was developed. This prototype, called piezoelectric grass, has been the focus of many experimental studies. In this paper the authors present a theoretical analysis of the piezoelectric grass harvester modeled as a single unimorph cantilever beam exposed to turbulent cross-flow. This distributed parameter model was developed using a combination of both analytical and statistical techniques. The analytical portion uses a Rayleigh–Ritz approximation method to describe the beam dynamics, and utilizes piezoelectric constitutive relationships to define the electromechanical coupling effects. The statistical portion of the model defines the turbulence-induced forcing function distributed across the beam surface. The model presented in this paper was validated using results from several experimental case studies. Preliminary results show that the model agrees quite well with experimental data. A parameter optimization study was performed with the proposed model. This study demonstrated how a new harvester could be designed to achieve maximum power output in a given turbulent fluid flow environment.

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

2014-11-01

149

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

Microsoft Academic Search

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

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

2009-01-01

150

Potential Energy of Small Vibrations of Complex Networks Ernesto Estrada1  

E-print Network

1 Potential Energy of Small Vibrations of Complex Networks Ernesto Estrada1 Department of Physics G1 1XH, UK Abstract We introduce a simple model to study small vibrations in complex networks constant value when the average degree is very large. In contrast, many real-world complex networks display

Mottram, Nigel

151

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

152

Vibrational energy relaxation of a diatomic molecule in a room-temperature ionic liquid  

NASA Astrophysics Data System (ADS)

Vibrational energy relaxation (VER) dynamics of a diatomic solute in ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate (EMI+PF6-) are studied via equilibrium and nonequilibrium molecular dynamics simulations. The time scale for VER is found to decrease markedly with the increasing solute dipole moment, consonant with many previous studies in polar solvents. A detailed analysis of nonequilibrium results shows that for a dipolar solute, dissipation of an excess solute vibrational energy occurs almost exclusively via the Lennard-Jones interactions between the solute and solvent, while an oscillatory energy exchange between the two is mainly controlled by their electrostatic interactions. Regardless of the anharmonicity of the solute vibrational potential, VER becomes accelerated as the initial vibrational energy increases. This is attributed primarily to the enhancement in variations of the solvent force on the solute bond, induced by large-amplitude solute vibrations. One interesting finding is that if a time variable scaled with the initial excitation energy is employed, dissipation dynamics of the excess vibrational energy of the dipolar solute tend to show a universal behavior irrespective of its initial vibrational state. Comparison with water and acetonitrile shows that overall characteristics of VER in EMI+PF6- are similar to those in acetonitrile, while relaxation in water is much faster than the two. It is also found that the Landau-Teller theory predictions for VER time scale obtained via equilibrium simulations of the solvent force autocorrelation function are in reasonable agreement with the nonequilibrium results.

Shim, Youngseon; Kim, Hyung J.

2006-07-01

153

Vibration-translation energy transfer in anharmonic diatomic molecules. II - The vibrational quantum-number dependence  

NASA Technical Reports Server (NTRS)

A semiclassical model of the inelastic collision between a vibrationally excited anharmonic oscillator and a structureless atom is used to predict the variation of thermally averaged vibrational-translational rate coefficients with temperature and initial-state quantum number. Multiple oscillator states are included in a numerical solution for collinear encounters. The results are compared with CO-He experimental values for both ground and excited initial states using several simplified forms of the interaction potential. The numerical model is also used as a basis for evaluating several less complete, but analytic, models. Two computationally simple analytic approximations are found that successfully reproduce the numerical rate coefficients for a wide range of molecular properties and collision partners. Their limitations are identified, and the relative rates of multiple-quantum transitions from excited states are evaluated for several molecular types.

Mckenzie, R. L.

1976-01-01

154

Dynamical traps lead to the slowing down of intramolecular vibrational energy flow.  

PubMed

The phenomenon of intramolecular vibrational energy redistribution (IVR) is at the heart of chemical reaction dynamics. Statistical rate theories, assuming instantaneous IVR, predict exponential decay of the population with the properties of the transition state essentially determining the mechanism. However, there is growing evidence that IVR competes with the reaction timescales, resulting in deviations from the exponential rate law. Dynamics cannot be ignored in such cases for understanding the reaction mechanisms. Significant insights in this context have come from the state space model of IVR, which predicts power law behavior for the rates with the power law exponent, an effective state space dimensionality, being a measure of the nature and extent of the IVR dynamics. However, whether the effective IVR dimensionality can vary with time and whether the mechanism for the variation is of purely quantum or classical origins are issues that remain unresolved. Such multiple power law scalings can lead to surprising mode specificity in the system, even above the threshold for facile IVR. In this work, choosing the well-studied thiophosgene molecule as an example, we establish the anisotropic and anomalous nature of the quantum IVR dynamics and show that multiple power law scalings do manifest in the system. More importantly, we show that the mechanism of the observed multiple power law scaling has classical origins due to a combination of trapping near resonance junctions in the network of classical nonlinear resonances at short to intermediate times and the influence of weak higher-order resonances at relatively longer times. PMID:25246538

Manikandan, Paranjothy; Keshavamurthy, Srihari

2014-10-01

155

ArHF vibrational predissociation dynamics using the diatomics-in-molecule potential energy surface  

Microsoft Academic Search

Vibrational predissociation dynamics of ArHF and ArDF complexes is investigated theoretically for the first time owing to the use of three-dimensional potential energy surfaces (PES's) based on the diatomics-in-molecule approach [J. Chem. Phys. 104, 5510 (1996)]. The original PES is improved empirically to yield a reasonable description of the lowest vibrational energy levels of the ArHF complex at J=0. Predissociation

A. A. Buchachenko; N. F. Stepanov; B. L. Grigorenko; A. V. Nemukhin

1999-01-01

156

ArHF vibrational predissociation dynamics using the diatomics-in-molecule potential energy surface  

Microsoft Academic Search

Vibrational predissociation dynamics of ArHF and ArDF complexes is investigated theoretically for the first time owing to the use of three-dimensional potential energy surfaces (PES’s) based on the diatomics-in-molecule approach [J. Chem. Phys. 104, 5510 (1996)]. The original PES is improved empirically to yield a reasonable description of the lowest vibrational energy levels of the ArHF complex at J=0. Predissociation

A. A. Buchachenko; N. F. Stepanov; B. L. Grigorenko; A. V. Nemukhin

1999-01-01

157

Anharmonic force field, vibrational energies, and barrier to inversion of SiH3-  

Microsoft Academic Search

The full quartic force field of the ground electronic state of the silyl anion (SiH3-) has been determined at the CCSD(T)-R12 level employing a [Si\\/H]=[16s11p6d5f\\/7s5p4d] basis set. The vibrational energy levels, using the quartic force field as a representation of the potential energy hypersurface around equilibrium, have been determined by vibrational perturbation theory carried out to second, fourth, and sixth

Kirsten Aarset; Attila G. Csįszįr; Edwin L. Sibert; Wim Klopper; Jozef Noga

2000-01-01

158

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

159

Resource Management and Scheduling in WSNs Powered by Ambient Energy Harvesting  

E-print Network

], vibrational [13], [18], wind [30] and thermal energy [29]) to replace/supplement batteries that power WSNsResource Management and Scheduling in WSNs Powered by Ambient Energy Harvesting Neyre Tekbiyik wireless sensor networks (WSNs) brings several advantages over traditional wired systems, including self

Uysal-Biyikoglu, Elif

160

Influence of hand forces and handle size on power absorption of the human hand arm exposed to zh-axis vibration  

NASA Astrophysics Data System (ADS)

The effect of handle size and hand forces, on the power absorbed by the hand-arm system, was investigated in a laboratory study using seven healthy male subjects exposed to two levels of broadband random vibration in the 8-1000 Hz frequency range along the zh-axis. The measurements were performed with three instrumented cylindrical handles of different diameter (30, 40 and 50 mm). The influence of hand forces applied by the subjects holding the vibrating handles was investigated under nine different grip/push force combinations. The posture adopted by the subjects consisted of the bent forearm with elbow angle of 90° and neutral wrist position, as described in the ISO 10819 standard. The pressure distribution at the hand-handle interface was also measured to quantify the static contact force corresponding to each combination of grip force, push force and handle size. The hand-handle coupling force, as defined in ISO/WD 15230, was further evaluated by summing the grip and push forces. The measured total absorbed power revealed relatively low inter-subject variability (generally less than 12%). Total absorbed power was found to be better correlated with coupling force than the contact force, while most of the absorbed power occurred in the low-frequency range, below 200 Hz. The magnitude of power absorbed within the hand and arm was observed to be strongly dependent upon the handle size; larger handles cause higher absorption of energy. The results also suggested that the power absorption is influenced by the grip as well as push force. The results attained from ANOVA confirmed the significance of all studied factors, i.e. vibration magnitude, handle diameter, and the grip and push forces on the power absorbed into the human hand and arm exposed to vibration.

Aldien, Y.; Marcotte, P.; Rakheja, S.; Boileau, P.-É.

2006-03-01

161

A general modal approach for the development of optimal multi-layer stacked vibration energy harvesters  

NASA Astrophysics Data System (ADS)

Piezoelectric vibration energy harvesters with multi-layer stacked structures have been developed. They consist of multi-layer beams, of zigzag configurations, with rigid masses attached between the beams. The rigid masses, which also serve as spacers, are attached to each layer to tune the frequencies of the harvester. Close resonance frequencies and considerable power output can be achieved in multiple modes by varying the positions of the masses. A modal approach is introduced to determine the modal performance conveniently using the mass ratio and the modal electromechanical coupling coefficient, and the required modal parameters are derived using the finite element method. Mass ratio represents the influence of modal mechanical behaviour on the power density. Since the modes with larger mass ratios cause the remaining modes to have smaller mass ratios and lower power densities, a screening process using the modal approach is developed to determine the optimal or near-optimal performance of the harvesters when altering mass positions. This procedure obviates the need for full analysis by pre-selecting the harvester configurations with close resonances and favourable values of mass ratio initially. Furthermore, the multi-layer stacked designs using the modal approach can be used to develop harvesters with different sizes with the power ranging from microwatts to milliwatts.

Xiong, Xingyu; Oyadiji, S. Olutunde

2014-10-01

162

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

163

The vibrational energy pattern in acetylene VII: (12)C(13)CH2.  

PubMed

In (12)C(13)CH(2) 129 vibrational term values up to 10,000 cm(-1) are merged, about 60% of which are newly reported. They are fitted using an effective Hamiltonian with a standard deviation of 0.22 cm(-1). The vibrational assignments and vibrational constants are listed and discussed. The energy pattern is found to be very similar to the one in (12)C2H2 with additional anharmonic resonances arising from the lack of u/g character in the asymmetric isotopolog. PMID:16375523

Robert, S; Fayt, A; Di Lonardo, G; Fusina, L; Tamassia, F; Herman, M

2005-11-01

164

Development of a simplified, mass producible hybridized ambient, low frequency, low intensity vibration energy scavenger (half-lives)  

NASA Astrophysics Data System (ADS)

Scavenging energy from environmental sources is an active area of research to enable remote sensing and microsystems applications. Furthermore, as energy demands soar, there is a significant need to explore new sources and curb waste. Vibration energy scavenging is one environmental source for remote applications and a candidate for recouping energy wasted by mechanical sources that can be harnessed to monitor and optimize operation of critical infrastructure (e.g. Smart Grid). Current vibration scavengers are limited by volume and ancillary requirements for operation such as control circuitry overhead and battery sources. This dissertation, for the first time, reports a mass producible hybrid energy scavenger system that employs both piezoelectric and electrostatic transduction on a common MEMS device. The piezoelectric component provides an inherent feedback signal and pre-charge source that enables electrostatic scavenging operation while the electrostatic device provides the proof mass that enables low frequency operation. The piezoelectric beam forms the spring of the resonant mass-spring transducer for converting vibration excitation into an AC electrical output. A serially poled, composite shim, piezoelectric bimorph produces the highest output rectified voltage of over 3.3V and power output of 145muW using ¼ g vibration acceleration at 120Hz. Considering solely the volume of the piezoelectric beam and tungsten proof mass, the volume is 0.054cm3, resulting in a power density of 2.68mW/cm3. Incorporation of a simple parallel plate structure that provides the proof mass for low frequency resonant operation in addition to cogeneration via electrostatic energy scavenging provides a 19.82 to 35.29 percent increase in voltage beyond the piezoelectric generated DC rails. This corresponds to approximately 2.1nW additional power from the electrostatic scavenger component and demonstrates the first instance of hybrid energy scavenging using both piezoelectric and synchronous electrostatic transduction. Furthermore, it provides a complete system architecture and development platform for additional enhancements that will enable in excess of 100muW additional power from the electrostatic scavenger.

Khbeis, Michael Tawfik

165

Vibrational and total energy dependence of the reaction rate of Na with CO2 laser-excited SF6  

Microsoft Academic Search

The rate of reaction between sodium and sulfur hexafluoride has been studied as a function of the vibrational energy and total thermal energy of the SF6 in the temperature range 380–440 °K. Vibrational energy was increased by absorption of radiation from a pulsed CO2 laser, and total energy was increased by heating the reaction system. The reaction rate was determined

Mark Eyal; Frederick R. Grabiner; Uri Agam; Leonard A. Gamss

1981-01-01

166

Intramolecular vibrational energy transfer in mixtures of anthraquinone with foreign gases  

Microsoft Academic Search

Properties of collision transfer of vibrational energy in the vibrational quasi-continuum of mixed singlet-triplet levels\\u000a of anthraquinone are studied by the method of time-resolved delayed fluorescence. The two-exponential fluorescence decay is\\u000a analyzed in the kinetic approximation. It is shown that dependences of the intensities and decay rates of the fast and slow\\u000a components on pressure can be used for estimating

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

2000-01-01

167

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

E-print Network

The Deng-Fan potential is used to discuss the reliability of the improved Greene-Aldrich approximation and the factorization recipe of Badawi et al.'s [17] for the central attractive/repulsive core. The factorization recipe is shown to be a more reliable approximation and is used to obtain the ro-vibrational energies for the lithium dimer. For each vibrational state only a limited number of the rotational levels are found to be supported by the lithium dimer.

Omar Mustafa

2014-07-04

168

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

E-print Network

The Deng-Fan potential is used to discuss the reliability of the improved Greene-Aldrich approximation and the factorization recipe of Badawi et al.'s [17] for the central attractive/repulsive core. The factorization recipe is shown to be a more reliable approximation and is used to obtain the ro-vibrational energies for the lithium dimer. For each vibrational state only a limited number of the rotational levels are found to be supported by the lithium dimer.

Mustafa, Omar

2014-01-01

169

Random vibration analysis of the Topaz-II nuclear reactor power system. Master`s thesis  

SciTech Connect

The TOPAZ-II Ya-21U is one of six Russian made space nuclear power systems which is based on theomionic power conversion. The U.S. is presently analyzing TOPAZ-II to determine the reliability and feasibility of using this system. A structural analysis test was conducted on the TOPAZ unit in May 1993 to provide data from which modal parameters could be identified. This test showed the fundamental frequency to be 10.5 Hz, yet the test results that the Russians conducted identified a fundamental frequency of 5 Hz. Another finite element model was created incorporating new developments in TOPAZ-II and modifications to the finite element model to better simulate the mass properties of the TOPAZ-II2. A second structural analysis test was conducted on the TOPAZ unit 06-09 September 1994. This thesis focuses on the random vibration analysis of the TOPAZ-II Ya-2lU utilizing the most recent test results and the Master Series (updated version) I-DEAS software. The modal respose of the model and simulated random vibration tests were within 8.33%. This model is a feasible tool which can be used to analyze the TOPAZ unit without testing the unit to fatigue.

Campbell, S.E.

1995-06-01

170

Nonlinear Time Series Analysis of Transformer's Core Vibration  

Microsoft Academic Search

The vibration signal of transformer's core is correlative with the conditions of core's compression and insulation, therefore, vibration monitor of transformer's core is an effective method for on-line monitoring the power transformer delitescent faults. A new method of obtaining the energy distribution with time and frequency of transformer's core vibration based on Hilbert-Huang transformation (HHT) was developed. Firstly, empirical mode

Weihua Xiong; Ruisong Ji

2006-01-01

171

Statistics of power injection in a plate set into chaotic vibration  

E-print Network

A vibrating plate is set into a chaotic state of wave turbulence by either a periodic or a random local forcing. Correlations between the forcing and the local velocity response of the plate at the forcing point are studied. Statistical models with fairly good agreement with the experiments are proposed for each forcing. Both distributions of injected power have a logarithmic cusp for zero power, while the tails are Gaussian for the periodic driving and exponential for the random one. The distributions of injected work over long time intervals are investigated in the framework of the fluctuation theorem, also known as the Gallavotti-Cohen theorem. It appears that the conclusions of the theorem are verified only for the periodic, deterministic forcing. Using independent estimates of the phase space contraction, this result is discussed in the light of available theoretical framework.

Cadot, Olivier; Touzé, Cyril

2008-01-01

172

Statistics of power injection in a plate set into chaotic vibration  

E-print Network

A vibrating plate is set into a chaotic state of wave turbulence by either a periodic or a random local forcing. Correlations between the forcing and the local velocity response of the plate at the forcing point are studied. Statistical models with fairly good agreement with the experiments are proposed for each forcing. Both distributions of injected power have a logarithmic cusp for zero power, while the tails are Gaussian for the periodic driving and exponential for the random one. The distributions of injected work over long time intervals are investigated in the framework of the fluctuation theorem, also known as the Gallavotti-Cohen theorem. It appears that the conclusions of the theorem are verified only for the periodic, deterministic forcing. Using independent estimates of the phase space contraction, this result is discussed in the light of available theoretical framework.

Olivier Cadot; Arezki Boudaoud; Cyril Touzé

2008-10-06

173

Evidence for energy coupling from the SiD vibration mode to the SiSi and SiO vibration modes at the SiO2 Si interface  

E-print Network

. Jackson, Appl. Phys. Lett., 69, 2441 1996 , we measured the SiĀ­H, SiĀ­D, and other vibrational modes vibrational modes. In this letter, we present the experimental measurement of vibrational modes at the SiO2Evidence for energy coupling from the SiĀ­D vibration mode to the SiĀ­Si and SiĀ­O vibration modes

Chen, Zhi

174

Utility-based Time and Power Allocation on an Energy Harvesting Downlink: The Optimal  

E-print Network

problem where the transmitter is aware of the energy arrival statistics of a frame before the frame starts advances in the areas of solar, piezoelectric and thermal energy har- vesting, enable systems harvest energy through solar cells, vibration absorption devices, thermoelectric generators, wind power

Uysal-Biyikoglu, Elif

175

Active Seismic Monitoring Using High-Power Moveable 40-TONS Vibration Sources in Altay-Sayn Region of Russia  

NASA Astrophysics Data System (ADS)

The paper presents data of operating vibroseismic observations using high-power stationary 100-tons and moveable 40-tons vibration sources, which have been carried out in Russia for 30 years. It is shown that investigations using high-power vibration sources open new possibilities for study stressedly-deformed condition of the Earth`s crust and the upper mantle and tectonic process in them. Special attention is given to developing operating seismic translucences of the Earth`s crust and the upper mantle using high-power 40-tons vibration sources. As a result of experimental researches there was proved high stability and repeatability of vibration effects. There were carried out long period experiments of many days with vibration source sessions of every two hours with the purpose of monitoring accuracy estimation. It was determined, that repeatability of vibroseismic effects (there was researched time difference of repeated sessions of P- and S-waves from crystal rocks surface) could be estimated as 10-3 - 10-4 sec. It is ten times less than revealed here annual variations of kinematic parameters according to regime vibroseismic observations. It is shown, that on hard high-speed grounds radiation spectrum becomes narrowband and is dislocated to high frequency; at the same time quantity of multiple high-frequency harmonic is growing. At radiation on soft sedimentary grounds (sand, clay) spectrum of vibration source in near zone is more broadband, correlograms are more compact. there Correspondence of wave fields from 40-tons vibration sources and explosions by reference waves from boundaries in he Earth`s crust and the upper mantle at record distance of 400 km was proved by many experiments in various regions of Russia; there was carried out the technique of high-power vibration sources grouping for increase of effectiveness of emanation and increase of record distance. According to results of long-term vibroseismic monitoring near Novosibirsk (1997-2012) there are determined variations in velocities of longitudinal and transverse waves. Both from 100-tons and 40-tons vibration sources there are distinctly determined annual and semiannual variations, and also variations of 120 and 90 days. There is determined correlations of revealed variations of P- and S-wave velocities with drowning of the upper part of the Earth`s crust because of season changes of water volumes in the biggest Novosibirsk water reservoir. There were carried out experiments on aperture widening of operating vibroseismic observations in seismic active zones of the South of Altay. All these results prove possibility of using moveable collapsible 40-tons vibration sources for active monitoring of seismic dangerous zones, nuclear power plants, nuclear waste storage etc.

Soloviev, V. M.; Seleznev, V. S.; Emanov, A. F.; Kashun, V. N.; Elagin, S. A.; Romanenko, I.; Shenmayer, A. E.; Serezhnikov, N.

2013-05-01

176

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

NASA Astrophysics Data System (ADS)

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

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

2007-11-01

177

Non-classicality of the molecular vibrations assisting exciton energy transfer at room temperature  

NASA Astrophysics Data System (ADS)

Advancing the debate on quantum effects in light-initiated reactions in biology requires clear identification of non-classical features that these processes can exhibit and utilize. Here we show that in prototype dimers present in a variety of photosynthetic antennae, efficient vibration-assisted energy transfer in the sub-picosecond timescale and at room temperature can manifest and benefit from non-classical fluctuations of collective pigment motions. Non-classicality of initially thermalized vibrations is induced via coherent exciton-vibration interactions and is unambiguously indicated by negativities in the phase-space quasi-probability distribution of the effective collective mode coupled to the electronic dynamics. These quantum effects can be prompted upon incoherent input of excitation. Our results therefore suggest that investigation of the non-classical properties of vibrational motions assisting excitation and charge transport, photoreception and chemical sensing processes could be a touchstone for revealing a role for non-trivial quantum phenomena in biology.

O'Reilly, Edward J.; Olaya-Castro, Alexandra

2014-01-01

178

The Power of Energy  

NSDL National Science Digital Library

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

Congden, Diana

2012-06-14

179

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

180

An ab initio potential energy surface and vibrational energy levels of HXeO  

NASA Astrophysics Data System (ADS)

The potential energy surfaces for the electronic ground state of the HXeO molecule is constructed from more than 3500 ab initio points at the internally contracted multi-reference configuration interaction with the Davidson correction (icMRCI + Q) level employing large basis sets. The stabilities and dissociation barriers are identified from the potential energy surfaces. The three-body dissociation channel is found to be the dominate dissociation channel for HXeO. Low-lying vibrational energy levels of both HXeO and DXeO are calculated on the three-dimensional potential energy surface using the Lanczos algorithm, and found to be in good agreement with known experimental band origins.

Huang, Zhengguo

2009-05-01

181

Energy 101: Concentrating Solar Power  

NSDL National Science Digital Library

This video describes how concentrating solar power (CSP) technologies reflect and collect solar energy to generate electricity. This video explains what CSP is, how it works, and focuses on parabolic troughs.

National Renewable Energy Laboratory (NREL)

182

Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling in Cytochrome c  

E-print Network

Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling process.4 Moreover, the recent studies suggested a mechanism of spatially anisotropic directed energy flow 02215 ReceiVed: April 30, 2003; In Final Form: July 24, 2003 The rate and mechanism of the kinetic

Straub, John E.

183

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

184

Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures  

NASA Technical Reports Server (NTRS)

The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

Vlahopoulos, Nickolas; Schiller, Noah H.

2011-01-01

185

The vibrational energies of ozone up to the dissociation threshold: Dynamics calculations on an accurate potential energy surface  

E-print Network

The vibrational energies of ozone up to the dissociation threshold: Dynamics calculations present an ab initio potential energy surface for the ground electronic state of ozone. It is global, i. All bound states of nonrotating ozone up to more than 99% of the dissociation energy are calculated

Farantos, Stavros C.

186

Energy transfer of highly vibrationally excited azulene. III. Collisions between azulene and argon  

Microsoft Academic Search

The energy transfer dynamics between highly vibrationally excited azulene molecules (37 582 cm-1 internal energy) and Ar atoms in a series of collision energies (200, 492, 747, and 983 cm-1) was studied using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. The angular resolved collisional energy-transfer probability distribution functions were measured directly from the scattering results of

Chen-Lin Liu; Hsu Chen Hsu; Jia-Jia Lyu; Chi-Kung Ni

2006-01-01

187

Energy transfer of highly vibrationally excited azulene: Collisions between azulene and krypton  

Microsoft Academic Search

The energy-transfer dynamics between highly vibrationally excited azulene molecules and Kr atoms in a series of collision energies (i.e., relative translational energies 170, 410, and 780 cm-1) was studied using a crossed-beam apparatus along with time-sliced velocity map ion imaging techniques. ``Hot'' azulene (4.66 eV internal energy) was formed via the rapid internal conversion of azulene initially excited to the

Chen-Lin Liu; Hsu-Chen Hsu; Jia-Jia Lyu; Chi-Kung Ni

2006-01-01

188

Vibrational energy transfer at a liquid gallium surface. Activation of unimolecular cyclobutene isomerization  

NASA Astrophysics Data System (ADS)

Single collision vibrational energy transfer for a canonical ensemble (t=300K) of cyclobutene molecules at a heated liquid gallium surface has been studied from 450K to 700K. Transport above the reaction threshold for isomerization to butadiene (E sub 0 = 32.4 kcal/mole) was used as the criterion for efficiency of vibrational energy accommodation. The efficiency was found to fall below strong collider behavior above 625K. Evidence of surface catalysis became important below 525K. The observed behavior is reminiscent of that found previously for other liquid (Sn) and solid (Au) metal surfaces.

Oswald, D. A.; Nilsson, W. B.; Rabinovitch, B. S.

1985-12-01

189

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

NASA Astrophysics Data System (ADS)

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

Somą, A.; De Pasquale, G.

2013-05-01

190

Dynamics of ground and excited state vibrational relaxation and energy transfer in transition metal carbonyls.  

PubMed

Nonlinear vibrational spectroscopy provides insights into the dynamics of vibrational energy transfer in and between molecules, a crucial phenomenon in condensed phase physics, chemistry, and biology. Here we use frequency-domain 2-dimensional infrared (2DIR) spectroscopy to investigate the vibrational relaxation (VR) and vibrational energy transfer (VET) rates in different solvents in both the electronic ground and excited states of Re(Cl)(CO)3(4,4'-diethylester-2,2'-bipyridine), a prototypical transition metal carbonyl complex. The strong C?O and ester C?O stretch infrared reporters, located on opposite sides of the molecule, were monitored in the 1600-2100 cm(-1) spectral region. VR in the lowest charge transfer triplet excited state ((3)CT) is found to be up to eight times faster than in the ground state. In the ground state, intramolecular anharmonic coupling may be solvent-assisted through solvent-induced frequency and charge fluctuations, and as such VR rates are solvent-dependent. In contrast, VR rates in the solvated (3)CT state are surprisingly solvent-insensitive, which suggests that predominantly intramolecular effects are responsible for the rapid vibrational deactivation. The increased VR rates in the excited state are discussed in terms of intramolecular electrostatic interactions helping overcome structural and thermodynamic barriers for this process in the vicinity of the central heavy atom, a feature which may be of significance to nonequilibrium photoinduced processes observed in transition metal complexes in general. PMID:25198700

Delor, Milan; Sazanovich, Igor V; Towrie, Michael; Spall, Steven J; Keane, Theo; Blake, Alexander J; Wilson, Claire; Meijer, Anthony J H M; Weinstein, Julia A

2014-10-01

191

Apparatus for high-resolution vibrational electron energy-loss spectroscopy of solid surfaces  

Microsoft Academic Search

A high-resolution vibrational electron energy-loss spectrometer of 127°-cylindrical electrostatic deflection type has been constructed for surface studies. In the direct mode, an electron current at the collector entrance of 2.3×10?11 A is obtained with the energy spread (full width at half-maximum) of 60 cm?1 for electrons whose energy at the sample position is 5 eV. A ghost reduction slit is

M. Nishijima; S. Masuda; H. Kobayashi; M. Onchi

1982-01-01

192

Power and energy for posterity  

NASA Technical Reports Server (NTRS)

The use of sophisticated space energy generation and storage systems to benefit the general public was examined. The utilization of these systems for pollution-free generation of energy to satisfy mankind's future electrical, thermal, and propulsion needs was of primary concern. Ground, air, and space transportation; commercial, peaking, and emergency electrical power; and metropolitan and unit thermal energy requirements were considered. Each type of energy system was first analyzed in terms of its utility in satisfying the requirement, and then its potential in reducing the air, noise, thermal, water, and nuclear pollution from future electrical and thermal systems was determined.

Barthelemy, R. F.; Cooper, R. F.

1972-01-01

193

Apparatus for high-resolution vibrational electron energy-loss spectroscopy of solid surfaces  

NASA Astrophysics Data System (ADS)

A high-resolution vibrational electron energy-loss spectrometer of 127°-cylindrical electrostatic deflection type has been constructed for surface studies. In the direct mode, an electron current at the collector entrance of 2.3×10-11 A is obtained with the energy spread (full width at half-maximum) of 60 cm-1 for electrons whose energy at the sample position is 5 eV. A ghost reduction slit is used to suppress spurious peaks due to the electron reflection from electrodes of the analyzer. Electron energy-loss spectroscopy can be combined in situ with low-energy electron diffraction, Auger electron spectroscopy, and thermal-desorption mass spectroscopy. Design and performance of the apparatus are reported. The vibrational spectrum of the Ni(110) (1×2)-H surface formed at room temperature is presented, and the location of hydrogen atoms on the surface is discussed.

Nishijima, M.; Masuda, S.; Kobayashi, H.; Onchi, M.

1982-06-01

194

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

E-print Network

vibrations Soon-Duck Kwon1 , Jinkyoo Park2 and Kincho Law2 1 Department of Civil Engineering, ChonbukElectromagnetic energy harvester with repulsively stacked multilayer magnets for low frequency National University, Chonju, Chonbuk, Korea. Email: sdkwon@chonbuk.ac.kr 2 Department of Civil

Stanford University

195

Reaction of CpH, with H and F TABLE I: Total Energies and Vibrational Frequencies  

E-print Network

.44282 -78.52532 -177.37031 ZPE 34.6 30.1 39.7 35.3 35.6 34.8 30.4 Vibrational Frequencies*,' 944 (826) 517 energy (ZPE) in kcalimol. For hydrogen atom HF/3-21G = -0.49620 and HF/6-31G* = -0.49823 au. For fluorine

Schlegel, H. Bernhard

196

Design and fabrication of a new system for vibration energy harvesting  

Microsoft Academic Search

Global simulations, designs and characterisations of a broadband vibration energy scavenging system are here reported. High damping electrostatic conversion structures have been investigated. Mathematical analytical models have been performed and confronted with ANSYS simulations. A scavenging electronics has also been developed: taking in account ohmic, capacitive and inductive losses, the global conversion efficiency has been calculated. Finally, a macro and

Ghislain Despesse; Thomas Jager; Jean-Jacques Chaillout; Jean-Michel Léger; Skandar Basrour

2005-01-01

197

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

E-print Network

were recorded and assigned. Both one and two-dimensional potential energy functions of 1,4-benzodioxan for the ring-twisting and ring-bending vibrations were carried out for the S0 and S1(ƏĀ?,ƏĀ?*) states, and these were consistent with the high...

Yang, Juan

2007-09-17

198

Transformation of potential energy surfaces for estimating isotopic shifts in anharmonic vibrational frequency calculations  

NASA Astrophysics Data System (ADS)

A transformation of potential energy surfaces (PES) being represented by multi-mode expansions is introduced, which allows for the calculation of anharmonic vibrational spectra of any isotopologue from a single PES. This simplifies the analysis of infrared spectra due to significant CPU-time savings. An investigation of remaining deviations due to truncations and the so-called multi-level approximation is provided. The importance of vibrational-rotational couplings for small molecules is discussed in detail. In addition, an analysis is proposed, which provides information about the quality of the transformation prior to its execution. Benchmark calculations are provided for a set of small molecules.

Meier, Patrick; Oschetzki, Dominik; Berger, Robert; Rauhut, Guntram

2014-05-01

199

Near-resonant energy transfer from vibrationally excited OH to N2  

NASA Astrophysics Data System (ADS)

The probabilities per collision of near-resonant vibration-to-vibration (VV) energy transfer (ET) from v =8 and 9 of OH to N2 , processes important in the terrestrial mesosphere, are calculated in the 100 - 450 K temperature range. The calculations are carried out using the long-range multipolar forces in the first and second order. The results of the calculations are compared with calculations of Shalashilin et al. [1992] as well as with experimental data [Dyer et al., 1997; Kalogerakis et al., 2007; Streit and Johnston, 1976].

Sharma, Ramesh; Burtt, Kelly; Sharma, Ramesh

200

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

201

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

202

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

203

Rotation–vibration energy level clustering in the X ? 2 B 1 ground electronic state of PH 2  

Microsoft Academic Search

We use previously determined potential energy surfaces for the Renner-coupled X?2B1 and A?2A1 electronic states of the phosphino (PH2) free radical in a calculation of the energies and wavefunctions of highly excited rotational and vibrational energy levels of the X? state. We show how spin–orbit coupling, the Renner effect, rotational excitation, and vibrational excitation affect the clustered energy level patterns

S. N. Yurchenko; W. Thiel; Per Jensen; P. R. Bunker

2006-01-01

204

Energy trapping of thickness-shear vibration modes of elastic plates with functionally graded materials.  

PubMed

Energy trapping has important applications in the design of thickness-shear resonators. Considerable efforts have been made for the effective utilization and improvement of energy trapping with variations of plate configurations, such as adding electrodes and contouring. As a new approach in seeking improved energy trapping feature, we analyze thickness-shear vibrations in an elastic plate with functionally graded material (FGM) of in-plane variation of mechanical properties, such as elastic constants and density. A simple and general equation governing the thickness-shear modes is derived from a variational analysis. A plate with piecewise constant material properties is analyzed as an example. It is shown that such a plate can support thickness-shear vibration modes with obvious energy trapping. Bechmann's number for the existence of only one trapped mode also can be determined accordingly. PMID:17375839

Wang, Ji; Yang, Jiashi; Li, Jiangyu

2007-03-01

205

The power output and efficiency of a negative capacitance shunt for vibration control of a flexural system  

NASA Astrophysics Data System (ADS)

A negative capacitance shunt is a basic, analog, active circuit electrically connected to a piezoelectric transducer to control the vibrations of flexural bodies. The shunt circuit consists of a resistor and a synthetic negative capacitor to introduce a real and imaginary impedance on a vibrating mechanical system. The electrical impedance of the negative capacitance shunt modifies the effective modulus of the piezoelectric transducer to reduce the stiffness and increase the damping, which causes a decrease in amplitude of the vibrating structure to which the elements are bonded. To gain an insight into the electromechanical coupling and power output, the shunt and the electrical properties of the piezoelectric transducer are modeled using circuit modeling software. The power output of the model is validated with experimental measurements of a shunt connected to a piezoelectric transducer pair bonded to a vibrating aluminum cantilever beam. The model is used to select the passive components of the negative capacitance shunt to increase the efficiency and quantify the voltage output limit of the op-amp.

Beck, Benjamin S.; Cunefare, Kenneth A.; Collet, Manuel

2013-06-01

206

Vibration Fault Detection and Diagnosis Method of Power System Generator Based on Wavelet Fractal Network  

Microsoft Academic Search

A novel fault diagnosis method for turbo-generator set based on fractal exponent theory and wavelet network is presented. When faults occur, they usually produce nonstationary vibration signals. The wavelet transform is used to localizes the characteristics of vibration signal in the time frequency domains and in a view of the inter relationship of wavelet transform between fractal theory, the whole

Kang Shanlin; Liang Baoshe; Fan Feng; Shen Songhua

2007-01-01

207

Exploitation of a tristable nonlinear oscillator for improving broadband vibration energy harvesting  

NASA Astrophysics Data System (ADS)

Numerical and experimental investigations of a broadband vibration energy harvester with triple-well are presented. The nonlinear restoring force of the tristable oscillator is experimentally identified as a high order polynomial that depends on the relative spacing and locations of the magnets in the magnetically coupled piezoelectric cantilever. Simulations and experiments are performed at different harmonic excitation levels ranging from 10 to 35 Hz. The tristable energy harvester possesses the unique jump characteristics of oscillation center stemming from excitation level and initial displacements. Its broad frequency range of 15.1-32.5 Hz is obtained from the transition among three wells. It is also demonstrated that the tristable nonlinear oscillator will be more helpful to improve the broadband performance for harvesting vibration energy under low frequency excitations.

Zhou, Shengxi; Cao, Junyi; Lin, Jing; Wang, Zezhou

2014-09-01

208

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.

209

Performance Evaluation of Vibration-Based Piezoelectric Energy Scavengers  

E-print Network

consumption for a large number of nodes. Unlike cellphones and laptops, whose users can periodically recharge. For example, at an average power consumption of 100 W (an order of magnitude smaller than any existing node, DOI 10.1007/978-0-387-76464-1 3 C Springer Science+Business Media, LLC 2009 79 #12;80 Y.C. Shu

Shu, Yi-Chung

210

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

211

Flow analysis and flow-induced vibration evaluation for low-pressure feedwater heater of a nuclear power plant  

Microsoft Academic Search

This paper performs a three-dimensional flow analysis and flow-induced vibration evaluation of a tube bundle for the low-pressure feedwater heater of a nuclear power plant. Using a commercial computational fluid dynamics software, CFX-4, a detailed shell side flow analysis model is first developed and the near-field cross flow around different locations of the tube bundle within a feedwater heater can

Chin-Cheng Huang; Jen-Sheng Hsieh; Pay-Chung Chen; Chin-Ho Lee

2008-01-01

212

Vibration isolator design via energy confinement through eigenvector assignment and piezoelectric networking  

NASA Astrophysics Data System (ADS)

The objective of this research is to investigate the feasibility of utilizing eigenvector assignment and piezoelectric networking for enhancing vibration isolator design through energy confinement. For a classical periodic isolator structure, the material discontinuity creates stop bands that could suppress the wave propagation of external excitation in a particular frequency range. While effective, such method can not always create wide enough stop bands such that all the disturbance frequencies are covered. In this study, the eigenvector assignment technique and piezoelectric networks are utilized to reduce the transmissibility of the isolator modes near the boundary of the stop bands, and therefore widen the effective frequency range and enhance the performance of the isolator. The eigenvector assignment principle is to alter the mode shapes of the system so that the modal components have smaller amplitude in concerned coordinates than in other parts of the system. By applying the eigenvector assignment method on the spatially tailored periodic isolator structure, the attenuated end (the end of the isolator designed to have small vibration) response amplitude at resonant frequencies near the stop band can be reduced, which enhances the vibration isolation performance in the frequency range of interest. On the other hand, piezoelectric networks connecting to the isolator structure increase the degrees of freedom of the integrated system, and enlarge the design space for achievable eigenvectors. The right eigenvectors of this integrated system are selected such that the modal energy in the concerned area is minimized by using the Rayleigh Principle. The integrated system with assigned eigenvectors will re-distribute vibratory energy of the complete electromechanical system. Small vibration at the attenuated end of the isolator is achieved since the energy is confined in the circuitry and other parts of the isolator. Numerical simulations are performed to evaluate the effectiveness of the proposed method on vibration confinement for isolator designs. Frequency responses of the different generalized coordinates in the selected frequency range are illustrated. It is shown that with the piezoelectric networking and eigenvector assignment, the system energy is redistributed and confined in the unconcerned areas, which can greatly enhance the performance of the vibration isolation system.

Wu, Tian-Yau; Wang, Kon-Well

2004-07-01

213

Vibrational energy dependence of the reactionN2+(v) +H2 ?N2H+ +H at thermal energies  

NASA Astrophysics Data System (ADS)

The hydrogen atom transfer reaction between N2+ and H2 has been studied at thermal energies as a function of the initial vibrational excitation of the N2+ molecular ion. The rate constant is approximately the same forv = 0 to v = 3 and is slightly smaller forv = 4. The absolute values exceed the Langevin rate, in good agreement with previous studies. The observations can be explained by a model in which the first step in the formation of N2H+ consists of a charge transfer at large intermolecular distances. Finally, it is shown that vibrational deactivation is of minor importance in theN2+(v) +H2 system.

de Gouw, Joost A.; Ding, Li Ning; Frost, Michael J.; Kato, Shuji; Bierbaum, Veronica M.; Leone, Stephen R.

1995-06-01

214

Vibrational energy dependence of the reactionN 2+( v) +H 2 ?N 2H + +H at thermal energies  

NASA Astrophysics Data System (ADS)

The hydrogen atom transfer reaction between N 2+ and H 2 has been studied at thermal energies as a function of the initial vibrational excitation of the N 2+ molecular ion. The rate constant is approximately the same for v = 0 to v = 3 and is slightly smaller for v = 4. The absolute values exceed the Langevin rate, in good agreement with previous studies. The observations can be explained by a model in which the first step in the formation of N 2H + consists of a charge transfer at large intermolecular distances. Finally, it is shown that vibrational deactivation is of minor importance in theN 2+( v) +H 2 system.

de Gouw, Joost A.; Ding, Li Ning; Frost, Michael J.; Kato, Shuji; Bierbaum, Veronica M.; Leone, Stephen R.

1995-06-01

215

Theoretical Rotation-Vibration Energies of X3B1NH 2+  

NASA Astrophysics Data System (ADS)

The present work reports rotation-vibration energies for the electronic ground state X3B1of the amidogen ion, NH 2+, predicted by means of the MORBID Hamiltonian and computer program (see P. Jensen in"Molecules in the Stellar Environment" (U. G. Jųrgensen, Ed.), Lecture Notes in Physics, No. 428. Springer-Verlag, Berlin, 1994, and references therein). The predictions are based on a potential energy function obtained by Barclay et al.( J. Chem. Phys.99,9709-9719 (1993)) in a least-squares fit to the available high-resolution rotation-vibration data for X3B1NH 2+(M. Okumura, B. D. Rehfuss, B. M. Dinelli, M. G. Bawendi, and T. Oka, J. Chem. Phys.90,5918-5923 (1989); Y. Kabbadj, T. R. Huet, D. Uy, and T. Oka, J. Mol. Spectrosc.175,277-288 (1996)). We hope that the predicted energies will facilitate the assignment of further rotation-vibration transitions of this interesting, extremely floppy molecule. Further, we give a detailed discussion of the correlation between the linear-molecule and the bent-molecule quantum numbers which have been used in the literature to label the energy levels of the quasilinear NH 2+ion.

Jensen, Per

1997-01-01

216

Interchange of Translational, Rotational and Vibrational Energy in Molecular Collisions  

Microsoft Academic Search

The change in internal energy of molecules upon collisions has been analysed. Formulae, (26) to (27-C), for the effective cross section of inelastic collisions have been obtained as functions of known properties of the molecules, subject to certain conditions. These conditions are: the atoms which come into contact during collision must belong to the first row of the periodic table;

Clarence Zener

1931-01-01

217

Anomalous vibrational energy diffusion in carbon nanotubes Gang Zhanga  

E-print Network

shall answer these questions by inves- tigating the energy diffusion in single-walled carbon nano- tubes in nano- tubes. Although some researches have been done,2Ā­10 many important and fundamental questions. The distance between the two layers in nano- tube or lattice in 1D lattice model is 1.26 and 1.44 Ć?

Li, Baowen

218

A new accurate ground-state potential energy surface of ethylene and predictions for rotational and vibrational energy levels  

NASA Astrophysics Data System (ADS)

In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82 542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm-1 for fundamental bands centers and 5.9 cm-1 for vibrational bands up to 7800 cm-1. Large scale vibrational and rotational calculations for 12C2H4, 13C2H4, and 12C2D4 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm-1 are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of 13C2H4 and 12C2D4 and rovibrational levels of 12C2H4.

Delahaye, Thibault; Nikitin, Andrei; Rey, Michaėl; Szalay, Péter G.; Tyuterev, Vladimir G.

2014-09-01

219

The vibrationally adiabatic torsional potential energy surface of trans-stilbene  

Microsoft Academic Search

The effect of vibrational Zero Point Energy (ZPE) on the torsional barriers of trans-stilbene is studied in the adiabatic approximation. The two torsional modes corresponding to phenyl rotation are explicitly separated, and the remaining modes are treated as normal coordinates. ZPE reduces the adiabatic barrier along the in-phase torsion from 198 to 13cm?1. A one-dimensional adiabatic potential for the anti-phase

Praveen D. Chowdary; Todd J. Martinez; Martin Gruebele

2007-01-01

220

Vibrational-rotational energies of all H2 isotopomers using Monte Carlo methods  

Microsoft Academic Search

Using variational Monte Carlo techniques, we have computed several of the lowest rotational-vibrational energies of all the hydrogen molecule isotopomers (H2, HD, HT, D2, DT, and T2). These calculations do not require the excited states to be explicitly orthogonalized. We have examined both the usual Gaussian wave function form as well as a rapidly convergent Padé form. The high-quality potential

S. A. Alexander; R. L. Coldwell

2006-01-01

221

Study of vibrational energy transfer at a surface by a time-of-flight method  

NASA Astrophysics Data System (ADS)

A single collision, time-of-flight extension of the VEM method for the study of molecule-surface vibrational energy transfer is introduced. This refined technique helps election between possible alternative trial analytic forms of the collisional transition probability function. A gaussian form is preferred over a boltzmann-exponential form for cyclobutene isomerization to 1,3-butadiene energized by collisions at a seasoned silica surface at 800 K. The study illustrates the difference between conventional accommodation coefficient measurements, which examine average energy changes, and the present studies which explore the energy transport at high levels corresponding to chemical reaction thresholds.

Yuan, W.; Rabinovitch, B. S.

1983-07-01

222

The Physics Classroom: Work, Energy, and Power  

NSDL National Science Digital Library

This chapter of The Physics Classroom tutorial ties together the concepts of work, power, and the Law of Conservation of Energy. Six interactive tutorials explore kinetic and potential energy, power, mechanical energy, and the relationship between energy and forces. It also gives students practice in calculating work and using energy bar charts. f

Henderson, Tom

2005-03-16

223

High-power, low frequency magnetostrictive actuation for anti-vibration applications  

Microsoft Academic Search

Two large actuators employing magnetostrictive Terfenol-D active elements have been manufactured for low frequency anti-vibration applications. Each driver element comprised two Terfenol-D rods of 254mm length by 30mm diameter utilised in series. These devices were designed to counter vibrations in a civil engineering structure that were between 1 and 10Hz. Through the use of a simple strain amplification lever mechanism,

P. A Bartlett; S. J Eaton; J Gore; W. J Metheringham; A. G Jenner

2001-01-01

224

The reduction of rotorcraft power and vibration using optimally controlled active gurney flap  

NASA Astrophysics Data System (ADS)

The main topic of the present study is the application of active control scheme for the reduction of rotorcraft main rotor power reduction and vibratory load. When the helicopter is operated near its flight boundary, the required power and vibratory loads rapidly increases which impose a limit on the helicopter operation. Various methods were proposed and studied in order to achieve performance improvement under such operating condition. The effect of active control scheme was examined for its impact on the performance improvement and vibration reduction in the present study. Numerical simulations are based on the UH-60A Blackhawk helicopter with an active Gurney flap spanning from 70%R to 80%R of the main rotor. For obtaining the aeroelastic response of the rotor blade, finite element method was used to represent elastic blade. The aerodynamic loads acting on the blade are provided by CFD based 2D lookup table. Prescribed wake model was used to resolve the induced inflow over the rotor disk. The unsteady aerodynamic behavior due to the higher harmonic actuation of active Gurney flap was resolved by the time-domain unsteady aerodynamic model. The first part of preliminary study covers parametric study using Gurney flap. Starting with simple rigid blade representation of the rotor blade, the effect of 1/rev Gurney flap actuation was examined on three different gross weights. The effect of active Gurney flap width, the chordwise location of active Gurney flap, the effect of unsteady aerodynamic model, and the effect of 2/rev actuation frequency were examined. The second part of preliminary study was conducted with the elastic blade model to include the effect of torsion dynamics. Performance improvement using active Gurney flap was examined for maximizing thrust capability at two flight speeds. 1/rev Gurney flap actuation increased the gross weight capability up to 1,000 lbs. Also, 1/rev actuation of Gurney flap increased maximum altitude limit of baseline rotor by 1,400 ft. Furthermore, it was predicted that the maximum level flight speed can be increased by 30 knots with respect to that of the baseline rotor. The effect of active Gurney flap on the vibration reduction was first examined at the stall condition. Using 1/rev actuation, in-plane vibratory force and moment can be reduced by 68% and 44%, respectively. The effects of higher harmonic frequencies were investigated at the high-speed cruise speed, and single frequency phase sweep was conducted to find the best phase angle that minimizes each vibratory components. 3/rev actuation yielded 36% reduction in in-plane vibratory moment. 74% reduction in vertical vibratory force was predicted with 4/rev actuation. With 5/rev actuation, 81% reduction in vertical vibratory load was observed. With the input-output information obtained from single frequency phase sweep, the plant model which correlates active control inputs to helicopter vibratory loads was constructed. Multicyclic controller was applied to the plant model, and 25% reduction in the cost function was reported. Vertical vibratory load was reduced by 51%, and inplane force and moment were reduced by 18%, 22%, respectively.

Bae, Eui Sung

225

Vibrational zero-point energies of bromo compounds  

Microsoft Academic Search

In this study, the contribution of the bond C–Br has been determined and incorporated in our empirical formula to calculate zero-point energies (ZPE) of bromo compounds. The calculated ZPE for 38 molecules containing this bond correlate well with experimental values. The comparison of these results with semiempirical (AM1) and ab initio (HF\\/6-31G*) ZPE appears very satisfactory.

M Rahal; A El Hajbi

2004-01-01

226

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

227

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. The linearity is not a real limitation, because the structural vibrations caused by the random excitations are usually small for rail vehicle applications. The impact of nonlinearities is usually covered by separate nonlinear models and only needed for the deterministic part of the loads. Linear vibration systems subjected to Gaussian vibrations respond with vibrations having also a Gaussian distribution. A non-Gaussian distribution in the excitation signal produces also a non-Gaussian response with statistical properties different from these excitations. A drawback is the fact that there is no simple mathematical relation between excitation and response concerning these deviations from the Gaussian distribution (see e.g. Ito calculus [6], which is usually not part of commercial codes!). There are a couple of well-established procedures for the prediction of fatigue load spectra from PSDs designed for Gaussian loads (see [4]); the question of the impact of non-Gaussian distributions on the fatigue load prediction has been studied for decades (see e.g. [3,4,11-13]) and is still subject of the ongoing research; e.g. [13] proposed a procedure, capable of considering non-Gaussian broadbanded loads. It is based on the knowledge of the response PSD and some statistical data, defining the non-Gaussian character of the underlying time signal. As already described above, these statistical data are usually not available for a PSD vibration response that has been calculated in the frequency domain. Summarizing the above and considering the fact of having highly non-Gaussian exci

Wolfsteiner, Peter; Breuer, Werner

2013-10-01

228

Tidal energy in electric power systems  

Microsoft Academic Search

This paper discusses the uses and advantages of tidal energy in restructured power systems. The paper defines the resources as well as the ways in which tidal energy is converted into electricity. The paper also reviews a few tidal power projects around the world. It also shows the working of hydro tidal power plant. A comparative review of renewable energy

S. Sheth; M. Shahidehpour

2005-01-01

229

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

230

Semiclassical stochastic trajectory investigation of vibrational-rotational-translational-phonon energy transfer: The role of attractive forces  

NASA Astrophysics Data System (ADS)

A semiclassical stochastic trajectory (SST) approach to the study of collision induced transitions in gas molecule-solid surface scattering is used to investigate vibrational-rotational-transiational-phonon energy transfer in the H 2, D 2, HD-(smooth)Pt systems. State-to-state rotationally and ro-vibrationally inelastic transition probabilities are determined using interaction potentials with varying strength of the long-range attractive component. Rigid and non-rigid surfaces are considered, the latter via the generalized Langevin-ghost atom technique. The results demonstrate that addition of a significant attractive interaction broadens the rotationally and ro-vibralionally inelastic probability distributions. This leads in the latter case to the replacement of the near-resonant vibration-rotation mechanism for vibrational relaxation by a much more effective and uniform vibration-rotation, translation mechanism.

Depristo, Andrew E.

1984-02-01

231

Harvesting traffic-induced vibrations for structural health monitoring of bridges  

Microsoft Academic Search

This paper discusses the development and testing of a renewable energy source for powering wireless sensors used to monitor the structural health of bridges. Traditional power cables or battery replacement are excessively expensive or infeasible in this type of application. An inertial power generator has been developed that can harvest traffic-induced bridge vibrations. Vibrations on bridges have very low acceleration

T. V. Galchev; J. McCullagh; R. L. Peterson; K. Najafi

2011-01-01

232

A new many-body potential energy surface for HCl clusters and its application to anharmonic spectroscopy and vibration-vibration energy transfer in the HCl trimer.  

PubMed

The hydrogen bond has been studied by chemists for nearly a century. Interest in this ubiquitous bond has led to several prototypical systems emerging to studying its behavior. Hydrogen chloride clusters stand as one such example. We present here a new many-body potential energy surface for (HCl)n constructed from one-, two-, and three-body interactions. The surface is constructed from previous highly accurate, semiempirical monomer and dimer surfaces, and a new high-level ab initio permutationally invariant full-dimensional three-body potential. The new three-body potential is based on fitting roughly 52,000 three-body energies computed using coupled cluster with single, doubles, perturbative triples, and explicit correlation and the augmented correlation consistent double-? basis set. The first application, described here, is to the ring HCl trimer, for which the many-body representation is exact. The new potential describes all known stationary points of the trimer as well its dissociation to either three monomers or a monomer and a dimer. The anharmonic vibrational energies are computed for the three H-Cl stretches, using explicit three-mode coupling calculations and local-monomer calculations with Hückel-type coupling. Both methods produce frequencies within 5 cm(-1) of experiment. A wavepacket calculation based on the Hückel model and full-dimensional classical calculation are performed to study the monomer H-Cl stretch vibration-vibration transfer process in the ring HCl trimer. Somewhat surprisingly, the results of the quantum and classical calculations are virtually identical, both exhibiting coherent beating of the excitation between the three monomers. Finally, this representation of the potential is used to study properties of larger clusters, namely to compute optimized geometries of the tetramer, pentamer, and hexamer and to perform explicit four-mode coupling calculations of the tetramer's anharmonic stretch frequencies. The optimized geometries are found to be in agreement with those of previous ab initio studies and the tetramer's anharmonic frequencies are computed within 11 cm(-1) of experiment. PMID:24444294

Mancini, John S; Bowman, Joel M

2014-09-01

233

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

E-print Network

Although nuclear energy density functionals are determined primarily by fitting to ground state properties, they are often applied in nuclear astrophysics to excited states, usually through the quasiparticle random phase approximation (QRPA). Here we test the Skyrme functionals SkM* and SLy4 along with the self-consistent QRPA by calculating properties of low-lying vibrational states in a large number of well-deformed even-even rare-earth nuclei. We reproduce trends in energies and transition probabilities associated with gamma-vibrational states, but our results are not perfect and indicate the presences of multi-particle-hole correlations that are not included in the QRPA. The Skyrme functional SkM* performs noticeably better than SLy4. In a few nuclei, changes in the treatment of the pairing energy functional have a significant effect. The QRPA is less successful with "beta-vibrational" states than with the gamma-vibrational states.

J. Terasaki; J. Engel

2011-05-19

234

Scavenging vibration energy from seismically isolated bridges using an electromagnetic harvester  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

235

Shock and vibration tests of uranium mononitride fuel pellets for a space power nuclear reactor  

NASA Technical Reports Server (NTRS)

Shock and vibration tests were conducted on cylindrically shaped, depleted, uranium mononitride (UN) fuel pellets. The structural capabilities of the pellets were determined under exposure to shock and vibration loading which a nuclear reactor may encounter during launching into space. Various combinations of diametral and axial clearances between the pellets and their enclosing structures were tested. The results of these tests indicate that for present fabrication of UN pellets, a diametral clearance of 0.254 millimeter and an axial clearance of 0.025 millimeter are tolerable when subjected to launch-induced loads.

Adams, D. W.

1972-01-01

236

Fusion EnergyFusion Energy Powering the XXI centuryPowering the XXI century  

E-print Network

the current energy sources Shortfall must be supplied by alternative sources 20th International Atomic Energy Agency, Fusion Energy Conference, Vilamoura, Portugal #12;Sources of Energy in XXISources of EnergyFusion EnergyFusion Energy Powering the XXI centuryPowering the XXI century Carlos Matos Ferreira

237

Vibrational energy relaxation dynamics of Si?H stretching modes on stepped H\\/Si(111) 1×1 surfaces  

Microsoft Academic Search

The vibrational energy relaxation rates of excited Si?H stretching modes on the monohydride steps of miscut H\\/Si(111) 1×1 surfaces are calculated using Bloch-Redfield theory combined with classical molecular dynamics (MD) simulation. The structure and vibrational frequencies of the surface are first investigated using the Car-Parrinello ab initio MD method. The calculated Si?Si?H bending frequencies and relaxed structures are then used

Ying-Chieh Sun; Huadong Gai; Gregory A. Voth

1995-01-01

238

Second Proof Work, Power, and Energy  

E-print Network

to as energy loss. fuel cell Device undergoing electrochemical cycle where electrical work is obtained during that they will be depleted in a finite time period at the current rate of consumption. power The energy rate per unit of timeSecond Proof Work, Power, and Energy M. KOSTIC Northern Illinois University DeKalb, Illinois

Kostic, Milivoje M.

239

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

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

240

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

241

Power quality improvement and uninterruptible power supply using a power conditioning system with energy storage capability  

Microsoft Academic Search

A power conditioning system with energy storage capability is proposed as a viable solution for improving the quality and the reliability of the electric energy supply. Several tasks can be performed at the same time, such as reactive power compensation, current harmonic reduction, and smoothing of pulsating loads. Moreover, the power conditioning system can operate as an uninterruptible power supply

D. Casadei; G. Grandi; G. Serra; C. Rossi

2005-01-01

242

Bonneville Power Administration's Purchasing of Energy Savings  

E-print Network

BONNEVILLE POWER ADMINISTRATION'S PURCHASE OF ENERGY SAVINGS Harold (Skip) Schick Leslie E. McMillan Bonneville Power Administration Port1and, Oregon INTRODUCTION The Bonneville Power Administration (BPA) is conducting a commercial... of several activities BPA is conductin9 to develop the capabil ity to conserve energy in the com mercial sector of electrical energy use. This paper describes the benefits of the approach, the program des ign, 1essons 1earned through field testing...

Schick, H.

243

A quasi-classical trajectory study of the OH + SO reaction: the role of ro-vibrational energy.  

PubMed

A study of the OH + SO ? H + SO2 reaction using a quasi-classical trajectory method is presented with the aim of investigating the role of the ro-vibrational energy of the reactants in the reactivity. The calculations were carried out using a previously reported global potential energy surface for HSO2((2)A). Different initial conditions with one and both reactants ro-vibrationally excited were studied. The reactive cross sections, for each studied combination, are calculated and then fitted to a capture-like model combined with a factor accounting for the recrossing effects. The Vibrational Energy Quantum Mechanical Threshold of the Complex method was used to correct for the zero-point vibrational energy leakage of the classical calculations. State specific and averaged rate constants are reported. The reactivity is affected when ro-vibrational energy of either of the reactants is changed. The present calculations provide a theoretical support for the experimental rate constant for temperatures below 550 K, but fail to account for the significant fall in the observed rate constant upon increasing the temperature above this value. PMID:24837441

Pires, W A D; Garrido, J D; Nascimento, M A C; Ballester, M Y

2014-07-01

244

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

245

Collisional relaxation of vibrational energy transients in the methylcyclopropane system. A variable encounter method study  

NASA Astrophysics Data System (ADS)

The variable encounter method has been used to study vibrational energy transients in the isomerization of methylcyclopropane to various butenes. This system was studied with reactor surface temperatures of 800 to 1130 K and average numbers of collisions per encounter with the reactor of 5.6 and 20.0. The reaction rate was treated on the basis of total, rather than individual butene rates, because of butene product interconversion. An exponential model of energy transfer was found to fit to the data with the average down step energy decreasing from 1860 to 1415 cm-1 with increase of temperature over the range studied. Incubation times increased from 14 to 19 collisions with increase in temperature, and these times, together with values of the conventional relative collision efficiency ? and values of , are compared with those of other molecules studied by VEM. The calculated transient population distributions and the associated sequential reaction probabilities are also displayed.

Kelley, D. F.; Kasai, T.; Rabinovitch, B. S.

1980-12-01

246

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

PubMed

Differential and integral cross section measurements, for incident electron energies in the 20-50 eV range, are reported for excitation of several composite vibrational modes in ?-tetrahydrofurfuryl alcohol (THFA). Optimisation and frequency calculations, using GAUSSIAN 09 at the B3LYP/aug-cc-pVDZ level, were also undertaken for the two most abundant conformers of THFA, with results being reported for their respective mode classifications and excitation energies. Those calculations assisted us in the experimental assignments of the composite features observed in our measured energy loss spectra. There are, to the best of our knowledge, no other experimental or theoretical data currently available in the literature against which we can compare the present results. PMID:24908007

Duque, H V; Chiari, L; Jones, D B; Pettifer, Z; da Silva, G B; Limćo-Vieira, P; Blanco, F; Garcķa, G; White, R D; Lopes, M C A; Brunger, M J

2014-06-01

247

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

248

Vibrational autodetachment-intramolecular vibrational relaxation translated into electronic motion.  

PubMed

If a negative ion has vibrational energy in excess of the binding energy of its most weakly bound electron, the anion can undergo vibrational autodetachment, similar to thermionic emission. When this effect occurs after targeted infrared excitation of a specific vibrational mode in the anion, it encodes information on the intramolecular vibrational relaxation processes that take place between excitation and electron emission. We present examples on how vibrational autodetachment can be used to obtain infrared spectra of molecular anions, and we discuss how a vibrational autodetachment photoelectron spectrum can be modeled, using vibrational autodetachment after excitation of CH stretching modes of nitromethane anions as a case study. PMID:20205435

Adams, C L; Schneider, H; Weber, J M

2010-04-01

249

The realization and performance of vibration energy harvesting MEMS devices based on an epitaxial piezoelectric thin film  

NASA Astrophysics Data System (ADS)

This paper focuses on the fabrication and evaluation of vibration energy harvesting devices by utilizing an epitaxial Pb(Zr0.2Ti0.8)O3 (PZT) thin film. The high quality of the c-axis oriented PZT layer results in a high piezoelectric coefficient and a low dielectric constant, which are key parameters for realizing high performance piezoelectric energy harvesters. Different cantilever structures, with and without a Si proof mass, are realized using micro-patterning techniques optimized for the epitaxial oxide layers, to maintain the piezoelectric properties throughout the process. The characteristics and the energy harvesting performances of the fabricated devices are experimentally investigated and compared against analytical calculations. The optimized device based on a 0.5 µm thick epitaxial PZT film, a cantilever beam of 1 mm × 2.5 mm × 0.015 mm, with a Si proof mass of 1 mm × 0.5 mm × 0.23 mm, generates an output power, current and voltage of, respectively, 13 µW g - 2, 48 µA g - 1 and 0.27 V g - 1 (g = 9.81 m s - 2) at the resonant frequency of 2.3 kHz for an optimal resistive load of 5.6 k?. The epitaxial PZT harvester exhibits higher power and current with usable voltage, while maintaining lower optimal resistive load as compared with other examples present in the literature. These results indicate the potential of epitaxial PZT thin films for the improvement of the performances of energy harvesting devices.

Isarakorn, D.; Briand, D.; Janphuang, P.; Sambri, A.; Gariglio, S.; Triscone, J.-M.; Guy, F.; Reiner, J. W.; Ahn, C. H.; de Rooij, N. F.

2011-02-01

250

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

251

Nuclear Power Trends Energy Economics and Sustainability  

E-print Network

Nuclear Power Trends Energy Economics and Sustainability L. H. Tsoukalas Purdue University Nuclear Nuclear Today Ā· 439 nuclear power reactors (31 countries) Ā· Over 12,000 years of operating experience Ā· Nuclear reactors supply 16% of the world's electricity as base-load power (372,000 MWe of total capacity

252

Thermal energy storage for power plant applications  

Microsoft Academic Search

This study was conducted by Pacific Northwest Laboratory (PNL) to evaluate alternative methods of using coal to generate peak and intermediate load power. The approach was to review the technical and economic feasibility of using thermal energy storage (TES) with a conventional coal-fired power plant and an integrated gasification combined cycle (IGCC) power plant. In the first case, conventional pulverized

S. Somasundaram; M. K. Drost; Z. I. Antoniak; D. R. Brown

1990-01-01

253

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

254

Harvesting microalgal biomass using a magnetically induced membrane vibration (MMV) system: filtration performance and energy consumption.  

PubMed

This study was performed to investigate the effectiveness of submerged microfiltration to harvest both a marine diatom Phaeodactylum tricornutum and a Chlorella vulgaris in a recently developed magnetically induced membrane vibrating (MMV) system. We assess the filtration performance by conducting the improved flux step method (IFM), fed-batch concentration filtrations and membrane fouling autopsy using two lab-made membranes with different porosity. The full-scale energy consumption was also estimated. Overall results suggest that the MMV offers a good fouling control and the process was proven to be economically attractive. By combining the membrane filtration (15× concentration) with centrifugation to reach a final concentration of 25% w/v, the energy consumption to harvest P. tricornutum and C. vulgaris was, respectively, as low as 0.84 and 0.77kWh/m(3), corresponding to 1.46 and 1.39 kWh/kg of the harvested biomass. PMID:23624051

Bilad, M R; Discart, V; Vandamme, D; Foubert, I; Muylaert, K; Vankelecom, Ivo F J

2013-06-01

255

Fundamental study of an electric power transmission system for implanted medical devices using magnetic and ultrasonic energy.  

PubMed

In this paper, the authors propose a novel electric power supply system for implanted medical devices. The system is noninvasive and uses two kinds of energy, magnetic and ultrasonic. The system can provide high power levels harmlessly. The energies are obtained by two types of vibrator, i.e., piezo and magnetostriction devices. A prototype was built and it was verified experimentally that the system is basically able to provide power. At high frequencies, such as 100 kHz, the output power was higher than the conventional system using a transformer. The normalized output power per unit volume also exceeded the transformer system. PMID:14598116

Suzuki, Shin-nosuke; Katane, Tamotsu; Saito, Osami

2003-01-01

256

An Application of Error Reduction and Harmonic Inversion schemes to the Semiclassical Calculation of Molecular Vibrational Energy Levels  

NASA Astrophysics Data System (ADS)

A singular value decomposition based harmonic inversion (HI) signal processing scheme is applied to the semiclassical initial value representation (IVR) calculation of molecular vibrational states. Relative to usual IVR procedure of Fourier analysis of a signal made from the Monte Carlo evaluation of the phase space integral in which many trajectories are needed, the new procedure obtains acceptable results with many fewer trajectories. Calculations are carried out for vibrational energy levels of H2O to illustrate the overall procedure. New results are given for the zero point energy (ZPE) of CH5+.

Taylor, Howard S.

2005-03-01

257

Industrial Arts 7-9. Power/Energy: Electricity/Electronics, Power Mechanics, Power/Energy.  

ERIC Educational Resources Information Center

This guide for industrial arts grades 7-9 provides teachers with a curriculum for the subject cluster of power/energy. An "Overview" section presents the rationale, discusses how the content of the program is related to the developmental stages of the adolescent, describes the structure of the industrial arts program, and lists program goals and…

Manitoba Dept. of Education, Winnipeg.

258

Protonated fluorine, HF2+: Ab initio potential energy surface and vibrational splittings for proton transfer  

NASA Astrophysics Data System (ADS)

We calculate 1542 ab initio points for the HF2+ ground state at the QCISD(T)/6-311++G(2df,2pd) level for a wide range of geometries. We fit the ab initio points to a multiparameter analytic function to obtain a multidimensional potential energy surface (PES) valid for large amplitude hydrogen motion. We then calculate and assign vibrational levels for this PES. There is intramolecular proton transfer when the hydrogen atom tunnels through a triangular transition state separating the two equivalent equilibrium geometries. The barrier to proton transfer is 9547 cm-1 (8340 cm-1 with zero-point correction). Below the barrier to proton transfer, the energy levels are split and measurable splittings are predicted for relatively low-lying vibrational levels that may be experimentally accessible. The first three levels with splitting greater than 0.01 cm-1 are, in order of increasing energy, (0,3,1), (0,4,0), and (0,3,2), while the first three levels with splitting greater than 0.1 cm-1 are, in order of increasing energy, (0,4,1), (0,5,0), and (0,4,2), where ?2 is the H-F-F bend quantum number and ?3 is the F-F stretch quantum number. We conclude that H-F-F bend excitation is essential for proton transfer, and that F-F stretch excitation facilitates proton transfer. In addition, there is a 3:1 Fermi resonance between the HF stretch (harmonic frequency 3334 cm-1) and the H-F-F bend (harmonic frequency 1141 cm-1), and levels with HF stretch excitation can have significant splittings. For example, the splitting is greater than 0.01 cm-1 for the (1,1,1) level, which is Fermi resonant with (0,4,1) and greater than 0.1 cm-1 for the (1,2,1) level, which is Fermi resonant with (0,5,1). This is relevant for the experimental observation of the vibrational splittings since the IR intensity of the HF stretch is four times that of the H-F-F bend.

Chan, Wai-To; Hamilton, I. P.

1998-11-01

259

Observation of vibrational energy exchange in a type-III antifreeze protein.  

PubMed

We performed time- and polarization-resolved pump-probe and two-dimensional infrared (2D-IR) experiments to study the dynamics of the amide I vibration of a 7 kDa type-III antifreeze protein. In the pump-probe experiments, we used femtosecond mid-infrared pulses to investigate the vibrational relaxation dynamics of the amide mode. The transient spectra show the presence of two spectral components that decay with different lifetimes, indicative of the presence of two distinct amide subbands. The 2D-IR experiments reveal the coupling between the two bands in the form of cross-peaks. On the basis of previous work by Demirdöven et al. ( J. Am. Chem. Soc. 2004 , 126 , 7981 - 7990 ), we assign the observed bands to the two infrared-active modes ?(-) and ?(+) found in protein ?-sheets. The amplitudes of the cross-peak were found to increase with delay time, indicating that the cross-peaks originate from population transfer between the coupled amide oscillators. The time constant of the energy transfer was found to be 6-7 ps. PMID:25051212

Lotze, S; Olijve, L L C; Voets, I K; Bakker, H J

2014-07-31

260

Accurate variational calculations and analysis of the HOCl vibrational energy spectrum  

SciTech Connect

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

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

1998-12-01

261

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

PubMed

Vibrational zero-point energies (ZPEs) determined from ab initio calculations are often scaled by empirical factors. An empirical scaling factor partially compensates for the effects arising from vibrational anharmonicity and incomplete treatment of electron correlation. These effects are not random but are systematic. We report scaling factors for 32 combinations of theory and basis set, intended for predicting ZPEs from computed harmonic frequencies. An empirical scaling factor carries uncertainty. We quantify and report, for the first time, the uncertainties associated with scaling factors for ZPE. The uncertainties are larger than generally acknowledged; the scaling factors have only two significant digits. For example, the scaling factor for B3LYP/6-31G(d) is 0.9757+/-0.0224 (standard uncertainty). The uncertainties in the scaling factors lead to corresponding uncertainties in predicted ZPEs. The proposed method for quantifying the uncertainties associated with scaling factors is based upon the Guide to the Expression of Uncertainty in Measurement, published by the International Organization for Standardization. We also present a new reference set of 60 diatomic and 15 polyatomic "experimental" ZPEs that includes estimated uncertainties. PMID:19317526

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

2009-03-21

262

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

NASA Astrophysics Data System (ADS)

Vibrational zero-point energies (ZPEs) determined from ab initio calculations are often scaled by empirical factors. An empirical scaling factor partially compensates for the effects arising from vibrational anharmonicity and incomplete treatment of electron correlation. These effects are not random but are systematic. We report scaling factors for 32 combinations of theory and basis set, intended for predicting ZPEs from computed harmonic frequencies. An empirical scaling factor carries uncertainty. We quantify and report, for the first time, the uncertainties associated with scaling factors for ZPE. The uncertainties are larger than generally acknowledged; the scaling factors have only two significant digits. For example, the scaling factor for B3LYP/6-31G(d) is 0.9757±0.0224 (standard uncertainty). The uncertainties in the scaling factors lead to corresponding uncertainties in predicted ZPEs. The proposed method for quantifying the uncertainties associated with scaling factors is based upon the Guide to the Expression of Uncertainty in Measurement, published by the International Organization for Standardization. We also present a new reference set of 60 diatomic and 15 polyatomic "experimental" ZPEs that includes estimated uncertainties.

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

2009-03-01

263

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

264

Vibrational spectroscopy in the electron microscope.  

PubMed

Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage. PMID:25297434

Krivanek, Ondrej L; Lovejoy, Tracy C; Dellby, Niklas; Aoki, Toshihiro; Carpenter, R W; Rez, Peter; Soignard, Emmanuel; Zhu, Jiangtao; Batson, Philip E; Lagos, Maureen J; Egerton, Ray F; Crozier, Peter A

2014-10-01

265

Vibrational spectroscopy in the electron microscope  

NASA Astrophysics Data System (ADS)

Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for `aloof' spectroscopy that largely avoids radiation damage.

Krivanek, Ondrej L.; Lovejoy, Tracy C.; Dellby, Niklas; Aoki, Toshihiro; Carpenter, R. W.; Rez, Peter; Soignard, Emmanuel; Zhu, Jiangtao; Batson, Philip E.; Lagos, Maureen J.; Egerton, Ray F.; Crozier, Peter A.

2014-10-01

266

Electron hole pair mediated vibrational excitation in CO scattering from Au(111): Incidence energy and surface temperature dependence  

NASA Astrophysics Data System (ADS)

We investigated the translational incidence energy (Ei) and surface temperature (Ts) dependence of CO vibrational excitation upon scattering from a clean Au(111) surface. We report absolute v = 0 ? 1 excitation probabilities for Ei between 0.16 and 0.84 eV and Ts between 473 and 973 K. This is now only the second collision system where such comprehensive measurements are available - the first is NO on Au(111). For CO on Au(111), vibrational excitation occurs via direct inelastic scattering through electron hole pair mediated energy transfer - it is enhanced by incidence translation and the electronically non-adiabatic coupling is about 5 times weaker than in NO scattering from Au(111). Vibrational excitation via the trapping desorption channel dominates at Ei = 0.16 eV and quickly disappears at higher Ei.

Shirhatti, Pranav R.; Werdecker, Jörn; Golibrzuch, Kai; Wodtke, Alec M.; Bartels, Christof

2014-09-01

267

Parametrically excited MEMS vibration energy harvesters with design approaches to overcome the initiation threshold amplitude  

NASA Astrophysics Data System (ADS)

Resonant-based vibration harvesters have conventionally relied upon accessing the fundamental mode of directly excited resonance to maximize the conversion efficiency of mechanical-to-electrical power transduction. This paper explores the use of parametric resonance, which unlike the former, the resonant-induced amplitude growth, is not limited by linear damping and wherein can potentially offer higher and broader nonlinear peaks. A numerical model has been constructed to demonstrate the potential improvements over the convention. Despite the promising potential, a damping-dependent initiation threshold amplitude has to be attained prior to accessing this alternative resonant phenomenon. Design approaches have been explored to passively reduce this initiation threshold. Furthermore, three representative MEMS designs were fabricated with both 25 and 10 ?m thick device silicon. The devices include electrostatic cantilever-based harvesters, with and without the additional design modification to overcome initiation threshold amplitude. The optimum performance was recorded for the 25 ?m thick threshold-aided MEMS prototype with device volume ˜0.147 mm3. When driven at 4.2 ms-2, this prototype demonstrated a peak power output of 10.7 nW at the fundamental mode of resonance and 156 nW at the principal parametric resonance, as well as a 23-fold decrease in initiation threshold over the purely parametric prototype. An approximate doubling of the half-power bandwidth was also observed for the parametrically excited scenario.

Jia, Yu; Yan, Jize; Soga, Kenichi; Seshia, Ashwin A.

2013-11-01

268

Self-powered smart blade: helicopter blade energy harvesting  

NASA Astrophysics Data System (ADS)

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

Bryant, Matthew; Fang, Austin; Garcia, Ephrahim

2010-04-01

269

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

E-print Network

Vibrational and Translational Energy Effects in the Reaction of Ammonia Ions with Water Molecules, and 22 amu. The cross section for proton transfer decreases with increasing collisional energy of vibrationally state-selected ammonia ions with deuterated water is investigated with a quadrupole

Zare, Richard N.

270

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

NASA Astrophysics Data System (ADS)

The basic purpose of a damper is to reduce the vibration and to have a better ride comfort, road handling and safety to the rider. Recent developments show that an active vibration damper can effectively work much better than a passive damper. The effectiveness and reliability can be further enhanced by using hybrid dampers, which is a combination of active and passive dampers. But the need to have energy optimization in any field need not be stressed. Consequently, novel suspension concepts are required, not only to improve the vehicle's dynamic performance, but also to see that the energy generated during vibration can be harvested by utilizing regeneration functions. Hence if a hybrid damper with energy harvesting capability be designed, it would serve both purposes. In the hybrid damper a combination of hydraulic damper to act as a passive damper and an electromagnetic (EM) damper to act as an active damper is considered. The hydraulic system has more reliability and is time tested and the EM system acts as a dynamic vibration system as well as energy harvester. In this study a hybrid EM damper is modeled, analyzed and validity is shown for frequency response functions and energy balance for its active use. It is also shown how the effectiveness of the suspension system can be enhanced by using a hybrid damper.

Hanumantha Rao, T. V.; Srinivasa Rao, M. S. S.; Apparao, B. V.; Satyanarayana, K.

2014-04-01

271

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

PubMed Central

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

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

2013-01-01

272

Laser Fusion Energy The High Average Power  

E-print Network

Laser Fusion Energy and The High Average Power Program John Sethian Naval Research Laboratory Dec for Inertial Fusion Energy with lasers, direct drive targets and solid wall chambers Lasers DPPSL (LLNL) Kr posters Snead Payne #12;Laser(s) Goals 1. Develop technologies that can meet the fusion energy

273

Energy storage for the electric power industry  

Microsoft Academic Search

The following energy storage systems for leveling the energy demands from power companies are briefly discussed: (1) pumped hydrostorage (2) compressed air storage,(3) secondary batteries, (4) liquid hydrogen storage, and (5) flywheels. Superconducting magnetic energy storage systems are also discussed.

W. E. Keller

1973-01-01

274

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.

275

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

E-print Network

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

Teodorescu, Remus

276

ZnO nanogenerators: energy generation through scavenging vibration, advantages of using a diode  

NASA Astrophysics Data System (ADS)

Recent developments on the use of the piezoelectric effect in ZnO nanorod-based p-n junctions for energy harvesting applications are presented. We describe a hybrid p-n nanostructured ZnO energy device combined with the semiconducting polymer poly(3,4-ethylene-dioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) to produce a kinetic energy harvesting. The load resistance-dependent power output from this p-n junction device is compared with the more common ZnO-PMMA device, which we make from ZnO nanorods manufactured using an identical process. It is shown that the PMMA device generates an open-circuit voltage of 150mV with a maximum power of 0.24?W/cm2 giving 0.03nJ of available energy when on a load resistance of 324 k?. The PEDOT:PSS device generates significantly more power, 28.9?W/cm2, when it is matched to a 1.6 k? load resistance. The energy output of the PEDOT:PSS device is 2.22nJ. Our results demonstrate the importance of measuring energy delivery to an electrical load to fully understand the output capability of these devices. By analysis of the time-dependent output of the devices the energy can be calculated giving a reasonable estimation as to the available energy and power in any given system.

Briscoe, Joe; Jalai, Nimra; Wooliams, Peter; Stewart, Mark; Cain, Markys; Weaver, Paul M.; Dunn, Steve

2013-05-01

277

Brillouin spectra and vibrational-translational energy exchange in liquid acetonitrile  

NASA Astrophysics Data System (ADS)

Polarized light scattering experiments in the GHz frequency range (Rayleigh-Brillouin spectra) are reported for liquid acetonitrile. Hypersonic velocities and absorption coefficients have been measured as a function of temperature and of transferred wave vector. The plots of these quantities versus frequency show characteristic dispersion which is indicative of relaxation phenomena. The occurring relaxation has been interpreted as due to a thermal process in which the translational energy of molecules is transferred, during the collisions or through dipolar interactions, into internal degrees of freedom of low quanta vibrational motions. The quite strange behavior of the relaxation time with the temperature has been interpreted and compared with the behavior of the relaxation time in liquid chloroform.

Sassi, Paola; Paliani, Giulio; Cataliotti, Rosario Sergio

1998-06-01

278

7/30/2014 Smart sensors that harvest power from sun, heat or vibrations https://ec.europa.eu/programmes/horizon2020/en/print/688 1/2  

E-print Network

2020/en/print/688 1/2 Date: 18/02/2014 - 19:37 Published on Horizon 2020 (https://ec.europa.eu/programmes/horizon7/30/2014 Smart sensors that harvest power from sun, heat or vibrations https://ec.europa.eu/programmes/horizon2020) Smart sensors that harvest power from sun, heat or vibrations Published by newsroom editor

Rossi, Michele

279

Accurate ab initio structure, dissociation energy, and vibrational spectroscopy of the F(-)-CH4 anion complex.  

PubMed

Accurate equilibrium structure, dissociation energy, global potential energy surface (PES), dipole moment surface (DMS), and the infrared vibrational spectrum in the 0-3000 cm(-1) range of the F(-)-CH4 anion complex have been obtained. The equilibrium electronic structure calculations employed second-order Mųller-Plesset perturbation theory (MP2) and coupled-cluster (CC) method up to single, double, triple, and perturbative quadruple excitations using the aug-cc-p(C)VXZ [X = 2(D), 3(T), 4(Q), and 5] correlation-consistent basis sets. The best equilibrium geometry has been obtained at the all-electron CCSD(T)/aug-cc-pCVQZ level of theory. The dissociation energy has been determined based on basis set extrapolation techniques within the focal-point analysis (FPA) approach considering (a) electron correlation beyond the all-electron CCSD(T) level, (b) relativistic effects, (c) diagonal Born-Oppenheimer corrections (DBOC), and (d) variationally computed zero-point vibrational energies. The final D(e) and D0 values are 2398 +/- 12 and 2280 +/- 20 cm(-1), respectively. The global PES and DMS have been computed at the frozen-core CCSD(T)/aug-cc-pVTZ and MP2/aug-cc-pVTZ levels of theory, respectively. Variational vibrational calculations have been performed for CH4 and F(-)-CH4 employing the vibrational configuration interaction (VCI) method as implemented in Multimode. PMID:18651724

Czakó, Gįbor; Braams, Bastiaan J; Bowman, Joel M

2008-08-14

280

Electronic energies, geometries, and vibrational frequencies of the ground and low-lying excited states of the boron trimer  

E-print Network

Electronic energies, geometries, and vibrational frequencies of the ground and low-lying excited structure calculations on several low-lying valence states of B, have been carried out using correlation. In this study, such information has been determined for several low-lying bent, triangular, and linear states

Simons, Jack

281

Volume 76. number 1 CHEMICAL PHYSICS LETTERS 15 November 1980 THE KINETICS OF VIBRATIONAL ENERGY TRANSFER AND RELAXATION PROCESSES  

E-print Network

Volume 76. number 1 CHEMICAL PHYSICS LETTERS 15 November 1980 THE KINETICS OF VIBRATIONAL ENERGY of the experimental apparatus is presented #12;Volume 76, number 1 CHELIICAL PHYSICS LETTERS I.5 November 1980 1 COW Received 11 August 1980 Subsequenttoe\\cmn_e1.~ b>--nCO 1 laser pulse,U~oiesccnceh~beenderccted,rom 1v3 of

Apkarian, V. Ara

282

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

283

Performance Assessment and Reinstatement of Vibrating Wire Strain Gauges in Nuclear Power Plant Structures  

Microsoft Academic Search

This paper presents the results of the analysis of failed gauges in Prestressed Concrete Pressure Vessels ( PCPVs) and their recovery at a Nuclear Power Station. Internationally, a significant number of nuclear power plants have now been operating for a period in excess of twenty years and some for more than thirty years. As a result, interest in the management

Leslie M. Smith; M. ASME FGS; Gary L. Brodt; Bryn Stafford

284

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

PubMed

The absolute cross sections (CSs) for vibrational excitations of cytosine by electron impact between 0.5 and 18 eV were measured by electron-energy loss (EEL) spectroscopy of the molecule deposited at monolayer coverage on an inert Ar substrate. The vibrational energies compare to those that have been reported from IR spectroscopy of cytosine isolated in Ar matrix, IR and Raman spectra of polycrystalline cytosine, and ab initio calculation. The CSs for the various H bending modes at 142 and 160 meV are both rising from their energy threshold up to 1.7 and 2.1 × 10(-17) cm(2) at about 4 eV, respectively, and then decrease moderately while maintaining some intensity at 18 eV. The latter trend is displayed as well for the CS assigned to the NH(2) scissor along with bending of all H at 179 meV. This overall behavior in electron-molecule collision is attributed to direct processes such as the dipole, quadrupole, and polarization contributions, etc. of the interaction of the incident electron with a molecule. The CSs for the ring deformation at 61 meV, the ring deformation with N-H symmetric wag at 77 meV, and the ring deformations with symmetric bending of all H at 119 meV exhibit common enhancement maxima at 1.5, 3.5, and 5.5 eV followed by a broad hump at about 12 eV, which are superimposed on the contribution due to the direct processes. At 3.5 eV, the CS values for the 61-, 77-, and 119-meV modes reach 4.0, 3.0, and 4.5 × 10(-17) cm(2), respectively. The CS for the C-C and C-O stretches at 202 meV, which dominates in the intermediate EEL region, rises sharply until 1.5 eV, reaches its maximum of 5.7 × 10(-17) cm(2) at 3.5 eV and then decreases toward 18 eV. The present vibrational enhancements, correspond to the features found around 1.5 and 4.5 eV in electron transmission spectroscopy (ETS) and those lying within 1.5-2.1 eV, 5.2-6.8 eV, and 9.5-10.9 eV range in dissociative electron attachment (DEA) experiments with cytosine in gas phase. While the ETS features are ascribed to shape resonances associated with the electron occupation of the second and third antibonding ?-orbitals of the molecule in its ground state, the correspondence with DEA features suggests the existence of common precursor anion states decaying with certain probabilities into the vibrationally excited ground state. PMID:22998289

Michaud, M; Bazin, M; Sanche, L

2012-09-21

285

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

286

SPS Energy Conversion Power Management Workshop  

NASA Astrophysics Data System (ADS)

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

1980-06-01

287

SPS Energy Conversion Power Management Workshop  

NASA Technical Reports Server (NTRS)

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

1980-01-01

288

Measurement of vibrational spectrum of liquid using monochromated scanning transmission electron microscopy-electron energy loss spectroscopy.  

PubMed

Investigations on the dynamic behavior of molecules in liquids at high spatial resolution are greatly desired because localized regions, such as solid-liquid interfaces or sites of reacting molecules, have assumed increasing importance with respect to improving material performance. In application to liquids, electron energy loss spectroscopy (EELS) observed with transmission electron microscopy (TEM) is a promising analytical technique with the appropriate resolutions. In this study, we obtained EELS spectra from an ionic liquid, 1-ethyl-3-methylimidazolium bis (trifluoromethyl-sulfonyl) imide (C2mim-TFSI), chosen as the sampled liquid, using monochromated scanning TEM (STEM). The molecular vibrational spectrum and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the liquid were investigated. The HOMO-LUMO gap measurement coincided with that obtained from the ultraviolet-visible spectrum. A shoulder in the spectrum observed ?0.4 eV is believed to originate from the molecular vibration. From a separately performed infrared observation and first-principles calculations, we found that this shoulder coincided with the vibrational peak attributed to the C-H stretching vibration of the [C2mim(+)] cation. This study demonstrates that a vibrational peak for a liquid can be observed using monochromated STEM-EELS, and leads one to expect observations of chemical reactions or aids in the analysis of the dynamic behavior of molecules in liquid. PMID:25015973

Miyata, Tomohiro; Fukuyama, Mao; Hibara, Akihide; Okunishi, Eiji; Mukai, Masaki; Mizoguchi, Teruyasu

2014-10-01

289

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

290

Power Technologies Energy Data Book - Third Edition  

SciTech Connect

This report, prepared by NREL's Energy Analysis Office, 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.

2005-04-01

291

Energy, environment, and advances in power electronics  

Microsoft Academic Search

The technology of power electronics has gone through rapid technological advancement during the last four decades, and recently, its applications are fast expanding in industrial, commercial, residential, military and utility environments. In the global industrial automation, energy conservation and environmental pollution control trends of the 21st Century, the widespread impact of power electronics is inevitable. The paper begins with a

Bimal K. Bose

2000-01-01

292

Vibration manual  

NASA Technical Reports Server (NTRS)

Guidelines of the methods and applications used in vibration technology at the MSFC are presented. The purpose of the guidelines is to provide a practical tool for coordination and understanding between industry and government groups concerned with vibration of systems and equipments. Topics covered include measuring, reducing, analyzing, and methods for obtaining simulated environments and formulating vibration specifications. Methods for vibration and shock testing, theoretical aspects of data processing, vibration response analysis, and techniques of designing for vibration are also presented.

Green, C.

1971-01-01

293

Power conversion from environmentally scavenged energy sources.  

SciTech Connect

As the power requirements for modern electronics continue to decrease, many devices which were once dependent on wired power are now being implemented as portable devices operating from self-contained power sources. The most prominent source of portable power is the electrochemical battery, which converts chemical energy into electricity. However, long lasting batteries require large amounts of space for chemical storage, and inevitably require replacement when the chemical reaction no longer takes place. There are many transducers and scavenging energy sources (SES) that are able to exploit their environment to generate low levels of electrical power over a long-term time period, including photovoltaic cells, thermoelectric generators, thermionic generators, and kinetic/piezoelectric power generators. This generated power is sustainable as long as specific environmental conditions exist and also does not require the large volume of a long lifetime battery. In addition to the required voltage generation, stable power conversion requires excess energy to be efficiently stored in an ultracapacitor or similar device and monitoring control algorithms to be implemented, while computer modeling and simulation can be used to complement experimental testing. However, building an efficient and stable power source scavenged from a varying input source is challenging.

Druxman, Lee Daniel

2007-09-01

294

A variational algebraic method used to study the full vibrational spectra and dissociation energies of some specific diatomic systems  

NASA Astrophysics Data System (ADS)

The algebraic method (AM) proposed by Sun et al. is improved to be a variational AM (VAM) to offset the possible experimental errors and to adapt to the individual energy expansion nature of different molecular systems. The VAM is used to study the full vibrational spectra {E?} and the dissociation energies De of 4HeH+-X1?+, 7Li2-13?g, Na2-C1?u, NaK-71?, Cs2-B1?u and 79Br2-?1g(3P2) diatomic electronic states. The results not only precisely reproduce all known experimental vibrational energies, but also predict correct dissociation energies and all unknown high-lying levels that may not be given by the original AM or other numerical methods or experimental methods. The analyses and the skill suggested here might be useful for other numerical simulations and theoretical fittings using known data that may carry inevitable errors.

Zhang, Yi; Sun, Weiguo; Fu, Jia; Fan, Qunchao; Ma, Jie; Xiao, Liantuan; Jia, Suotang; Feng, Hao; Li, Huidong

2014-01-01

295

A variational algebraic method used to study the full vibrational spectra and dissociation energies of some specific diatomic systems.  

PubMed

The algebraic method (AM) proposed by Sun et al. is improved to be a variational AM (VAM) to offset the possible experimental errors and to adapt to the individual energy expansion nature of different molecular systems. The VAM is used to study the full vibrational spectra {E?} and the dissociation energies De of (4)HeH(+)-X(1)?(+), (7)Li2-1(3)?g,Na2-C(1)?u,NaK-7(1)?, Cs2-B(1)?u and (79)Br2-?1g((3)P2) diatomic electronic states. The results not only precisely reproduce all known experimental vibrational energies, but also predict correct dissociation energies and all unknown high-lying levels that may not be given by the original AM or other numerical methods or experimental methods. The analyses and the skill suggested here might be useful for other numerical simulations and theoretical fittings using known data that may carry inevitable errors. PMID:24013115

Zhang, Yi; Sun, Weiguo; Fu, Jia; Fan, Qunchao; Ma, Jie; Xiao, Liantuan; Jia, Suotang; Feng, Hao; Li, Huidong

2014-01-01

296

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

297

Energy conserving electrical power control circuit  

SciTech Connect

An energy conserving circuit for controlling supply of electrical power to various loads such as a street lamp or a hot water heater comprises a photoelectric device for starting a timer when a change from daylight to dark is sensed at sundown, and a load power control responsive to the timer to switch between power-off and power-on states. With a street lamp the timer and power control means are connected to switch the power control means to power-on state at the beginning of the delay period at sundown and later, well before sunrise, to switch to power-off state. In the case of a household hot water heater the switching of the power control to power-on state is delayed until the peak demand hours have ended after sundown. The photoelectric device will normally cause the power control to switch to poweroff state at sunrise. But a second timer may be added which is responsive to the photoelectric device to start a second timing period ending after normal sunrise so that switching to power-off will occur if the photoelectric device does not or cannot respond to sunrise.

Grady, J.K.

1982-12-07

298

Simulated vibrational spectra of aflatoxins and their demethylated products and the estimation of the energies of the demethylation reactions  

NASA Astrophysics Data System (ADS)

The structure of four natural mycotoxins, the aflatoxin B 1, B 2, G 1 and G 2 and their demethylated products were optimized with quantum chemical method. The energies and the thermodynamic functions of the molecules were calculated and applied to calculation of the reaction energies of the demethylations. Further results of the calculations are the vibrational force constants, the infrared spectra of the molecules and the assignments of the spectral bands.

Billes, Ferenc; Móricz, Įgnes M.; Tyihįk, Ern?; Mikosch, Hans

2006-06-01

299

Collisional relaxation of highly vibrationally excited CF2O prepared with different initial energies and distribution functions  

Microsoft Academic Search

The collisional relaxation of highly vibrationally excited CF2O* molecules prepared by infrared laser multiphoton absorption is compared with the results obtained when CF2O* is generated as a product of the reactions of CF3 and CF2Cl radicals with NO2. The three methods produce molecules with probably different energy distributions and also different average excitation energies ?E?. Thus, IR laser excitation results

G. A. Pino; C. A. Rinaldi; E. A. Coronado; J. C. Ferrero

1999-01-01

300

Collisional relaxation of highly vibrationally excited CF2O prepared with different initial energies and distribution functions  

Microsoft Academic Search

The collisional relaxation of highly vibrationally excited CF2O* molecules prepared by infrared laser multiphoton absorption is compared with the results obtained when CF2O* is generated as a product of the reactions of CF3 and CF2Cl radicals with NO2. The three methods produce molecules with probably different energy distributions and also different average excitation energies . Thus, IR laser excitation results

G. A. Pino; C. A. Rinaldi; E. A. Coronado; J. C. Ferrero

1999-01-01

301

Energy conversion improvement in ferroelectrics: application to energy harvesting and self-powered systems  

Microsoft Academic Search

The proliferation of consumer electronics, combined with the constant progress in ultra-low power devices and increasing demand in terms of autonomous sensors and sensor networks, has enabled the conception of systems powered up using ambient sources such as vibrations, hence allowing the replacement of batteries that present maintenance issues and environmental problems. However, the power output of microgenerators is still

Daniel GUYOMAR; M. Lallart

2009-01-01

302

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

303

The power of thermionic energy conversion  

NASA Astrophysics Data System (ADS)

Thermionic energy conversion to generate electric power at high operating temperatures to enable space missions requiring specific power sources to meet their power and propulsion needs is discussed. Thermionic energy conversion is one of several technologies vying to satisfy the requirements of future lunar and Martian exploration missions. The specific power for thermionic nuclear space power systems ranges from 10 W/kg at 10 kWe to about 100 W/kg at 2 MWe. Based on independent studies, it was determined that the U.S. would significantly benefit by making the thermionic reactor technology of the former Soviet Union available for future military, civil, and commercial space mission. The fiber-reinforced creep-resistant thermionic emitter electrode concept, as well as calculated lifetimes for emitter electrodes reinforced with fiber, and calculated temperature distributions near the thermionic fuel element fuel-lead region interface, are illustrated.

Ramalingam, Mysore L.; Young, Timothy J.

1993-09-01

304

Power and energy requirements for electromagnetic launchers  

NASA Astrophysics Data System (ADS)

A large data base exists covering almost all aspects of the requirements for the successful development of electromagnetic launchers. To extend the use of electromagnetic launchers to the limits of technology for such exotic applications as hypervelocity weaponry or space launch systems, it is useful to examine the energy and power requirements for such uses. One way to do this is to purposely neglect all system losses in order to determine minimum power and energy requirements. Actual power requirements will most likely be higher by at least a factor of three. Calculations are presented for minimum power requirements, launch acceleration time, projectile kinetic energy, and projectile inertial force as a function of projectile mass, projectile terminal velocity, and the length of the launch tube. Results of these calculations are presented.

Lottes, P. A.; Holtz, R. E.; Uherka, K. L.

305

Optimal Power Allocation for Renewable Energy Source  

E-print Network

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

Sinha, Abhinav

2011-01-01

306

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

307

Nuclear power: an essential energy. [Conference paper  

Microsoft Academic Search

Dr. Agnew notes that the public fails to remember that the electric utilities and equipment manufacturers did not invent nuclear energy; they only choose whether or not to use it to generate power. The effort to regain world leadership in nuclear energy will require recognizing that the rest of the world needs it too. Opposition to the use of nuclear

Agnew

1980-01-01

308

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.

309

Energy $ Savings From Power Capacitors  

E-print Network

.. ~ Reactor Size (3 kVA) Figure 7. Current limiting reactor full load annual load loss. 853 ESL-IE-82-04-153 Proceedings from the Fourth Industrial Energy Technology Conference, Houston, TX, April 4-7, 1982 100 0.2 100 0.1 10 Capacitor Installation... .. ~ Reactor Size (3 kVA) Figure 7. Current limiting reactor full load annual load loss. 853 ESL-IE-82-04-153 Proceedings from the Fourth Industrial Energy Technology Conference, Houston, TX, April 4-7, 1982 100 0.2 100 0.1 10 Capacitor Installation...

Harder, J. E.

1982-01-01

310

Energy Servers Deliver Clean, Affordable Power  

NASA Technical Reports Server (NTRS)

K.R. Sridhar developed a fuel cell device for Ames Research Center, that could use solar power to split water into oxygen for breathing and hydrogen for fuel on Mars. Sridhar saw the potential of the technology, when reversed, to create clean energy on Earth. He founded Bloom Energy, of Sunnyvale, California, to advance the technology. Today, the Bloom Energy Server is providing cost-effective, environmentally friendly energy to a host of companies such as eBay, Google, and The Coca-Cola Company. Bloom's NASA-derived Energy Servers generate energy that is about 67-percent cleaner than a typical coal-fired power plant when using fossil fuels and 100-percent cleaner with renewable fuels.

2010-01-01

311

Energy storage for a competitive power market  

SciTech Connect

This article discusses briefly the status of energy storage technologies and explores opportunities for their application in the rapidly changing US energy marketplace. Traditionally, electric utility energy storage has been used to store low-priced purchased or generated electric energy for later sale or use when energy cost would otherwise be much higher. But deregulation and restructuring in the electric industry, coupled with an expanding portfolio of storage alternatives, may lead to many new opportunities for energy storage, especially within the energy distribution infrastructure, and for maintaining or providing power quality at large customer sites. Small, modular, robust energy storage technologies could be used to solve a range of energy supply and infrastructure-related needs. This article provides quantitative evidence of utility-related storage status, benefits, and opportunities.

Schoenung, S.M. [Longitude 122 West, Inc., Menlo Park, CA (United States)] [Longitude 122 West, Inc., Menlo Park, CA (United States); Eyer, J.M.; Iannucci, J.J.; Horgan, S.A. [Distributed Utility Associates, San Ramon, CA (United States)] [Distributed Utility Associates, San Ramon, CA (United States)

1996-12-31

312

Adiabatic Jacobi corrections on the vibrational energy levels of H2+ isotopologues  

Microsoft Academic Search

The effect of an adiabatic approximation, named adiabatic Jacobi correction (AJC) and introduced in J. Chem. Phys. 126, 024102 (2007), was investigated on the complete set of vibrational levels of H2+ and its isotopologues, most importantly on the highest-lying vibrational states of HD+. In order to perform clamped nuclei calculations employing finite nuclear masses a constrained Hamiltonian has been derived

Csaba Fįbri; Gįbor Czakó; Gyula Tasi; Attila G. Csįszįr

2009-01-01

313

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

SciTech Connect

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

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

1998-08-01

314

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

NASA Astrophysics Data System (ADS)

A semi-global, permutationally invariant potential energy surface for NO3 is constructed from a subset of roughly 5000 Multi-State CASPT2 calculations (MS-CAS(17e,13o)PT2/aug-cc-pVTZ) reported by Morokuma and co-workers [H. Xiao, S. Maeda, and K. Morokuma, J. Chem. Theory Comput. 8, 2600 (2012)]. The PES, with empirical adjustments to modify the energies of two fundamentals and a hot-band transition, is used in full-dimensional vibrational self-consistent field/virtual state configuration interaction calculations using the code MULTIMODE. Vibrational energies and assignments are given for the fundamentals and low-lying combination states, including two that have been the focus of some controversy. Energies of a number of overtone and combinations are shown to be in good agreement with experiment and previous calculations using a model vibronic Hamiltonian [C. S. Simmons, T. Ichino, and J. F. Stanton, J. Phys. Chem. Lett. 3, 1946 (2012)]. Notably, the fundamental v3 is calculated to be at 1099 cm-1 in accord with the prediction from the vibronic analysis, although roughly 30 cm-1 higher. The state at 1493 cm-1 is assigned as v3 + v4, which is also in agreement with the vibronic analysis and some experiments. Vibrational energies for 15NO3 are also presented and these are also in good agreement with experiment.

Homayoon, Zahra; Bowman, Joel M.

2014-10-01

315

Energy storage options for space power  

NASA Astrophysics Data System (ADS)

Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels are assessed; the results obtained suggest that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal energy storage densities of 1500 kJ/kg to 2000 kJ/kg at temperatures to 1675 K. Innovative techniques allow these media to operate in direct contact with the heat engine working fluid. Enhancing thermal conductivity and/or modifying PCM crystallization habit provide other options. Flywheels of low-strain graphite and Kevlar fibers have achieved mechanical energy storage densities of 300 kJ/kg. With high-strain graphite fibers, storage densities appropriate to space power needs (about 500 kJ/kg) seem feasible. Coupling advanced flywheels with emerging high power density homopolar generators and compulsators could result in electric pulse-power storage modules of significantly higher energy density.

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

316

The collisional relaxation of highly vibrationally excited molecules: Glimpses of the energy transfer mechanism and distribution function  

NASA Astrophysics Data System (ADS)

The relaxation of highly vibrationally excited donor molecules, C4H4N2 and C6F6, (E vib ~ 5 eV), by collisions with a bath of CO2 is investigated using high resolution, infrared transient absorption spectroscopy. The vibrationally hot donor molecules are formed by 248 nm excimer laser pumping, followed by rapid radiationless decay to the ground electronic state. This technique yields the nascent bath quantum state distributions following a single donor/bath collision. Absolute energy transfer rates are measured along with the partitioning of energy among the bath degrees of freedom. These measurements provide insight into the nature of the intermolecular forces mediating the energy transfer and allow the construction of energy transfer distribution functions, P(E,E') for these systems. Pyrazine/CO2 collisions which result in the excitation of bath vibrational modes, including the anti- symmetric stretch (0001), the Fermi-mixed symmetric stretch/bending overtone (1000 r1 and 1000 r2) and the unmixed bending overtone (0220), are studied. The vibrational energy transfer is accompanied by very little rotational and translational excitation and displays the characteristic strong, inverse temperature dependence (probability of transfer increases with decreasing temperature) expected of energy transfer mediated by a long range attractive interaction. Collisions between highly vibrationally excited C6F6 and CO2, which result in significant excitation of the bath rotational and translational degrees of freedom, are examined. This type of energy transfer is mediated by the short range repulsive region of the C6F6/CO2 intermolecular potential. A gap law model is used to fit the weak temperature dependence of these scattering processes in an effort to quantify the energy transfer magnitudes. A prescription for mapping bath quantum state resolved energy transfer rate constants onto an energy transfer probability distribution function, P(E,E') is described in detail. Analysis of earlier experimental data allows a calculation of the high ?E=E- E' region (-7000 cm-1 < E-E'< -1500 cm-1) of P(E,E') for the pyrazine (E' = 40,640 cm-1)/CO2 and C6F6 (E' = 41,822 cm- 1)/CO2 systems. The use of Atomic Force Microscopy (AFM) in the analysis of nanoscale GaAs features fabricated by magnetron enhanced reactive-ion etching is discussed. Recent progress in the use of carbon nanotubes as force probes in AFM is also reviewed.

Michaels, Chris Arthur

317

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

E-print Network

-cost, and low-power node feasible and applicable to a wide range of applications built for WSNs. For example and locate the structural damages in such as bridges, buildings, dams, ships, aircrafts, etc. Each node of energy and solar light is not alway

Lim, Sunho

318

A millimeter-sized electret-energy-harvester with microfabricated horizontal arrays and vertical protrusions for power generation enhancement  

Microsoft Academic Search

This paper describes a millimeter-sized electret vibrational energy harvester fabricated by a MEMS-based process for power generation enhancement. To increase current generation, we developed a new “slit-and-slider” structure with horizontal arrays and vertical protrusions. This structure enables us to increase an area and to narrow a gap of energy conversion in the limited size. The structure was fabricated by gold-electroplating.

K. Ono; N. Sato; T. Shimamura; M. Ugajin; T. Sakata; S. Mutoh; Y. Sato

2011-01-01

319

Noise and vibration  

NASA Technical Reports Server (NTRS)

The characteristics of acoustic energy and protection of humans from noise during space flight are described. Vibration characteristic factors are also discussed, including the variety of vibration, systems and resonance, spacecraft operations, biodynamics, physiological and psychological effects, and subjective reactions. The criteria and limits for human exposure are cited.

Vongierke, H. E.; Nixon, C. W.; Guignard, J. C.

1975-01-01

320

A study on applications of energy storage for the wind power operation in power systems  

Microsoft Academic Search

Energy storage system (ESS) has been studied as a high-tech solution for managing power flows from wind turbine generator (WTG), and making them be competitive energy sources without putting power systems at risk. This paper illustrates possible applications of the energy storage for the wind power operating in power systems focusing on its short-duration prospective. Employing a sample power system,

Kyung Soo Kook; Keith J. McKenzie; Yilu Liu; Stan Atcitty

2006-01-01

321

Ultrafast redistribution of vibrational energy after excitation of NH stretching modes in DNA oligomers  

NASA Astrophysics Data System (ADS)

Vibrational relaxation after spectrally selective excitation within the NH stretching band of adenine-thymine base pairs in DNA oligomers was studied by subpicosecond infrared-pump/anti-Stokes Raman-probe spectroscopy. The decay of the different NH stretching vibrations populates distinct accepting modes in the NH bending range with a rise time of 0.6 ps that is close to the NH stretching decay times. The population of thymine fingerprint modes after excitation of the adenine antisymmetric NH 2 stretching mode points to an ultrafast excitation transfer to the thymine NH stretching vibration before relaxation. The nonequilibrium fingerprint populations decay on a time scale of several picoseconds.

Kozich, V.; Szyc, ?.; Nibbering, E. T. J.; Werncke, W.; Elsaesser, T.

2009-04-01

322

Local heat flux and energy loss in a 2D vibrated granular gas  

E-print Network

We performed event-driven simulations of a two-dimensional granular gas between two vibrating walls and directly measured the local heat flux and energy dissipation rate in the stationary state. Describing the local heat flux as a function of the coordinate x in the direction perpendicular to the driving walls, we use a generalization of Fourier's law, q_x(x) = kappa d_x T(x) + mu d_x rho(x), to relate the local heat flux to the local gradients of the temperature and density. This ansatz accounts for the fact that density gradients also generate heat flux, not only temperature gradients. The transport coefficients kappa and mu are assumed to be independent of x, and we check the validity of this assumption in the simulations. Both kappa and mu are determined for different system parameters, in particular, for a wide range of coefficients of restitution. We also compare our numerical results to existing hydrodynamic theories. Agreement is found for kappa for very small inelasticities only. Beyond this region, kappa and mu exhibit a striking non-monotonic behavior.

Olaf Herbst; Peter Müller; Annette Zippelius

2004-12-13

323

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

Microsoft Academic Search

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

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

2011-01-01

324

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

E-print Network

, and environmental disposal. Extreme and harsh downhole conditions necessitate that the flywheel module withstands temperatures and pressures exceeding 300 ?F and 20 kpsi, respectively, as well as violent vibrations encountered during drilling. Moreover, the flywheel...

Saeed, Ahmed

2012-07-16

325

Internal Coordinate Formulation for Vibration-Rotation Energies of Polyatomic Molecules  

PubMed

The theory of vibration-rotation interactions in polyatomic molecules using curvilinear internal coordinates for the vibrational degrees of freedom is extended to the situation where the initial molecular axis system is not the principal axis system of the equilibrium configuration. For this new situation, the transformation coefficient rhoit is derived as well as the vibrational coefficients (G-1tt')0. This new transformation may not be useful nor necessary when all of the internal motions are of small amplitude. However, in the case of vibration-rotation-internal rotation interactions, the new transformation is helpful when the internal rotor is a symmetric top and necessary when the internal rotor is an asymmetric top. Copyright 1998 Academic Press. Copyright 1998Academic Press PMID:9473436

Quade

1998-02-01

326

Effects of soft electron precipitation on the distribution of vibrational energy of N2  

NASA Technical Reports Server (NTRS)

The paper investigates the direct effect of soft electron precipitation on the nitrogen vibrational distribution and on the rate coefficient for the ion-atom interchange reaction between O(+) and N2, using a spectrum of the precipitating electrons characteristic of the dayside cusp region. Substantial increases in the nitrogen vibrational temperature and in the rate of the O(+) destruction reaction do not occur unless the flux of incident electrons is as large as 1 trillion per sq cm/sec. For such large fluxes, departures of the vibrational distribution from a Boltzmann distribution have a significant effect on the rate coefficient. Incident fluxes less than 100 billion per sq cm/sec, such as are usually observed, have little direct effect on nitrogen vibration, although the indirect effect resulting from enhanced electron temperatures might be important.

Newton, G. P.; Walker, J. C. G.; Mantas, G. P.

1977-01-01

327

Analysis of the dominant vibration frequencies of rail bridges for structure-borne noise using a power flow method  

NASA Astrophysics Data System (ADS)

The use of concrete bridges in urban rail transit systems has raised many concerns regarding low-frequency (20-200 Hz) structure-borne noise due to the vibration of bridges when subjected to moving trains. Understanding the mechanism that determines the dominant frequencies of bridge vibrations is essential for both vibration and noise reduction. This paper presents a general procedure based on the force method to obtain the power flows within a coupled vehicle-track-bridge system, the point mobility of the system and the dynamic interaction forces connecting various components. The general coupling system consists of multi-rigid-bodies for the vehicles, infinite Euler beams representing the rails, two-dimensional or three-dimensional elements of the concrete bridges, and spring-dashpot pairs to model the wheel-rail contacts, the vehicle suspensions, the rail pads and the bridge bearings. The dynamic interaction of the coupled system is solved in the frequency domain by assuming the combined wheel-rail roughness moves forward relative to the stationary vehicles. The proposed procedure is first applied to a rail on discrete supports and then to a real urban rail transit U-shaped concrete bridge. The computed results show that the wheel-rail contact forces, the power flows to the rail/bridge subsystem and the accelerations of the bridge are primarily dominated by the contents around the natural frequency of a single wheel adhered to the elastically supported rail. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same rigid body, then ?mnab(?) can be expressed as ?mnab(?)=-{(}/{Ml?}, where Ml is the mass of the lth rigid body. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same infinite rail, ?mnab(?) can be expressed as [8] ?mnab(?)=-j{((e-je)}/{4EIk}, where xm and xn are the x-coordinates of the mth and nth spring-dashpot pairs respectively; E and I denote the elastic module and the bending moment of inertia of the infinite rail; and k is the wavenumber of the unsupported infinite rail k=(EI)1/4, where mr is the mass per unit length of the rail. If the ath node of the mth spring-dashpot pair and the bth node of the nth spring-dashpot pair are connected to the same bridge component, then ?mnab(?) can be obtained by applying the mode superposition method ?mnab(?)=?i=1Nl{(?}/{lia?lib?li2-?+2j???}, where ? and ? are the damped natural frequency and damping ratio of the ith mode of the lth bridge component; ?lia and ?lib denote the generalised mode shape amplitudes of the the lth bridge component to which the ath and bth nodes of the two spring-dashpot pairs are connected; and Nl is the mode number of interest. It can be observed from Eqs. (2)-(7) that the theorem of reciprocal displacements is met as follows: ?(?)=?(?). An external point excitation can be regarded as a force produced by a spring-dashpot pair with its first node connected to the excitation point and the second node fixed to the ground. Therefore, each element in vector ?P(?) can be easily attained using the first and last terms of Eq. (3): ?mp(?)=?mp11(?)+?mp21(?), where the subscript p denotes the fictitious spring-dashpot pair used to simulate the external harmonic force. The dominant frequency of the wheel-rail contact forces and power input to the rail on elastic supports is found to be consistent with the natural frequency of the single wheel adhered to the elastically supported rail. The simple formula derived to predict this dominant frequency matches well with the numerical results. The acceleration response of the bridge is also dominated by the natural frequency of the single wheel adhered to the elastically supported rail. Although the vehicle speed has an insignificant effect on the dominant frequency of the bridge response, it does influence the magnitude of the response. The findings in this paper and the proposed method can be applied to mitigate the vibration and noise from

Li, Q.; Wu, D. J.

2013-09-01

328

High-Temperature Vibration Damper  

NASA Technical Reports Server (NTRS)

Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

Clarke, Alan; Litwin, Joel; Krauss, Harold

1987-01-01

329

Solvent-mediated vibrational energy relaxation from Vaska's complex adducts in binary solvent mixtures.  

PubMed

A vibrational pump-probe and FTIR study was performed on two different adducts of Vaska's complex in two different sets of binary solvent mixtures. The carbonyl vibrational mode in the oxygen adduct exhibits solvatochromic shifts of ~10 cm(-1) in either benzyl alcohol or chloroform relative to benzene-d6, whereas this vibration is nearly unchanged for the iodine adduct for the same three solvents. The width and center frequency of the carbonyl stretch for each adduct are compared to its vibrational lifetime in binary mixtures of benzene-d6 with either benzyl alcohol or chloroform. In neat solvents, the trends in line width, frequency, and vibrational lifetime are consistent for the two adducts, but complex relationships emerge when the trends in each property are compared as a function of mixed solvent composition. ?(CO) is more sensitive to the solvation environment around the trans ligand, whereas the line width and lifetime depend on the environment around the CO group itself. The carbonyl frequency and width vary nonlinearly across the two binary solvent series, indicating preferential solvation. In contrast, the vibrational lifetime changes linearly with solvent composition and is correlated with the mole fraction of chloroform but anticorrelated with the mole fraction of benzyl alcohol. The results are explained by differences in the densities of solvent modes that affect intermolecular relaxation of the carbonyl mode. PMID:23531048

Jones, Brynna H; Huber, Christopher J; Massari, Aaron M

2013-07-25

330

Solar power satellite life-cycle energy recovery consideration  

Microsoft Academic Search

The construction, in-orbit installation and maintenance of a solar power satellite (SPS) will demand large amounts of energy. As a minimum requirement for an energy effective power satellite it is asked that this amount of energy be recovered. The energy effectiveness in this sense resulting in a positive net energy balance is a prerequisite for cost-effective power satellite. This paper

S. Weingartner; J. Blumenberg

1994-01-01

331

Demonstration of the effect of piezoelectric polarization vector on the performance of a vibration energy harvester  

NASA Astrophysics Data System (ADS)

This manuscript is motivated by research that shows the shear, d15, mode energy harvesters offer significant improvement in power generation over the traditional normal, d31, mode based harvesters. The premise behind this study is to examine the effect of expanding the design domain of PZT based energy harvesters by considering an arbitrary poling angle. In the first part of the manuscript, we derive the equation of motions of a harvester based on Timoshenko beam theory in an unimorph configuration. The resulting equations are solved using a Rayleigh Ritz analysis. The electric displacement depends on both the normal and shear strain. Thus the proposed device operates using a combination of shear and normal modes to extract power. The extent to which each mode is used depends on the polarization orientation. We examine the effect of poling on the fundamental short and open circuit frequencies. Next, the poling angle is examined over a range to determine the effect on the power harvested at the fundamental modal frequencies of the system. The study demonstrates that an arbitrary poled piezoelectric increases the power that the harvester produces over traditionally poled devices; however, the performance is highly dependent on the geometry.

Gibert, James M.

2014-04-01

332

Hydroelectric power and America's energy future  

SciTech Connect

This article discusses the debate over the merit of hydroelectric power and the part it will play in providing energy in America in the future. The environmental impact, reliability, efficiency, and regulation of hydroelectric projects are discussed with examples and references to other publications. FERC application of existing regulations in the licensing and relicensing process is also discussed.

Boxall, J.A. Jr.

1990-02-01

333

Novel Nuclear Powered Photocatalytic Energy Conversion  

Microsoft Academic Search

The University of Massachusetts Lowell Radiation Laboratory (UMLRL) is involved in a comprehensive project to investigate a unique radiation sensing and energy conversion technology with applications for in-situ monitoring of spent nuclear fuel (SNF) during cask transport and storage. The technology makes use of the gamma photons emitted from the SNF as an inherent power source for driving a GPS-class

John R. White; Douglas Kinsmen; Thomas M. Regan; Leo M. Bobek

2005-01-01

334

Power conversion mechanisms for wave energy  

Microsoft Academic Search

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

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

2002-01-01

335

Coordinated Management: Power, Performance, Energy, and Temperature  

E-print Network

Coordinated Management: Power, Performance, Energy, and Temperature Heather Hanson Stephen W and performance. 1.1 Coordinated Management The coordinated manager's central component is a multi- criteria, and temperature. The manager will select a goal, such as "maxi- mum performance within fixed temperature

Keckler, Stephen W.

336

US Department of Energy: Concentrating Solar Power  

NSDL National Science Digital Library

This website provides an introduction to the US Department of Energy's research and developments in concentrating solar power. The site outlines the department's three main technologies and the programs goals. Links to more information about solar heating, solar lighting, and photovoltaics are also provided.

2007-09-26

337

Sound Absorption in Molecular Gas Mixtures: Master Equation for Rotational and Vibrational Excitation, Relaxation, and Energy Transfer  

NASA Astrophysics Data System (ADS)

Laboratory sound absorption measurements provide much of what we know about the vibrational kinetics of air mixtures, forming the core basis for retrieving the altitude profile of water in the mesosphere from infrared emissions between 6.3 and 6.9 ?m. Here we show that sound-absorption and laser-excitation experiments follow exactly the same kinetics, reflect the same underlying reaction rates, and can be vulnerable to similar ambiguities. This has not been obvious because the literature lacks a consistent prescription for calculating the sound absorption frequency spectrum from the reaction rate coefficients. We have developed the first general theoretical formalism for calculating the absolute magnitude of sound absorption per-unit-length, versus sound frequency, for any number of collisional excitation, relaxation, and energy transfer processes, for any mixture of atomic and molecular gases. This new formalism, and the computer code that implements it, provide the first systematic means for inferring collisional rate coefficients from sound absorption measurements in which more than one rotational or vibrational mode is active, such as N2/O2/H2O/CO2 gas mixtures in the laboratory and the atmosphere. When a sound wave travels through a gas, the alternating compression and expansion cycles heat and cool the gas. If the acoustic frequency roughly matches the rate of vibrational relaxation, then the effective vibrational temperature lags behind the translational temperature and the energy in the sound wave is attenuated. The measured frequency of maximum absorption is proportional to the vibrational relaxation rate. In the simplest laser-based experiment, we excite a single molecular level and record its exponential time decay, with the vibrational relaxation rate being proportional to the decay frequency. In both experiments we derive the relaxation rate coefficient from the linear graph versus gas pressure. The technical problem is that any mixture of molecular gases will have more than one relaxation time constant. Thus we write the chemical kinetics master equation as (1) (d/dt) Nm = ?npq [ - kmn?pq Nm Nn + kpq?mn Np Nq ] which has the well-known time-dependent solution given by (2) Nm(t) = ?n Cmn exp(-?n t) where the ?n values are the decay frequencies and the Cmn coefficients depend on how the gas was initially excited. What we have contributed is the frequency-dependent sound absorption solution to Equation (1): (3) cvint(?) = ?nk Wn / (1 + i ?/?n) where cvint(?) is the complex heat capacity (per molecule), ? is the circular sound frequency, 2?f, the ?n are the calculated decay frequencies [as in Equation (2)] and k Wn is the real effective heat capacity for decay mode n. As pointed out by Landau and Teller [Phys. Z. Sowjet. 10, 34-43 (1936)], for a simple case when the decay modes correspond to vibrational modes, Wn is the ordinary heat capacity of the vibrational mode. In the more complicated case involving one or more reversible energy-transfer steps, e.g., water and oxygen, the vibrational modes and the decay modes do not correspond to each other, and we need to use the rate coefficients in Equation (1) to calculate both ?n and Wn.

Huestis, D. L.

2008-12-01

338

Wind power: The new energy policy 1  

NASA Astrophysics Data System (ADS)

Increasing use of renewable energy sources is an important aspect of the new energy policy of the State government of Schleswig-Holstein. Technical and industrial innovation are involved. By expanding and developing these regionally available inexhaustible energy sources to generate electricity and heat, we are contributing to environmental protection and helping to reduce adverse affects on the climate. We are also taking our limited resources into account and expanding energy generation in a logical manner. Wind energy is the most attractive renewable energy source for Schleswig-Holstein because our State is well known for its strong winds and constant fresh breeze. For this reason the State government has made expansion of wind energy one of its primary areas of emphasis. The goals of our promotion measures includes ongoing technical and engineering development of wind energy facilities, increasing the level of use of the wind, and increasing the percentage of wind energy used for power generation. This brochure is intended to demonstrate the significance and possibilities of wind energy for our State, to outline the legal requirements for erecting wind energy facilities, and to explain the many promotion measures. It represents a favorable breeze for wind.

1991-10-01

339

Nuclear Power and the World's Energy Requirements  

E-print Network

The global requirements for energy are increasing rapidly as the global population increases and the under-developed nations become more advanced. The traditional fuels used in their traditional ways will become increasingly unable to meet the demand. The need for a review of the energy sources available is paramount, although the subsequent need to develop a realistic strategy to deal with all local and global energy requirements is almost as important. Here attention will be restricted to examining some of the claims and problems of using nuclear power to attempt to solve this major question.

V. Castellano; R. F. Evans; J. Dunning-Davies

2004-06-10

340

Testing Skyrme energy-density functionals with the quasiparticle random-phase approximation in low-lying vibrational states of rare-earth nuclei  

SciTech Connect

Although nuclear energy-density functionals are determined primarily by fitting to ground-state properties, they are often applied in nuclear astrophysics to excited states, usually through the quasiparticle random-phase approximation (QRPA). Here we test the Skyrme functionals SkM* and SLy4 along with the self-consistent QRPA by calculating properties of low-lying vibrational states in a large number of well-deformed even-even rare-earth nuclei. We reproduce trends in energies and transition probabilities associated with {gamma}-vibrational states, but our results are not perfect and indicate the presence of multiparticle-hole correlations that are not included in the QRPA. The Skyrme functional SkM* performs noticeably better than SLy4. In a few nuclei, changes in the treatment of the pairing energy functional have a significant effect. The QRPA is less successful with ''{beta}-vibrational'' states than with the {gamma}-vibrational states.

Terasaki, J.; Engel, J. [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599-3255 (United States)

2011-07-15

341

Elastic electron scattering and vibrational excitation of isoxazole molecules in the energy range from 2 to 20 eV  

NASA Astrophysics Data System (ADS)

Differential cross sections for elastic electron scattering and the excitation of the C-H vibrational modes of isoxazole molecules were measured in the energy range from 2 to 20 eV and over the scattering angle range from 10° to 180°. The cross sections at the scattering angles of and above 90° were accessible with the use of a magnetic angle changer. The differential cross sections were integrated to yield integral and momentum transfer cross sections. The negative ion resonances in the elastic scattering at 2.7 eV and in the vibrational excitation of isoxazole at 5.5 and 10 eV were observed. The present cross sections for elastic scattering are compared with the corresponding results in furan.

Linert, Ireneusz; Zubek, Mariusz

2012-08-01

342

Benchmark atomization energy of ethane: Importance of accurate zero-point vibrational energies and diagonal Born–Oppenheimer corrections for a ‘simple’ organic molecule  

Microsoft Academic Search

A benchmark calculation of the atomization energy of the ‘simple’ organic molecule C2H6 (ethane) has been carried out by means of W4 theory. While the molecule is straightforward in terms of one-particle and n-particle basis set convergence, its large zero-point vibrational energy (and anharmonic correction thereto) and nontrivial diagonal Born–Oppenheimer correction (DBOC) represent interesting challenges. For the W4 set of

Amir Karton; Branko Ruscic; Jan M. L. Martin

2007-01-01

343

Calculation of kinetic energy functions for the ring-twisting and ring-bending vibrations of tetralin and related molecules  

NASA Astrophysics Data System (ADS)

Vector methods have been developed for the computation of the kinetic energy (reciprocal reduced mass) expressions for the ring-twisting and ring-bending vibrations of bicyclic molecules in the tetralin family. The definitions of the bond vectors in terms of these coordinates are presented. Both one- and two-dimensional kinetic energy surfaces have been calculated for tetralin and 1,4-benzodioxan and both are significantly coordinate dependent. The results for the S0 electronic ground states and S1(?, ?*) excited states are presented.

Yang, Juan; Laane, Jaan

2006-10-01

344

Unbundling of electric power and energy services  

SciTech Connect

The world-wide movement to restructure the electric and power and energy industry is now well underway in the United States. The most recent thrust came this year, with the Federal Energy Regulatory Commission`s (FERC`s) issuance on April 24th of new regulations designed to open the interconnected transmission grid to all qualified wholesale users. Other movements have been in the many forms of earlier statutes and regulations promulgated in 1978 to make more efficient use of fuels burned; utility diversification efforts; utility creation of affiliate and subsidiary organizations and operations; introduction into the market of private non-utility power developers; utilities obtaining clearance from the Securities and Exchange Commission (SEC) to venture in international markets; massive mergers and acquisitions; bankruptcies; the entry into the market of nonutility power marketers and brokers, including entities from the gas and securities industries not previously involved in the electric power and energy industry; additional congressional consideration of outright repeal of Holding Company legislation dating back to 1935; some states entering into an era of abandoning the control past in favor of complete re-regulation of the industry on the basis of performance; the coming of Independent System Operators (ISO`s), Regional Transmission Groups (RTG`s), and the possible coming of Capacity Reservation Tariffs (CRT`s), to name a few.

Keith, D.M. [Keith and Associates, Ltd., Stilwell, KS (United States); Lewis, B.R. [UtiliCorp United Inc., Kansas City, MO (United States)

1996-12-31

345

Multifunctional power electronic converters for flexible energy management in shipboard power systems  

Microsoft Academic Search

Multifunctional power electronic converters are used in shipboard power systems for various needs including energy conversion from one form to the other, power generation, and transmission. The ability to do more functions with a single power electronic converter is desired in shipboard power systems, especially when there is an inadequate energy management resource, or unexpected demand that may appear as

Konstantin Borisov

2008-01-01

346

On the study of the vibrational energy levels of Arsine molecule  

NASA Astrophysics Data System (ADS)

We compare two formalisms applied to the vibrational modes of the molecule of AsH3 of C3 v molecular symmetry group. Indeed, the close stretching modes of this molecule may be considered as those of a three-dimensional oscillator whereas the bending modes may be considered either as a one-dimensional oscillator of symmetry A1 and a two-dimensional oscillator of symmetry E or as an approximate three-dimensional oscillator. So, we have applied the U( p + 1) formalism to the both stretching and bending modes and introduced coupling terms acting on an appropriate coupled vibrational basis through a local mode formalism. We have then compared the result of our fitting with those obtained with the coupling of a local mode formalism adapted to the stretching vibrations with a normal mode formalism for the bending ones. Finally we compare our results with other methods recently proposed in the literature.

Sanzharov, N. A.; Leroy, C.; Ulenikov, O. N.; Bekhtereva, E. S.

2008-01-01

347

Electric Power From Ambient Energy Sources  

SciTech Connect

This report summarizes research on opportunities to produce electric power from ambient sources as an alternative to using portable battery packs or hydrocarbon-fueled systems in remote areas. The work was an activity in the Advanced Concepts Project conducted by Pacific Northwest National Laboratory (PNNL) for the Office of Research and Development in the U.S. Department of Energy Office of Nonproliferation and National Security.

DeSteese, John G.; Hammerstrom, Donald J.; Schienbein, Lawrence A.

2000-10-03

348

Liquid wall inertial fusion energy power plants  

Microsoft Academic Search

Liquid walls interposed between the microexplosions and the chamber structural wall give an inertial fusion energy (IFE) power plant designer flexibility and result in profound advantages. For example, the fusion chamber walls behind the liquid can be made using existing materials (e.g. steel) and last as long as the plant itself without replacement while still meeting non-nuclear-grade construction standards and

Ralph W. Moir

1996-01-01

349

Energy predictions of turbulent boundary layer induced mid-high frequency structural vibrations  

Microsoft Academic Search

This paper addresses the study of vibrations induced by turbulent boundary layers (TBLs) flowing over plate-like structures. The aim is here to propose a predictive method in order to evaluate the vibroacoustical behaviour of a plate excited by TBL pressure fluctuations. The ultimate goal is to develop tools for predicting internal cabin noise in an aircraft during flight. Hence TBL

M. N. Ichchou; O. Bareille; Y. Jacques

2009-01-01

350

Stresa, Italy, 25-27 April 2007 STEP-UP CONVERTER FOR ELECTROMAGNETIC VIBRATIONAL ENERGY  

E-print Network

-dc conversion required to convert the low voltage AC generated by an electromagnetic vibrational generator-500 mV (peak) at 100 Hz frequency, so that step up conversion id required. Size and efficiency a voltage multiplier (VM) circuit which can step up a minimum voltage of 150 mV (peak). The operation

Boyer, Edmond

351

Simultaneous Energy Harvesting and Vibration Control of Structures with Tuned Mass Dampers  

E-print Network

Xiudong Tang and Lei Zuo* Department of Mechanical Engineering State University of New York at Stony Brook, such as Taipei 101 in Taipei, Citi Group in New York, and many others. The original TMD, which was invented loadings from the winds, earthquakes, water waves, traffics and human motions. The large vibration

Zuo, Lei

352

NIST Measurement Services: cw Laser Power and Energy  

E-print Network

NIST Measurement Services: cw Laser Power and Energy Calibrations at NIST NIST Special Publication Measurement Services: cw Laser Power and Energy Calibrations at NIST Joshua Hadler Christopher L. Cromer John

353

Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power Plants  

E-print Network

1 Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power Plants by Sarah Bashadi and Policy Program #12;2 #12;3 Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power-combustion capture retrofits are expected to a near-term option for mitigating CO2 emissions from existing coal

354

Power quality and reliability supply improvement using a power conditioning system with energy storage capability  

Microsoft Academic Search

A power conditioning system with energy storage capability is proposed as a viable solution for improving the quality and the reliability of the electric energy supply. Several tasks can be performed at the same time, such as reactive power compensation, current harmonic reduction, and smoothing of pulsating loads. Moreover, the power conditioning system can operate as an uninterruptible power supply

D. Casadei; G. Grandi; C. Rossi

2004-01-01

355

Power Conversion and Energy Storage System for a Fusion Reactor 2.Electric Power Flow in a Nuclear Fusion Power Plant  

Microsoft Academic Search

The ultimate purpose of fusion energy development is to utilize the produced fusion power mainly as electric power for ease of transmission and conversion. Irrespective of the type of fusion power plant, large circulating electric power should exist in the plant for the purpose of plasma heating, current drive, and soon. This chapter describes the typical electric power flow in

Makoto Matsukawa; Kenji Tobita; Hirotaka Chikaraishi; Akio Sagara; Takayoshi Norimatsu

2004-01-01

356

Pulse power systems using inductive energy storage  

SciTech Connect

For the last 10-15 years Efremov Institute has been involved in research and development activities in the field of pulse power inductive storages (IS). The wide range of problems associated with IS-systems (Inductor Storage System) has been investigated: storage system, magnets energy transfer network, etc. Different charging sources have been designed using synchronous generators, high-power thyristor converters, homopolar generators. Magnet systems were optimized for different requirements. As a result of these studies inductive storages up to 9 {center dot} 10{sup 8} J have been designed and constructed. Different options of energy transfer networks are investigated and realized. The wide range of single-shot and multi-shot switches (breakers and closers) with peak currents up to 300 kA and voltage up to 40 kV have been tested, some of them are working on different installations. In this paper three types of pulse power systems using IS and their main performances are given. Besides the design features of different switches are described.

Druzhinin, A.S.; Kuchinsky, V.G.; Larionov, B.A.; Roshal, A.G.; Silin, V.P.; Soikin, V.F. (D.V. Efremov Scientific Research Inst. of Electrophysical Apparatus, Leningrad (SU))

1992-01-01

357

Camargo Waste to Energy Power Plant Hamed Zamenian1  

E-print Network

Camargo Waste to Energy Power Plant Hamed Zamenian1 , Eminou Nasser 1 , Matt Ray2 , Tom Iseley3 1 and Technology, IUPUI The Camargo Waste to Energy Power plant project is being proposed to dispose of Municipal are discarded in landfills. The Camargo Waste to Energy (WTE) power station is an opportunity to continue

Zhou, Yaoqi

358

Electrical Power Production Facilities from Green Energy Sources  

Microsoft Academic Search

Green power refers to electricity supplied from more readily renewable energy sources than traditional electrical power sources. Green power products have become widespread in many electricity markets worldwide and can be derived from renewable energy sources. The environmental advantages of the production and use of green electricity by using green electricity seem to be clear. Using green energy sources like

Ayhan Demirbas

2006-01-01

359

Measuring Power and Energy of CMOS Circuits: A Comparative Analysis  

E-print Network

DD(t), it is possible to calculate the charge, energy and power consumed by an IC. The main problem lays on the properMeasuring Power and Energy of CMOS Circuits: A Comparative Analysis J. Rius, A. Peidro, S. Manich presents and compares a set of experimental results on the measurement of power and energy consumed using

Boemo, Eduardo

360

Power electronic grid-interface for renewable ocean wave energy  

Microsoft Academic Search

This paper presents information on ocean wave energy converters and power electronics grid-interface. In the introduction a basic terms and methods of ocean wave energy capture are discussed. Further several most important ocean wave energy conversion prototypes are briefly described. The generators and power electronics solutions for Power Take Off (PTO) system are presented on the example of Wave Dragon

Marian P. Kazmierkowski; Marek Jasinski

2011-01-01

361

Power and Energy Management for Server Systems Ricardo Bianchini  

E-print Network

, of servers and supporting cooling infrastructures. Research on power and energy management for servers canPower and Energy Management for Server Systems Ricardo Bianchini and Ram Rajamony Department, NJ Austin, TX ricardob@cs.rutgers.edu rajamony@us.ibm.com Abstract Power and energy consumption

Bianchini, Ricardo

362

Energy conservation in the transient response of nonlinear beam vibration problems subjected to pulse loading - A numerical approach  

NASA Technical Reports Server (NTRS)

The nonlinear vibration response of a double cantilevered beam subjected to pulse loading over a central sector is studied. The initial response is generated in detail to ascertain the energetics of the response. The total energy is used as a gauge of the stability and accuracy of the solution. It is shown that to obtain accurate and stable initial solutions an extremely high spatial and time resolution is required. This requirement was only evident through an examination of the energy of the system. It is proposed, therefore, to use the total energy of the system as a necessary stability and accuracy criterion for the nonlinear response of conservative systems. The results also demonstrate that even for moderate nonlinearities, the effects of membrane forces have a significant influence on the system. It is also shown that while the fundamental response is contained in a first mode envelope, the fluctuations caused by the higher order modes must be resolved.

Moyer, E. T., Jr.

1984-01-01

363

Vibrational energy flow through the green fluorescent protein-water interface: communication maps and thermal boundary conductance.  

PubMed

We calculate communication maps for green fluorescent protein (GFP) to elucidate energy transfer pathways between the chromophore and other parts of the protein in the ground and excited state. The approach locates energy transport channels from the chromophore to remote regions of the protein via residues and water molecules that hydrogen bond to the chromophore. We calculate the thermal boundary conductance between GFP and water over a wide range of temperature and find that the interface between the protein and the cluster of water molecules in the ?-barrel poses negligible resistance to thermal flow, consistent with facile vibrational energy transfer from the chromophore to the ?-barrel waters observed in the communication maps. PMID:24471982

Xu, Yao; Leitner, David M

2014-07-17

364

Vibration Test Demonstrated Dynamic Capability of an Operating Stirling Convertor  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center and the U.S. Department of Energy are currently developing a high-efficiency, long-life, free piston Stirling convertor for use as an advanced spacecraft power system for future NASA missions. As part of this development, a Stirling Technology Demonstrator Converter (TDC), developed by Stirling Technology Company for the Department of Energy, was vibration tested at Glenn's Structural Dynamics Laboratory in November and December 1999. This testing demonstrated that the Stirling TDC is able to withstand the harsh random vibration (20 to 2000 Hz) seen during a typical spacecraft launch and to survive with no structural damage or functional power performance degradation, thereby enabling its use in future spacecraft power systems. Glenn and Stirling personnel conducted tests on a single 55 We TDC. The purpose was to characterize the TDC's structural response to vibration and to determine if the TDC could survive the vibration criteria established by the Jet Propulsion Laboratory for launch environments. The TDC was operated at full-stroke and full power conditions during the vibration testing.

Hughes, William O.

2001-01-01

365

Good Vibrations  

NSDL National Science Digital Library

This lesson (on pages 15-24 of PDF) explores how sound is caused by vibrating objects. It explains that we hear by feeling vibrations passing through the air. Learners take part in several demonstrations, making those vibrations visible. They put a tuning fork in a shallow pan of water and use it to bounce a ping-pong ball, showing the fact that the tuning fork is vibrating when it's making a sound. There are extensions described involving comb kazoos, rubber band guitars, and putting rice or cereal on top of a drum.

Omsi

2010-01-01

366

Solar power satellite—Life-cycle energy recovery considerations  

Microsoft Academic Search

The construction, in-orbit installation and maintenance of a solar power satellite (SPS) will demand large amounts of energy. As a minimum requirement for an energy effective power satellite it is asked that this amount of energy be recovered. The energy effectiveness in this sense resulting in a positive net energy balance is a prerequisite for a cost-effective power satellite.This paper

J. Blumenberg

1995-01-01

367

77 FR 22472 - Energy Conservation Program: Energy Conservation Standards for Certain External Power Supplies...  

Federal Register 2010, 2011, 2012, 2013

...Energy Conservation Standards for Certain External Power Supplies; Correction AGENCY...energy conservation standards for certain external power supplies to re-insert a table...conservation standards for all Class A external power supplies to meet. DATES:...

2012-04-16

368

Photovoltaic power - An important new energy option  

NASA Technical Reports Server (NTRS)

A review of photovoltaic (PV) power technology is presented with an emphasis of PV as an economical and technically feasible alternative source of energy. The successful completion of the development and transfer of emerging low-cost technologies into a fully commercialized status are identified as the means to the realization of this option's full potential. The DOE National Photovoltaics Program, a significant sponsor of PV R&D, expects both flat-plate and concentrator collectors to meet established cost targets. Citing the DOE large flat-plate grid-connected system project of the Sacramento Municipal Utility District, current technology modules priced at near $5/Wp (1983 dollars) are steadily reducing costs. A recent DOE study suggests that PV-generated electricity produced at a 30-year levelized cost of 15 cents per kWh would represent a viable energy supply alternative for the nation.

Ferber, R. R.

1983-01-01

369

Electric power processing, distribution, management and energy storage  

NASA Technical Reports Server (NTRS)

Power distribution subsystems are required for three elements of the SPS program: (1) orbiting satellite, (2) ground rectenna, and (3) Electric Orbiting Transfer Vehicle (EOTV). Power distribution subsystems receive electrical power from the energy conversion subsystem and provide the power busses rotary power transfer devices, switchgear, power processing, energy storage, and power management required to deliver control, high voltage plasma interactions, electric thruster interactions, and spacecraft charging of the SPS and the EOTV are also included as part of the power distribution subsystem design.

Giudici, R. J.

1980-01-01

370

Quasi-classical trajectory study of the role of vibrational and translational energy in the Cl(2P) + NH3 reaction.  

PubMed

A detailed state-to-state dynamics study was performed to analyze the effects of vibrational excitation and translational energy on the dynamics of the Cl((2)P) + NH(3)(v) gas-phase reaction, effects which are connected to such issues as mode selectivity and Polanyi's rules. This reaction evolves along two deep wells in the entry and exit channels. At low and high collision energies quasi-classical trajectory calculations were performed on an analytical potential energy surface previously developed by our group, together with a simplified model surface in which the reactant well is removed to analyze the influence of this well. While at high energy the independent vibrational excitation of all NH(3)(v) modes increases the reactivity by a factor ?1.1-2.9 with respect to the vibrational ground-state, at low energy the opposite behaviour is found (factor ? 0.4-0.9). However, when the simplified model surface is used at low energy the independent vibrational excitation of all NH(3)(v) modes increases the reactivity, showing that the behaviour at low energies is a direct consequence of the existence of the reactant well. Moreover, we find that this reaction exhibits negligible mode selectivity, first because the independent excitation of the N-H symmetric and asymmetric stretch modes, which lie within 200 cm(-1) of each other, leads to reactions with similar reaction probabilities, and second because the vibrational excitation of the reactive N-H stretch mode is only partially retained in the products. For this "late transition-state" reaction, we also find that vibrational energy is more effective in driving the reaction than an equivalent amount of energy in translation, consistent with an extension of Polanyi's rules. Finally, we find that the non-reactive events, Cl((2)P)+NH(3)(v) ? Cl((2)P) + NH(3)(v'), lead to a great number of populated vibrational states in the NH(3)(v') product, even starting from the NH(3)(v = 0) vibrational ground state at low energies, which is unphysical in a quantum world. This result is interpreted on the basis of non-conservation of the ZPE per mode. PMID:22526719

Monge-Palacios, M; Corchado, J C; Espinosa-Garcia, J

2012-05-28

371

Wind Power Today: 2000 Wind Energy Program Highlights  

Microsoft Academic Search

Wind Power Today is an annual publication that provides an overview of the U.S. Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers

Weis-Taylor

2001-01-01

372

Wind power today: 1999 Wind Energy program highlights  

Microsoft Academic Search

Wind Power Today is an annual publication that provides an overview for the Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy for the 21st century. Content objectives

Weis-Taylor

2000-01-01

373

Geothermal Energy--Clean Power From the Earth's Heat  

E-print Network

in providing alternative sources of energy. Alternative technologies that employ the Sun's energy (solar Geothermal Energy--Clean Power From the Earth's Heat Circular 1249 U.S. Department of the Interior U.S. Geological Survey #12;Geothermal Energy--Clean Power From the Earth's Heat By Wendell A

374

Good Vibrations  

NSDL National Science Digital Library

In this activity, learners experiment with their voices and noisemakers to understand the connections between vibrations and the sounds created by those vibrations. This resource includes three quick demonstration activities that can be used independently or as a group to introduce learners to the basic elements of sound.

Omsi

2004-01-01

375

Vibrational Coupling  

SciTech Connect

By homing in on the distribution patterns of electrons around an atom, a team of scientists team with Berkeley Lab's Molecular Foundry showed how certain vibrations from benzene thiol cause electrical charge to "slosh" onto a gold surface (left), while others do not (right). The vibrations that cause this "sloshing" behavior yield a stronger SERS signal.

None

2011-01-01

376

Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices  

DOEpatents

Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

Chassin, David P. (Pasco, WA); Donnelly, Matthew K. (Kennewick, WA); Dagle, Jeffery E. (Richland, WA)

2011-12-06

377

Design considerations for energy storage power electronics interfaces for high penetration of renewable energy sources  

Microsoft Academic Search

This paper discusses design considerations of power electronics interfaces between renewable energy sources and energy storage. When renewable energy sources—including photovoltaic modules, wind generators, and fuel cells—are used to generate power, there are certain electrical properties of each source that need to be considered for the design of energy storage power electronics interface. In addition, energy storage's charging and discharging

Junseok Song; Ruichen Zhao; Alexis Kwasinski

2011-01-01

378

Measuring Vibrations With Nonvibration Sensors  

NASA Technical Reports Server (NTRS)

Information about vibrations of structure and/or of nonvibration sensor attached to structure extracted from output of sensor. Sensor operated in usual way except, output fed to power-spectral-density analyzer. Vibrational components easily distinguishable in analyzer output because they have frequencies much higher than those of more-slowly-varying temperature, pressure, or other normally desired components. Spectral-analysis technique applied successfully to high-frequency resistance changes in output of platinum-wire resistance thermometer: vibrational peaks in resistance frequency spectrum confirmed by spectrum from accelerometer. Technique also showed predicted 17-kHz vibrational resonance in strain-guage-supporting beam in pressure sensor.

Hill, Arthur J.

1988-01-01

379

Potential energy surfaces for vibrational structure calculations from a multiresolution adaptive density-guided approach: implementation and test calculations.  

PubMed

A multiresolution procedure to construct potential energy surfaces (PESs) for use in vibrational structure calculations is developed in the framework of the adaptive density-guided approach. The implementation of the method allows the construction of hybrid PESs with different mode-coupling terms calculated with a variety of combinations of electronic structure methods and basis sets. Furthermore, the procedure allows the construction of hybrid PESs that incorporate a variety of contributions and corrections to the electronic energy, such as infinite basis set extrapolation and core correlation effects. A full account of the procedure is given together with a rather large set of benchmark calculations on a set of 20 small molecules, from diatomics to tetratomics. PMID:19583195

Sparta, Manuel; Hųyvik, Ida-Marie; Toffoli, Daniele; Christiansen, Ove

2009-07-30

380

A theoretical study of the vibrational energy spectrum of the HOCl/HClO system on an accurate {ital ab initio} potential energy surface  

SciTech Connect

A new, global analytical potential energy surface is constructed for the X&hthinsp;{sup 1}A{sup {prime}} electronic ground state of HOCl that accurately includes the HClO isomer. The potential is obtained by using accurate {ital ab initio} data from a previously published surface [Skokov {ital et al.}, J. Chem. Phys. {bold 109}, 2662 (1998)], as well as a significant number of new data for the HClO region of the surface at the same multireference configuration interaction, complete basis set limit level of theory. Vibrational energy levels and intensities are computed for both HOCl and HClO up to the OH+Cl dissociation limit and above the isomerization barrier. After making only minor adjustments to the {ital ab initio} surface, the errors with respect to experiment for HOCl are generally within a few cm{sup {minus}1} for 22 vibrational levels with the largest error being 26 cm{sup {minus}1}. A total of 813 bound vibrational states are calculated for HOCl. The HClO potential well supports 57 localized states, of which only the first 3 are bound. The strongest dipole transitions for HClO were computed for the fundamentals{emdash}33, 2.9, and 25 km/mol for {nu}{sub 1}, {nu}{sub 2}, and {nu}{sub 3}, respectively. From exact J=1 ro-vibrational calculations, state dependent rotational constants have been calculated for HClO. Lastly, resonance calculations with the new potential demonstrate that the presence of the HClO minimum has a negligible effect on the resonance states of HOCl near the dissociation threshold due to the relatively high and wide isomerization barrier. {copyright} {ital 1999 American Institute of Physics.}

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

1999-10-01

381

Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints  

NASA Astrophysics Data System (ADS)

Over the past decade, a significant amount of research activity has been devoted to developing electromechanical systems that can convert ambient mechanical vibrations into usable electric power. Such systems, referred to as vibratory energy harvesters, have a number of useful of applications, ranging in scale from self-powered wireless sensors for structural health monitoring in bridges and buildings to energy harvesting from ocean waves. One of the most challenging aspects of this technology concerns the efficient extraction and transmission of power from transducer to storage. Maximizing the rate of power extraction from vibratory energy harvesters is further complicated by the stochastic nature of the disturbance. The primary purpose of this dissertation is to develop feedback control algorithms which optimize the average power generated from stochastically-excited vibratory energy harvesters. This dissertation will illustrate the performance of various controllers using two vibratory energy harvesting systems: an electromagnetic transducer embedded within a flexible structure, and a piezoelectric bimorph cantilever beam. Compared with piezoelectric systems, large-scale electromagnetic systems have received much less attention in the literature despite their ability to generate power at the watt--kilowatt scale. Motivated by this observation, the first part of this dissertation focuses on developing an experimentally validated predictive model of an actively controlled electromagnetic transducer. Following this experimental analysis, linear-quadratic-Gaussian control theory is used to compute unconstrained state feedback controllers for two ideal vibratory energy harvesting systems. This theory is then augmented to account for competing objectives, nonlinearities in the harvester dynamics, and non-quadratic transmission loss models in the electronics. In many vibratory energy harvesting applications, employing a bi-directional power electronic drive to actively control the harvester is infeasible due to the high levels of parasitic power required to operate the drive. For the case where a single-directional drive is used, a constraint on the directionality of power-flow is imposed on the system, which necessitates the use of nonlinear feedback. As such, a sub-optimal controller for power-flow-constrained vibratory energy harvesters is presented, which is analytically guaranteed to outperform the optimal static admittance controller. Finally, the last section of this dissertation explores a numerical approach to compute optimal discretized control manifolds for systems with power-flow constraints. Unlike the sub-optimal nonlinear controller, the numerical controller satisfies the necessary conditions for optimality by solving the stochastic Hamilton-Jacobi equation.

Cassidy, Ian L.

382

Lowest Energy Vibrational Modes of Nine Naphthalene Derivatives; Experiment and Theory  

NASA Astrophysics Data System (ADS)

FIR gas phase absorption spectra of nine naphthalene derivatives (azulene, quinoline, isoquinoline, biphenyl, diphenylmethane, bibenzyl, 2-, 3-, and 4-phenyltoluene) have been recorded at medium resolution (0.5 wn) using a Fourier transform Bruker IFS125 interferometer located on the AILES beamline of SOLEIL synchrotron. Assignments of these weak vibrational bands were performed using density-functional theory calculations carried out at the harmonic and anharmonic levels (B97-1/6-311G(d,p)). Molecular structure dependence of the FIR spectra is discussed based on the comparative study of several selected FIR modes.

Martin-Drumel, M. A.; Pirali, O.; Laquais, Y.; Falvo, C.; Parneix, P.; Brechignac, Ph.

2013-06-01

383

Capabilities, Design, Construction and Commissioning of New Vibration, Acoustic, and Electromagnetic Capabilities Added to the World's Largest Thermal Vacuum Chamber at NASA's Space Power Facility  

NASA Technical Reports Server (NTRS)

NASA s human space exploration plans developed under the Exploration System Architecture Studies in 2005 included a Crew Exploration Vehicle launched on an Ares I launch vehicle. The mass of the Crew Exploration Vehicle and trajectory of the Ares I coupled with the need to be able to abort across a large percentage of the trajectory generated unprecedented testing requirements. A future lunar lander added to projected test requirements. In 2006, the basic test plan for Orion was developed. It included several types of environment tests typical of spacecraft development programs. These included thermal-vacuum, electromagnetic interference, mechanical vibration, and acoustic tests. Because of the size of the vehicle and unprecedented acoustics, NASA conducted an extensive assessment of options for testing, and as result, chose to augment the Space Power Facility at NASA Plum Brook Station, of the John H. Glenn Research Center to provide the needed test capabilities. The augmentation included designing and building the World s highest mass capable vibration table, the highest power large acoustic chamber, and adaptation of the existing World s largest thermal vacuum chamber as a reverberant electromagnetic interference test chamber. These augmentations were accomplished from 2007 through early 2011. Acceptance testing began in Spring 2011 and will be completed in the Fall of 2011. This paper provides an overview of the capabilities, design, construction and acceptance of this extraordinary facility.

Motil, Susan M.; Ludwiczak, Damian R.; Carek, Gerald A.; Sorge, Richard N.; Free, James M.; Cikanek, Harry A., III

2011-01-01

384

24 DTU International Energy Report 2013 Stochastic power generation  

E-print Network

that their power output can be curtailed if necessary. Renewable energy sources such as wind, solar, wave and tidal24 DTU International Energy Report 2013 Stochastic power generation Introduction Our path towards intheformofheatandelectricity.ByJune2012,cumula- tive installed wind power capacity worldwide had reached 254

Paris-Sud XI, UniversitƩ de

385

A self-powered mechanical strain energy sensor  

Microsoft Academic Search

With the growing use of sensors in various structural and mechanical systems, the powering and communication of these sensors will become a critical factor. Wireless communication electronics are becoming ubiquitous and with the decreasing electrical power requirements for these circuits it is now feasible to generate power from the conversion of mechanical energy into electrical energy. This paper focuses on

Niell G. Elvin; Alex A. Elvin; Myron Spector

2001-01-01

386

Contribution to the Chapter on Wind Power Energy Technology  

E-print Network

Contribution to the Chapter on Wind Power Energy Technology Perspectives 2008 JĆørgen Lemming; Poul in the wind energy sector. As a result, better electrical grids suited for wind power are being developed&D areas to foster continued growth in wind power are to increase the value and reduce uncertainties

387

Renewable energy credit driven wind power growth for system reliability  

Microsoft Academic Search

Environmental concerns over electric power generation from conventional sources has led to widespread public support for renewable energy sources. Governments throughout the world have responded by providing various forms of financial incentives to promote power generation from renewable energy sources. The rapid growth of wind power since the last decade has primarily been driven by governmental subsidies. Long-term growth of

Rajesh Karki

2007-01-01

388

The impact of diffuse orbitals on low energy electron vibrational scattering from a nitrogen molecule  

NASA Astrophysics Data System (ADS)

The impacts of diffuse orbitals to the correlation/polarization potentials, and hence to the vibrational scattering cross sections, are investigated in this study. We compute the BTAD (better than adiabatic) and DSG (distributed spherical Gaussian) potentials based on the Dunning basis from cc-pVDZ to aug-cc-pV6Z, and apply them to the vibrational scattering of an e–N2 molecule. The results show that the diffuse functions are important for scattering and that the frequently used basis of size up to cc-pVTZ is not sufficient. The correlation-consistent aug-cc-pVXZ series, which include s, p, d, f, g, h, and i Gaussian orbitals, apparently affect the correlation/polarization potentials and, hence, could give the cross sections on the Hartree–Fock limit. Furthermore, in the process of reaching the Hartree–Fock limit by enlarging the basis, the differential cross sections may oscillate, which makes the Hartree–Fock limit very important in testing different theoretical models.

Fu, Jia; Zhu, Bing; Zhang, Yi; Feng, Hao; Sun, Weiguo

2014-10-01

389

Saturation wind power potential and its implications for wind energy  

E-print Network

Saturation wind power potential and its implications for wind energy Mark Z. Jacobsona,1 to determine the maximum theo- retical wind power potential on Earth, based on the concept of "saturation". The saturation wind power potential (SWPP) is the maximum wind power that can be extracted upon increasing

390

A MEMS electret generator with electrostatic levitation for vibration-driven energy-harvesting applications  

NASA Astrophysics Data System (ADS)

In this paper, we propose a passive gap-spacing control method in order to avoid stiction between top and bottom structures in in-plane sensor/actuator/generator applications. A patterned electret using a high-performance perfluoro polymer material is employed to induce a repulsive electrostatic force. An out-of-plane repulsive force is successfully demonstrated with our early prototype, in both air and liquid. By using the present electret-based levitation method to keep the air gap, a MEMS electret generator has been developed for energy-harvesting applications. A dual-phase electrode arrangement is adopted in order to reduce the horizontal electrostatic damping force. With the present prototype, about 0.5 µW is obtained for both phases of the generator, resulting in a total power output of 1.0 µW at an acceleration of 2 g with 63 Hz. With our electromechanical model of the generator, we have confirmed that the model can mimic the response of the generator prototype.

Suzuki, Yuji; Miki, Daigo; Edamoto, Masato; Honzumi, Makoto

2010-10-01

391

Progress Towards the Accurate Calculation of Anharmonic Vibrational States of Fluxional Molecules and Clusters Without a Potential Energy Surface  

NASA Astrophysics Data System (ADS)

The accurate calculation of anharmonic vibrational states of highly fluxional systems is complicated by the need to first obtain the full-dimensional potential energy surface(PES). Although commonly exploited as a way around this problem, grid-based methodologies scale exponentially with system size while reduced dimensional approaches are highly system dependent, both in terms of the details of their application and in terms of their suitability. Moreover, the achievement of converged variational calculations of highly anharmonic systems is complicated by the necessity of using a very large basis and hence the construction and diagonalization of enormous Hamiltonian matrices. We report here our recent efforts to develop an algorithm capable of accurately calculating anharmonic vibrational energies, even for very floppy systems, without first obtaining a PES and using only a handful of basis functions per degree of freedom. More specifically, the potential energy and G-matrix elements are calculated on a set of points obtained from a Monte Carlo sampling of the most important regions of configuration space, allowing for a significant reduction in the number of required sampling points. The Hamiltonian matrix is then constructed using an evolving basis which, with each iteration, captures the effect of building H from an ever-expanding basis despite the fact that the actual dimensionality of H is fixed throughout the calculation. This latter property of the algorithm also greatly reduces the size of basis needed for the calculation relative to more traditional variational approaches. The results obtained from the application of our method to several test systems, including ion water complexes, will be reported along with its observed convergence properties.

Petit, Andrew S.; McCoy, Anne B.

2011-06-01

392

Maximum wind energy extraction strategies using power electronic converters  

Microsoft Academic Search

This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine

Quincy Qing Wang

2003-01-01

393

Economic efficiency of power stations using renewable energy sources  

SciTech Connect

This article examines the viability of power stations using the renewable resources of wind energy, tidal energy, and geothermal energy. General pros and cons of renewable resources are discussed, and the socioeconomic impacts and environmental impacts of these resources are listed and compared to those of traditional thermal and hydroelectric power plants.

Voronkin, A.F.; Lisochkina, T.V.; Malinina, T.V. [and others

1995-12-01

394

How Speculation Can Save Power and Energy Matthew Frank  

E-print Network

that can reduce both power and energy consumption for bandwidth limited applications. 1 Introduction, for bandwidth constrained applications, parallelism combined with voltage scaling can reduce energy consumption-delay for reduced power and energy. First let's generalize our calculation of Ā” . Suppose that we have a correct

Frank, Matthew I.

395

Optimal Power Cost Management Using Stored Energy in Data Centers  

E-print Network

the aver- age price of 1 MW-Hour of electricity. Consequently, mini- mization of energy consumption needOptimal Power Cost Management Using Stored Energy in Data Centers Rahul Urgaonkar, Bhuvan Urgaonkar that arise by the use of uninterrupted power supply (UPS) units as energy storage devices. This rep- resents

Urgaonkar, Bhuvan

396

Hydrogen storage of energy for small power supply systems  

E-print Network

Power supply systems for cell phone base stations using hydrogen energy storage, fuel cells or hydrogen-burning generators, and a backup generator could offer an improvement over current power supply systems. Two categories ...

Monaghan, Rory F. D. (Rory Francis Desmond)

2005-01-01

397

Benchmark atomization energy of ethane : importance of accurate zero-point vibrational energies and diagonal Born-Oppenheimer corrections for a 'simple' organic molecule.  

SciTech Connect

A benchmark calculation of the atomization energy of the 'simple' organic molecule C2H6 (ethane) has been carried out by means of W4 theory. While the molecule is straightforward in terms of one-particle and n-particle basis set convergence, its large zero-point vibrational energy (and anharmonic correction thereto) and nontrivial diagonal Born-Oppenheimer correction (DBOC) represent interesting challenges. For the W4 set of molecules and C2H6, we show that DBOCs to the total atomization energy are systematically overestimated at the SCF level, and that the correlation correction converges very rapidly with the basis set. Thus, even at the CISD/cc-pVDZ level, useful correlation corrections to the DBOC are obtained. When applying such a correction, overall agreement with experiment was only marginally improved, but a more significant improvement is seen when hydrogen-containing systems are considered in isolation. We conclude that for closed-shell organic molecules, the greatest obstacles to highly accurate computational thermochemistry may not lie in the solution of the clamped-nuclei Schroedinger equation, but rather in the zero-point vibrational energy and the diagonal Born-Oppenheimer correction.

Karton, A.; Martin, J. M. L.; Ruscic, B.; Chemistry; Weizmann Institute of Science

2007-06-01

398

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO+(H2O) cluster using accurate potential energy and dipole moment surfaces  

NASA Astrophysics Data System (ADS)

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO+(H2O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO+(H2O) and NO+(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO+(H2O) and NO+(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO+(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

Homayoon, Zahra

2014-09-01

399

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO(+)(H2O) cluster using accurate potential energy and dipole moment surfaces.  

PubMed

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO(+)(H2O) cluster is reported. The PES is based on fitting of roughly 32?000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO(+)(H2O) and NO(+)(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO(+)(H2O) and NO(+)(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO(+)(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing. PMID:25273441

Homayoon, Zahra

2014-09-28

400

Analysis and modeling of a piezoelectric energy harvester for powering a wireless sensor  

NASA Astrophysics Data System (ADS)

The work presented aims at modeling, designing and implementing an energy harvesting system capable of generating electricity from environmental vibrations. Subject of the analysis is a piezoelectric bimorph; this particular transducer, composed of two layers of piezoceramic material, is clamped in a cantilever configuration and is dynamically bent due to vibrations. The resulting deformation ensures enough current to power the electronic circuit of a wireless sensor. An analytical model is adopted, that describes the dynamics of the mechanical system using an electrical duality. In particular the coupling of the variables is represented by an equivalent transformer. The obtainable voltage and power are investigated, focusing on the influence of the electric load on the performance of the conversion process. In addition, to overcome the limitations related to the analytical study, a finite element model is provided, capable of simulating the behavior of the system more accurately. Finally, both models are validated by means of experimental tests, showing the mutual influence between the mechanical and the electrical domain.

Bassetti, Marco; Braghin, Francesco; Milani, Damiano; Ripamonti, Francesco; Tomasini, Gisella

2013-04-01

401

Dynamic Power Allocation For Maximizing Throughput in Energy Harvesting  

E-print Network

1 Dynamic Power Allocation For Maximizing Throughput in Energy Harvesting Communication System general case of arbitrarily varying energy arrivals is considered, where neither the future energy arrival strategy that invests available energy uniformly over all remaining slots until the next energy arrival

Vaze, Rahul

402

Dissociative Attachment of Low-Energy Electrons to Vibrationally Excited Hydrogen Molecules  

NASA Astrophysics Data System (ADS)

Dissociative electron attachment to hot hydrogen molecules is studied in the framework of nonlocal resonance model. The method based on the use of the Bateman approximation, well known in nuclear physics, is adapted for solving the Lippmann-Schwinger integral equation of the nonlocal resonance model and applied to the calculation of cross sections of inelastic resonant electron-molecule collisions. The proposed method is compared with the Schwinger-Lanczos algorithm used extensively for the treatment of these processes. It is shown that the Bateman approximation is very useful and efficient for treating the non-separable nonlocal potentials appearing in the integral kernels of the nonlocal resonance models. The calculated cross sections for the dissociative attachment of electrons to vibrationally excited hydrogen molecules are of importance for astrophysics.

Houfek, K.; ?ķžek, M.; Horį?ek, J.

2002-01-01

403

Accurate bond dissociation energy of water determined by triple-resonance vibrational spectroscopy and ab initio calculations  

NASA Astrophysics Data System (ADS)

Triple-resonance vibrational spectroscopy is used to determine the lowest dissociation energy, D0, for the water isotopologue HD16O as 41 239.7 ± 0.2 cm-1 and to improve D0 for H216O to 41 145.92 ± 0.12 cm-1. Ab initio calculations including systematic basis set and electron correlation convergence studies, relativistic and Lamb shift effects as well as corrections beyond the Born-Oppenheimer approximation, agree with the measured values to 1 and 2 cm-1 respectively. The improved treatment of high-order correlation terms is key to this high theoretical accuracy. Predicted values for D0 for the other five major water isotopologues are expected to be correct within 1 cm-1.

Boyarkin, Oleg V.; Koshelev, Maxim A.; Aseev, Oleg; Maksyutenko, Pavel; Rizzo, Thomas R.; Zobov, Nikolay F.; Lodi, Lorenzo; Tennyson, Jonathan; Polyansky, Oleg L.

2013-05-01

404

Observation of wave turbulence in vibrating plates  

E-print Network

The nonlinear interaction of waves in a driven medium may lead to wave turbulence, a state such that energy is transferred from large to small lengthscales. Here, wave turbulence is observed in experiments on a vibrating plate. The frequency power spectra of the normal velocity of the plate may be rescaled on a single curve, with power-law behaviors that are incompatible with the weak turbulence theory of D{\\"u}ring et al. [Phys. Rev. Lett. 97, 025503 (2006)]. Alternative scenarios are suggested to account for this discrepancy -- in particular the occurrence of wave breaking at high frequencies. Finally, the statistics of velocity increments do not display an intermittent behavior.

Arezki Boudaoud; Olivier Cadot; Benoīt Odille; Cyril Touzé

2008-10-06

405

Vibration generators  

SciTech Connect

Apparatus for generating vibrations in a medium, such as the ground, comprises a first member which contacts the medium, means , preferably electromagnetic, which includes two relatively movable members for generating vibrations in the apparatus and means operatively connecting the said two members to said first member such that the relatively amplitudes of the movements of said three members can be adjusted to match the impedances of the apparatus and the medium.

Lerwill, W.E.

1980-09-16

406

Vibration sensors  

NASA Astrophysics Data System (ADS)

Today, vibration sensors with low and medium sensitivities are in great demand. Their applications include robotics, navigation, machine vibration monitoring, isolation of precision equipment & activation of safety systems e.g. airbags in automobiles. Vibration sensors have been developed at SSPL, using silicon micromachining to sense vibrations in a system in the 30 - 200 Hz frequency band. The sensing element in the silicon vibration sensor is a seismic mass suspended by thin silicon hinges mounted on a metallized glass plate forming a parallel plate capacitor. The movement of the seismic mass along the vertical axis is monitored to sense vibrations. This is obtained by measuring the change in capacitance. The movable plate of the parallel plate capacitor is formed by a block connected to a surrounding frame by four cantilever beams located on sides or corners of the seismic mass. This element is fabricated by silicon micromachining. Several sensors in the chip sizes 1.6 cm x 1.6 cm, 1 cm x 1 cm and 0.7 cm x 0.7 cm have been fabricated. Work done on these sensors, techniques used in processing and silicon to glass bonding are presented in the paper. Performance evaluation of these sensors is also discussed.

Gupta, Amita; Singh, Ranvir; Ahmad, Amir; Kumar, Mahesh

2003-10-01

407

Frequency-energy plots of steady-state solutions for forced and damped systems, and vibration isolation by nonlinear mode localization  

NASA Astrophysics Data System (ADS)

We study the structure of the periodic steady-state solutions of forced and damped strongly nonlinear coupled oscillators in the frequency-energy domain by constructing forced and damped frequency - energy plots (FEPs). Specifically, we analyze the steady periodic responses of a two degree-of-freedom system consisting of a grounded forced linear damped oscillator weakly coupled to a strongly nonlinear attachment under condition of 1:1 resonance. By performing complexification/averaging analysis we develop analytical approximations for strongly nonlinear steady-state responses. As an application, we examine vibration isolation of a harmonically forced linear oscillator by transferring and confining the steady-state vibration energy to the weakly coupled strongly nonlinear attachment, thereby drastically reducing its steady-state response. By comparing the nonlinear steady-state response of the linear oscillator to its corresponding frequency response function in the absence of a nonlinear attachment we demonstrate the efficacy of drastic vibration reduction through steady-state nonlinear targeted energy transfer. Hence, our study has practical implications for the effective passive vibration isolation of forced oscillators.

Kurt, Mehmet; Eriten, Melih; McFarland, D. Michael; Bergman, Lawrence A.; Vakakis, Alexander F.

2014-08-01

408

Spectral compressor vibration analysis techniques  

Microsoft Academic Search

Studies at GAT have verified that the spectral distribution of energy in gaseous diffusion compressor vibrations contains information pertinent to the state of the compressor's ''health.'' Based on that conclusion, vibration analysis capabilities were included in the CUP computer data acquisition system. In order for that information to be used for diagnosis of incipient failure mechanisms, however, spectral features must

1982-01-01

409

Calculation of Rotation-Vibration Energy Levels of the Water Molecule with Near-Experimental Accuracy Based on an ab Initio Potential Energy Surface  

NASA Astrophysics Data System (ADS)

A recently computed, high-accuracy ab initio Born-Oppenheimer (BO) potential energy surface (PES) for the water molecule is combined with relativistic, adiabatic, quantum electrodynamics, and, crucially, nonadiabatic corrections. Calculations of ro-vibrational levels are presented for several water isotopologues and shown to have unprecedented accuracy. A purely ab initio calculation reproduces some 200 known band origins associated with seven isotopologues of water with a standard deviation (?) of about 0.35 cm-1. Introducing three semiempirical scaling parameters, two affecting the BO PES and one controlling nonadiabatic effects, reduces ? below 0.1 cm-1. Introducing one further rotational nonadiabatic parameter gives ? better than 0.1 cm-1 for all observed ro-vibrational energy levels up to J = 25. We conjecture that the energy levels of closed-shell molecules with roughly the same number of electrons as water, such as NH3, CH4, and H3O+, could be calculated to this accuracy using an analogous procedure. This means that near-ab initio calculations are capable of predicting transition frequencies with an accuracy only about a factor of 5 worse than high resolution experiments.

Polyansky, Oleg L.; Ovsyannikov, Roman I.; Kyuberis, Aleksandra A.; Lodi, Lorenzo; Tennyson, Jonathan; Zobov, Nikolai F.

2013-10-01

410

Vibration absorbing brace for study of work-related upper extremity musculoskeletal disorders.  

PubMed

The use of hand-held power tools can result in absorption of significant vibration energy by the worker's hand and arm, and is a causal factor in the development of various muskuloskeletal disorders (MSD's) such as carpal tunnel syndrome (CTS) and hand-arm vibration syndrome (HAYS). A novel brace incorporating vibration damping materials is proposed that could reduce this energy absorption, resulting in lower incidence of vibration-related occupational MSD's. The National Occupational Research Agenda (NORA) has identified this type of injury as a priority research area. The proposed brace will have utility in the top three NORA-sponsored areas for research tools and approaches: clinical assessment of exposure to environmental vibration; practical use as improved personal protective gear; and evaluating the effects of reduced vibration exposure on MSD incidence. Clinical test results for prototype braces on human volunteers are reported: splints with piezoelectric material showed a median improvement of 12% in vibration damping as compared to otherwise identical nonpiezoelectric splints (median allowable error of +/- 1.5%). The use of these splints to further study how the hand-arm system absorbs vibration energy is also discussed. PMID:17270772

Pottenger, M D; Benhaim, P

2004-01-01

411

Externally tuned vibration absorber  

DOEpatents

A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

Vincent, Ronald J. (Latham, NY)

1987-09-22

412

12 IEEE power & energy magazine september/october 2009 guesteditorial  

E-print Network

consumer of energy. Power is more institutionalized and easier to control than millions of citizens using this in a sustainable balance with the environment. Today, energy policy, particularly in the developed world

Catholic University of Chile (Universidad CatĆ³lica de Chile)

413

Rate coefficients at 300 K for the vibrational energy transfer reactions from N2(v=1) to O + 2(v=0) and NO + (v=0)  

NASA Astrophysics Data System (ADS)

Rate coefficients for the reactions N2(v=1)+O+2 (v=0)?N2(v=0)+O+2 (v=1) and N2(v=1)+NO+(v=0)?N2(v=0)+NO+(v=1) have been measured in a SIFT/flowing afterglow system at 300 K, the first measurements of thermal energy vibrational transfer from neutrals to ions. The values are k=1×10-12 and <10-13 cm3 s-1, respectively. These values are consistent with an intermediate complex vibrational predissociation model which has been successful in rationalizing earlier ion vibrational relaxations by neutral collisions. The NO+ result establishes that the efficient quenching of NO+(v=1) by N2 is not a resonant V?V process as was previously assumed.

Ferguson, E. E.; Adams, N. G.; Smith, D.; Alge, E.

1984-06-01

414

Energy-Saving RAM-Power Tap  

NASA Technical Reports Server (NTRS)

Reverse-flow HEXFET(R) minimizes voltage drop and power dissipation. HEXFET(R) scheme reduces voltage drop by approximately 80 percent. Design for power tap for random-access memory (RAM) has potential application in digital systems.

Bruner, Alan Roy

1987-01-01

415

NEW POWER SOURCES AND ENERGY CONVERTERS  

Microsoft Academic Search

Progress in the development of portable electrical power sources is ; reported. A comparison of the power output of the different power systems as a ; function of service time (projected to the 1965-70 period when the newer systems ; should be available) is given. The curves show typical performance, but a wide ; variation in performance is to be

1962-01-01

416

Consideration of Thermoelectric Power Generation by Using Hot Spring Thermal Energy or Industrial Waste Heat  

NASA Astrophysics Data System (ADS)

Today, we face some significant environmental and energy problems such as global warming, urban heat island, and the precarious balance of world oil supply and demand. However, we have not yet found a satisfactory solution to these problems. Waste heat recovery is considered to be one of the best solutions because it can improve energy efficiency by converting heat exhausted from plants and machinery to electric power. This technology would also prevent atmospheric temperature increases caused by waste heat, and decrease fossil fuel consumption by recovering heat energy, thus also reducing CO2 emissions. The system proposed in this research generates electric power by providing waste heat or unharnessed thermal energy to built-in thermoelectric modules that can convert heat into electric power. Waste heat can be recovered from many places, including machinery in industrial plants, piping in electric power plants, waste incineration plants, and so on. Some natural heat sources such as hot springs and solar heat can also be used for this thermoelectric generation system. The generated power is expected to be supplied to auxiliary machinery around the heat source, stored as an emergency power supply, and so on. The attributes of this system are (1) direct power generation using hot springs or waste heat; (2) 24-h stable power generation; (3) stand-alone power system with no noise and no vibration; and (4) easy maintenance attributed to its simple structure with no moving parts. In order to maximize energy use efficiency, the temperature difference between both sides of the thermoelectric (TE) modules built into the system need to be kept as large as possible. This means it is important to reduce thermal resistance between TE modules and heat source. Moreover, the system's efficiency greatly depends on the base temperature of the heat sources and the material of the system's TE modules. Therefore, in order to make this system practical and efficient, it is necessary to choose the heat source first and then design the most appropriate structure for the source by applying analytical methods. This report describes how to design a prototype of a thermoelectric power generator using the analytical approach and the results of performance evaluation tests carried out in the field.

Sasaki, Keiichi; Horikawa, Daisuke; Goto, Koichi

2014-05-01

417

Identifying Energy Waste through Dense Power Sensing and Utilization Monitoring  

E-print Network

Identifying Energy Waste through Dense Power Sensing and Utilization Monitoring Maria Kazandjieva the efficiency of such a computing system requires detailed data of both en- ergy consumption and energy waste to differentiate energy used well from energy waste. This is an important difference from pre- vious work [8, 14

Stanford University

418

Renewable Energy Scheduling for Fading Channels with Maximum Power Constraint  

E-print Network

Renewable Energy Scheduling for Fading Channels with Maximum Power Constraint Zhe Wang Electrical--In this paper, we develop efficient algorithm to obtain the optimal energy schedule for fading channel with energy harvesting. We assume that the side information of both the channel states and energy harvesting

Greenberg, Albert

419

Maximum Power Point Tracking for Ocean Wave Energy Conversion  

Microsoft Academic Search

Many forms of renewable energy exist in the world's oceans, with ocean wave energy showing great potential. However, the ocean environment presents many challenges for cost-effective renewable energy conversion, including optimal control of a wave energy converter (WEC). This paper presents a maximum power point tracking (MPPT) algorithm for control of a point absorber WEC. The algorithm and testing hardware

Ean A. Amon; Ted K. A. Brekken; Alphonse A. Schacher

2012-01-01

420

Towards and embeddable structural health monitoring sensor : design and optimization of MEMS piezoelectric vibration energy harvesters  

E-print Network

Wireless structural health monitoring (SHM) has gained considerable interest as a potential method of reducing aircraft maintenance costs while increasing safety. Distributed power supplies for the sensing nodes are needed ...

Mracek, Anna Marie

2006-01-01

421

Single stage AC-DC converter for Galfenol-based micro-power energy harvesters  

NASA Astrophysics Data System (ADS)

Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.

Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

2014-06-01

422

Waste to Energy Power Production at DOE and DOD Sites  

E-print Network

Waste to Energy Power Production at DOE and DOD Sites January 13, 2011 #12;Overview Ā­ Federal Agency Innovations DOE: Savannah River Site Ā· BiomassHeat and Power USAF: Hill Air Force Base Ā· Landfill Challengesfaced by DOE-SR Ā· AgingInfrastructure Ameresco independent Ā· Coal and fuel oil power plants Ā· Increased

423

Localized and delocalized vibrations on TiO2(110) studied by high-resolution electron-energy-loss spectroscopy  

Microsoft Academic Search

Electronic as well as localized and delocalized vibrational losses were studied on TiO2(110) by electron-energy-loss spectroscopy. Electronic loss features at defect surfaces around 0.8 eV indicate band-gap defect states. In the higher loss-energy range above 3 eV well-known interband transitions were detected, which were found to be sensitive to ion bombardment, but not to the formation of point defects produced

G. Rocker; J. A. Schaefer; W. Göpel

1984-01-01

424

Nuclear Power and Sustainable Energy Policy: Promises and Perils  

Microsoft Academic Search

The author examines the challenges and opportunities of nuclear power in meeting the projected large absolute increase in energy demand, especially electricity, throughout the industrialized and developing world, while helping to mitigate the threat of climate change. A significant global nuclear power deployment would engender serious risks related to proliferation, safety, and waste disposal. Unlike renewable sources of energy, nuclear

Ioannis N. Kessides

2010-01-01

425

Optimal Power Cost Management Using Stored Energy in Data Centers  

E-print Network

Optimal Power Cost Management Using Stored Energy in Data Centers Rahul Urgaonkar, Bhuvan Urgaonkar of uninterrupted power supply (UPS) units as energy storage devices. This rep- resents a deviation from the usual, making it attractive in the presence of workload and pricing uncertainties. An inter- esting feature

Giles, C. Lee

426

Nonlinear vibrational microscopy  

DOEpatents

The present invention is a method and apparatus for microscopic vibrational imaging using coherent Anti-Stokes Raman Scattering or Sum Frequency Generation. Microscopic imaging with a vibrational spectroscopic contrast is achieved by generating signals in a nonlinear optical process and spatially resolved detection of the signals. The spatial resolution is attained by minimizing the spot size of the optical interrogation beams on the sample. Minimizing the spot size relies upon a. directing at least two substantially co-axial laser beams (interrogation beams) through a microscope objective providing a focal spot on the sample; b. collecting a signal beam together with a residual beam from the at least two co-axial laser beams after passing through the sample; c. removing the residual beam; and d. detecting the signal beam thereby creating said pixel. The method has significantly higher spatial resolution then IR microscopy and higher sensitivity than spontaneous Raman microscopy with much lower average excitation powers. CARS and SFG microscopy does not rely on the presence of fluorophores, but retains the resolution and three-dimensional sectioning capability of confocal and two-photon fluorescence microscopy. Complementary to these techniques, CARS and SFG microscopy provides a contrast mechanism based on vibrational spectroscopy. This vibrational contrast mechanism, combined with an unprecedented high sensitivity at a tolerable laser power level, provides a new approach for microscopic investigations of chemical and biological samples.

Holtom, Gary R. (Richland, WA); Xie, Xiaoliang Sunney (Richland, WA); Zumbusch, Andreas (Munchen, DE)

2000-01-01

427

Analysis of vibration and pressure pulsation in positive displacement drilling motors  

SciTech Connect

Three, Moineau principle, positive displacement (drilling) motors were tested on a dynamometer using water, air/mist, and foam. In conjunction with a traditional motor performance test, data were collected at 5000 samples per second using an adapted seismic data acquisition system. Shaft speed, torque, pressure, and three-axis vibration data were processed using Seismic Analysis Code (SAC) to obtain energy density spectrums (EDSs). Cascade plots were generated by plotting the EDSs against shaft speed. The cascade plots revealed that pressure pulses and motor vibrations are closely related to the eccentric rotation of the rotor in the power section. Excessive no-load vibrations were not observed in the small motors and test apparatus used; increasing torque usually decreases the amplitude of vibrations observed. Motor vibration amplitudes were as a rule not increased when compressible fluids were substituted for water.

Hamlin, D.B.; Dreesen, D.S.

1998-12-31

428

Vibrational analysis of HOCl up to 98{percent} of the dissociation energy with a Fermi resonance Hamiltonian  

SciTech Connect

We have analyzed the vibrational energies and wave functions of HOCl obtained from previous {ital ab initio} calculations [J. Chem. Phys. {bold 109}, 2662 (1998); {bold 109}, 10273 (1998)]. Up to approximately 13&hthinsp;000 cm{sup {minus}1}, the normal modes are nearly decoupled, so that the analysis is straightforward with a Dunham model. In contrast, above 13&hthinsp;000 cm{sup {minus}1} the Dunham model is no longer valid for the levels with no quanta in the OH stretch (v{sub 1}=0). In addition to v{sub 1}, these levels can only be assigned a so-called polyad quantum number P=2v{sub 2}+v{sub 3}, where 2 and 3 denote, respectively, the bending and OCl stretching normal modes. In contrast, the levels with v{sub 1}{ge}2 remain assignable with three v{sub i} quantum numbers up to the dissociation (D{sub 0}=19&hthinsp;290&hthinsp;cm{sup {minus}1}). The interaction between the bending and the OCl stretch ({omega}{sub 2}{congruent}2{omega}{sub 3}) is well described with a simple, fitted Fermi resonance Hamiltonian. The energies and wave functions of this model Hamiltonian are compared with those obtained from {ital ab initio} calculations, which in turn enables the assignment of many additional {ital ab initio} vibrational levels. Globally, among the 809 bound levels calculated below dissociation, 790 have been assigned, the lowest unassigned level, No. 736, being located at 18&hthinsp;885 cm{sup {minus}1} above the (0,0,0) ground level, that is, at about 98{percent} of D{sub 0}. In addition, 84 {open_quotes}resonances{close_quotes} located above D{sub 0} have also been assigned. Our best Fermi resonance Hamiltonian has 29 parameters fitted with 725 {ital ab initio} levels, the rms deviation being of 5.3 cm{sup {minus}1}. This set of 725 fitted levels includes the full set of levels up to No. 702 at 18&hthinsp;650 cm{sup {minus}1}. The {ital ab initio} levels, which are assigned but not included in the fit, are reasonably predicted by the model Hamiltonian, but with a typical error of the order of 20 cm{sup {minus}1}. The classical analysis of the periodic orbits of this Hamiltonian shows that two bifurcations occur at 13&hthinsp;135 and 14&hthinsp;059 cm{sup {minus}1} for levels with v{sub 1}=0. Above each of these bifurcations two new families of periodic orbits are created. The quantum counterpart of periodic orbits are wave functions with {open_quotes}pearls{close_quotes} aligned along the classical periodic orbits. The complicated sequence of {ital ab initio} wave functions observed within each polyad is nicely reproduced by the wave functions of the Fermi resonance Hamiltonian and by the corresponding shapes of periodic orbits. We also present a comparison between calculated and measured energies and rotational constants for 25 levels, leading to a secure vibrational assignment for these levels. The largest difference between experimental and calculated energies reaches 22 cm{sup {minus}1} close to D{sub 0}. {copyright} {ital 1999 American Institute of Physics.}

Jost, R. [Grenoble High Magnetic Field Laboratory, MPI-FKF and CNRS, BP 166, F-38042 Grenoble Cedex 09 (France)] [Grenoble High Magnetic Field Laboratory, MPI-FKF and CNRS, BP 166, F-38042 Grenoble Cedex 09 (France); Joyeux, M. [Laboratoire de Spectrometrie Physique, CNRS UMR 5588, Universite Joseph Fourier-Grenoble I, BP 87, F-38402 St Martin dHeres Cedex (France)] [Laboratoire de Spectrometrie Physique, CNRS UMR 5588, Universite Joseph Fourier-Grenoble I, BP 87, F-38402 St Martin dHeres Cedex (France); Skokov, S.; Bowman, J. [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)] [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)

1999-10-01

429

Relativistic correction to the potential energy surface and vibration-rotation levels of water  

Microsoft Academic Search

The relativistic correction to the electronic energy of the water molecule is calculated as a function of geometry using CCSD(T) wavefunctions and first-order perturbation theory applied to the one-electron mass-velocity and Darwin terms. Based on the calculated 324 energy points, a fitted relativistic correction surface is constructed. This surface is used with a high-accuracy ab initio non-relativistic Born–Oppenheimer potential energy

Attila G. Csįszįr; J. Sophie Kain; Oleg L. Polyansky; Nikolai F. Zobov; Jonathan Tennyson

1998-01-01

430

1 Energy Markets and Policy Group Energy Analysis Department The Impact of Wind Power Projects  

E-print Network

1 Energy Markets and Policy Group Ā· Energy Analysis Department The Impact of Wind Power Projects) This analysis was funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy Ā· Conclusions and Further Research #12;3 Energy Markets and Policy Group Ā· Energy Analysis Department Proximity

Firestone, Jeremy

431

Relationship Among Efficiency and Output Power of Heat Energy Converters  

E-print Network

Relationship among efficiency and output power of heat-electric energy converters as well as of any converters for transforming of heat energy into any other kind of energy is considered. It is shown, that the parameter efficiency does not determine univocally the output power of a converter. It is proposed to use another parameter for determination of working ability of heat energy converters. It is shown, that high output power can not be achieved by any kind of Stirling-type converters in spite of their high efficiency.

Alexander Luchinskiy

2004-09-02

432

Quantum chemical vibrational study, molecular property, FTIR, FT-Raman spectra, NBO, HOMO-LUMO energies and thermodynamic properties of 1-methyl-2-phenyl benzimidazole.  

PubMed

The solid phase FT-IR and FT-Raman spectra of 1-methyl-2-phenyl benzimidazole (MPBZ) have been recorded in the condensed state. In this work, experimental and theoretical study on the molecular structure, quantum chemical calculations of energies and vibrational wavenumbers of MPBZ is presented. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311+G(d,p) and 6-311++G(d,p) basis set for optimized geometry and were compared with Fourier transform infrared spectrum (FTIR) in the region of 4000-400 cm(-1) and with Fourier transform Raman spectrum in the region of 4000-100 cm(-1). Complete vibrational assignments, analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values. The study is extended to calculate the HOMO-LUMO energy gap, NBO, mapped molecular electrostatic potential (MEP) surfaces, polarizability, Mulliken charges and thermodynamic properties of the title compound. PMID:24785089

Karnan, M; Balachandran, V; Murugan, M; Murali, M K

2014-09-15

433

Polar lunar power ring: Propulsion energy resource  

NASA Technical Reports Server (NTRS)

A ring shaped grid of photovoltaic solar collectors encircling a lunar pole at 80 to 85 degrees latitude is proposed as the primary research, development, and construction goal for an initial lunar base. The polar Lunar Power Ring (LPR) is designed to provide continuous electrical power in ever increasing amounts as collectors are added to the ring grid. The LPR can provide electricity for any purpose indefinitely, barring a meteor strike. The associated rail infrastructure and inherently expandable power levels place the LPR as an ideal tool to power an innovative propulsion research facility or a trans-Jovian fleet. The proposed initial output range is 90 Mw to 90 Gw.

Galloway, Graham Scott

1990-01-01