2,923 research outputs found
THE INFLUENCE OF VIBRATION-ROTATION INTERACTION ON LINE INTENSITIES IN THE PERPENDICULAR AND PARALLEL INFRARED BANDS OF THE LINEAR SYMMETRIC X-Y-X MOLECULE
No full text1Hanson, H., Nielsen, H. H., Shaffer, W. H., and Waggoner, J. H., Jr., J. Chem. Phys. 27, 40 (1957). Herman, R. C., and Wallis, R. F., J. Chem. Phys. 23, 637 (1955).Author Institution: Department of Physics and Astronomy, The Ohio State University“Vibration-rotation interaction manifests itself in the Hamiltonian of the linear symmetric X-Y-X molecule through the terms ) and () where is the normal coordinate for the breathing mode, P is the total angular momentum operator, is the internal vibrational angular momentum operator, and the z coordinate axis lies along the equilibrium internuclear axis. Corrections to the dipole moment matrix elements due to these terms are obtained; the contact transformation method of Hanson, Nielson, Shaffer, and is used to simplify the calculations. The resulting intensity expressions indicate, just as the results of Herman and for the diatomic molecule, that vibration-rotation interaction gives rise to band asymmetry.
RADIAL MATRIX ELEMENTS OF FOR TWOFOLD AND THREEFOLD OSCILLATORS
No full text W H. Shaffer, Rev. Mod. Phys. 16, 245-259 (1944). Present address of Burton J. Krohn: Los Alamos Scientific Laboratory, Theoretical Division, University of California, Los Alamos, New Mexico, 87544.""Author Institution: Department of Physics, The Florida State University; Department of Physics, The Ohio State UniversityThe spectroscopically relevant nonvanishing RME^{\prime} of for two-fold and threefold isotropic harmonic oscillators, for 0 n 7, and the diagonal element of , have been formulated using the generating function for associated Laguerre An improved system of notation reveals symmetries and patterns which emerge as n increases, and streamlines computer programming of the RME^{\prime} s in molecular vibration problems
Wave energy in the Netherlands: Past, present and future perspectives
No full textWith the renewable targets of 2020 reaching ever closer, Europe is continuing its ambitious plans for 2030 of developing innovative projects that assist tackling climate change and increase renewable energy integration. The Netherlands are trying to develop their renewable energy portfolio, to create a viable long-term decarbonized sustainable society. So far majority of development has been focused on wind and solar, with offshore wind gaining significant traction over the past years. However, for the renewable energy transition to be fully realised, all indigenous resources must be evaluated and utilized. The Netherlands have a long history of dealing with water, and have an extensive industrial base in ocean engineering and water infrastructure. However, when it comes to the development of wave energy the sector is lacking significantly compared to other offshore renewables. This study discusses the past, present and future status of wave energy in the Netherlands. We discuss the various schemes and propose a hybrid support scheme for the development of wave energy. Furthermore, we also consider the unique spatial characteristics of the coastlines and suggest a multizonal scheme, that can act beneficially and support development of different wave converter concepts.Finally, based on the spatial and a techno-economic, we propose that by 2030 the policy focus should be to install up to 24 MW and by 2040 to 44 MW, with initial estimations on reductions per Unit Cost also discussed. With wave technologies in early stages of development in terms of technology and regional applications, there are numerous opportunities that can assist in “unlocking” thewave energy industry in the Netherlands.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
NEW TERMS IN THE POTENTIAL FUNCTION OF THE
No full text This paper constitutes a portion of a PH. D. thesis submitted to the Graduate Council of The University of Tennessee. The work was supported by the Office of Ordnance Research, U. S. Army. W. H. Shaffer and A. H. Nielsen, J. Chem. Phys. 9, 847 (1941).""Author Institution: Department of Physics, The University of Tennessee; Department of Physics and Astronomy, Ohio State UniversityA reexamination of the infrared spectrum of acetylene at high dispersion, recently concluded, disclosed some serious difficulties with regard to band assignments and consistency among the vibrational constants. These difficulties led to a reexamination of the paper on the theory of the linear molecule by Shaffer and From this study it became apparent that several permitted terms had been omitted from the cubic and quartic portions of their expression for the potential energy, namely: {hc}\beta_{345}{q}_{3}({r}_{4}{s}_{5}-{r}_{5}{s}_{4}), \quad {hc}\Sigma^{2}_{{i}=1}\gamma_{i 354}{q}_{1}{q}_{3}({r}_{4}{s}_{5}-{r}_{5}{s}_{4}), \quad {hc}\gamma^{\prime}_{4455^{({r}_{4}{s}_{5}-{r}_{5}{s}_{4})^{2}}} and , where the notation is the same as in the original paper. With polar coordinate substitutions the above terms may all be seen to depend upon the phase angle between the degenerate vibrations and . As they have symmetry it seems reasonable to include them in the potential energy expression. The new terms affect the energy of the molecule by contributing to , , and , and by introducing an entirely new constant which is the coefficient of . While the contributions to , and do not affect the interpretation of the spectrum or the experimental values previously obtained for them, the new constant does affect the agreement between theory and experiment; the interpretation and assignment of the bands; and the values obtained for several of the other constants. The experimental value of was found to be . The new terms become important in the accidental degeneracy involving and , which are separated by only . A resonance between these levels is postulated in order to make their observed positions consistent with data from other observed bands. The term has non-zero, off-diagonal matrix elements, connecting the upper levels of these bands, which remove the difficulty about their position, while the Shaffer-Nielsen potential function contains no such terms
Interaction of ocean wave energy converters
No full textIt is expected that several identical Point Absorber Wave Energy Converters (PAWECs) will be arranged in arrays to form a Wave Energy Farm. One of the key challenges in designing such a WEC array is their spatial configuration, as the WECs in the farm interact hydrodynamically with each other. This study focuses on different potential PAWEC deployments to identify the best relative position in order to maximise energy output. This is done by resolving the hydrodynamic interactions between a modelled WEC point absorber, with use of open-source Boundary Element Methods (BEM) and time domain WEC simulator. The results from the numerical model are also compared with wave tank testing, to verifythe accuracy of the analysis. The simulations show that the relative position can significantly increase a WEC’s individual power output. A spatial pattern of relative positions that result in higher potential power extraction was shown, with increases up to 20% compared to a single WEC on its own. However, the computational results showed realistic results for only a select number of configurations. As for the experiment, unexpected variations in test conditions occurred, inhibiting the possibility to isolate certain events. Therefore, when cross checking results from both simulations and experiments, the identified simulated trends only partially showed adherence with the experimental data. Henceforth, the knowledge gathered from the simulations can’t conclusively be validated by the experiments conducted in this study. This study shows that the spatial configuration of two WECs influences their individual power outputs.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
Wind effects in the parametrisation of physical characteristics for a nearshore wave model
No full textTo properly assess the energy and waves at a region, it is vital to obtain suitable long term metocean conditions. Although, wave buoys are a significant source of information they are not able to provide a detailed and complete resource assessment, as they have inherent spatiotemporal and recording limitations. Therefore, numerical wave models are often used to estimate wave power and metocean conditions. A wave model can provide realistic representation of physical processes, but it should entail careful tuning of parameters, which are often based on empirical and semi-empirical configurations. The study presents calibration of a wave numerical model and examines its performance, for nearshore wave assessments. Parametrisations of wind growth and whitecappingcoefficients have direct effects on evolution of locally generated waves, swells, and can reduce uncertainty in the results of a hindcast. The results are used to explain the physical meaning of differences, and provide a detail comparison of metocean parameters with nearshore and shallow water buoys as in-situ benchmarkers. Inter-model comparisons also indicate differences in spatial wave generation and propagation, as affected by wind growth and dissipation rates. The “optimal” solution will result in a model that will be used to provide a long-term high resolution metocean and wave power assessment for the Netherlands, that so far has been lacking in wave energy resource characterisation.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
Wave excitations in adjacent vortex filaments
No full textThe interactions of the nearest neighbour vortices are argued to play a significant role in the crossover range of scales that lies between the Kolmogorov-Richardson cascade and the Kelvin wave driven cascade in superfluid turbulence. In this work, we study how a wave excitation (a Kelvin wave or a soliton) on a vortex affects a nearby straight vortex. Our numerical simulations reveal that coherent excitations can hop from one vortex filament to another whilst retaining their coherent properties
REMARKS CONCERNING THE TWO-STEP PROCEDURE IN COMMON USE FOR CALCULATION OF MOLECULAR VIBRATIONROTATION ENERGIES
No full textAuthor Institution: Department of Physics, The Ohio State UniversityMathematical complexities preclude attempts to solve the Schr\”{u}dinger equation H = E for molecular vibration-rotation energies or wave functions in a single perturbation procedure. It is the purpose of this paper to justify the following two-step procedure, which is in common use: (i) One solves the Schr\”{u}dinger equation, assuming the rotational state to be fixed. Perturbation theory, with or without the contact trasformation, yields energies in terms of vibrational quantum numbers and angular momenta , and provided that the order of these factors in each additive term is preserved throughout the calculation. (ii) One uses the results of (i) to formulate the hamiltonian for a non-rigid rotator in a fixed state of vibration. Matrix algebra or perturbation theory is commonly employed to determine rotational energies. The justification is based upon the complete separation of the vibrational and rotational parts of the zero order hamiltonian and the fact that one knowns the commutation relations among the angular momentum operators
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Wave Modeling Results: Baseline Observations and Modeling for the Reedsport Wave Energy Site
No full textOffshore wave conditions along the Oregon coastline are measured at a handful of buoy locations where directional wave information is available. Most of these buoys are located in deep waters and incoming waves undergo changes as they travel from deep water onto the shelf where wave energy conversion arrays are likely to be deployed. These changes can be in the form of wave focusing or defocusing due to the presence of underwater banks, shoals, or canyons. Also, wave dissipation mechanisms such as bottom friction or wave breaking can be at play. Wave models can take into account such processes and produce predictions of the local conditions at the site of a wave energy conversion (WEC) array. Knowledge of local conditions can aid in the design of the devices for the specific local conditions to which they will be subjected and can also provide advance knowledge of wave conditions to power companies once a WEC array is in place. The work performed herein was geared towards two goals. First, transformation of the wave field from deep water to the site of the buoy deployment was assessed. Second, preliminary predictions about the potential impact of the buoys on the wave field are made. The results are discussed separately below. Note that model code used herein is freely available soft ware and can be obtained through http://www.wldelft.nl/soft/swan/. Input files specific to this work can be obtained through the author
Calculation of the Normal Modes of a Relatively Large Symmetrical Molecule Cyclopentane as an Example
No full textAuthor Institution: Dept. of Chemistry, The Ohio State University; Department of Physics, The Ohio State UniversityPresentations without an abstract printed in the proceedings do not have an abstract (image or text) in the Knowledge Bank record
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