Monothiodibenzoylmethane: Structural and vibrational assignments
Hansen, Bjarke Knud Vilster; Gorski, Alexander; Posokhov, Yevgen
2007-01-01
The vibrational structure of the title compound (1,3-diphenyl-3-thioxopropane-1-one, TDBM) was studied by a variety of experimental and theoretical methods. The stable ground state configuration of TDBM was investigated by IR absorption measurements in different media, by LD polarization spectros......The vibrational structure of the title compound (1,3-diphenyl-3-thioxopropane-1-one, TDBM) was studied by a variety of experimental and theoretical methods. The stable ground state configuration of TDBM was investigated by IR absorption measurements in different media, by LD polarization...... spectroscopy of samples partially aligned in a stretched polymer matrix, and by Raman spectroscopy. The investigation of the metastable photoproduct of TDBM was based on the previously published spectrum of the product trapped in argon matrix (Posokhov et al., Chem. Phys. Lett. 350 (2001) 502). The observed...
Monothiodibenzoylmethane: Structural and vibrational assignments
Hansen, Bjarke Knud Vilster; Gorski, Alexander; Posokhov, Yevgen
2007-01-01
The vibrational structure of the title compound (1,3-diphenyl-3-thioxopropane-1-one, TDBM) was studied by a variety of experimental and theoretical methods. The stable ground state configuration of TDBM was investigated by IR absorption measurements in different media, by LD polarization spectros...... to an “open”, non-chelated enethiol form (t-TCC), thereby supporting the previous conclusions by Posokhov et al. No obvious indications of the contribution of other forms to the observed spectra could be found....
Bağlayan, Özge; Kaya, Mehmet Fatih; Güneş, Esma; Şenyel, Mustafa
2016-10-01
FT-IR and FT-Raman spectra of 1-butylpiperazine (1bpa) were experimentally recorded in the region of 4000-10 cm-1 and 4000-100 cm-1, respectively. The optimized geometric parameters, conformational equilibria, normal mode frequencies and corresponding vibrational assignments of 1bpa (C8H18N2) are theoretically examined by means of B3LYP hybrid density functional theory (DFT) method together with 6-31++G(d,p) basis set. Also, reliable conformational investigation and vibrational assignments have been performed by the potential energy surface (PES) and potential energy distribution (PED) analysis, respectively. Calculations are made for four possible conformations. According to the experimental and theoretical data, density functional B3LYP method provides reliable results for predicting vibrational wavenumbers and equatorial-equatorial conformer is considered to be the most stable form of 1bpa.
A new algorithm for reliable and general NMR resonance assignment.
Schmidt, Elena; Güntert, Peter
2012-08-01
reliability and flexibility to replace most manual and semi-automatic assignment procedures for NMR studies of proteins.
Raman vapor spectrum and vibrational assignment for pyridine
Klots, T. D.
1998-09-01
Assignment modifications for the pyridine fundamentals are proposed, based on first time Raman vapor measurements, and a more complete set of infrared and Raman spectra for the gas and liquid. Raman polarization measurements are newly given for some 70 lines between 1600 and 3000 cm -1. The Kakiuti et al. (Kakiuti et al., J. Mol. Spectrosc. 61 (1976) 164) assignment for the nonplanar modes in CS 2 solution is shown to be the only previous correct assignment. Planar assignment modifications, though generally small, are warranted because of the benchmark nature of pyridine. A previous set of vibrational frequencies, derived from a scaled 4-21G force field calculation (Pongor et al., J. Am. Chem. Soc. 106 (1984) 2765; Pongor et al., J. Mol. Spectrosc. 114 (1985) 445), is in excellent agreement with the observed fundamentals, and in fact, tips the balance in favor of assigning ν22 to 1053 cm -1. Ideal-gas entropies derived from spectroscopic constants are also seen to be in excellent agreement with those from calorimetry (Chirico et al., J. Chem. Thermodyn. 28 (1996) 797; Chirico and Steele, J. Chem. Thermodyn. 28 (1996) 819).
Reliability Analysis of Random Vibration Transmission Path Systems
Wei Zhao
2017-01-01
Full Text Available The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was provided. The transfer reliability of vibration transfer path system with uncertain path parameters including path mass and path stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were derived. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most random path parameters can be considered to solve the random problems for vibration transfer path systems, which can avoid the system resonance failure.
Block-decoupling vibration control using eigenstructure assignment
Wei, Xiaojun; Mottershead, John E.
2016-06-01
A theoretical study is presented on the feasibility of applying active control for the purpose of vibration isolation in lightweight structures by block diagonalisation of the system matrices and at the same time assigning eigenvalues (natural frequencies and damping) to the chosen substructures separately. The methodology, based on eigenstructure assignment using the method of receptances, is found to work successfully when the eigenvalues of the open-loop system are controllable and the open- and closed-loop eigenvalues are distinct. In the first part of the paper results are obtained under the restriction that the mass matrix is diagonal (lumped). This is certainly applicable in the case of numerous engineering systems consisting of discrete masses with flexible interconnections of negligible mass. Later in the paper this restriction is lifted to allow bandedness of the mass matrix. Several numerical examples are used to illustrate the working of the proposed algorithm.
Absolute configuration assignment of (+)-fluralaner using vibrational circular dichroism.
Kong, John; Joyce, Leo A; Liu, Jinchu; Jarrell, Tiffany M; Culberson, J Chris; Sherer, Edward C
2017-10-05
The absolute configurations of the separated enantiomers of fluralaner, a racemic animal health product used to prevent fleas and ticks, have been assigned using vibrational circular dichroism (VCD). The crystallographic structure of the active enantiomer (+)-fluralaner has previously been shown to have the (S) configuration using small molecule crystallography. We sought a faster analytical method to determine the absolute configuration of the separated enantiomers. When comparing the measured IR (infrared) and VCD spectra, it is apparent that the amide carbonyl groups appear in the IR but are nearly absent in the VCD. Computational work to calculate the VCD and IR using in vacuo models, implicit solvation, and explicitly solvated complexes has implicated conformational averaging of the carbonyl VCD intensities. © 2017 Wiley Periodicals, Inc.
Dai, Peng; Jiang, Nan; Tan, Ren-Xiang
2016-01-01
Elucidation of absolute configuration of chiral molecules including structurally complex natural products remains a challenging problem in organic chemistry. A reliable method for assigning the absolute stereostructure is to combine the experimental circular dichroism (CD) techniques such as electronic and vibrational CD (ECD and VCD), with quantum mechanics (QM) ECD and VCD calculations. The traditional QM methods as well as their continuing developments make them more applicable with accuracy. Taking some chiral natural products with diverse conformations as examples, this review describes the basic concepts and new developments of QM approaches for ECD and VCD calculations in solution and solid states.
Rate Adaptive Selective Segment Assignment for Reliable Wireless Video Transmission
Sajid Nazir
2012-01-01
Full Text Available A reliable video communication system is proposed based on data partitioning feature of H.264/AVC, used to create a layered stream, and LT codes for erasure protection. The proposed scheme termed rate adaptive selective segment assignment (RASSA is an adaptive low-complexity solution to varying channel conditions. The comparison of the results of the proposed scheme is also provided for slice-partitioned H.264/AVC data. Simulation results show competitiveness of the proposed scheme compared to optimized unequal and equal error protection solutions. The simulation results also demonstrate that a high visual quality video transmission can be maintained despite the adverse effect of varying channel conditions and the number of decoding failures can be reduced.
MEMS reliability in a vibration environment
TANNER,DANELLE M.; WALRAVEN,JEREMY A.; HELGESEN,KAREN SUE; IRWIN,LLOYD W.; GREGORY,DANNY LYNN; STAKE,JOHN R.; SMITH,NORMAN F.
2000-02-03
MicroElectricalMechanical Systems (MEMS) were subjected to a vibration environment that had a peak acceleration of 120g and spanned frequencies from 20 to 2000 Hz. The device chosen for this test was a surface-micromachined microengine because it possesses many elements (springs, gears, rubbing surfaces) that may be susceptible to vibration. The microengines were unpowered during the test. The authors observed 2 vibration-related failures and 3 electrical failures out of 22 microengines tested. Surprisingly, the electrical failures also arose in four microengines in the control group indicating that they were not vibration related. Failure analysis revealed that the electrical failures were due to shorting of stationary comb fingers to the ground plane.
A Study on the Reliability of a Large Vibration Machine
无
2001-01-01
This study aims at the reliability of a large vibration machine ZM2800, including the measurement and analysis of its dynamic load, the stress and reliability analysis of key fragile components as well as the system reliability analysis and calculation of the ma chine. The result of the study provides valuable reference for the evaluation and improve-ment of the structure and performance of the machine.
Mohammad Rastgaar
2009-01-01
Full Text Available This paper provides a state-of-the-art review of eigenstructure assignment methods for vibration cancellation. Eigenstructure assignment techniques have been widely used during the past three decades for vibration suppression in structures, especially in large space structures. These methods work similar to mode localization in which global vibrations are managed such that they remain localized within the structure. Such localization would help reducing vibrations more effectively than other methods of vibration cancellation, by virtue of confining the vibrations close to the source of disturbance. The common objective of different methods of eigenstructure assignment is to provide controller design freedom beyond pole placement, and define appropriate shapes for the eigenvectors of the systems. These methods; however, offer a large and complex design space of options that can often overwhelm the control designer. Recent developments in orthogonal eigenstructure control offers a significant simplification of the design task while allowing some experience-based design freedom. The majority of the papers from the past three decades in structural vibration cancellation using eigenstructure assignment methods are reviewed, along with recent studies that introduce new developments in eigenstructure assignment techniques.
Structural Reliability Sensitivities under Nonstationary Random Vibrations
Rita Greco
2013-01-01
Full Text Available Response sensitivity evaluation is an important element in reliability evaluation and design optimization of structural systems. It has been widely studied under static and dynamic forcing conditions with deterministic input data. In this paper, structural response and reliability sensitivities are determined by means of the time domain covariance analysis in both classically and nonclassically damped linear structural systems. A time integration scheme is proposed for covariance sensitivity. A modulated, filtered, white noise input process is adopted to model the stochastic nonstationary loads. The method allows for the evaluation of sensitivity statistics of different quantities of dynamic response with respect to structural parameters. Finally, numerical examples are presented regarding a multistorey shear frame building.
S Gunasekaran; S Kumaresan; R Arunbalaji; G Anand; S Srinivasan
2008-05-01
The FTIR and FT Raman spectra of dacarbazine were recorded in the regions 4000-400 and 3500-100 cm-1, respectively. The optimized geometry, wavenumber, polarizability and several thermodynamic properties of dacarbazine were studied using ab initio Hartree-Fock, MP2 and DFT methods. A complete vibrational assignment aided by the theoretical harmonic wavenumber analysis was proposed. The calculated harmonic vibrational frequencies were compared with experimental FTIR and FT Raman spectra. Based on the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes were made. The X-ray geometry and experimental frequencies were compared with the results of theoretical calculations.
Development of seismic technology and reliability based on vibration tests
Sasaki, Youichi [Nuclear Power Engineering Corp., Tokyo (Japan)
1997-03-01
This paper deals with some of the vibration tests and investigations on the seismic safety of nuclear power plants (NPPs) in Japan. To ensure the reliability of the seismic safety of nuclear power plants, nuclear power plants in Japan have been designed according to the Technical Guidelines for Aseismic Design of Nuclear Power Plants. This guideline has been developed based on technical date base and findings which were obtained from many vibration tests and investigations. Besides the tests for the guideline, proving tests on seismic reliability of operating nuclear power plants equipment and systems have been carried out. In this paper some vibration tests and their evaluation results are presented. They have crucially contributed to develop the guideline. (J.P.N.)
Bai, Zheng-Jian; Wan, Qiu-Yue
2017-05-01
In this paper, we consider the partial quadratic eigenvalue assignment problem (PQEAP) in vibration by active feedback control. Based on the receptance measurements and system matrices, we propose a constructive method for solving PQEAP, where we only need to solve a small linear system and only a few undesired open-loop eigenvalues with associated eigenvectors are needed. Our method is designed for both single-input and multiple-input vibration controls of vibrating structures. The real form of our method is also presented. Numerical tests show that our method is effective for constructing a solution to PQEAP with both single-input and multiple-input vibration controls.
Vibrational spectra, ab initio calculations and vibrational assignments of 3-butyn-1-ol
Nielsen, Claus J.; Horn, Anne; Klaeboe, Peter; Guirgis, Gamil A.
2008-08-01
The infrared spectra of 3-butyn-1-ol, HC tbnd CCH 2CH 2OH, have been recorded as a vapour in the range 3600-50 cm -1 and as a liquid between 3600 and 400 cm -1. Additional spectra of the alcohol isolated in an argon matrix at ca. 5 K were obtained and spectra were recorded after annealing to various temperatures between 10 and 35 K. Raman spectra of the liquid were recorded at room temperature and at various temperatures between 295 and 143 K. Spectra of an amorphous solid were recorded at 78 K. In spite of several attempts and many different annealing temperatures, the sample crystallized neither in the IR nor in the Raman cryostats. In the variable temperature Raman spectra, some bands of the liquid changed in relative intensity and were interpreted in terms of conformational equilibria between two of the five possible conformers. Complete assignments were made for all the bands of the most stable conformer gg, in which the OH group is approaching the triple bond, forming an intramolecular hydrogen bond. From various bands assigned to a second conformer aa, in which OH is oriented anti to the sbnd C tbnd C sbnd bond, or a third conformer ag, the conformational enthalpy difference was found to be Δ confH( ag-gg) = 0.9 kJ mol -1 in the liquid. The two highest energy conformers g'g and ag were not detected. Quantum-chemical calculations have been carried out at the MP2 and B3LYP levels with a variety of basis sets. The calculations revealed that gg was the low energy conformer and CBS-QB3 calculations suggested the gg conformer was more stable by 5.4 and 4.2 kJ mol -1 relative to ag and aa, respectively, in the vapour. Vibrational wavenumbers and infrared and Raman band intensities for the three low energy conformers are reported from B3LYP/cc-pVTZ calculations.
Co-Assignment of the Molecular Vibrational Frequencies in Different Electronic States
Panchenko, Yurii; Abramenkov, Alexander
2016-06-01
Ultrafast electron diffraction experimental data for the structural parameters of molecules in excited electronic states are comparatively uncommon, hence these parameters are largely unknown. However, because differences between the molecular geometries of excited and ground electronic states cause differences in their experimental vibrational spectra it is important to establish a correspondence between the molecular vibrational frequencies in the ground state and those of the excited state of interest. The correct co-assignment of the experimental vibrational frequencies between two different electronic states of a molecule may be determined by the analog of the Duschinsky matrix D. This matrix D is defined as D = (LI)-1LII where LI and LII are the matrices of the vibrational modes of the two states of the molecule under investigation. They are obtained by solving the vibrational problems in the I and II electronic states, respectively. Choosing the dominant elements in columns of the D matrix and permuting these columns to arrange these elements along the diagonal of the transformed matrix Dast makes it possible to establish the correct co-assignment of the calculated frequencies in the two electronic states. The rows of Dast are for the vibrations in the I electronic state, whereas the columns are for vibrations in the II electronic state. The results obtained may be tested by analogous calculations of Dast for isotopologues. The feasibility of co-assignments of the vibrational frequencies in the ground and T_1 and S_1 excited electronic states are demonstrated for trans-C_2O_2F_2. The analogs of the Duschinsky matrix Dast were used to juxtapose the vibrational frequencies of this molecule calculated at the CASPT2/cc-pVTZ level in the S_0, T_1 and S_1 states. F. Duschinsky, Acta Physicochim. URSS, 7(4), 551-566 (1937). Yu. N. Panchenko, Vibrational spectroscopy, 68, 236-240 (2013).
Assigning the Vibration-Rotation Spectra Using the Lww Program Package
Lodyga, Wieslaw; Kreglewski, Marek
2016-06-01
The LWW program package is based on traditional methods used in assigning rotationally resolved IR molecular spectra. The Loomis-Wood diagrams, which are used to visualize spectral branches and facilitate their identification, are combined with the power of interactive lower state combination difference (LSCD) checking, which provides immediate verification of correct assignments of quantum numbers to spectral lines. The traditional Giessen/Cologne type Loomis-Wood algorithm is also implemented. Predictions of vibration-rotation wavenumbers are calculated from a table of vibration-rotation energies, which can be imported from any external fitting program. Program includes many additional tools like simulation of a spectrum from a catalog file (list of transitions with intensities), build-up of a vibration-rotation band from individual branches and simultaneous displaying of two IR spectra - active one used for assignments and a reference one, both with full link to their peak-list files. Importing energies as well as exporting assigned data for fitting in an external program is made easy and flexible by a user-programmed import/export interface, which facilitates iterative refining of energy levels and gives a possibility of using directly exact vibration-rotation energies. Program is available in tree versions: for symmetric top, asymmetric top and molecules with large amplitude motions. The program is designed for the Windows operating systems and is available with full documentation on www.lww.amu.edu.pl .
Vibrational Spectra, Assignments and Ab initio/DFT Analysis for 2-Methyl-3-nitrophenyl isocyanate
Prasannakumar, Sushanti; Yenagi, Jayashree; Tonannavar, J.
2008-11-01
The FT-IR (4000-400 cm-1) and Raman (3200-100 cm-1) spectral measurements have been made for 2-Methyl-3-nitrophenyl isocyanate. Electronic energy, optimized geometry and harmonic vibrational spectra have been computed using ab initio and DFT methods, namely, at RHF/6-311G* and B3LYP/6-311G* levels of theory. The methyl, nitro and isocyanate vibrations observed in their characteristic regions, have been accurately computed by the B3LYP/6-311G* level. Computed low frequencies have been assigned to out-of-plane, wagging and torsional vibrations of these groups. A complete assignment of the observed as well as computed spectra has been proposed.
Reliability Testing Procedure for MEMS IMUs Applied to Vibrating Environments
Aurelio Somà
2010-01-01
Full Text Available The diffusion of micro electro-mechanical systems (MEMS technology applied to navigation systems is rapidly increasing, but currently, there is a lack of knowledge about the reliability of this typology of devices, representing a serious limitation to their use in aerospace vehicles and other fields with medium and high requirements. In this paper, a reliability testing procedure for inertial sensors and inertial measurement units (IMU based on MEMS for applications in vibrating environments is presented. The sensing performances were evaluated in terms of signal accuracy, systematic errors, and accidental errors; the actual working conditions were simulated by means of an accelerated dynamic excitation. A commercial MEMS-based IMU was analyzed to validate the proposed procedure. The main weaknesses of the system have been localized by providing important information about the relationship between the reliability levels of the system and individual components.
Vibrational Mode Assignment of α-Pinene by Isotope Editing: One Down, Seventy-One To Go
Upshur, Mary Alice; Chase, Hilary M.; Strick, Benjamin F.; Ebben, Carlena J.; Fu, Li; Wang, Hongfei; Thomson, Regan J.; Geiger, Franz M.
2016-05-05
This study aims to reliably assign the vibrational sum frequency generation (SFG) spectrum of α-pinene at the vapor/solid interface using a method involving deuteration of various methyl groups. The synthesis of five different deuterated isotopologues of α-pinene is presented in order to determine the impact that removing contributions from methyl group C$-$H oscillators has on its SFG response. 0.6 cm^{-1} Resolution SFG spectra of these isotopologues show varying degrees of differences in the C–H stretching region when compared to the SFG response of unlabeled α-pinene. The largest spectral changes were observed for the isotopologue containing a fully deuterated vinyl methyl group. Noticeable losses in signal intensities allow us to reliably assign the 2860 cm^{-1} peak to the vinyl methyl symmetric stretch. Furthermore, upon removing the vinyl methyl group entirely by synthesizing apopinene, the steric influence of the unlabeled C_{9}H_{14} fragment on the SFG response of α-pinene SFG can be readily observed. The work presented here brings us one step closer to understanding the vibrational spectroscopy of α-pinene.
A generic method for assignment of reliability scores applied to solvent accessibility predictions
Petersen, Bent; Petersen, Thomas Nordahl; Andersen, Pernille
2009-01-01
the relative exposure of the amino acids. The method assigns a reliability score to each surface accessibility prediction as an inherent part of the training process. This is in contrast to the most commonly used procedures where reliabilities are obtained by post-processing the output. CONCLUSION...
Velicka, M.; Radzvilaite, M.; Ceponkus, J.; Urboniene, V.; Pucetaite, M.; Jankevicius, F.; Steiner, G.; Sablinskas, V.
2017-02-01
Surface enhanced Raman scattering (SERS) spectroscopy is a useful method for detection of trace amounts of molecules. It has already been successfully implemented for detection of explosives, food additives, biomarkers in blood or urine, etc. In the last decade, SERS spectroscopy was introduced into the field of health sciences and has been especially focused on early disease detection. In the recent years, application of SERS spectroscopy for detection of various types of human cancerous tissues emerged. Furthermore, SERS spectroscopy of extracellular fluid shows great potential for the differentiation of normal and cancerous tissues; however, due to high variety of molecules present in such biological samples, the experimental spectrum is a combination of many different overlapping vibrational spectral bands. Thus, precise assignment of these bands to the corresponding molecular vibrations is a difficult task. In most cases, researchers try to avoid this task satisfying just with tentative assignment. In this study, low temperature SERS measurements of extracellular fluid of cancerous and healthy kidney tissue samples were carried out in order to get a deeper understanding of the nature of vibrational spectral bands present in the experimental spectrum. The SERS spectra were measured in temperature range from 300 K down to 100 K. SERS method was implemented using silver nanoparticle colloidal solution. The results of the low temperature SERS experiment were analysed and compared with the results of theoretical calculations. The analysis showed that the SERS spectrum of extracellular fluid of kidney tissue is highly influenced by the vibrational bands of adenine and Lcystine molecules.
Quadratic partial eigenvalue assignment problem with time delay for active vibration control
Pratt, J. M.; Singh, K. V.; Datta, B. N.
2009-08-01
Partial pole assignment in active vibration control refers to reassigning a small set of unwanted eigenvalues of the quadratic eigenvalue problem (QEP) associated with the second order system of a vibrating structure, by using feedback control force, to suitably chosen location without altering the remaining large number of eigenvalues and eigenvectors. There are several challenges of solving this quadratic partial eigenvalue assignment problem (QPEVAP) in a computational setting which the traditional pole-placement problems for first-order control systems do not have to deal with. In order to these challenges, there has been some work in recent years to solve QPEVAP in a computationally viable way. However, these works do not take into account of the practical phenomenon of the time-delay effect in the system. In this paper, a new "direct and partial modal" approach of the quadratic partial eigenvalue assignment problem with time-delay is proposed. The approach works directly in the quadratic system without requiring transformation to a standard state-space system and requires the knowledge of only a small number of eigenvalues and eigenvectors that can be computed or measured in practice. Two illustrative examples are presented in the context of active vibration control with constant time-delay to illustrate the success of our proposed approach. Future work includes generalization of this approach to a more practical complex time-delay system and extension of this work to the multi-input problem.
Letellier, R; Ghomi, M; Taillandier, E
1989-02-01
A calculated approach based on the Higgs method for assigning the vibration modes of an infinite helicoidal polymeric chain has been performed on the basis of a reliable valence force field. The calculated results allowed the phosphate-backbone marker modes of the A and B forms, to be interpreted. In the dynamic models used, the bases have been omitted and no interchain interaction was considered. The calculation can also interprete quite satisfactorily the characteristic Raman peaks and infrared bands in the 1250-700 cm-1 spectral region arising from the sugar or sugar-phosphate association and reproduce their evolution upon the B----A DNA conformational transition. They clearly show that the phosphate-backbone modes in the above mentioned spectral region constitute the optical branches of the phonon dispersion curves with no detectable variation in the first Brillouin-zone.
Note: Reliable low-vibration piezo-mechanical shutter.
Bauer, Michael; Franzreb, Philipp Pierre; Spethmann, Nicolas; Widera, Artur
2014-09-01
We present a mechanical shutter based on a bending piezo-actuator. The shutter features an active aperture of about 2 mm, allowing for full extinction and lossless transmission of a beam. Acoustic noise and mechanical vibrations produced are very low and the shutter is outstandingly long-lived; a test device has undergone 20 × 10(6) cycles without breaking. A reflector makes the shutter capable of reliably interrupting a beam with at least 2 W of cw power at 780 nm. The shutter is well suited to create pulses as short as 16 ms, while pulse lengths down to 1 ms are possible. The rise and fall times are approximately 120 µs, with a delay of 2 ms. Jitter stays below 10 µs, while long-term drifts stay well below 500 µs.
Vibrational assignment and vibronic interaction for NO3 in the ground electronic state
Hirota, Eizi
2015-04-01
Two important problems exist for the NO3 free radical. One is the frequency of the degenerate N-O stretching mode ν3. It has been assigned to a band at 1492 cm-1 (Assignment I), whereas Stanton calculated it by an ab initio MO method to be around 1000 cm-1 (Assignment II). The second concerns an anomalous ν4 progression, which appeared in the photoelectron spectra of the NO3 anion and was accounted for by Herzberg-Teller (H-T) mechanism, but the interaction parameter derived was too large. The present study critically examines Assignment II and the H-T vibronic interaction model against the results of high-resolution infrared (IR) spectroscopy supplemented with dispersed fluorescence (DF), and concludes Assignment I to be correct and the H-T mechanism to be complemented by a new vibronic interaction model, based upon the observations: (1) Stanton's ab initio MO ν3 appeared in neither IR nor DF spectra, (2) only one A-E type subband was present in the Z-ν4 hot band (Z denotes the upper state of the 1492 cm-1 band), at variance with the two predicted by Assignment II, (3) the ℓ-type doubling constant and the first-order Coriolis coupling constant derived for the Z state by assuming Assignment II were not acceptable, and (4) anomalous features expected from the H-T vibronic interaction model for the ν4 fundamental state were not observed at all. Infrared spectroscopic results on a few 2E‧ degenerate states indicated that the first-order Coriolis coupling constant and the effective spin-orbit interaction constant were closely correlated, suggesting that the unpaired electron azimuthal motion was affected much by that of the degenerate vibrational mode. This sort of vibronic interaction has been well known for linear polyatomic free radicals in 2Σ electronic states with a bending mode singly excited. A similar vibronic interaction should be present also in symmetric-top free radicals, where a degenerate vibrational mode is singly excited. However, few examples
Validity and inter-observer reliability of subjective hand-arm vibration assessments
Coenen, P.; Formanoy, M.; Douwes, M.; Bosch, T.; Kraker, H. de
2014-01-01
Exposure to mechanical vibrations at work (e.g., due to handling powered tools) is a potential occupational risk as it may cause upper extremity complaints. However, reliable and valid assessment methods for vibration exposure at work are lacking. Measuring hand-arm vibration objectively is often di
Ignatyev, Igor S; Partal, F; López González, J J; Sundius, Tom
2004-04-01
The assignment of the SiOH group vibrations of trimethylsilanol, which is still controversial, is proposed. This assignment is based on theoretical B3LYP force field scaled using the constants of the (CH3)3Si group optimized to fit experimental vibrational frequencies of (CH3)3SiF and (CD3)3SiF molecules as well as the OH stretching scale factor from methanol. The ab initio force field defined in this way gives a good agreement of the theoretical vibrational frequencies of trimethylsilanol with the positions of IR and Raman bands observed in the gas phase. This force field predicts the greatest contribution of the delta SiOH coordinates to the vibration with frequency of 804 cm(-1). The elimination of the coupling of the SiOH deformation with methyl rocking modes by the normal coordinate treatment of (CD3)3SiOH gives 832 cm(-1) for silanol deformation which is in a good agreement with the 834 cm(-1) value proposed earlier for the bending mode of free silanol groups. The geometry and force field of the open chain H3SiOH trimer is computed to model the change of the delta SiOH frequencies upon formation of the hydrogen-bonded polymers. This model predicts a significant shift of SiOH bending frequencies to the 1000-1200 cm(-1) range while those of SiOD to the 800-850 cm(-1) range. These predictions allow us to ascribe the 1087 cm(-1) band observed in the IR spectrum of crystalline (CH3)3SiOH and the Raman 775 cm(-1) band of the liquid (CH3)3SiOD to deformations of the hydrogen-bonded silanol groups. Copyright 2003 Elsevier B.V.
Sawant, Dattatray K.; Klaassen, Joshua J.; Panikar, Savitha S.; Durig, James R.
2014-09-01
Infrared spectra (3200-220 cm-1) of gaseous and Raman spectra (3200-40 cm-1) of liquid isopropyl isocyanide ((CH3)2CHNC) have been recorded. By utilizing the microwave rotational constants combined with the structural parameters predicted from MP2(full)/6-311+G(d,p) calculations, adjusted r0 parameters have been obtained for isopropyl isocyanide. The heavy atom distances in Å are: r (C1tbnd N2) = 1.176(3), r (N2sbnd C3) = 1.437(3), r (C3sbnd C4,5) = 1.525(5) and the angles in (°) are ∠C1N2C3 = 178.6(5); ∠N2C3C4,5 = 109.4(5); ∠C4C3C5 = 113.0(5). A complete vibrational assignment is proposed for isopropyl isocyanide based on infrared band contours, relative intensities, depolarization values, and group frequencies. The vibrational assignments were supported by normal coordinate calculation utilizing the force constants from ab inito MP2(full)/6-31G(d). The results are discussed and compared to those obtained for some similar molecules.
Thaunay, Florian; Dognon, Jean-Pierre; Ohanessian, Gilles; Clavaguéra, Carine
2015-10-21
The calculation of infrared spectra by molecular dynamics simulations based on the AMOEBA polarizable force field has recently been demonstrated [Semrouni et al., J. Chem. Theory Comput., 2014, 10, 3190]. While this approach allows access to temperature and anharmonicity effects, band assignment requires additional tools, which we describe in this paper. The Driven Molecular Dynamics approach, originally developed by Bowman, Kaledin et al. [Bowman et al. J. Chem. Phys., 2003, 119, 646, Kaledin et al. J. Chem. Phys., 2004, 121, 5646] has been adapted and associated with AMOEBA. Its advantages and limitations are described. The IR spectrum of the Ac-Phe-Ala-NH2 model peptide is analyzed in detail. In addition to differentiation of conformations by reproducing frequency shifts due to non-covalent interactions, DMD allows visualizing the temperature-dependent vibrational modes.
Yamada, Osamu; Hiura, Hidehumi; Igarashi, Takashi; Kaneko, Norio; Takahashi, Hiroaki
By comparison of the infrared spectra of S-methyl-, S-ethyl- and S-isopropyidithizones in the solid state, the configuration-sensitive i.r. bands have been obtained for the trans-syn-s-trans and trans-anti-s-trans configurations with respect to the NN, CN and CN bonds of the formazan skeleton. The vibrational assignment of S-methyldithizone has been made based on the frequency shifts on isotopic substitutions: 1,5- 15N- and 2,4- 15N- substitutions, deuterium substitutions of the methyl group, phenyl groups and NH group, and deuterium substitutions of both phenyl and NH groups.
Meninno, Sara; Rizzo, Paola; Abbate, Sergio; Longhi, Giovanna; Mazzeo, Giuseppe; Monaco, Guglielmo; Lattanzi, Alessandra; Zanasi, Riccardo
2016-02-01
Density functional theory calculation of the vibrational circular dichroism spectrum was used to assign the absolute configuration of an all-carbon quaternary β-stereocenter of a γ-butyrolactone recently synthesized through an asymmetric organocatalytic tandem aldol/lactonization sequence. Comparison with the experimental spectrum is satisfactory, on account of the fact that spectroscopic features are weak due to the presence of multiple conformers. As a result, the (R) absolute configuration was assigned to the (+) optical isomer.
A generic method for assignment of reliability scores applied to solvent accessibility predictions
Nielsen Morten
2009-07-01
Full Text Available Abstract Background Estimation of the reliability of specific real value predictions is nontrivial and the efficacy of this is often questionable. It is important to know if you can trust a given prediction and therefore the best methods associate a prediction with a reliability score or index. For discrete qualitative predictions, the reliability is conventionally estimated as the difference between output scores of selected classes. Such an approach is not feasible for methods that predict a biological feature as a single real value rather than a classification. As a solution to this challenge, we have implemented a method that predicts the relative surface accessibility of an amino acid and simultaneously predicts the reliability for each prediction, in the form of a Z-score. Results An ensemble of artificial neural networks has been trained on a set of experimentally solved protein structures to predict the relative exposure of the amino acids. The method assigns a reliability score to each surface accessibility prediction as an inherent part of the training process. This is in contrast to the most commonly used procedures where reliabilities are obtained by post-processing the output. Conclusion The performance of the neural networks was evaluated on a commonly used set of sequences known as the CB513 set. An overall Pearson's correlation coefficient of 0.72 was obtained, which is comparable to the performance of the currently best public available method, Real-SPINE. Both methods associate a reliability score with the individual predictions. However, our implementation of reliability scores in the form of a Z-score is shown to be the more informative measure for discriminating good predictions from bad ones in the entire range from completely buried to fully exposed amino acids. This is evident when comparing the Pearson's correlation coefficient for the upper 20% of predictions sorted according to reliability. For this subset, values of 0
Performance-driven assignment and mapping for reliable networks-on-chips
Qian-qi LE; Guo-wu YANG; William N.N.HUNG; Xiao-yu SONG; Fu-you FAN
2014-01-01
Network-on-chip (NoC) communication architectures present promising solutions for scalable communication re-quests in large system-on-chip (SoC) designs. Intellectual property (IP) core assignment and mapping are two key steps in NoC design, significantly affecting the quality of NoC systems. Both are NP-hard problems, so it is necessary to apply intelligent algorithms. In this paper, we propose improved intelligent algorithms for NoC assignment and mapping to overcome the draw-backs of traditional intelligent algorithms. The aim of our proposed algorithms is to minimize power consumption, time, area, and load balance. This work involves multiple conflicting objectives, so we combine multiple objective optimization with intelligent algorithms. In addition, we design a fault-tolerant routing algorithm and take account of reliability using comprehensive perfor-mance indices. The proposed algorithms were implemented on embedded system synthesis benchmarks suite (E3S). Experimental results show the improved algorithms achieve good performance in NoC designs, with high reliability.
Validity and inter-observer reliability of subjective hand-arm vibration assessments.
Coenen, Pieter; Formanoy, Margriet; Douwes, Marjolein; Bosch, Tim; de Kraker, Heleen
2014-07-01
Exposure to mechanical vibrations at work (e.g., due to handling powered tools) is a potential occupational risk as it may cause upper extremity complaints. However, reliable and valid assessment methods for vibration exposure at work are lacking. Measuring hand-arm vibration objectively is often difficult and expensive, while often used information provided by manufacturers lacks detail. Therefore, a subjective hand-arm vibration assessment method was tested on validity and inter-observer reliability. In an experimental protocol, sixteen tasks handling powered tools were executed by two workers. Hand-arm vibration was assessed subjectively by 16 observers according to the proposed subjective assessment method. As a gold standard reference, hand-arm vibration was measured objectively using a vibration measurement device. Weighted κ's were calculated to assess validity, intra-class-correlation coefficients (ICCs) were calculated to assess inter-observer reliability. Inter-observer reliability of the subjective assessments depicting the agreement among observers can be expressed by an ICC of 0.708 (0.511-0.873). The validity of the subjective assessments as compared to the gold-standard reference can be expressed by a weighted κ of 0.535 (0.285-0.785). Besides, the percentage of exact agreement of the subjective assessment compared to the objective measurement was relatively low (i.e., 52% of all tasks). This study shows that subjectively assessed hand-arm vibrations are fairly reliable among observers and moderately valid. This assessment method is a first attempt to use subjective risk assessments of hand-arm vibration. Although, this assessment method can benefit from some future improvement, it can be of use in future studies and in field-based ergonomic assessments.
Bai, Zheng-Jian; Datta, Biswa Nath; Wang, Jinwei
2010-04-01
The partial quadratic eigenvalue assignment problem (PQEVAP) concerns reassigning a few undesired eigenvalues of a quadratic matrix pencil to suitably chosen locations and keeping the other large number of eigenvalues and eigenvectors unchanged (no spill-over). The problem naturally arises in controlling dangerous vibrations in structures by means of active feedback control design. For practical viability, the design must be robust, which requires that the norms of the feedback matrices and the condition number of the closed-loop eigenvectors are as small as possible. The problem of computing feedback matrices that satisfy the above two practical requirements is known as the Robust Partial Quadratic Eigenvalue Assignment Problem (RPQEVAP). In this paper, we formulate the RPQEVAP as an unconstrained minimization problem with the cost function involving the condition number of the closed-loop eigenvector matrix and two feedback norms. Since only a small number of eigenvalues of the open-loop quadratic pencil are computable using the state-of-the-art matrix computational techniques and/or measurable in a vibration laboratory, it is imperative that the problem is solved using these small number of eigenvalues and the corresponding eigenvectors. To this end, a class of the feedback matrices are obtained in parametric form, parameterized by a single parametric matrix, and the cost function and the required gradient formulas for the optimization problem are developed in terms of the small number of eigenvalues that are reassigned and their corresponding eigenvectors. The problem is solved directly in quadratic setting without transforming it to a standard first-order control problem and most importantly, the significant "no spill-over property" of the closed-loop eigenvalues and eigenvectors is established by means of a mathematical result. These features make the proposed method practically applicable even for very large structures. Results on numerical experiments show
Panchenko, Yurii N.
2013-06-01
The shifts of the molecular vibrational frequencies when going from the ground electronic state to the lowest excited electronic states pose some problems for the mutual co-assignment of the calculated vibrational frequencies in the different excited states. The trans-{C_2 O_2 F_2} shift of the frequency of the symmetrical ν(C=O) stretching vibration between the S_0 and T_1 is 373 wn. The feasibility of mutual co-assignments of the vibrational frequencies in these electronic states has been demonstrated for trans-{C_2 O_2 F_2}. Matrices analogous to the Duschinsky matrix were used to juxtapose the a_g vibrational frequencies of this molecule calculated at the CASPT2/cc-pVTZ level in the ground S_0 and excited triplet T_1 and singlet S_1 electronic states. The analog of the Duschinsky matrix D was obtained for this molecule using the equation D = (L_{I})^{-1} L_{II} where L_{I} and L_{II} are the matrices of the vibrational modes (normalized atomic displacements) obtained by solving the vibrational problems for the S_0 and T_1 electronic states, respectively. Choosing the dominant elements in columns of the D matrix and permuting these columns to arrange these elements along the diagonal of the transformed matrix D^* makes it possible to establish the correct mutual co-assignments of the calculated a_g vibrational frequencies of the trans-{C_2 O_2 F_2} molecule in the S_0 and T_1 electronic states. The analogous procedure was performed for the trans-{C_2 O_2 F_2} molecule in the T_1 and S_1 excited electronic states. The recent reassignments of the νb{2} and νb{3} calculated vibrational frequencies in the trans-{C_2 O_2 F_2} molecule in the ground state were also obtained for the triplet T_1 and singlet S_1 excited electronic states. The approach set forth in this text makes it possible to juxtapose the calculated vibrational frequencies of the same molecule in the different electronic states and to refine the assignments of these frequencies. This is essential
Leguy, Aurélien M A; Frost, Jarvist M; Skelton, Jonathan; Brivio, Federico; Rodríguez-Martínez, Xabier; Weber, Oliver J; Pallipurath, Anuradha; Alonso, M Isabel; Campoy-Quiles, Mariano; Weller, Mark T; Nelson, Jenny; Walsh, Aron; Barnes, Piers R F
2016-01-01
We present Raman and terahertz absorbance spectra of methylammonium lead halide single crystals (MAPbX3, X = I, Br, Cl) at temperatures between 80 and 370 K. These results show good agreement with density-functional-theory phonon calculations.1 Comparison of experimental spectra and calculated vibrational modes enables confident assignment of most of the vibrational features between 50 and 3500 cm-1. Reorientation of the methylammonium cations, unlocked in their cavities at the orthorhombic-to-tetragonal phase transition, plays a key role in shaping the vibrational spectra of the different compounds. Calculations show that these dynamics effects split Raman peaks and create more structure than predicted from the independent harmonic modes. This explains the presence of extra peaks in the experimental spectra that have been a source of confusion in earlier studies. We discuss singular features, in particular the torsional vibration of the C-N axis, which is the only molecular mode that is strongly influenced b...
Guirgis, Gamil A; Dukes, Horace W; Wyatt, Justin K; Nielsen, Claus J; Horn, Anne; Aleksa, Valdemaras; Klaeboe, Peter
2015-02-05
Raman spectra of 1,1-difluoro-1-silacyclohexane as a liquid, and as a solid at 78 K were recorded and depolarization data obtained. The infrared spectra of the vapour, liquid and amorphous and crystalline solids have been studied. In the low temperature IR and Raman spectra eight and three bands, respectively, were shifted a few cm(-1) when the sample crystallized. No bands vanished after crystallization in agreement with the assumption that only one conformer (chair) was present in all the states of aggregation. The compound exists in the stable chair conformation, whereas in the parent silacyclohexane a possible twist form should have more than 15 kJ mol(-1) higher energies than the chair, as derived from various calculations. The wavenumbers of the vibrational modes were calculated in the harmonic and anharmonic approximation employing B3LYP/cc-pVTZ calculations. The 27 A' and 21 A″ fundamentals were assigned on the basis of the calculations, infrared vapour contours, Raman depolarization measurements and infrared and Raman band intensities. An average, relative deviation of 1.5% was found between the observed and the anharmonic wavenumbers for the 48 modes.
Brahma, Sanjoy; Datta, Biswa
2009-07-01
The partial quadratic eigenvalue assignment problem (PQEVAP) concerns the reassignment of a small number of undesirable eigenvalues of a quadratic matrix pencil, while leaving the remaining large number of eigenvalues and the corresponding eigenvectors unchanged. The problem arises in controlling undesirable resonance in vibrating structures and in stabilizing control systems. The solution of this problem requires computations of a pair of feedback matrices. For practical effectiveness, these feedback matrices must be computed in such a way that their norms and the condition number of the closed-loop eigenvector matrix are as small as possible. These considerations give rise to the minimum norm partial quadratic eigenvalue assignment problem (MNPQEVAP) and the robust partial quadratic eigenvalue assignment problem (RPQEVAP), respectively. In this paper we propose new optimization based algorithms for solving these problems. The problems are solved directly in a second-order setting without resorting to a standard first-order formulation so as to avoid the inversion of a possibly ill-conditioned matrix and the loss of exploitable structures of the original model. The algorithms require the knowledge of only the open-loop eigenvalues to be replaced and their corresponding eigenvectors. The remaining open-loop eigenvalues and their corresponding eigenvectors are kept unchanged. The invariance of the large number of eigenvalues and eigenvectors under feedback is guaranteed by a proven mathematical result. Furthermore, the gradient formulas needed to solve the problems by using the quasi-Newton optimization technique employed are computed in terms of the known quantities only. Above all, the proposed methods do not require the reduction of the model order or the order of the controller, even when the underlying finite element model has a very large degree of freedom. These attractive features, coupled with minimal computational requirements, such as solutions of small
Design of Accelerated Reliability Test for CNC Motorized Spindle Based on Vibration Signal
Chen Chao
2016-01-01
Full Text Available Motorized spindle is the key functional component of CNC machining centers which is a mechatronics system with long life and high reliability. The reliability test cycle of motorized spindle is too long and infeasible. This paper proposes a new accelerated test for reliability evaluation of motorized spindle. By field reliability test, authors collect and calculate the load data including rotational speed, cutting force and torque. Load spectrum distribution law is analyzed. And authors design a test platform to apply the load spectrum. A new method to define the fuzzy acceleration factor based on the vibration signal is proposed. Then the whole test plan of accelerated reliability test is done.
Chen, Shao-Tuan; Du, Sijun; Arroyo, Emmanuelle; Jia, Yu; Seshia, Ashwin
2017-10-01
This paper presents a novel application of utilising nonlinear air damping as a soft mechanical stopper to increase the shock reliability for microelectromechanical systems (MEMS) vibration energy harvesters. The theoretical framework for nonlinear air damping is constructed for MEMS vibration energy harvesters operating in different air pressure levels, and characterisation experiments are conducted to establish the relationship between air pressure and nonlinear air damping coefficient for rectangular cantilever MEMS micro cantilevers with different proof masses. Design guidelines on choosing the optimal air pressure level for different MEMS vibration energy harvesters based on the trade-off between harvestable energy and the device robustness are presented, and random excitation experiments are performed to verify the robustness of MEMS vibration energy harvesters with nonlinear air damping as soft stoppers to limit the maximum deflection distance and increase the shock reliability of the device.
Meral Bayraktar
2014-01-01
Full Text Available The effect of vibration on the axle has been considered. Vibration measurements at different speeds have been performed on the axle of a running rail vehicle to figure out displacement, acceleration, time, and frequency response. Based on the experimental works, equivalent stress has been used to find out life of the axles for 90% and 10% reliability. Calculated life values of the rail vehicle axle have been compared with the real life data and it is found that the life of a vehicle axle taking into account the vibration effects is in good agreement with the real life of the axle.
Fry-Petit, A. M., E-mail: mcqueen@jhu.edu, E-mail: afry@fullerton.edu; Sheckelton, J. P.; McQueen, T. M., E-mail: mcqueen@jhu.edu, E-mail: afry@fullerton.edu [Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218 (United States); Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States); Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Rebola, A. F.; Fennie, C. J. [Department of Applied Physics, Cornell University, Ithaca, New York 14853 (United States); Mourigal, M.; Valentine, M.; Drichko, N. [Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)
2015-09-28
For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn{sub 2}Mo{sub 3}O{sub 8}, this approach allows direct assignment of the constrained rotational mode of Mo{sub 3}O{sub 13} clusters and internal modes of MoO{sub 6} polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems.
Profeta, Luisa T. M.; Sams, Robert L.; Johnson, Timothy J.; Williams, Stephen D.
2011-09-08
Glyoxal, methylglyoxal, and 2,3-butanedione (diacetyl) are all known biomass burning effluents and suspected aerosol precursors. Pressure-broadened quantitative infrared spectra of glyoxal, methylglyoxal, and diacetyl vapors covering the 520–6500 cm^{–1} range are reported at 0.112 cm^{–1} resolution, each with a composite spectrum derived from a minimum of 10 different sample pressures for the compound, representing some of the first quantitative intensity data for these analytes. Many vibrational assignments for methylglyoxal are reported for the first time, as are some near-IR and far-IR bands of glyoxal and diacetyl. To complete the vibrational assignments, the far-infrared spectra (25–600 cm^{–1}) of all three vapors are also reported, those of methylglyoxal for the first time. Density functional theory and ab initio MP2 theory are used to help assign vibrational modes. Finally, potential bands for atmospheric monitoring are discussed.
Liang, Yao; Yamaura, Hiroshi; Ouyang, Huajiang
2017-06-01
As friction couples tangential and lateral degrees-of-freedom of a structure at contact interfaces, the resulting asymmetric dynamic system is prone to dynamic instability. Using state-feedback control, such a frictional asymmetric system can be stabilized through assigning the system desirable eigenvalues; but uncertainties in system parameters can cause assigned eigenvalues to deviate from desired locations and thus stability may be lost. This study presents a robust stabilization method that assigns both desirable eigenvalues and their sensitivities and thus render assigned eigenvalues stable and insensitive to perturbations in uncertain contact parameters (the friction coefficient, contact damping, and contact stiffness). This method utilizes receptances of the corresponding symmetric part of the asymmetric system. The optimal control input location is first determined by minimizing the Frobenius norm of the normalized eigen-sensitivity matrix. The normalized eigen-sensitivities indicate that the friction coefficient and contact stiffness intrinsically have similar crucial effects on the stability of the system. To demonstrate the application of the proposed control method, the eigen-sensitivities with respect to only the friction coefficient are assigned. A constrained over-determined least-squares problem is solved to assign both required eigenvalues and eigen-sensitivities. Numerical examples validate the effectiveness of the proposed robust control scheme by Monte Carlo simulations.
Li, Yunlong; Wang, Xiaojun; Wang, Lei; Fan, Weichao; Qiu, Zhiping
2017-01-01
A systematic non-probabilistic reliability analysis procedure for structural vibration active control system with unknown-but-bounded parameters is proposed. The state-space representation of active vibration control system with uncertain parameters is presented. Compared with the robust control theory, which is always over-conservative, the reliability-based analysis method is more suitable to deal with uncertain problem. Stability is the core of the closed-loop feedback control system design, so stability criterion is adopted to act as the limited state function for reliability analysis. The uncertain parameters without enough samples are modeled as interval variables. Interval perturbation method is employed to estimate the interval bounds of eigenvalues, which can be used to characterize the stability of the closed-loop active control system. Formulation of defining the reliability of active control system based on stability is discussed. A novel non-probabilistic reliability measurement index is discussed and used to determine the probability of the stability based on the area ratio. The feasibility and efficiency of the proposed method are demonstrated by two numerical examples.
Brizuela, Alicia Beatriz; Castillo, María Victoria; Raschi, Ana Beatriz; Davies, Lilian; Romano, Elida; Brandán, Silvia Antonia
2014-03-31
In the present study, a complete assignment of the vibrational spectra of sucrose in aqueous medium was performed combining Pulay's Scaled Quantum Mechanics Force Field (SQMFF) methodology with self-consistent reaction field (SCRF) calculations. Aqueous saturated solutions of sucrose and solutions at different molar concentrations of sucrose in water were completely characterized by infrared, HATR, and Raman spectroscopies. In accordance with reported data of the literature for sucrose, the theoretical structures of sucrose penta and sucrose dihydrate were also optimized in gas and aqueous solution phases by using the density functional theory (DFT) calculations. The solvent effects for the three studied species were analyzed using the solvation PCM/SMD model and, then, their corresponding solvation energies were predicted. The presence of pure water, sucrose penta-hydrate, and sucrose dihydrate was confirmed by using theoretical calculations based on the hybrid B3LYP/6-31G(∗) method and the experimental vibrational spectra. The existence of both sucrose hydrate complexes in aqueous solution is evidenced in the IR and HATR spectra by means of the characteristic bands at 3388, 3337, 3132, 1648, 1375, 1241, 1163, 1141, 1001, 870, 851, 732, and 668cm(-1) while in the Raman spectrum, the groups of bands in the regions 3159-3053cm(-1), 2980, 2954, and 1749-1496cm(-1) characterize the vibration modes of those complexes. The inter and intra-molecular H bond formations in aqueous solution were studied by Natural Bond Orbital (NBO) and Atoms in Molecules theory (AIM) investigation.
Active partial eigenvalue assignment for friction-induced vibration using receptance method
Liang, Y.; Ouyang, H. J.; Yamaura, H.
2016-09-01
Generally, a mechanical system always has symmetric system matrices. Nevertheless, when some non-conservative forces are included, such as friction and aerodynamic force, the symmetry of the stiffness matrix or damping matrix or both violated. Moreover, such an asymmetric system is prone to dynamic instability. Distinct from the eigenvalue assignment for symmetric systems to reassign their natural frequencies, the main purpose of eigenvalue assignment for asymmetric systems is to shift the unstable eigenvalues to the stable region. In this research, only the unstable eigenvalues and eigenvalues which are close to the imaginary axis of the complex eigenvalue plane are assigned due to their predominant influence on the response of the system. The remaining eigenvalues remain unchanged. The state-feedback control gains are obtained by solving the constrained linear least-squares problems in which the linear system matrices are deduced based on the receptance method and the constraint is derived from the unobservability condition. The numerical simulation results demonstrate that the proposed method is capable of partially assigning those targeted eigenvalues of the system for stabilisation.
Reliability and Validity of the OMNI-Vibration Exercise Scale of Perceived Exertion
Marín, Pedro J.; Santos-Lozano, Alejandro; Santin-Medeiros, Fernanda; Robertson, Robert J.; Garatachea, Nuria
2012-01-01
This study examined reliability and concurrent validity of the newly developed OMNI-vibration exercise scale (OMNI-VIBRO) to measure Ratings of Perceived Exertion (RPE) during vibration exercise in twenty recreationally active students (12 males and 8 females). The criterion variables were muscle activity of the Vastus Medialis (VM), Vastus Lateralis (VL), Biceps Femoris (BF), and Medial Gastrocnemius (MG) muscles, as well as accelerations (12.5, 20.2, 30.9, 36.3, 60.1, and 88.4 m·s-2). RPE was registered during the final of each 30 s condition. Each participant attended two laboratory testing sessions. Positive linear regression coefficients (p < 0.001) were found between RPE (OMNI-VIBRO) and acceleration (r = 0.976) and muscle activity of lower-body muscles (r = 0.942). Between session (test-retest), reliability of RPE (OMNI-VIBRO) was good (ICC: 0.790. 95% CI: 0.699-0.854). Conclusions: findings provided concurrent validation of the OMNI-VIBRO to measure RPE for the active muscle and overall body in recreationally active students performing lower-body vibration exercise. Key pointsThe pictorial-verbal category scale of perception of exertion (OMNI-VIBRO) during lower body vibration exercise on a vibration platform showed good concurrent validity.The OMNI-VIBRO method in conjunction with WBV exercise would allow coaches, fitness professionals, or health-care personnel to assess the intensity that corresponds to the level of the vibratory stimulus.The OMNI-VIBRO could be a useful tool of measuring the different intensities of a vibratory-training session and altering the vibratory stimulus in a periodized fashion. PMID:24149351
RELIABILITY AND VALIDITY OF THE OMNI-VIBRATION EXERCISE SCALE OF PERCEIVED EXERTION
Pedro J. Marín
2012-09-01
Full Text Available This study examined reliability and concurrent validity of the newly developed OMNI-vibration exercise scale (OMNI-VIBRO to measure Ratings of Perceived Exertion (RPE during vibration exercise in twenty recreationally active students (12 males and 8 females. The criterion variables were muscle activity of the Vastus Medialis (VM, Vastus Lateralis (VL, Biceps Femoris (BF, and Medial Gastrocnemius (MG muscles, as well as accelerations (12.5, 20.2, 30.9, 36.3, 60.1, and 88.4 m·s-2. RPE was registered during the final of each 30 s condition. Each participant attended two laboratory testing sessions. Positive linear regression coefficients (p < 0.001 were found between RPE (OMNI-VIBRO and acceleration (r = 0.976 and muscle activity of lower-body muscles (r = 0.942. Between session (test-retest, reliability of RPE (OMNI-VIBRO was good (ICC: 0.790. 95% CI: 0.699-0.854. Conclusions: findings provided concurrent validation of the OMNI-VIBRO to measure RPE for the active muscle and overall body in recreationally active students performing lower-body vibration exercise
Reliability based multiobjective optimization for design of structures subject to random vibrations
无
2008-01-01
Based on a multiobjective approach whose objective function (OF) vector collects stochastic reliability performance and structural cost indices, a structural optimization criterion for mechanical systems subject to random vibrations is presented for supporting engineer's design. This criterion differs from the most commonly used conventional optimum design criterion for random vibrating structure, which is based on minimizing displacement or acceleration variance of main structure responses,without considering explicitly required performances against failure. The proposed criterion can properly take into account the design-reliability required performances, and it becomes a more efficient support for structural engineering decision making. The multiobjective optimum (MOO) design of a tuned mass damper (TMD) has been developed in a typical seismic design problem, to control structural vibration induced on a multi-storey building structure excited by nonstationary base acceleration random process.A numerical example for a three-storey building is developed and a sensitivity analysis is carried out. The results are shown in a useful manner for TMD design decision support.
Raissi, Heidar; Nowroozi, Alireza; Mohammdi, Reza; Hakimi, Mohammad
2006-11-01
The intramolecular hydrogen bond, molecular structure and vibrational frequencies of tetra-acetylethane have been investigated by means of high-level density functional theory (DFT) methods with most popular basis sets. Fourier transform infrared and Fourier transform Raman spectra of this compound and its deuterated analogue were recorded in the regions 400-4000 cm(-1) and 40-4000 cm(-1), respectively. The calculated geometrical parameters of tetra-acetylethane were compared to the experimental results of this compound and its parent molecule (acetylacetone), obtained from X-ray diffraction. The O...O distance in tetra-acetylethane, about 2.424A, suggests that the hydrogen bond in this compound is stronger than acetylacetone. This conclusion is well supported by the NMR proton chemical shifts and O-H stretching mode at 2626 cm(-1). Furthermore, the calculated hydrogen bond energy in the title compound is 17.22 kcal/mol, which is greater than the acetylacetone value. On the other hand, the results of theoretical calculations show that the bulky substitution in alpha-position of acetylacetone results in an increase of the conjugation of pi electrons in the chelate ring. Finally, we applied the atoms in molecules (AIM) theory and natural bond orbital method (NBO) for detail analyzing the hydrogen bond in tetra-acetylethane and acetylacetone. These results are in agreement with the vibrational spectra interpretation and quantum chemical calculation results. Also, the conformations of methyl groups with respect to the plane of the molecule and with respect to each other were investigated.
Vadiraja, G. K.; Mahapatra, D. Roy
2009-03-01
In this paper we incorporate a novel approach to synthesize a class of closed-loop feedback control, based on the variational structure assignment. Properties of a viscoelastic system are used to design an active feedback controller for an undamped structural system with distributed sensor, actuator and controller. Wave dispersion properties of onedimensional beam system have been studied. Efficiency of the chosen viscoelastic model in enhancing damping and stability properties of one-dimensional viscoelastic bar have been analyzed. The variational structure is projected on a solution space of a closed-loop system involving a weakly damped structure with distributed sensor and actuator with controller. These assign the phenomenology based internal strain rate damping parameter of a viscoelastic system to the usual elastic structure but with active control. In the formulation a model of cantilever beam with non-collocated actuator and sensor has been considered. The formulation leads to the matrix identification problem of two dynamic stiffness matrices. The method has been simplified to obtain control system gains for the free vibration control of a cantilever beam system with collocated actuator-sensor, using quadratic optimal control and pole-placement methods.
Durig, James R., E-mail: durigj@umkc.edu [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Guirgis, Gamil A. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States); Sawant, Dattatray K. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Seifert, Nathan A. [Department of Chemistry , University of Virginia, Charlottesville, VA 22904 (United States); Deodhar, Bhushan S. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Pate, Brooks H. [Department of Chemistry , University of Virginia, Charlottesville, VA 22904 (United States); Panikar, Savitha S.; Groner, Peter [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Overby, Jason S.; Askarian, Sahand M. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States)
2014-12-05
Highlights: • The most stable cis conformer has been identified from microwave spectra. • Enthalpy difference has been determined between the two forms. • Adjusted r{sub 0} structures were obtained for cis and gauche form. • Ab initio calculations were performed for the two conformers. - Abstract: The FT-microwave spectrum (6000–19,800 MHz) of cyclopropylcyanosilane, c-C{sub 3}H{sub 5}SiH{sub 2}CN has been recorded and 773 transitions for the {sup 28}Si, {sup 29}Si, {sup 30}Si, {sup 13}C and {sup 15}N isotopomers have been assigned for cis and gauche conformers. Infrared spectra (3200–220 cm{sup −1}) of gas and Raman spectra (3200–40 cm{sup −1}) of the liquid have been recorded as well as the variable temperature (−60 to −100 °C) studies of the infrared spectra of the sample dissolved in liquid xenon. The enthalpy difference between the conformers in xenon solutions has been determined to be 123 ± 13 cm{sup −1} (1.47 ± 0.16 kJ mol{sup −1}) with the cis conformer as the more stable form. Approximately 48 ± 2% of the cis form is present at ambient temperature. By utilizing the microwave rotational constants of six isotopomers for cis and seven isotopomers for gauche combined with the structural parameters predicted from MP2(full)/6-311+G(d,p) calculations, adjusted r{sub 0} parameters have been obtained for both conformers.
Afifi, Mahmoud S; Farag, Rabei S; Shaaban, Ibrahim A; Wilson, Lee D; Zoghaib, Wajdi M; Mohamed, Tarek A
2013-07-01
The infrared (4000-200 cm(-1)) spectrum for 4-amino-5-pyrimidinecarbonitrile (APC, C5H4N4) was acquired in the solid phase. In addition, the (1)H and (13)C NMR spectra of APC were obtained in DMSO-d6 along with its mass spectrum. Initially, six isomers were hypothesized and then investigated by means of DFT/B3LYP and MP2(full) quantum mechanical calculations using a 6-31G(d) basis set. Moreover, the (1)H and (13)C NMR chemical shifts were predicted using a GIAO approximation at the 6-311+G(d,p) basis set and the B3LYP method with (and without) solvent effects using PCM method. The correlation coefficients showed good agreement between the experimental/theoretical chemical shift values of amino tautomers (1 and 2) rather than the eliminated imino tautomers (3-6), in agreement with the current quantum mechanical calculations. Structures 3-6 are less stable than the amino tautomers (1 and 2) by about 5206-8673 cm(-1) (62.3-103.7 kJ/mol). The MP2(full)/6-31G(d) computational results favor the amino structure 1 with a pyramidal NH2 moiety and calculated real vibrational frequencies, however; structure 2 is considered a transition state owing to the calculated imaginary frequency. It is worth mentioning that, the calculated structural parameters suggest a strong conjugation between the amino nitrogen and pyrimidine ring. Aided by frequency calculations, normal coordinate analysis, force constants and potential energy distributions (PEDs), a complete vibrational assignment for the observed bands is proposed herein. Finally, NH2 internal rotation barriers for the stable non-planar isomer (1) were carried out using MP2(full)/6-31G(d) optimized structural parameters. Our results are discussed herein and compared to structural parameters for similar molecules whenever appropriate.
Klaassen, Joshua J; Darkhalil, Ikhlas D; Deodhar, Bhushan S; Gounev, Todor K; Gurusinghe, Ranil M; Tubergen, Michael J; Groner, Peter; Durig, James R
2013-08-01
The FT-microwave spectrum of cyclobutylcarboxylic acid chloride, c-C4H7C(O)Cl, has been recorded and 153 transitions for the (35)Cl and (37)Cl isotopologues have been assigned for the gauche-equatorial (g-Eq) conformation. The ground state rotational constants were determined for (35)Cl [(37)Cl]: A = 4349.8429(25) [4322.0555(56)] MHz, B = 1414.8032(25) [1384.5058(25)] MHz, and C = 1148.2411(25) [1126.3546(25)] MHz. From these rotational constants and ab initio predicted parameters, adjusted r0 parameters are reported with distances (Å) rCα-C = 1.491(4), rC═O = 1.193(3), rCα-Cβ = 1.553(4), rCα-Cβ' = 1.540(4), rCγ-Cβ = 1.547(4), rCγ-Cβ' = 1.546(4), rC-Cl = 1.801(3) and angles (deg) τCγCβCβ'Cα = 30.9(5). Variable temperature (-70 to -100 °C) infrared spectra (4000 to 400 cm(-1)) were recorded in liquid xenon and the g-Eq conformer was determined the most stable form, with enthalpy differences of 91 ± 9 cm(-1) (1.09 ± 0.11 kJ/mol) for the gauche-axial (g-Ax) form and 173 ± 17 cm(-1) (2.07 ± 0.20 kJ/mol) for the trans-equatorial (t-Eq) conformer. The relative amounts at ambient temperature are 54% g-Eq, 35 ± 1% g-Ax, and 12 ± 1% t-Eq forms. Vibrational assignments have been provided for the three conformers and theoretical calculations were carried out. The results are discussed and compared to corresponding properties of related molecules.
Wang, Lin; Ishiyama, Tatsuya; Morita, Akihiro
2017-09-14
Using the flexible and polarizable model in the preceding paper, we performed comprehensive analysis of C-H stretching vibrations of ethanol and partially deuterated ones by molecular dynamics (MD) simulation. The overlapping band structures of the C-H stretching region including (i) methyl and methylene, (ii) the number of modes with Fermi resonances, and (iii) different trans/gauche conformers are disentangled by various analysis methods, such as isotope exchange, empirical potential parameter shift analysis, and separate calculations of conformers. The present analysis with MD simulation revealed unified assignment of infrared, Raman, and sum frequency generation (SFG) spectra. The analysis confirmed that the different conformers have significant influence on the assignment of CH2 vibrations. Band components and their signs in the imaginary χ((2)) spectra of SFG under various polarizations are also understood from the common assignment with the infrared and Raman spectra.
Costa, Renyer A.; Pitt, Priscilla Olliveira; Pinheiro, Maria Lucia B.; Oliveira, Kelson M. T.; Salomé, Kahlil Schwanka; Barison, Andersson; Costa, Emmanoel Vilaça
2017-03-01
A combined experimental and theoretical DFT study of the structural, vibrational and electronic properties of liriodenine is presented using B3LYP function with 6-311G (2d, p) basis set. The theoretical geometry optimization data were compared with the X-ray data for a similar structure in the associated literature, showing similar values. In addition, natural bond orbitals (NBOs), HOMO-LUMO energy gap, mapped molecular Electrostatic Potential (MEP) surface calculation, first and second order hyperpolarizabilities were also performed with the same calculation level. Theoretical UV spectrum agreed well with the measured experimental data, with transitions assigned. The molecular electrostatic potential map shows opposite potentials regions that forms hydrogen bonds that stabilize the dimeric form, which were confirmed by the close values related to the C dbnd O bond stretching between the dimeric form and the experimental IR spectra (1654 cm- 1 for the experimental, 1700 cm- 1 for the dimer form). Calculated HOMO/LUMO gaps shows the excitation energy for Liriodenine, justifying its stability and kinetics reaction. Molecular docking studies with Candida albicans dihydrofolate reductase (DHFR) and Candida albicans secreted aspartic protease (SAP) showed binding free energies values of - 8.5 and - 8.3 kcal/mol, suggesting good affinity between the liriodenine and the target macromolecules.
Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters
Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.
2015-10-01
Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture.
Reliability of vibration energy harvesters of metal-based PZT thin films
Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.
2014-11-01
This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s2. However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s2. The transverse piezoelectric coefficient (e31,f) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s2 and 36% at 25 m/s2 if we continue to excite the PVEHs for 30 years.
Won-Suk Kim
2015-01-01
Full Text Available The utilization of wireless mesh networks (WMNs has greatly increased, and the multi-interface multichannel (MIMC technic has been widely used for the backbone network. Unfortunately, the ad hoc on-demand distance vector (AODV routing protocol defined in the IEEE 802.11s standard was designed for WMNs using the single-interface single-channel technic. So, we define a problem that happens when the legacy AODV is used in MIMC WMNs and propose an interface assignment-based AODV (IA-AODV in order to resolve that problem. IA-AODV, which is based on multitarget path request, consists of the PREQ prediction scheme, the PREQ loss recovery scheme, and the PREQ sender assignment scheme. A detailed operation according to various network conditions and services is introduced, and the routing efficiency and network reliability of a network using IA-AODV are analyzed over the presented system model. Finally, after a real-world test-bed for MIMC WMNs using the IA-AODV routing protocol is implemented, the various indicators of the network are evaluated through experiments. When the proposed routing protocol is compared with the existing AODV routing protocol, it performs the path update using only 14.33% of the management frames, completely removes the routing malfunction, and reduces the UDP packet loss ratio by 0.0012%.
Durig, James R; Panikar, Savitha S; Obenchain, Daniel A; Bills, Brandon J; Lohan, Patrick M; Peebles, Rebecca A; Peebles, Sean A; Groner, Peter; Guirgis, Gamil A; Johnston, Michael D
2012-01-28
The microwave spectrum (6500-18 ,500 MHz) of 1-fluoro-1-silacyclopentane, c-C(4)H(8)SiHF has been recorded and 87 transitions for the (28)Si, (29)Si, (30)Si, and (13)C isotopomers have been assigned for a single conformer. Infrared spectra (3050-350 cm(-1)) of the gas and solid and Raman spectrum (3100-40 cm(-1)) of the liquid have also been recorded. The vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twist form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict the envelope-axial and envelope-equatorial conformers to be saddle points with nearly the same energies but much lower energy than the planar conformer. By utilizing the microwave rotational constants for seven isotopomers ((28)Si, (29)Si, (30)Si, and four (13)C) combined with the structural parameters predicted from the MP2(full)/6-311+G(d,p) calculations, adjusted r(0) structural parameters have been obtained for the twist conformer. The heavy atom distances in Å are: r(0)(SiC(2)) = 1.875(3); r(0)(SiC(3)) = 1.872(3); r(0)(C(2)C(4)) = 1.549(3); r(0)(C(3)C(5)) = 1.547(3); r(0)(C(4)C(5)) = 1.542(3); r(0)(SiF) = 1.598(3) and the angles in degrees are: [angle]CSiC = 96.7(5); [angle]SiC(2)C(4) = 103.6(5); [angle]SiC(3)C(5) = 102.9(5); [angle]C(2)C(4)C(5) = 108.4(5); [angle]C(3)C(5)C(4) = 108.1(5); [angle]F(6)Si(1)C(2) = 110.7(5); [angle]F(6)Si(1)C(3) = 111.6(5). The heavy atom ring parameters are compared to the corresponding r(s) parameters. Normal coordinate calculations with scaled force constants from MP2(full)/6-31G(d) calculations were carried out to predict the fundamental vibrational frequencies, infrared intensities, Raman activities, depolarization values, and infrared band contours. These experimental and theoretical results are compared to the corresponding quantities of some other five-membered rings.
Gao, Rui-Qi; Fan, Jun; Tan, Qi; Guo, Dong; Chen, Tao; He, Ru-Jian; Li, Dan; Zhang, Hui; Zhang, Wei-Guang
2017-09-01
Resolution of chiral compounds has played an important role in the pharmaceutical field, involving detailed studies of pharmacokinetics, physiological, toxicological, and metabolic activities of enantiomers. Herein, a reliable method by high-performance liquid chromatography (HPLC) coupled with an optical rotation detector was developed to separate isoborneol enantiomers. A cellulose tris(3, 5-dimethylphenylcarbamate)-coated chiral stationary phase showed the best separation performance for isoborneol enantiomers in the normal phase among four polysaccharide chiral packings. The effects of alcoholic modifiers and column temperature were studied in detail. Resolution of the isoborneol racemate displayed a downward trend along with an increase in the content of ethanol and column temperature, indicating that less ethanol in the mobile phase and lower temperature were favorable to this process. Moreover, two isoborneol enantiomers were obtained via a semipreparative chiral HPLC technique under optimum conditions, and further characterized by analytical HPLC, and experimental and calculated vibrational circular dichroism (VCD) spectroscopy, respectively. The solution VCD spectrum of the first-eluted component was consistent with the Density Functional Theory (DFT) calculated pattern based on the SSS configuration, indicating that this enantiomer should be (1S, 2S, 4S)-(+)-isoborneol. Briefly, these results have provided reliable information to establish a method for analysis, preparative separation, and absolute configuration of chiral compounds without typical chromophoric groups. © 2017 Wiley Periodicals, Inc.
Bai, Zheng-Jian; Chen, Mei-Xiang; Datta, Biswa Nath
2013-02-01
The partial quadratic eigenvalue assignment problem (PQEAP) is to compute a pair of feedback matrices such that a small number of unwanted eigenvalues in a structure are reassigned to suitable locations while keeping the remaining large number of eigenvalues and the associated eigenvectors unchanged. The problem arises in active vibration control of structures. For real-life applications, it is not enough just to compute the feedback matrices. They should be computed in such a way that both closed-loop eigenvalue sensitivity and feedback norms are as small as possible. Also, for practical effectiveness, the time-delay between the measurement of the state and implementation of the feedback controller should be considered while solving the PQEAP. These problems are usually solved using only system matrices and do not necessarily take advantage of the receptances which are available by measurements. In this paper, we propose hybrid methods, combining the system matrices and measured receptances, for solutions of the multi-input PQEAP and the minimum-norm PQEAP, both for systems with and without time-delay. These hybrid methods are more efficient than the standard methods which only use the system matrices and not the receptances. These hybrid methods also offer several other computational advantages over the standard methods. Our results generalize the recent work by Ram et al. [Partial pole placement with time delay in structures using the receptance and the system matrices, Linear Algebra and its Applications 434 (2011) 1689-1696]. The results of numerical experiments demonstrate the effectiveness of the proposed methods.
Shaaban, Ibrahim A.; Karoyo, Abdalla; Wilson, Lee D.; Mohamed, Tarek A.
2017-08-01
The Raman spectrum (3700-100 cm- 1) of meso-2,3-Dimercaptosuccinic acid (meso-DMSA; C4H6O4S2) was recorded in the solid phase using 514.5 and 785 nm excitation lines. Whereas, the DRIFT spectrum (4000-400 cm- 1) of the sample powdered in KBr was obtained. Moreover, DFT-B3LYP/6-31G(d) geometry optimization and frequency calculations were carried out for centrosymmetric trans (Ci), gauche (C1; G+/G-) and eclipsed (Cs; Ef and C1; E+/E-) rotational isomers in favor of a trans conformation, the least energy with real frequencies. However, other conformers were found at either local minima or local maxima as a result of the rotation of carboxyl, hydroxyl and thiol groups according to a potential energy surface scan. Moreover, an imaginary wavenumber was predicted; therefore, they are considered transition states. On the other hand, the mass spectrum of the sample dissolved in an acetonitrile/methanol mixture reveal 4-6% dimer through intermolecular hydrogen bonding interactions via the dicarboxylic groups. Therefore, we have modeled the complex structure obeying Ci restricted symmetry for an isolated dimer unit using DFT-B3LYP/6-31G(d) and for two molecules per unit cell in the solid phase implementing DFT-PBE functional. Thus, the meso-DMSA forms long strands in which individual molecules are bonded together at each termini through hydrogen bonding. Aided by normal coordinate analysis, complete vibrational assignments were provided herein which support Ci configuration of meso-DMSA in the solid state which found consistent with the observed broadening, composite, split bands, and the mutual exclusion rule.
ZHANG; Yimin; (张义民); WANG; Shun; (王; 顺); LIU; Qiaoling; (刘巧伶); WEN; Bangchun; (闻邦椿)
2003-01-01
Based on the generalized probabilistic finite element method, this paper presents an approximate solution technique for general multi-degree-of-freedom nonlinear random vibration systems with random parameters. The fourth-moment technique, maximum entropy theory and incomplete probability information theory are employed to systematically develop a reliability analysis method for dynamic random structural systems with correlation failure modes under unavailable joint probability density functions of basic random variables. The first passage problem of multi-degree-of-freedom nonlinear random vibration systems is solved.
Trommsdorff, H.P.; Zelsmann, H.R.
1985-01-01
Far-infrared (20–230 cm–1) absorption spectra of p-benzoquinone-h4,-d4 and of toluquinone have been measured. In the vapor phase, the lowest frequency vibration of these three compounds is found at 88.9, 87.5, and 82.3 cm–1, respectively. In the condensed phase the frequency increases by
Trommsdorff, H.P.; Zelsmann, H.R.
1985-01-01
Far-infrared (20–230 cm–1) absorption spectra of p-benzoquinone-h4,-d4 and of toluquinone have been measured. In the vapor phase, the lowest frequency vibration of these three compounds is found at 88.9, 87.5, and 82.3 cm–1, respectively. In the condensed phase the frequency increases by approximate
杨小震
1995-01-01
A method of simulation of vibrational spectra by using the "internal coordinatecorrelation" based on molecular dynamics algorithms and auto-correlation function has been developed.The in-ternal coordinates,such as bond stretching,bond angle bending,out-of-plane bending and torsion,are treatedas the dynamic variables to obtain a density spectrum or the "internal coordinate correlation" spectrum Theadvantages of this method are as follows:i)it is easier to assign vibration modes for the density spectra;ii)itsimply connects the Fourier transformed "internal coordinate correlation" function to the eigenvectors innormal coordinate analysis;iii)it is a basis for simulating IR and Raman active spectra of a large molecularsystem.
Andersen, J.; Heimdal, J.; Mahler, D. W.; Nelander, B.; Larsen, R. Wugt
2014-03-01
Terahertz absorption spectra have been recorded for the weakly bound CO2-H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems' flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm-1 from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm-1 for the dissociation energy D0.
Andersen, J.; Mahler, D. W.; Larsen, R. Wugt, E-mail: rewl@kemi.dtu.dk [Department of Chemistry, Technical University of Denmark, Kemitorvet 206, 2800 Kgs. Lyngby (Denmark); Heimdal, J.; Nelander, B. [MAX-IV Laboratory, Lund University, P. O. Box 118, 22100 Lund (Sweden)
2014-03-07
Terahertz absorption spectra have been recorded for the weakly bound CO{sub 2}–H{sub 2}O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H{sub 2}O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm{sup −1} from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm{sup −1} for the dissociation energy D{sub 0}.
Andersen, Jonas; Heimdal, J.; Wallin Mahler Andersen, Denise; Nelander, B.; Larsen, René Wugt
2014-01-01
Terahertz absorption spectra have been recorded for the weakly bound CO2–H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point e...
Andersen, J.; Heimdal, Jimmy; Mahler, D W; Nelander, Bengt; Wugt Larsen, R
2014-01-01
Terahertz absorption spectra have been recorded for the weakly bound CO2-H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems' flat intermolecular potential energy surface. A (semi)-empirical value for the zero-poi...
Jone Pradeepa, S; Sundaraganesan, N
2014-05-05
In this present investigation, the collective experimental and theoretical study on molecular structure, vibrational analysis and NBO analysis has been reported for 2-aminofluorene. FT-IR spectrum was recorded in the range 4000-400 cm(-1). FT-Raman spectrum was recorded in the range 4000-50 cm(-1). The molecular geometry, vibrational spectra, and natural bond orbital analysis (NBO) were calculated for 2-aminofluorene using Density Functional Theory (DFT) based on B3LYP/6-31G(d,p) model chemistry. (13)C and (1)H NMR chemical shifts of 2-aminofluorene were calculated using GIAO method. The computed vibrational and NMR spectra were compared with the experimental results. The total energy distribution (TED) was derived to deepen the understanding of different modes of vibrations contributed by respective wavenumber. The experimental UV-Vis spectra was recorded in the region of 400-200 nm and correlated with simulated spectra by suitably solvated B3LYP/6-31G(d,p) model. The HOMO-LUMO energies were measured with time dependent DFT approach. The nonlinearity of the title compound was confirmed by hyperpolarizabilty examination. Using theoretical calculation Molecular Electrostatic Potential (MEP) was investigated.
Kiana, Samaneh; Yazdanbakhsh, Mohammad; Jamialahmadi, Mina; Tayyari, Sayyed Faramarz
2014-09-15
[Fe3O(OOCH)6(H2O)3]OOCH·HCOOH, and [Cr3O(OOCH)6(H2O)3]OOCH·2.5HNO3 were synthesized and the molecular structure and vibrational assignments of their cations were investigated by means of density functional theory (DFT) calculations. The harmonic vibrational frequencies of [Fe3O(OOCH)6(H2O)3]+ and [Cr3O(OOCH)6(H2O)3]+ were obtained at the UB3LYP level using a series of basis sets. The topological properties of the charge distribution of both cations in their ground states are discussed in detail by means of natural bond orbital (NBO) theory and of [Fe3O(OOCH)6(H2O)3]+ by the quantum theory of atoms in molecules (AIM). The calculated geometrical parameters and vibrational frequencies were compared with the experimental results. The scaled theoretical frequencies and the structural parameters were found to be in good agreement with the experimental data.
Ghalla, Houcine; Issaoui, Noureddine; Castillo, María Victoria; Brandán, Silvia Antonia; Flakus, Henryk T.
2014-03-01
The structural and vibrational properties of cyclic dimer of 2-furoic acid (2FA) were predicted by combining the available experimental infrared and Raman spectra in the solid phase and ab initio calculations based on density functional theory (DFT) with Pople's basis sets. The calculations show that there are two cyclic dimers for the title molecule that have been theoretically determined in the gas phase, and that only one of them, cis conformer, is present in the solid phase. The complete assignment of the 66 normal vibrational modes for the cis cyclic dimer was performed using the Pulay's Scaled Quantum Mechanics Force Field (SQMFF) methodology. Four strong bands in the infrared spectrum at 1583, 1427, 1126 and 887 cm-1 and the group of bands in the Raman spectrum at 1464, 1452, 1147, 1030, 885, 873, 848, 715 and 590 cm-1 are characteristic of the dimeric form of 2FA in the solid phase. In this work, the calculated structural and vibrational properties of both dimeric species were analyzed and compared between them. In addition, three types of atomic charges, bond orders, possible charge transfer, topological properties of the furan rings, Natural Bond Orbital (NBO) and Atoms in Molecules (AIM) theory calculations were employed to study the stabilities and intermolecular interactions of the both dimers of 2FA.
Toy, Mehmet; Tanak, Hasan
2016-01-05
In the present work, a combined experimental and theoretical study on ground state molecular structure, spectroscopic and nonlinear optical properties of azo compound 3'-chloro-4-dimethlamino azobenzene are reported. The molecular geometry, vibrational wavenumbers and the first order hyperpolarizability of the title compound were calculated with the help of density functional theory computations. The optimized geometric parameters obtained by using DFT (B3LYP/6-311++G(d,p)) show good agreement with the experimental data. The vibrational transitions were identified based on the recorded FT-IR spectra in the range of 4000-400cm(-1) for solid state. The (1)H isotropic chemical shifts with respect to TMS were also calculated using the gauge independent atomic orbital (GIAO) method and compared with the experimental data. Using the TD-DFT method, electronic absorption spectra of the title compound have been predicted, and good agreement is determined with the experimental ones. To investigate the NLO properties of the title compound, the polarizability and the first hyperpolarizability were calculated using the density functional B3LYP method with the 6-311++G(d,p) basis set. According to results, the title compound exhibits non-zero first hyperpolarizability value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential and frontier molecular orbitals were also performed at 6-311++G(d,p) level of theory.
Toy, Mehmet; Tanak, Hasan
2016-01-01
In the present work, a combined experimental and theoretical study on ground state molecular structure, spectroscopic and nonlinear optical properties of azo compound 3‧-chloro-4-dimethlamino azobenzene are reported. The molecular geometry, vibrational wavenumbers and the first order hyperpolarizability of the title compound were calculated with the help of density functional theory computations. The optimized geometric parameters obtained by using DFT (B3LYP/6-311++G(d,p)) show good agreement with the experimental data. The vibrational transitions were identified based on the recorded FT-IR spectra in the range of 4000-400 cm-1 for solid state. The 1H isotropic chemical shifts with respect to TMS were also calculated using the gauge independent atomic orbital (GIAO) method and compared with the experimental data. Using the TD-DFT method, electronic absorption spectra of the title compound have been predicted, and good agreement is determined with the experimental ones. To investigate the NLO properties of the title compound, the polarizability and the first hyperpolarizability were calculated using the density functional B3LYP method with the 6-311++G(d,p) basis set. According to results, the title compound exhibits non-zero first hyperpolarizability value revealing second order NLO behavior. In addition, DFT calculations of the title compound, molecular electrostatic potential and frontier molecular orbitals were also performed at 6-311++G(d,p) level of theory.
Pate, Brooks H.; Seifert, Nathan A. [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States); Guirgis, Gamil A. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States); Deodhar, Bhushan S.; Klaassen, Joshua J.; Darkhalil, Ikhlas D. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Crow, Joseph A. [Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Wyatt, Justin K.; Dukes, Horace W. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States); Durig, James R., E-mail: durigj@umkc.edu [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States)
2013-04-18
Highlights: • Structural parameters have been determined for the stable twist conformer. • Rotational constants for the six isotopologues for the twist conformer were determined from the microwave spectra. • Vibrational assignments are given for the molecule. • Ab intio and density functional theory calculations have been carried out for all possible conformers. - Abstract: The FT-microwave spectrum of 1,1,3,3-tetrafluoro-1,3-disilacyclopentane (c-C{sub 3}H{sub 6}Si{sub 2}F{sub 4}) has been recorded and 339 transitions for 6 isotopologues have been assigned for the twist conformation. The ground state rotational constants were determined with values for the normal species: A = 2102.74026(68), B = 751.34319(32), C = 736.51478(31). Adjusted r{sub 0} parameters are reported with distances (Å): rC{sub α}–Si = 1.859(2), rSi–C{sub β} = 1.864(2), rSi–F{sub 1} = 1.583(3), rSi–F{sub 2} = 1.578(3), and rC{sub β}–C{sub β} = 1.559(3), and angles (°): ∠SiC{sub α}Si = 102.8(3), ∠C{sub α}SiC{sub β} = 104.3(3), ∠SiC{sub β}C{sub β′} = 106.6(3), τC{sub β}SiC{sub α}Si = 10.7(3), and τ SiC{sub β}C{sub β′}Si = 40.8(3). The conformational stabilities have been predicted from ab initio calculations utilizing several various basis sets. Vibrational assignments have been provided for the observed bands for the twist conformer which are supported by ab initio calculations to predict harmonic force constants, vibrational wavenumbers, infrared intensities, Raman activities and depolarization ratios. The results are discussed and compared to the corresponding properties of some related molecules.
Won-Suk Kim; Sang-Hwa Chung
2015-01-01
The utilization of wireless mesh networks (WMNs) has greatly increased, and the multi-interface multichannel (MIMC) technic has been widely used for the backbone network. Unfortunately, the ad hoc on-demand distance vector (AODV) routing protocol defined in the IEEE 802.11s standard was designed for WMNs using the single-interface single-channel technic. So, we define a problem that happens when the legacy AODV is used in MIMC WMNs and propose an interface assignment-based AODV (IA-AODV) in o...
Palings, I; van den Berg, E M; Lugtenburg, J; Mathies, R A
1989-02-21
Resonance Raman vibrational spectra of the retinal chromophore in bathorhodopsin have been obtained after regenerating bovine visual pigments with an extensive series of 13C- and deuterium-labeled retinals. A low-temperature spinning cell technique was used to produce high-quality bathorhodopsin spectra exhibiting resolved hydrogen out-of-plane wagging vibrations at 838, 850, 858, 875, and 921 cm-1. The isotopic shifts and a normal coordinate analysis permit the assignment of these lines to the HC7 = C8H Bg, C14H, C12H, C10H, and C11H hydrogen out-of-plane wagging modes, respectively. The coupling constant between the C11H and C12H wags as well as the C12H wag force constant are unusually low compared to those of retinal model compounds. This quantitatively confirms the lack of coupling between the C11H and C12H wags and the low C12H wag vibrational frequency noted earlier by Eyring et al. [(1982) Biochemistry 21, 384]. The force constants for the C10H and C14H wags are also significantly below the values observed in model compounds. We suggest that the perturbed hydrogen out-of-plane wagging and C-C stretching force constants for the C10-C11 = C12-C13 region of the chromophore in bathorhodopsin result from electrostatic interactions with a charged protein residue. This interaction may also contribute to the 33 kcal/mol energy storage in bathorhodopsin.
GAO Hai-feng; BAI Guang-chen
2015-01-01
To ameliorate reliability analysis efficiency for aeroengine components, such as compressor blade, support vector machine response surface method (SRSM) is proposed. SRSM integrates the advantages of support vector machine (SVM) and traditional response surface method (RSM), and utilizes experimental samples to construct a suitable response surface function (RSF) to replace the complicated and abstract finite element model. Moreover, the randomness of material parameters, structural dimension and operating condition are considered during extracting data so that the response surface function is more agreeable to the practical model. The results indicate that based on the same experimental data, SRSM has come closer than RSM reliability to approximating Monte Carlo method (MCM); while SRSM (17.296 s) needs far less running time than MCM (10958 s) and RSM (9840 s). Therefore, under the same simulation conditions, SRSM has the largest analysis efficiency, and can be considered a feasible and valid method to analyze structural reliability.
Craig, Norman C.; Hanson, Keith A.; Moore, M C.; Sams, Robert L.
2005-02-10
Butadiene-113C1 was synthesized, and its high-resolution (0.002 cm-1) infrared spectrum was recorded for several bands in the mid-infrared region. A complete analysis of the rotational structure in the C-type bands at 900.0 and 909 cm-1 were performed. Of these latter two bands, which are of comparable intensity, the higher frequency one is largely CH2 out-of-plane wagging and the lower frequency one is largely 13CH2 out-of-plane wagging. Taken together these bands correlate with one infrared-active au fundamental and one Raman-active bg fundamental of butadiene. The ground state rotational constants are A=1.3887919(6), B=0.1436683(3), and C=0.1302251(3) cm-1, and upper state rotational constants are reported for the bands at 524.485 and 900.0 cm-1. Medium resolution infrared and Raman spectra gave a complete assignment of the vibrational fundamentals, including 11 fundamentals observed directly for the first time.
Craig, Norman C.; Hanson, Keith A.; Moore, Michael C.; Sams, Robert L.
2005-05-01
Butadiene-1- 13C 1 was synthesized, and its high-resolution (0.002 cm -1) infrared spectrum was recorded for several bands in the mid-infrared region. A complete analysis of the rotational structure in the C-type band at 524.485 cm -1 for CH 2 twisting and a partial analysis of the rotational structure in the C-type bands at 900.0 and 909 cm -1 were performed. Of these latter two bands, which are of comparable intensity, the higher frequency one is largely CH 2 out-of-plane wagging and the lower frequency one is largely 13CH 2 out-of-plane wagging. Taken together these bands correlate with one infrared-active au fundamental and one Raman-active bg fundamental of butadiene. The ground state rotational constants are A=1.3887919 (6), B=0.1436683 (3), and C=0.1302251 (3) cm -1, and upper state rotational constants are reported for the bands at 524.485 and 900.0 cm -1. Medium resolution infrared and Raman spectra gave a complete assignment of the vibrational fundamentals, including 11 fundamentals observed directly for the first time.
Shaltout, I; Mohamed, Tarek A
2007-06-01
Chozen system of tellurite glasses doped with rare earth oxides (95% alpha-TeO(2)+5% Sm2O3) was prepared by melt quenching. Consequently, the Raman spectrum (150-1250 cm(-1)) of the modified tellurite have been recorded. As a continuation to our normal coordinate analysis, force constants and quantum mechanical (QM) calculations for tbp TeO4(4-) (triagonal bipyramid, C(2v)) and TeO(3+1); Te2O7(6-) (bridged tetrahedral), we have carried out ab initio frequency calculations for tpy TeO3(2-) (triagonal pyramidal, C(3v) and C(s)) and tp TeO3(2-) (triagonal planar, D(3h)) ions. The quantum mechanical calculations at the levels of RHF, B3LYP and MP2 allow confident vibrational assignments and structural identification in the binary oxide glass (95% alpha-TeO2 +5% Sm2O3). The dominant three-dimensional network structures in the modified glass are triagonal pyramidal TeO3 with minor features of short range distorted tbp TeO4 and bridged tetrahedral unit of TeO(3+1), leading to a structure of infinite chain. Therefore, alpha-TeO2/Sm2O3 (95/5%) glass experience structural changes from TeO4 (tbp); Te2O7 (TeO(3+1))-->TeO3 (tpy).
Shaltout, I.; Mohamed, Tarek A.
2007-06-01
Chozen system of tellurite glasses doped with rare earth oxides (95% α-TeO 2 + 5% Sm 2O 3) was prepared by melt quenching. Consequently, the Raman spectrum (150-1250 cm -1) of the modified tellurite have been recorded. As a continuation to our normal coordinate analysis, force constants and quantum mechanical (QM) calculations for tbp TeO 44- (triagonal bipyramid, C2v) and TeO 3+1; Te 2O 76- (bridged tetrahedral), we have carried out ab initio frequency calculations for tpy TeO 32- (triagonal pyramidal, C3v and Cs) and tp TeO 32- (triagonal planar, D3h) ions. The quantum mechanical calculations at the levels of RHF, B3LYP and MP2 allow confident vibrational assignments and structural identification in the binary oxide glass (95% α-TeO 2 + 5% Sm 2O 3). The dominant three-dimensional network structures in the modified glass are triagonal pyramidal TeO 3 with minor features of short range distorted tbp TeO 4 and bridged tetrahedral unit of TeO 3+1, leading to a structure of infinite chain. Therefore, α-TeO 2/Sm 2O 3 (95/5%) glass experience structural changes from TeO 4 (tbp); Te 2O 7 (TeO 3+1) → TeO 3 (tpy).
Yu, Wookyung [Pusan National University, Department of Physics, Center for Proteome Biophysics (Korea, Republic of); Lee, Woonghee; Lee, Weontae [Yonsei University, Department of Biochemistry, Structural Biochemistry and Molecular Biophysics Laboratory (Korea, Republic of); Kim, Suhkmann [Pusan National University, Department of Chemistry, Biochemistry and Bio-NMR Laboratory (Korea, Republic of); Chang, Iksoo, E-mail: iksoochang@pusan.ac.kr [Pusan National University, Department of Physics, Center for Proteome Biophysics (Korea, Republic of)
2011-12-15
Unravelling the complex correlation between chemical shifts of {sup 13}C{sup {alpha}}, {sup 13}C{sup {beta}}, {sup 13}C Prime , {sup 1}H{sup {alpha}}, {sup 15}N, {sup 1}H{sup N} atoms in amino acids of proteins from NMR experiment and local structural environments of amino acids facilitates the assignment of secondary structures of proteins. This is an important impetus for both determining the three-dimensional structure and understanding the biological function of proteins. The previous empirical correlation scores which relate chemical shifts of {sup 13}C{sup {alpha}}, {sup 13}C{sup {beta}}, {sup 13}C Prime , {sup 1}H{sup {alpha}}, {sup 15}N, {sup 1}H{sup N} atoms to secondary structures resulted in progresses toward assigning secondary structures of proteins. However, the physical-mathematical framework for these was elusive partly due to both the limited and orthogonal exploration of higher-dimensional chemical shifts of hetero-nucleus and the lack of physical-mathematical understanding underlying those correlation scores. Here we present a simple multi-dimensional hetero-nuclear chemical shift score function (MDHN-CSSF) which captures systematically the salient feature of such complex correlations without any references to a random coil state of proteins. We uncover the symmetry-breaking vector and its reliability order not only for distinguishing different secondary structures of proteins but also for capturing the delicate sensitivity interplayed among chemical shifts of {sup 13}C{sup {alpha}}, {sup 13}C{sup {beta}}, {sup 13}C Prime , {sup 1}H{sup {alpha}}, {sup 15}N, {sup 1}H{sup N} atoms simultaneously, which then provides a straightforward framework toward assigning secondary structures of proteins. MDHN-CSSF could correctly assign secondary structures of training (validating) proteins with the favourable (comparable) Q3 scores in comparison with those from the previous correlation scores. MDHN-CSSF provides a simple and robust strategy for the
Andrejeva, Anna; Tuttle, William D.; Harris, Joe P.; Wright, Timothy G., E-mail: Tim.Wright@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)
2015-12-28
We report vibrationally resolved spectra of the S{sub 1}←S{sub 0} transition of bromobenzene using resonance-enhanced multiphoton ionization spectroscopy. We study bromobenzene-h{sub 5} as well as its perdeuterated isotopologue, bromobenzene-d{sub 5}. The form of the vibrational modes between the isotopologues and also between the S{sub 0} and S{sub 1} electronic states is discussed for each species, allowing assignment of the bands to be achieved and the activity between states and isotopologues to be established. Vibrational bands are assigned utilizing quantum chemical calculations, previous experimental results, and isotopic shifts. Previous work and assignments of the S{sub 1} spectra are discussed. Additionally, the vibrations in the ground state cation, D{sub 0}{sup +}, are considered, since these have also been used by previous workers in assigning the excited neutral state spectra. We also examine the vibrations of iodobenzene in the S{sub 0} and D{sub 0}{sup +} states and comment on the previous assignments of these. In summary, we have been able to assign the corresponding vibrations across the whole monohalobenzene series of molecules, in the S{sub 0}, S{sub 1}, and D{sub 0}{sup +} states, gaining insight into vibrational activity and vibrational couplings.
Haji Hosseinloo, Ashkan; Ehteshami, Mohsen Mousavi
2017-10-01
Performance reliability and mechanical integrity are the main bottlenecks in mass commercialization of PEMFCs for applications with inherent harsh environment such as automotive and aerospace applications. Imparted shock and vibration to the fuel cell in such applications could bring about numerous issues including clamping torque loosening, gas leakage, increased electrical resistance, and structural damage and breakage. Here, we provide a comprehensive review and critique of the literature focusing on the effects of mechanically harsh environment on PEMFCs, and at the end, we suggest two main future directions in FC technology research that need immediate attention: (i) developing a generic and adequately accurate dynamic model of PEMFCs to assess the dynamic response of FC devices, and (ii) designing effective and robust shock and vibration protection systems based on the developed models in (i).
Barsberg, Søren Talbro; Sanadi, Anand Ramesh; Jørgensen, Henning
2011-01-01
method for polysaccharide IR band assignments. Palm kernel cake is enzymatically hydrolyzed and fermented, which targets cellulose and mannan in particular. The DFT method helps to identify their spectral changes and gives new knowledge on their spectral signatures. This method thus provides...... a prerequisite for FT-IR analysis. The removal of mannan is identified and correlates with positional shifts of both the mannan glycosidic linkage vibration at 1180 cm-1 and the 896 cm-1 cellulose exocyclic C6H2 vibration. This indicates a cellulose environment change, and for mannan the theoretical results show...... a decreasing degree of polymerization to be a plausible cause, although others may interfere. Keywords: Cellulose; Mannan; FT-IR; DFT; Molecular modelling; Palm kernel...
Vennila, P.; Govindaraju, M.; Venkatesh, G.; Kamal, C.
2016-05-01
Fourier transform - Infra red (FT-IR) and Fourier transform - Raman (FT-Raman) spectroscopic techniques have been carried out to analyze O-methoxy benzaldehyde (OMB) molecule. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT). The vibrational analysis of stable isomer of OMB has been carried out by FT-IR and FT-Raman in combination with theoretical method simultaneously. The first-order hyperpolarizability and the anisotropy polarizability invariant were computed by DFT method. The atomic charges, hardness, softness, ionization potential, electronegativity, HOMO-LUMO energies, and electrophilicity index have been calculated. The 13C and 1H Nuclear magnetic resonance (NMR) have also been obtained by GIAO method. Molecular electronic potential (MEP) has been calculated by the DFT calculation method. Electronic excitation energies, oscillator strength and excited states characteristics were computed by the closed-shell singlet calculation method.
樊铁钢
2000-01-01
The vibrational systems of a class of Timoshenko-beams are discussed.The conditions of the asymptotic stability and pole-assignment of the closed-loop systems of Timoshenko-beam are given out,where the theory of semigroups of linear operators and unconditional basis theory and the theory of (D) operators are used.%利用了算子半群理论、无条件基理论和(D)类算子理论讨论了一类Timoshenko梁振动系统,给出了闭环系统渐近稳定与极点配置的条件.
Andersen, Jonas; Heimdal, J.; Wallin Mahler Andersen, Denise
2014-01-01
Terahertz absorption spectra have been recorded for the weakly bound CO2–H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit...
Endres, Christian; Caselli, Paola; Martin-Drumel, Marie-Aline; McCarthy, Michael C.; Pirali, Olivier; Wehres, Nadine; Schlemmer, Stephan; Thorwirth, Sven
2016-06-01
Vibrational spectra of small organic nitriles, propionitrile and n-butyronitrile, have been investigated at high spectral resolution at the French national synchroton facility SOLEIL using Fourier-transform far-infrared spectroscopy (A. Martin-Drumel, C. P. Endres, O. Zingsheim, T. Salomon, J. van Wijngaarden, O. Pirali, S. Gruet, F. Lewen, S. Schlemmer, M. C. McCarthy, and S. Thorwirth 2015, J. Mol. Spectrosc. 315, 72
振动环境下MEMS加速度计的可靠性评估%Reliability Evaluation of MEMS Accelerometer in Vibration Environment
秦丽; 王孟美; 何蕴泽; 于丽霞; 刘俊
2016-01-01
Based on the accelerated life test and accelerated degradation test of MEMS accelerometer,the reliability technology of MEMS accelerometer in vibration environment is studied. The failure mode and failure mechanism of MEMS accelerometer in vibration environment are analyzed by theory,the accelerated life test and accelerated deg-radation test scheme are designed,and the reliability evaluation of the failure data of MEMS accelerometer under vi-bration environment is carried out. The results show that the evaluation results of the two evaluation methods are ba-sically consistent. The accelerated performance degradation assessment method is suitable for the reliability study of MEMS accelerometer in vibration environment,and the method is simple,accurate and feasible. It can provide important reference for MEMS accelerometer in practical application.%在MEMS加速度计加速寿命试验及加速性能退化试验研究的基础上,对MEMS加速度计在振动环境下的可靠性技术进行了研究.通过理论分析MEMS加速度计在振动环境下的失效模式和失效机理,结合具体的试验条件设计了加速度计加速寿命试验及加速性能退化试验方案,并对MEMS加速度计在振动环境下的失效数据分别进行了加速寿命可靠性评估及加速性能退化可靠性评估.研究表明,两种评估方法得到的评估结果基本一致;加速性能退化评估方法适用于MEMS加速度计在振动环境中的可靠性研究,且该方法简捷、正确可行、节省试验费用,为MEMS加速度计在实际应用中提供了重要的参考依据.
Malik, Magdalena; Wysokiński, Rafał; Zierkiewicz, Wiktor; Helios, Katarzyna; Michalska, Danuta
2014-08-28
Picoplatin, cis-[PtCl2(NH3)(2-picoline)], is a new promising anticancer agent undergoing clinical trials, which reveals high efficacy against many tumors and greatly reduced toxicity, in comparison to cisplatin. In this work, we present for the first time the Fourier-transform Raman and infrared spectra of picoplatin, in the region of 3500-50 cm(-1). The comprehensive theoretical studies on the molecular structure, the nature of Pt-ligand bonding, vibrational frequencies, and intensities were performed by employing different DFT methods, including hybrid (PBE0, mPW1PW, and B3LYP) and long-range-corrected hybrid density functionals (LC-ωPBE, CAM-B3LYP). Various effective core potentials (ECP) and basis sets have been used. In the prediction of the molecular structure of picoplatin, the best results have been obtained by LC-ωPBE, followed by PBE0, mPW1PW, and CAM-B3LYP density functionals, while the least accurate is B3LYP. The use of the LanL2TZ(f) ECP/basis set for Pt, in conjunction with all tested DFT methods, improves the calculated geometry of the title complex. The PBE0, mPW1PW, and CAM-B3LYP methods have shown the best performance in the calculations of the frequencies of Pt-ligand vibrations. A clear-cut assignment of all the bands in the IR and Raman spectra have been made on the basis of the calculated potential energy distribution (PED). The nature of the "vibrational signatures" of picoplatin have been determined. These results are indispensable for further investigation on drug-target interactions using vibrational spectroscopy.
Kabbara, Alan; McCarthy, John; Burnett, Timm; Forster, Ian [National Oilwell Varco Downhole Ltd. (NOV), Houston, TX (United States)
2012-07-01
This paper describes the work, on test rigs and full-scale drilling rigs, carried out with respect to placement of an Asymmetric Vibration Damping Tool (AVDT) within drilling while under reaming operations. An AVDT, by virtue of the forward synchronous motion imposed on the drill string, offers benefits in minimizing down hole vibration-related tool failures and therefore maximizing rate of penetration (ROP). Of interest in using the AVDT is the tendency to minimize stick slip by means of the parasitic torque it generates. This is of particular importance during under reaming operations. While under reaming, stick slip can result in low (ROP) and potentially an increased incidence of down hole tool failures. The use of an AVDT in these operations has been shown to significantly reduce stick slip. However, due to the forward synchronous motion caused by the AVDT, there is the potential to cause eccentric wear to the Bottom Hole Assembly (BHA) components in the vicinity of the AVDT. If allowed to progress, this eccentric wear can cause a reduction in down hole tool life and drilling performance. Eliminating eccentric wear would be beneficial in reducing repair costs, extending component life and further improving drilling performance. To minimize eccentric wear and maximize drilling performance, the placement of the AVDT within the BHA is critical. This paper describes how the placement of intermediate stabilizers between the AVDT and the under reamer can minimize eccentric wear to the under reamer and the adjacent drill string due to the forward synchronous whirl induced by the AVDT. This approach allows the full benefits of the AVDT to be recognized while reducing the potentially damaging effects of eccentric wear to other BHA components. The work has drawn upon small-scale rig testing, full-scale testing at the Ullrigg test facility in Norway and from real-world drilling and under reaming operations in the USA. (author)
Haress, Nadia G.; Al-Omary, Fatmah; El-Emam, Ali A.; Mary, Y. Sheena; Panicker, C. Yohannan; Al-Saadi, Abdulaziz A.; War, Javeed Ahmad; Van Alsenoy, Christian
2015-01-01
FT-IR and FT-Raman spectra of 2-(Adamantan-1-yl)-5-(4-nitrophenyl)-1,3,4-oxadiazole were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign vibrational bands obtained experimentally. The energy barriers of the internal rotations about the Csbnd C bonds connecting the oxadiazole to the adamantane and benzene rings are reported. The geometrical parameters (DFT) of the title compound are in agreement with the XRD results. The calculated HOMO and LUMO energies allow the calculations of atomic and molecular properties and they also showed that charge transfer occurs in the molecule. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. As can be seen from the MEP map of the title compound, which regions having the negative potential are over the electro negative atoms, the region having the positive potential are over the phenyl and adamantine rings and the remaining species are surrounded by zero potential. The molecular docking studies reveal that the adamantyl derivative may exhibit C-South African HIV-proteas inhibitory activity.
Zahedi-Tabrizi, Mansoureh; Gerivani, Bentolhoda; Tayyari, Sayyed Faramarz
2015-02-01
The molecular structure of 3-(ortho-methoxyphenylthio) pentane-2,4-dione (o-MPTPD) and 3-(para-methoxyphenylthio) pentane-2,4-dione (p-MPTPD) has been investigated by means of Density Functional Theory (DFT) calculations. The results were compared with 3-(phenylthio) pentane-2,4-dione (PTPD), 3-(methylthio) pentane-2,4-dione (MTPD), and their parent, pentane-2,4-dione (known as acetylacetone, AA). The full optimized geometry, the IR and Raman frequencies and their intensities has been calculated at the B3LYP/6-311++G∗∗ level of theory. The calculated frequencies were compared with the experimental results. The IR and Raman spectra of o-MPTPD and p-MPTPD and their deuterated analogs are recorded in the 3200-200 cm-1 range. The quantum theory of atoms in molecules (QTAIM) was applied to calculate the topological parameters of electron density distributions and charge transfer energy associated with the intramolecular hydrogen bond (IHB). Natural bond orbital analysis (NBO) was performed for investigation of electron delocalization in these compounds. According to the theoretical and experimental data, the hydrogen bond strength in the 3-thio-pentane-2,4-dione derivatives is much stronger than that in AA. The results of theoretical calculations are in excellent agreement with the vibrational and NMR spectroscopy data.
Zhang, Bochao; Meng, Wenzhao; Prak, Eline T Luning; Hershberg, Uri
2015-12-01
Immune repertoires are collections of lymphocytes that express diverse antigen receptor gene rearrangements consisting of Variable (V), (Diversity (D) in the case of heavy chains) and Joining (J) gene segments. Clonally related cells typically share the same germline gene segments and have highly similar junctional sequences within their third complementarity determining regions. Identifying clonal relatedness of sequences is a key step in the analysis of immune repertoires. The V gene is the most important for clone identification because it has the longest sequence and the greatest number of sequence variants. However, accurate identification of a clone's germline V gene source is challenging because there is a high degree of similarity between different germline V genes. This difficulty is compounded in antibodies, which can undergo somatic hypermutation. Furthermore, high-throughput sequencing experiments often generate partial sequences and have significant error rates. To address these issues, we describe a novel method to estimate which germline V genes (or alleles) cannot be discriminated under different conditions (read lengths, sequencing errors or somatic hypermutation frequencies). Starting with any set of germline V genes, this method measures their similarity using different sequencing lengths and calculates their likelihood of unambiguous assignment under different levels of mutation. Hence, one can identify, under different experimental and biological conditions, the germline V genes (or alleles) that cannot be uniquely identified and bundle them together into groups of specific V genes with highly similar sequences.
Lindenmaier, Rodica; Scharko, Nicole K.; Tonkyn, Russell G.; Nguyen, Kiet T.; Williams, Stephen D.; Johnson, Timothy J.
2017-12-05
Xylenes contain a blend of the ortho-, meta-, and para- isomers, and all are abundant contaminants in the ground, surface waters, and air. To better characterize xylene and to better enable its detection, we report high quality quantitative vapor-phase infrared spectra of all three isomers over the 540˗6500 cm-1 range. All fundamental vibrational modes are assigned based on these vapor-phase infrared spectra, liquid-phase infrared and Raman spectra, along with density functional theory (DFT), ab initio MP2 and high energy-accuracy compound theoretical model (W1BD) calculations. Both MP2 and DFT predict a single conformer with C2v symmetry for ortho-xylene, and two conformers each for meta- and para-xylene, depending on the preferred orientations of the methyl groups. For meta-xylene the two conformers have Cs and C2 symmetry, and for para-xylene these conformers have C2v or C2h symmetry. Since the relative population of the two conformers is approximately 50% for both isomers and predicted frequencies and intensities are very similar for each conformer, we made an arbitrary choice to discuss the Cs conformer for meta-xylene and the C2v conformer for para-xylene. We report integrated band intensities for all isomers. Using the quantitative infrared data, we determine the global warming potential values of each isomer and discuss potential bands for atmospheric monitoring.
Yamamoto, Shigeki; Miyada, Mai; Sato, Harumi; Hoshina, Hiromichi; Ozaki, Yukihiro
2017-02-09
Low-frequency vibrational modes of lamellar crystalline poly(glycolic acid) (PGA) were measured on Raman and far-infrared (FIR) spectra. Among the observed bands, an FIR band at ∼70 cm(-1) and a Raman band at 125 cm(-1) showed a gradual lower-frequency shift with increasing temperature from 20 °C to the melting point at ∼230 °C. Their polarization direction was perpendicular to the chain axis of PGA. Both spectra were quantum-mechanically simulated with the aid of a fragment method, the Cartesian-coordinate tensor transfer, which enabled an explicit consideration of molecular interactions between two adjacent polymer chains. Good agreement was achieved between the experiment and theory in both spectra. The temperature-sensitive bands at ∼70 cm(-1) in FIR and at 125 cm(-1) in Raman comprise the out-of-plane C═O bending motion. The temperature-dependent shifts of the low-frequency bands were successfully simulated by the DFT-spectral calculation, exploring that the main origin of the shifts is the thermal expansion of the crystal lattice. This result indicates that the thermally shifted bands may be used as an indicator of the lattice expansion of PGA. Possible changes in intermolecular interactions of PGA under temperature rising were ascribed on the basis of natural bond orbital theory. The steric repulsion between the carbonyl O atom in one chain and the H-C bond in the adjacent chain will be a dominant interaction in the lattice-expanding process, which would cause the observed thermal shifts of the bending modes. Comparisons of the spectral assignment for PGA obtained in this study and that for poly-(R)-3-hydroxybutyrate (PHB) reported by us suggest that crystalline polyesters give vibrational modes composed of out-of-plane bending motion of C═O groups between ∼70 and ∼125 cm(-1), the modes of which are sensitive to the thermal expansion of crystal lattice and its concomitant changes in their intermolecular interactions.
Vibrational properties of uracil
WANG Zhiping; ZHANG Fengshou; ZENG Xianghua; ZHOU Hongyu; GU Bin; CHENG Wei
2006-01-01
A semiempirical molecular dynamics model is developed to study the vibrational frequencies of uracil at very low kinetic temperature by using the Fourier transform of velocity autocorrelation function of trajectories of molecular dynamics simulations. The finite difference harmonic method is used to assign the vibrational frequency of each mode. The calculated frequencies are found to be in good agreement with experimental measurements. Moreover, we make up for the lost vibrational modes in experiments self-consistently. A total of 30 vibrational modes and their corresponding frequencies are reported.
Vibration of hydraulic machinery
Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong
2013-01-01
Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...
Vogt, Natalja; Khaikin, Leonid S; Grikina, Olga E; Rykov, Anatolii N; Vogt, Jürgen
2008-08-21
Thymine is one of the nucleobases which forms the nucleic acid (NA) base pair with adenine in DNA. The study of molecular structure and dynamics of nucleobases can help to understand and explain some processes in biological systems and therefore it is of interest. Because the scattered intensities on the C, N, and O atoms as well as some bond lengths in thymine are close to each other the structural problem cannot been solved by the gas phase electron diffraction (GED) method alone. Therefore the rotational constants from microvawe (MW) studies and differences in the groups of N-C, C=O, N-H, and C-H bond lengths from MP2 (full)/cc-pVQZ calculations were used as supplementary data. The analysis of GED data was based on the C(s) molecular symmetry according to results of the structure optimizations at the MP2 (full) level using 6-311G (d,p), cc-pVTZ, and cc-pVQZ basis sets confirmed by vibrational frequency calculations with 6-311G (d,p) and cc-pVTZ basis sets. Mean-square amplitudes as well as harmonic and anharmonic vibrational corrections to the internuclear distances (r(e)-r(a)) and to the rotational constants (B(e)(k)-B(0)(k), where k = A, B, C) were calculated from the quadratic (MP2 (full)/cc-pVTZ) and cubic (MP2 (full)/6-311G (d,p)) force constants (the latter were used only for anharmonic corrections). The harmonic force field was scaled using published IR and Raman spectra of the parent and N1,N3-dideuterated species, which were for the first time completely assigned in the present work. The main equilibrium structural parameters of the thymine molecule determined from GED data supplemented by MW rotational constants and results of MP2 calculations are the following (bond lengths in Angstroms and bond angles in degrees with 3sigma in parentheses): r(e) (C5=C6) = 1.344 (16), r(e) (C5-C9) = 1.487 (8), r(e) (N1-C6) = 1.372 (3), r(e) (N1-C2) = 1.377 (3), r(e) (C2-N3) = 1.378 (3), r(e) (N3-C4) = 1.395 (3), r(e) (C2=O7) = 1.210 (1), r(e) (C4=O8) = 1.215 (1
太阳电池阵运输过程的振动环境及可靠性分析%Vibration environment and reliability analysis of solar array in transportation
张华; 宗益燕
2014-01-01
The vibration data of the solar array of satellites in transportation are analyzed. It is shown that the environment of the airplane transportation and the rail transportation are better than that of the road transportation. The vibration responses in transportation are primarily of low-frequency and small magnitude, and the lateral vibration responses are significantly smaller in magnitude than the longitudinal responses. The transportation vibration responses are influenced by the road conditions and the speed of the vehicle. The damping performance of the shock absorber varies in different cases, and the vibration response of the solar array transported alone is basically the same as when it is transported with the satellite. Reliability analysis results indicate that transportation will not lead to fatigue damages of the solar array.%文章分析了一些卫星的太阳电池阵运输数据，结果表明：空中运输和铁路运输的环境优于公路运输环境；运输振动响应主要为低频振动且量级较小，其水平向振动响应明显小于竖直向响应；运输振动响应受路况和车速影响较大；不同减振器的隔振效果不尽相同；太阳电池阵单独运输和装星运输的振动响应量级基本相当。经可靠性分析，运输不会对太阳电池阵产生疲劳损伤。
McKellar, A. R. W.; Billinghurst, B. E.; Xu, Li-Hong; Lees, R. M.
2015-11-01
Using spectra obtained at the Canadian Light Source synchrotron radiation facility, a previously unobserved out-of-plane vibration of trans-acrolein (propenal) is reliably assigned for the first time. Its origin is at 1002.01 cm-1, which is about 20 cm-1 higher than usually quoted in the past. This mode is thus labelled as v14, leaving the label v15 for the known vibration at 992.66 cm-1. Weak combination bands 171182 ← 182, 171131 ← 131, 121182 ← 181, and 171182 ← 181 are studied for the first time, and assignments in the known v11, v16, and v15 fundamental bands are also extended. The seven excited vibrations involved in these bands are analyzed, together with five more unobserved vibrations in the same region (850-1020 cm-1), in a large 12-state simultaneous fit which accounts for most of the many observed perturbations in the spectra.
Microwave spectroscopy of furfural in vibrationally excited states
Motiyenko, R. A.; Alekseev, E. A.; Dyubko, S. F.
2007-07-01
The results of microwave spectrum investigation of the excited vibrational states of furfural in the frequency range between 49 and 149 GHz are reported. In total 15 excited vibrational states (9 for trans-furfural and 6 for cis-furfural) were assigned and analyzed. Six of the 15 investigated states were assigned for the first time. Accurate values of rigid rotor and quartic centrifugal distortion constants of asymmetric top Hamiltonian have been determined for 13 excited states. Also for some states several sextic and octic level constants were needed in order to fit the data within experimental accuracy. The vt = 3 and vs = 1, va = 1 states of trans-furfural were found to be strongly perturbed and only rotational transitions with low Ka values can be reliably identified in this study.
Vibrational spectra of ordered perovskites
Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.
1972-01-01
The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.
Lindenmaier, Rodica; Williams, Stephen D.; Sams, Robert L.; Johnson, Timothy J.
2016-12-16
Methyl vinyl ketone (MVK) and crotonaldehyde are chemical isomers; both are also important species in tropospheric chemistry. We report quantitative vapor-phase infrared spectra of crotonaldehyde and MVK vapors over the 540-6500 cm-1 range. Vibrational assignments of all fundamental modes are made for both molecules based on far- and mid-infrared vapor-phase spectra, liquid Raman spectra, along with density functional theory and ab initio MP2 and high energy-accuracy compound theoretical models (W1BD). Theoretical results indicate that at room temperature the crotonaldehyde equilibrium mixture is approximately 97% s-trans and only 3% s-cis conformer. Nearly all observed bands are thus associated with the s-trans conformer, but a few appear to be uniquely associated the s-cis conformer, notably ν16c at 730.90 cm-1, which displays a substantial intensity increase with temperature (62% upon going from 5 to 50 oC). The intensity of the corresponding mode of the s-trans conformer decreases with temperature. Under the same conditions, the MVK equilibrium mixture is approximately 69% s-trans conformer and 31% s-cis. W1BD calculations indicate that for MVK this is one of those (rare) cases where there are comparable populations of both conformers, ~doubling the number of observed bands and exacerbating the vibrational assignments. We uniquely assign the bands associated with both the MVK s-cis conformer as well as those of the s-trans, thus completing the vibrational analyses of both conformers from the same set of experimental spectra. Integrated band intensities are reported for both molecules along with global warming potential values. Using the quantitative IR data, potential bands for atmospheric monitoring are also discussed.
Amberger, Hanns-Dieter; Reddmann, Hauke
2014-04-24
The far and mid infrared spectra of powdered La(η(5)-C5Me4H)3 as well as polarized Raman spectra of an oriented single crystal (where the principal axes of the two molecules per unit cell are uniformly oriented) have been recorded. Applying the selection rules of C3h symmetry to the experimental data, numerous signals were assigned which agree well with the predictions of a calculation based on density functional theory. Neglecting νC-H and γCp-H (out of plane) modes, an r.m.s. deviation of 21.9 cm(-1) for 71 assignments was achieved. Skeletal and intra-ligand vibrations were separated and an inspection of the vibronic sidebands of the purely electronic hypersensitive absorption transitions (4)I9/2→(4)G5/2 of Nd(η(5)-C5Me4H)3 showed that mainly the latter are coupled.
[Theoretical investigation on the structure and vibration spectrum of D-luciferin].
Zhu, Yuan-Qiang; Zhang, Li; Guo, Jian-Chun
2014-09-01
In the present study, the geometry of D-Luciferin was fully optimized by the density functional theory at the B3LYP/6-311++G** and B3PW91/6-311++G** level, and the Cartesian coordinate force constant was calculated at the same level. The scaled quantum mechanism force field (SQM) method was performed to analyze the vibration spectrum. The local internal symmetry coordinates were defined using the method given by Pulay. The theoretical force field matrix, which was obtained through molecular vibration calculation programs, was transformed from Cartesian coordinates into the local internal coordinates. A normal coordinate analysis was carried out using GF matrix method developed by Wilson to give the scaled vibration frequencies and the potential energy distributions (PEDs). In order to make the vibration frequencies in good agreement with the experimental values, we empirically scale the theoretical force fields. According to PEDs, all vibration modes were assigned reliably to certain vibration frequencies. The calculated results show that the D-Luciferin molecule belongs to the point group C1 and involves 66 free degrees of vibration. All vibration modes are infrared and Raman activity. In the Infrared spectrum, the vibration frequency of the strongest absorption peak is 1,780 cm(-1), and the absorption intensity is 507 KM · mol(-1), which is mainly contributed by the stretching vibration mode of the C21==O22, double bond with the PEDs of 93%. In the Raman spectrum, the vibration frequency in the range of 1,200-1.700 cm(-1) presented strong Raman activity, the frequency of the strongest absorption peak is 1,573 cm(-1), and the absorpiton intensity is 297 KM · mol, which is mainly contributed by the stretching vibration made of the C21==N22 double bond in the five-membered ring. The results are helpful to further studying the structure and the luminescence activity of Luciferin derivatives in experiment and theory.
丁锋; 郭航; 冯伟泉; 王剑
2015-01-01
In the vibration test of spacecraft, some of its components will undergo the processes of aging, even failure because of long time use. For a qualitative analysis, the FMEA method is used to analyze the overall test bench, and the weakest link for the test bench is identified. For a horizontal sliding table's reliability series model in the subsystem, it is shown that it complies with the weak correlation theory. Then, the traditional reliability formula and the weak correlation are used, respectively, to predict the reliability of the model. A comparison shows that the weak correlation is better than the traditional reliability formula under the condition that all parts are not completely independent according to the actual situation. That is to say it is more effective for the reliability assessment of the horizontal sliding bench. The method is of theoretical and practical significance for mechanical system reliability calculations.%航天器振动试验台部分元件在长时间使用的情况下易老化，甚至失效。采用FMEA方法对试验台整体定性分析，得出最薄弱环节；针对试验台中水平滑台的可靠性串联模型，分析并确定了其符合弱相关界限理论。使用传统可靠性公式和弱相关界限理论对串联模型的可靠性进行了计算，通过对比证实，弱相关界限理论比传统可靠性公式更符合实际情况，对水平滑台可靠度的评定更有效。该方法对机械系统可靠度计算具有理论和实际指导意义。
Vibrational spectroscopy of resveratrol
Billes, Ferenc; Mohammed-Ziegler, Ildikó; Mikosch, Hans; Tyihák, Ernő
2007-11-01
In this article the authors deal with the experimental and theoretical interpretation of the vibrational spectra of trans-resveratrol (3,5,4'-trihydroxy- trans-stilbene) of diverse beneficial biological activity. Infrared and Raman spectra of the compound were recorded; density functional calculations were carried out resulting in the optimized geometry and several properties of the molecule. Based on the calculated force constants, a normal coordinate analysis yielded the character of the vibrational modes and the assignment of the measured spectral bands.
蔡宁泊; 侯乃先; 张成成
2016-01-01
为了评估航空发动机应变片粘贴误差对振动应力测量结果的影响程度，利用有限元计算与蒙特卡洛分析方法对压气机转子叶片的贴片方案进行了研究，并提出基于可靠度的贴片方案优化准则。分析结果表明：当贴片位置由应变梯度较小的B点移动至应变梯度较大的A点时，相对应变误差增加了0.5倍，贴片可靠度降低了0.3倍；当贴片方向与最大主应变方向之间的夹角由0°增加至30°时，相对应变误差增大了0.6倍，贴片可靠度降低了0.4倍；根据可靠度准则，所选贴片方案可同时对两阶模态的振动应力进行有效测量，其可靠度达到限制值0.9以上，表明将该准则用于贴片方案寻优是合适的。%The strain-gauge application schemes were investigated through finite element analysis and Mon⁃te Carlo simulation methods, so as to evaluate the impact of sensor placement tolerances on vibratory response during aero-engine vibration test. The strain-gauge application scheme optimum criterion was put forward based on reliability theory. The analysis results show that when the strain-gauge was placed from point B to point A,be⁃cause of the raising of strain gradient,the relative strain error increased by 0.5 times,and the reliability of the scheme was decreased by 0.3 times. When the angle between strain-gauge placement orientation and maximum principle strain orientation was expanded from 0° to 30°,the relative strain error increased by 0.6 times,while the reliability of the scheme was decreased by 0.4 times. According to the reliability criterion, the selected strain-gauge application scheme could effectively measure the vibration stress of two modes simultaneously,and it’s reliability exceeded the limit value of 0.9. The research indicates that it is adequate to use the reliability crite⁃rion for the strain-gauge application scheme optimization.
Improving active eigenvector assignment through passive modifications
Belotti, R.; Richiedei, D.
2016-09-01
Specifications on the dynamic behavior of feedback-controlled vibrating systems are often expressed in terms of its eigenstructure, i.e. eigenvalues and eigenvectors. The notion of controllability establishes the possibility to assign eigenvalues through state feedback, but it is not adequate to assure the assignment of arbitrary eigenvectors. Indeed, assignable eigenvectors are just those belonging to the allowable vector subspace, which depends on the physical properties of the vibrating system (mass, damping and stiffness matrices) and of the actuators. To overcome this limitation, this paper proposes a hybrid approach that exploits passive modification of the system physical parameters to modify the allowable subspace in such a way that it spans (or closely approximates) the desired eigenvectors. Then, once that the system modifications have been computed, standard techniques for control synthesis can be employed to compute the gains assigning the desired poles and the eigenvectors. The modification of the allowable subspace is cast in this work as a rank minimization problem, which can be efficiently tackled through semi-definite programming. The proposed method is numerically validated on a lumped parameter system, by proving that the assignment of eigenvectors by hybrid control is significantly enhanced compared with sole active control.
Random vibrations theory and practice
Wirsching, Paul H; Ortiz, Keith
1995-01-01
Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...
Martínez Medina, Juan J.; Torres, Carola A.; Alegre, Walter S.; Franca, Carlos A.; López Tévez, Libertad L.; Ferrer, Evelina G.; Okulik, Nora B.; Williams, Patricia A. M.
2015-11-01
Calculations based on density functional methods were carried out for the [Zn(phen)2(cnge)(H2O)](NO3)2·H2O complex taking into account the presence of two different conformers for the cyanoguanidine ligand. The calculated geometrical parameters and the vibrational IR and Raman spectra were in agreement with the experimental data. On the other hand, the activities of the complex, the ligands and the metal against fungal strains have been measured. The complexation increased the antifungal activity of the metal and the ligand cyanoguanidine, and slightly decreased the antifungal activity of the ligand 1,10-phenanthroline against Candida albicans, C. albicans ATCC 10231 and Candida krusei (not against the others strains of Candida). The ligand 1,10-phenanthroline and the zinc complex showed in some cases higher activity than the common antifungal drug fluconazole. The complexation also increased the post-antifungal effect in the tested strains, except for Candida parapsilosis, even with a better efficiency than those of some conventional antifungal agents. Antifungal studies were coupled with safety evaluations using the Artemia salina and the Ames tests. The zinc complex behaved as a non-mutagenic and non-toxic compound at the tested concentrations. Moreover, the zinc complex could be safer than the ligand when used as an antifungal agent. Therefore, the interaction of zinc(II) with N-containing ligands may provide a promising strategy for the development of novel and more secure drugs with antifungal activity.
PREFACE: Vibrations at surfaces Vibrations at surfaces
Rahman, Talat S.
2011-12-01
This special issue is dedicated to the phenomenon of vibrations at surfaces—a topic that was indispensible a couple of decades ago, since it was one of the few phenomena capable of revealing the nature of binding at solid surfaces. For clean surfaces, the frequencies of modes with characteristic displacement patterns revealed how surface geometry, as well as the nature of binding between atoms in the surface layers, could be different from that in the bulk solid. Dispersion of the surface phonons provided further measures of interatomic interactions. For chemisorbed molecules on surfaces, frequencies and dispersion of the vibrational modes were also critical for determining adsorption sites. In other words, vibrations at surfaces served as a reliable means of extracting information about surface structure, chemisorption and overlayer formation. Experimental techniques, such as electron energy loss spectroscopy and helium-atom-surface scattering, coupled with infra-red spectroscopy, were continually refined and their resolutions enhanced to capture subtleties in the dynamics of atoms and molecules at surfaces. Theoretical methods, whether based on empirical and semi-empirical interatomic potential or on ab initio electronic structure calculations, helped decipher experimental observations and provide deeper insights into the nature of the bond between atoms and molecules in regions of reduced symmetry, as encountered on solid surfaces. Vibrations at surfaces were thus an integral part of the set of phenomena that characterized surface science. Dedicated workshops and conferences were held to explore the variety of interesting and puzzling features revealed in experimental and theoretical investigations of surface vibrational modes and their dispersion. One such conference, Vibrations at Surfaces, first organized by Harald Ibach in Juelich in 1980, continues to this day. The 13th International Conference on Vibrations at Surfaces was held at the University of
Post, Robert E.; Johnson, Jack E.
1982-01-01
Presents two assignments that show (1) how George Orwell's "Politics and the English Language" can be applied to business writing and (2) how structured student-teacher conferences can generate enthusiasm for oral expression in a business communication course. (AEA)
Historical WBAN ID Assignments
National Oceanic and Atmospheric Administration, Department of Commerce — 4"x6" index cards represent the first written assignments of Weather Bureau Army Navy (WBAN) station identifier numbers by the National Climatic Data Center....
Method of task assignment for optimization of automotive system reliability%一种面向汽车系统可靠性优化的任务分配方法
李蕊; 雷群泌
2011-01-01
Tasks allocation to electronic control unit is one of the most important works in the stage of designing automotive e-lectronics software. The problem of finding an optimal task allocation with maximum system reliability has been shown to be NP-hard. This paper presented an improved particle swarm optimization algorithm for finding the near-optimal task allocation. By embedding a new mutation operator in the basic particle swarm optimization algorithm,improved the convergence speed of the algorithm and obtained a better result could. Experiments show that this method has a good effectiveness and feasibility.%对电子控制单元进行任务分配是汽车电子软件设计阶段一项非常重要的工作;以最大化系统可靠性为目标进行任务最优分配是一个NP-难问题.提出了一种改进的粒子群优化算法用于对任务进行近似最优分配以尽量提高系统的可靠性;通过在基本粒子群优化算法中引入一个新的变异操作有效提高了算法的收敛速度和解的精度.实验仿真表明该算法具有良好的有效性和可行性.
Nicolas, Maxime
2016-01-01
Engineering school; This course is designed for students of Polytech Marseille, engineering school. It covers first the physics of vibration of the harmonic oscillator with damping and forcing, coupled oscillators. After a presentation of the wave equation, the vibration of strings, beams and membranes are studied.
Qiu, Shi; De Gussem, Ewoud; Tehrani, Kourosch Abbaspour; Sergeyev, Sergey; Bultinck, Patrick; Herrebout, Wouter
2013-11-14
The stereochemistry of all four stereoisomers of tadalafil is determined using vibrational circular dichroism (VCD), electronic circular dichroism (ECD), and optical rotatory dispersion (ORD) spectroscopy. By comparing experimentally obtained VCD spectra to computationally simulated ones, the absolute configuration of the enantiomeric pair (6R, 12aR)/(6S, 12aS) can be confidently assigned without prior knowledge of their relative stereochemistry. IR and NMR spectra are used to aid the assignment of the relative stereochemistry. The IR and VCD difference spectra further confirm the assignment of all stereoisomers. ECD and ORD spectra are used to investigate the complementarity of the three chiroptical techniques. VCD spectroscopy itself is found to have the ability to identify diastereoisomers, and simultaneous use of these chiroptical spectroscopic methods and NMR chemical shifts aids in increasing the reliability of stereochemistry assignment of diastereoisomers.
42 CFR 433.146 - Rights assigned; assignment method.
2010-10-01
... 42 Public Health 4 2010-10-01 2010-10-01 false Rights assigned; assignment method. 433.146 Section 433.146 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... Assignment of Rights to Benefits § 433.146 Rights assigned; assignment method. (a) Except as specified...
2016-01-01
Full Text Available The article is devoted to the airline scheduling process and methods of its modeling. This article describes the main stages of airline scheduling process (scheduling, fleet assignment, revenue management, operations, their features and interactions. The main part of scheduling process is fleet assignment. The optimal solution of the fleet assignment problem enables airlines to increase their incomes up to 3 % due to quality improving of connections and execution of the planned number of flights operated by less number of aircraft than usual or planned earlier. Fleet assignment of scheduling process is examined and Conventional Leg-Based Fleet Assignment Model is analyzed. Finally strong and weak aspects of the model (SWOT are released and applied. The article gives a critical analysis of FAM model, with the purpose of identi- fying possible options and constraints of its use (for example, in cases of short-term and long-term planning, changing the schedule or replacing the aircraft, as well as possible ways to improve the model.
Laynebaril1
2017-01-01
NR 512 All Assignments Click Link Below To Buy: http://hwcampus.com/shop/nr-512-assignments/ Or Visit www.hwcampus.com NR512 Week 4 Scavenger Hunt Latest 2017 W4_NR512 Second Life (SL) Scavenger Hunt Work Sheet Student Name: Dorinda Ezell Avatar Name: Dvezellnr512 INSTRUCTIONS Instructions: 1. As you complete the Scavenger Hunt, please write your answers to the questions on this worksheet. 2. Save it as a MS Word document in the following format: ...
Random Cell Identifiers Assignment
Robert Bestak
2012-01-01
Full Text Available Despite integration of advanced functions that enable Femto Access Points (FAPs to be deployed in a plug-and-play manner, the femtocell concept still cause several opened issues to be resolved. One of them represents an assignment of Physical Cell Identifiers (PCIs to FAPs. This paper analyses a random based assignment algorithm in LTE systems operating in diverse femtocell scenarios. The performance of the algorithm is evaluated by comparing the number of confusions for various femtocell densities, PCI ranges and knowledge of vicinity. Simulation results show that better knowledge of vicinity can significantly reduce the number of confusions events.
Vibrational dynamics of crystalline L-alanine
Bordallo, H.N.; Eckert, J. [Los Alamos National Lab., NM (United States); Barthes, M. [Univ. Montpellier II (France)
1997-11-01
The authors report a new, complete vibrational analysis of L-alanine and L-alanine-d{sub 4} which utilizes IINS intensities in addition to frequency information. The use of both isotopomers resulted in a self-consistent force field for and assignment of the molecular vibrations in L-alanine. Some details of the calculation as well as a comparison of calculated and observed IINS spectra are presented. The study clarifies a number of important issues on the vibrational dynamics of this molecule and presents a self-consistent force field for the molecular vibrations in crystalline L-alanine.
Dominguez-Martinez, S.
2009-01-01
An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching fr
Panesar, Lucy
2007-01-01
Good Vibrations was a market research exercise conducted by Felicity (my alter-ego) and assistants to help develop marketing and packaging for an electro-therapeutic device (vibrator) used to treat hysteria and other female stress related disorders. It was a live art work commissioned by The Live Art Development Agency for East End Collaborations on 6th May 2007 and the South London Gallery for Bonkersfest on 2nd June 2007.
Gupta, Amita; Singh, Ranvir; Ahmad, Amir; Kumar, Mahesh
2003-10-01
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.
Design of Wind Turbine Vibration Monitoring System
Shoubin Wang; Wei Gong; Gang Su; Hongyue Sun
2013-01-01
In order to ensure safety of wind turbine operation and to reduce the occurrence of faults as well as to improve the reliability of wind turbine operation, a vibration monitoring for wind turbine is developed...
Laboratory spectroscopic study and astronomical detection of vibrationally excited n-propyl cyanide
Müller, Holger S. P.; Walters, Adam; Wehres, Nadine; Belloche, Arnaud; Wilkins, Olivia H.; Liu, Delong; Vicente, Rémi; Garrod, Robin T.; Menten, Karl M.; Lewen, Frank; Schlemmer, Stephan
2016-11-01
Context. We performed a spectral line survey called Exploring Molecular Complexity with ALMA (EMoCA) toward Sagittarius B2(N) between 84.1 and 114.4 GHz with the Atacama Large Millimeter/submillimeter Array (ALMA) in its Cycles 0 and 1. We determined line intensities of n-propyl cyanide in the ground vibrational states of its gauche and anti conformers toward the hot molecular core Sagittarius B2(N2) which suggest that we should also be able to detect transitions pertaining to excited vibrational states. Aims: We wanted to determine spectroscopic parameters of low-lying vibrational states of both conformers of n-propyl cyanide to search for them in our ALMA data. Methods: We recorded laboratory rotational spectra of n-propyl cyanide in two spectral windows between 36 and 127 GHz. We searched for emission lines produced by these states in the ALMA spectrum of Sagittarius B2(N2). We modeled their emission and the emission of the ground vibrational states assuming local thermodynamic equilibrium (LTE). Results: We have made extensive assignments of a- and b-type transitions of the four lowest vibrational states of the gauche conformer which reach J and Ka quantum numbers of 65 and 20, respectively. We assigned mostly a-type transitions for the anti conformer with J and Ka quantum numbers up to 48 and 24, respectively. Rotational and Fermi perturbations between two anti states allowed us to determine their energy difference. The resulting spectroscopic parameters enabled us to identify transitions of all four vibrational states of each conformer in our ALMA data. The emission features of all states, including the ground vibrational state, are well-reproduced with the same LTE modeling parameters, which gives us confidence in the reliability of the identifications, even for the states with only one clearly detected line. Conclusions: Emission features pertaining to the highest excited vibrational states of n-propyl cyanide reported in this work have been identified just
The efficacy of airflow and seat vibration on reducing visually induced motion sickness.
D'Amour, Sarah; Bos, Jelte E; Keshavarz, Behrang
2017-06-20
Visually induced motion sickness (VIMS) is a well-known sensation in virtual environments and simulators, typically characterized by a variety of symptoms such as pallor, sweating, dizziness, fatigue, and/or nausea. Numerous methods to reduce VIMS have been previously introduced; however, a reliable countermeasure is still missing. In the present study, the effect of airflow and seat vibration to alleviate VIMS was investigated. Eighty-two participants were randomly assigned to one of four groups (airflow, vibration, combined airflow and vibration, and control) and then exposed to a 15 min long video of a bicycle ride shot from first-person view. VIMS was measured using the Fast Motion Sickness Scale (FMS) and the Simulator Sickness Questionnaire (SSQ). Results showed that the exposure of airflow significantly reduced VIMS, whereas the presence of seat vibration, in contrast, did not have an impact on VIMS. Additionally, we found that females reported higher FMS scores than males, however, this sex difference was not found in the SSQ scores. Our findings demonstrate that airflow can be an effective and easy-to-apply technique to reduce VIMS in virtual environments and simulators, while vibration applied to the seat is not a successful method.
WANG Gui-Xiang; GONG Xue-Dong; XIAO He-Ming
2008-01-01
Nitro derivatives of benzene and anilines were optimized to obtain their molecular geometries and electronic structures at a DFT-B3LYP/6-31G* level. Their IR spectra were obtained and assigned by vibrational analysis. Comparing the calculated IR spectra with these of experiments known, all the IR data obtained in this paper were considered to be reliable. Based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics, the thermodynamic properties were evaluated, which were linearly related with the number of nitro and amino groups as well as the temperature, obviously showing good group additivity.
Zero Assignment in Multivariable System Using Pole Assignment Method
Smagina, Ye.
2002-01-01
In the paper we consider the invariant zero assignment problem in a linear multivariable system with several inputs/outputs by constructing a system output matrix. The problem is reduced to the pole assignment problem by a state feedback (modal control) in a descriptor system or a regular one. It is shown that the zero assignment and pole assignment are mathematically equivalent problems.
Scaffolding students’ assignments
Slot, Marie Falkesgaard
2013-01-01
This article discusses scaffolding in typical student assignments in mother tongue learning materials in upper secondary education in Denmark and the United Kingdom. It has been determined that assignments do not have sufficient scaffolding end features to help pupils understand concepts and build...... objects. The article presents the results of empirical research on tasks given in Danish and British learning materials. This work is based on a further development of my PhD thesis: “Learning materials in the subject of Danish” (Slot 2010). The main focus is how cognitive models (and subsidiary explicit...... learning goals) can help students structure their argumentative and communica-tive learning processes, and how various multimodal representations can give more open-ended learning possibilities for collaboration. The article presents a short introduction of the skills for 21st century learning and defines...
Assignments of autoionization states of O2-asterisk
Wu, C. Y. Robert
1987-01-01
Attention is given to the uncertainties that remain concerning the autoionization states of O2 leading to the a 4Pi(u) and A 2Pi(u) states of O2(+), as well as some of the assignments of the autoionization states and the determinations of effective quantum numbers and quantum defects. The former problems of vibrational assignments are unambiguously established in view of a study of isotopic oxygen molecules. A systematic examination of the known Rydberg series is conducted, and new assignments and interpretations for several autoionization states leading to the various states of O2(+) are suggested.
Fonari, A.; Corbin, N. S.; Coropceanu, V., E-mail: jean-luc.bredas@kaust.edu.sa, E-mail: coropceanu@gatech.edu [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 (United States); Vermeulen, D.; McNeil, L. E. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255 (United States); Goetz, K. P.; Jurchescu, O. D. [Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109-7507 (United States); Bredas, J. L., E-mail: jean-luc.bredas@kaust.edu.sa, E-mail: coropceanu@gatech.edu [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 (United States); Solar and Photovoltaics Engineering Research Center, Division of Physical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)
2015-12-14
We establish a reliable quantum-mechanical approach to evaluate the vibrational properties of donor-acceptor molecular crystals. The anthracene-PMDA (PMDA = pyromellitic dianhydride) crystal, where anthracene acts as the electron donor and PMDA as the electron acceptor, is taken as a representative system for which experimental non-resonance Raman spectra are also reported. We first investigate the impact that the amount of nonlocal Hartree-Fock exchange (HFE) included in a hybrid density functional has on the geometry, normal vibrational modes, electronic coupling, and electron-vibrational (phonon) couplings. The comparison between experimental and theoretical Raman spectra indicates that the results based on the αPBE functional with 25%-35% HFE are in better agreement with the experimental results compared to those obtained with the pure PBE functional. Then, taking αPBE with 25% HFE, we assign the vibrational modes and examine their contributions to the relaxation energy related to the nonlocal electron-vibration interactions. The results show that the largest contribution (about 90%) is due to electron interactions with low-frequency vibrational modes. The relaxation energy in anthracene-PMDA is found to be about five times smaller than the electronic coupling.
Fonari, A.
2015-12-10
We establish a reliable quantum-mechanical approach to evaluate the vibrational properties of donor-acceptor molecular crystals. The anthracene-PMDA (PMDA = pyromellitic dianhydride) crystal, where anthracene acts as the electron donor and PMDA as the electron acceptor, is taken as a representative system for which experimental non-resonance Raman spectra are also reported. We first investigate the impact that the amount of nonlocal Hartree-Fock exchange (HFE) included in a hybrid density functional has on the geometry, normal vibrational modes, electronic coupling, and electron-vibrational (phonon) couplings. The comparison between experimental and theoreticalRaman spectra indicates that the results based on the αPBE functional with 25%-35% HFE are in better agreement with the experimental results compared to those obtained with the pure PBE functional. Then, taking αPBE with 25% HFE, we assign the vibrational modes and examine their contributions to the relaxation energy related to the nonlocal electron-vibration interactions. The results show that the largest contribution (about 90%) is due to electron interactions with low-frequency vibrational modes. The relaxation energy in anthracene-PMDA is found to be about five times smaller than the electronic coupling.
Morrison, Ann; Knudsen, L.; Andersen, Hans Jørgen
2012-01-01
In this paper we describe a field study conducted with a wearable vibration belt where we test to determine the vibration intensity sensitivity ranges on a large diverse group of participants with evenly distributed ages and...... lab studies in that we found a decreased detection rate in busy environments. Here we test with a much larger sample and age range, and contribute with the first vibration sensitivity testing outside the lab in an urban public...
The Dynamic Frequency Assignment Problem
Dupont, Audrey; Linhares, Andréa,; Artigues, Christian; Feillet, Dominique; Michelon, Philippe; Vasquez, Michel
2008-01-01
21 pages; International audience; In this paper, we consider a frequency assignment problem occurring in a military context. The main originality of the problem pertains to its dynamic dimension: new communications requiring frequency assignments need to be established throughout a deployment. The problem decomposes in three phases: assignment of an initial kernel of communications, dynamic assignment of new communication links and reparation when no assignment is possible. Different solution...
Camiña, Ester
2002-01-01
The proposed game is a natural extension of the Shapley and Shubik Assignment Game to the case where each seller owns a set of different objets instead of only one indivisible object. We propose definitions of pairwise stability and group stability that are adapted to our framework. Existence of both pairwise and group stable outcomes is proved. We study the structure of the group stable set and we finally prove that the set of group stable payoffs forms a complete lattice with one optimal gr...
Hartzell, Allyson L; Shea, Herbert R
2010-01-01
This book focuses on the reliability and manufacturability of MEMS at a fundamental level. It demonstrates how to design MEMs for reliability and provides detailed information on the different types of failure modes and how to avoid them.
Wang Xiaowei; Wang Qiang, E-mail: qiangwang@cjlu.edu.cn [Department of Quality and Safety Engineering, China Jiliang University, Hangzhou, 310018 (China)
2011-02-01
In the room temperature and nitrogen conditions, we presented well-resolved absorption spectra and indexes of refraction of bactericide molecules in the far infrared radiation (FIR) spectral region recorded by terahertz time-domain spectroscopy (THz-TDS). As illustrative examples we discussed the absorption spectra of captan and folpet in THz region. The absorption coefficient and index of refraction of them were obtained. Meanwhile, density functional theory (DFT) with software package Gaussian 03 using B3LYP theory was employed for optimization and vibration analysis. With the help of Gaussian View 3.09, the distinct absorption peaks of those molecules were assigned with reliable accuracy. They were caused by intermolecular hydrogen-bonding, molecular torsion or vibration modes, absorption of water molecules, etc. As the absorption spectra are highly sensitive to the overall structure and configuration of the molecules, the THz-TDS procedure can provide a direct fingerprint of the molecular structure or conformational state of a compound.
Umesh P. Agarwal; Rajai Atalla
2010-01-01
Vibrational spectroscopy is an important tool in modern chemistry. In the past two decades, thanks to significant improvements in instrumentation and the development of new interpretive tools, it has become increasingly important for studies of lignin. This chapter presents the three important instrumental methods-Raman spectroscopy, infrared (IR) spectroscopy, and...
2009-01-01
Ed Witten is one of the leading scientists in the field of string theory, the theory that describes elementary particles as vibrating strings. This week he leaves CERN after having spent a few months here on sabbatical. His wish is that the LHC will unveil supersymmetry.
Bendell, A
1986-01-01
Software Reliability reviews some fundamental issues of software reliability as well as the techniques, models, and metrics used to predict the reliability of software. Topics covered include fault avoidance, fault removal, and fault tolerance, along with statistical methods for the objective assessment of predictive accuracy. Development cost models and life-cycle cost models are also discussed. This book is divided into eight sections and begins with a chapter on adaptive modeling used to predict software reliability, followed by a discussion on failure rate in software reliability growth mo
Evaluation of a UMLS Auditing Process of Semantic Type Assignments.
Gu, Huanying Helen; Hripcsak, George; Chen, Yan; Morrey, C Paul; Elhanan, Gai; Cimino, James; Geller, James; Perl, Yehoshua
2007-10-11
The UMLS is a terminological system that integrates many source terminologies. Each concept in the UMLS is assigned one or more semantic types from the Semantic Network, an upper level ontology for biomedicine. Due to the complexity of the UMLS, errors exist in the semantic type assignments. Finding assignment errors may unearth modeling errors. Even with sophisticated tools, discovering assignment errors requires manual review. In this paper we describe the evaluation of an auditing project of UMLS semantic type assignments. We studied the performance of the auditors who reviewed potential errors. We found that four auditors, interacting according to a multi-step protocol, identified a high rate of errors (one or more errors in 81% of concepts studied) and that results were sufficiently reliable (0.67 to 0.70) for the two most common types of errors. However, reliability was low for each individual auditor, suggesting that review of potential errors is resource-intensive.
Flexible taxonomic assignment of ambiguous sequencing reads
Jansson Jesper
2011-01-01
Full Text Available Abstract Background To characterize the diversity of bacterial populations in metagenomic studies, sequencing reads need to be accurately assigned to taxonomic units in a given reference taxonomy. Reads that cannot be reliably assigned to a unique leaf in the taxonomy (ambiguous reads are typically assigned to the lowest common ancestor of the set of species that match it. This introduces a potentially severe error in the estimation of bacteria present in the sample due to false positives, since all species in the subtree rooted at the ancestor are implicitly assigned to the read even though many of them may not match it. Results We present a method that maps each read to a node in the taxonomy that minimizes a penalty score while balancing the relevance of precision and recall in the assignment through a parameter q. This mapping can be obtained in time linear in the number of matching sequences, because LCA queries to the reference taxonomy take constant time. When applied to six different metagenomic datasets, our algorithm produces different taxonomic distributions depending on whether coverage or precision is maximized. Including information on the quality of the reads reduces the number of unassigned reads but increases the number of ambiguous reads, stressing the relevance of our method. Finally, two measures of performance are described and results with a set of artificially generated datasets are discussed. Conclusions The assignment strategy of sequencing reads introduced in this paper is a versatile and a quick method to study bacterial communities. The bacterial composition of the analyzed samples can vary significantly depending on how ambiguous reads are assigned depending on the value of the q parameter. Validation of our results in an artificial dataset confirm that a combination of values of q produces the most accurate results.
Ahmed, A. Ben; Feki, H.; Abid, Y.; Boughzala, H.; Minot, C.; Mlayah, A.
2009-02-01
In this work, we report a combined experimental and theoretical study on molecular structure and vibrational spectra of L-histidinium dihydrogen phosphate-phosphoric acid, with particular emphasize on the correlation between the intermolecular hydrogen bonds and the hyperpolarizability. Single crystal of L-histidinium dihydrogen phosphate-phosphoric acid has been subjected to X-ray diffraction and Raman spectroscopy. The title compound crystallises in the non-centrosymmetric space group P2 1. Raman spectra have been recorded in the frequency range [150-3350 cm -1]. To obtain a more reliable assignment of the Raman and IR spectra, we have calculated the geometry and the frequencies using HF and DFT methods. All the experimental vibrational bands have been discussed and assigned to normal mode or to combinations and overtones on the basis of our calculations. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP and BLYP) are in well agreement with the experimental data. The results of DFT-B3LYP method have shown better fit to experimental ones than HF in evaluating vibrational frequencies. To investigate microscopic second order non-linear optical behaviour of the examined complex, the electric dipole μ, the polarizability α and the hyperpolarizability β were computed using DFT//B3LYP/6-31 G(d) method. According to our calculation, the title compound exhibits non-zero β value revealing microscopic second order NLO behaviour.
Job Assignments under Moral Hazard
Koch, Alexander; Nafziger, Julia
Inefficient job assignments are usually explained with incomplete information about employees' abilities or contractual imperfections. We show that inefficient assignments arise even without uncertainty about the employee's ability and with complete contracts. Building on this result we provide a...
Adaptive Piezoelectric Absorber for Active Vibration Control
Sven Herold
2016-02-01
Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.
Huang, Xinchuan; Taylor, Peter R.; Lee, Timothy J.
2011-01-01
High levels of theory have been used to compute quartic force fields (QFFs) for the cyclic and linear forms of the C H + molecular cation, referred to as c-C H + and I-C H +. Specifically the 33 3333 singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations, CCSD(T), has been used in conjunction with extrapolation to the one-particle basis set limit and corrections for scalar relativity and core correlation have been included. The QFFs have been used to compute highly accurate fundamental vibrational frequencies and other spectroscopic constants using both vibrational 2nd-order perturbation theory and variational methods to solve the nuclear Schroedinger equation. Agreement between our best computed fundamental vibrational frequencies and recent infrared photodissociation experiments is reasonable for most bands, but there are a few exceptions. Possible sources for the discrepancies are discussed. We determine the energy difference between the cyclic and linear forms of C H +, 33 obtaining 27.9 kcal/mol at 0 K, which should be the most reliable available. It is expected that the fundamental vibrational frequencies and spectroscopic constants presented here for c-C H + 33 and I-C H + are the most reliable available for the free gas-phase species and it is hoped that 33 these will be useful in the assignment of future high-resolution laboratory experiments or astronomical observations.
Interactive Assignments for Online Students
Pam Lowry
2009-04-01
Full Text Available Students can experience first hand through interactive assignments what is involved in teaching an online course. Most students develop a whole new appreciation for the student learning process. Faculty are beginning to realize that online instruction is more than a series of readings posted to a course management system. This paper summarizes the faculty member's instructional strategies involved when creating student interaction assignments. The paper also summarizes the assignments, discussion board, and trends in education from the student's perspective. In summary, it concludes with the faculty's overall perspective concerning these assignments and how the assignments could be more effective for the student.
Unexpected red shift of C-H vibrational band of Methyl benzoate
Maiti, Kiran Sankar; Scheurer, Christoph
2016-01-01
The C-H vibrational bands become more and more important in the structural determination of biological molecules with the development of CARS microscopy and 2DIR spectroscopy. Due to the congested pattern, near degeneracy, and strong anharmonicity of the C-H stretch vibrations, assignment of the C-H vibrational bands are often misleading. Anharmonic vibrational spectra calculation with multidimensional potential energy surface interprets the C-H vibrational spectra more accurately. In this article we have presented the importance of multidimensional potential energy surface in anharmonic vibrational spectra calculation and discuss the unexpected red shift of C-H vibrational band of Methyl benzoate.
Optical fiber grating vibration sensor for vibration monitoring of hydraulic pump
Zhang, Zhengyi; Liu, Chuntong; Li, Hongcai; He, Zhenxin; Zhao, Xiaofeng
2017-06-01
In view of the existing electrical vibration monitoring traditional hydraulic pump vibration sensor, the high false alarm rate is susceptible to electromagnetic interference and is not easy to achieve long-term reliable monitoring, based on the design of a beam of the uniform strength structure of the fiber Bragg grating (FBG) vibration sensor. In this paper, based on the analysis of the vibration theory of the equal strength beam, the principle of FBG vibration tuning based on the equal intensity beam is derived. According to the practical application of the project, the structural dimensions of the equal strength beam are determined, and the optimization design of the vibrator is carried out. The finite element analysis of the sensor is carried out by ANSYS, and the first order resonant frequency is 94.739 Hz. The vibration test of the sensor is carried out by using the vibration frequency of 35 Hz and the vibration source of 50 Hz. The time domain and frequency domain analysis results of test data show that the sensor has good dynamic response characteristics, which can realize the accurate monitoring of the vibration frequency and meet the special requirements of vibration monitoring of hydraulic pump under specific environment.
Vibration-rotation-tunneling dynamics in small water clusters
Pugliano, N.
1992-11-01
The goal of this work is to characterize the intermolecular vibrations of small water clusters. Using tunable far infrared laser absorption spectroscopy, large amplitude vibration-rotation-tunneling (VRT) dynamics in vibrationally excited states of the water dimer and the water trimer are investigated. This study begins with the measurement of 12 VRT subbands, consisting of approximately 230 transitions, which are assigned to an 82.6 cm{sup {minus}1} intermolecular vibration of the water dimer-d{sub 4}. Each of the VRT subbands originate from K{sub a}{double_prime}=0 and terminate in either K{sub a}{prime}=0 or 1. These data provide a complete characterization of the tunneling dynamics in the vibrationally excited state as well as definitive symmetry labels for all VRT energy levels. Furthermore, an accurate value for the A{prime} rotational constant is found to agree well with its corresponding ground state value. All other excited state rotational constants are fitted, and discussed in terms of the corresponding ground state constants. In this vibration, the quantum tunneling motions are determined to exhibit large dependencies with both the K{sub a}{prime} quantum number and the vibrational coordinate, as is evidenced by the measured tunneling splittings. The generalized internal-axis-method treatment which has been developed to model the tunneling dynamics, is considered for the qualitative description of each tunneling pathway, however, the variation of tunneling splittings with vibrational excitation indicate that the high barrier approximation does not appear to be applicable for this vibrational coordinate. The data are consistent with a motion possessing a{prime} symmetry, and the vibration is assigned as the {nu}{sub 12} acceptor bending coordinate. This assignment is in agreement with the vibrational symmetry, the resultsof high level ab initio calculations, and preliminary data assigned to the analogous vibration in the D{sub 2}O-DOH isotopomer.
Vibration-rotation-tunneling dynamics in small water clusters
Pugliano, N.
1992-11-01
The goal of this work is to characterize the intermolecular vibrations of small water clusters. Using tunable far infrared laser absorption spectroscopy, large amplitude vibration-rotation-tunneling (VRT) dynamics in vibrationally excited states of the water dimer and the water trimer are investigated. This study begins with the measurement of 12 VRT subbands, consisting of approximately 230 transitions, which are assigned to an 82.6 cm[sup [minus]1] intermolecular vibration of the water dimer-d[sub 4]. Each of the VRT subbands originate from K[sub a][double prime]=0 and terminate in either K[sub a][prime]=0 or 1. These data provide a complete characterization of the tunneling dynamics in the vibrationally excited state as well as definitive symmetry labels for all VRT energy levels. Furthermore, an accurate value for the A[prime] rotational constant is found to agree well with its corresponding ground state value. All other excited state rotational constants are fitted, and discussed in terms of the corresponding ground state constants. In this vibration, the quantum tunneling motions are determined to exhibit large dependencies with both the K[sub a][prime] quantum number and the vibrational coordinate, as is evidenced by the measured tunneling splittings. The generalized internal-axis-method treatment which has been developed to model the tunneling dynamics, is considered for the qualitative description of each tunneling pathway, however, the variation of tunneling splittings with vibrational excitation indicate that the high barrier approximation does not appear to be applicable for this vibrational coordinate. The data are consistent with a motion possessing a[prime] symmetry, and the vibration is assigned as the [nu][sub 12] acceptor bending coordinate. This assignment is in agreement with the vibrational symmetry, the resultsof high level ab initio calculations, and preliminary data assigned to the analogous vibration in the D[sub 2]O-DOH isotopomer.
Vibrational spectra of corticosteroid hormones in the terahertz range
Cherkasova, O. P.; Nazarov, M. M.; Sapozhnikov, D. A.; Man'kova, A. A.; Fedulova, E. V.; Volodin, V. A.; Minaeva, V. A.; Minaev, B. F.; Baryshnikov, G. V.
2010-11-01
The terahertz time-domain and Raman spectra of corticosteroid hormones in the region of low-frequency infrared vibrations have been measured. On the ground of quantum chemical calculations of the frequencies and normal modes the assignments of vibrational bands in the THz-spectra are performed.
Singh, Gurpreet; Dogra, Sukh Dev; Kaur, Sarvpreet; Tripathi, S K; Prakash, Satya; Rai, Bimal; Saini, G S S
2015-01-01
The vibrational properties of glutathione have been investigated by infrared absorption and Raman spectroscopic techniques, and density functional theory calculations at the B3LYP/6-31+G(d,p) level. Assignments of all the experimentally observed vibrational bands have been done with the help of simulated vibrational spectra and potential energy distribution calculations of glutathione water cluster, which includes the effect of hydrogen bonding. Optimized molecular parameters of energy minimized structure have been compared with the available experimental values. Calculated molecular parameters of glutathione-water cluster match well with the experimental values. Some of the calculated molecular parameters and vibrational frequencies of vapor phase glutathione-water cluster suggest participation of some atoms of glutathione in hydrogen bonding. Experimentally observed UV-Visible absorption spectrum of glutathione has also been reported. Observed band at 203 nm has been assigned to electronic transitions calculated with time dependent density functional theory. Copyright © 2015 Elsevier B.V. All rights reserved.
Pole assignment in descriptor periodic systems
FAN; Hung-Yuan; LIN; Wen-Wei; XU; Shufang
2005-01-01
In this paper a pole assignment problem is considered for the descriptor linear discrete-time periodic systems, which is using the periodic proportional-derivative feedback to modify a given system such that the closed loop system has a specified selfconjugate set of eigenvalues. It is shown that the complete reachability of an open loop periodic system is equivalent to the possibility of assigning an arbitrary set of the eigenvalues to the system by choosing the suitable periodic proportional-derivative feedback.A computational approach is also proposed to solve the problem, which uses the reliable numerical techniques based on the orthogonal transformations. Numerical examples are presented to illustrate the effectiveness of the proposed approach.
Explicit pattern matching assignment algorithm
Levedahl, Mark
2002-08-01
Sharing data between two tracking systems frequently involves use of an object map: the transmitting system sends a frame of data with multiple observations, and the receiving system uses an assignment algorithm to correlate the information with its local observation data base. The usual prescription for this problem is an optimal assignment algorithm (such as JVC or auction) using a cost matrix based upon chi-squared distances between the local and remote observation data. The optimal assignment algorithm does not actually perform pattern matching, so this approach is not robust to large registration errors between the two systems when there exist differences in the number of observations held by both systems. Performance of a new assignment algorithm that uses a cost function including terms for both registration errors and track to track random errors is presented: the cost function explicitly includes a bias between the two observation sets and thus provides a maximum likelihood solution to the assignment problem. In practice, this assignment approach provides near perfect assignment accuracy in cases where the bias errors exceed the dimension of the transmitted object map and there exist mismatches in the numbers of observations made by the two systems. This performance extends to many cases where the optimal assignment algorithm methodology produces errors nearly 100% of the time. The paper includes the theoretical foundation of the assignment problem solved and comparison of achieved accuracy with existing optimal assignment approaches.
Lazzaroni, Massimo
2012-01-01
This book gives a practical guide for designers and users in Information and Communication Technology context. In particular, in the first Section, the definition of the fundamental terms according to the international standards are given. Then, some theoretical concepts and reliability models are presented in Chapters 2 and 3: the aim is to evaluate performance for components and systems and reliability growth. Chapter 4, by introducing the laboratory tests, puts in evidence the reliability concept from the experimental point of view. In ICT context, the failure rate for a given system can be
The bicriterion multimodal assignment problem
Pedersen, Christian Roed; Nielsen, Lars Relund; Andersen, Kim Allan
2008-01-01
We consider the bicriterion multimodal assignment problem, which is a new generalization of the classical linear assignment problem. A two-phase solution method using an effective ranking scheme is presented. The algorithm is valid for generating all nondominated criterion points...... or an approximation. Extensive computational results are conducted on a large library of test instances to test the performance of the algorithm and to identify hard test instances. Also, test results of the algorithm applied to the bicriterion assignment problem are provided....
Optimizing Marine Security Guard Assignments
2011-06-01
Bangkok , Thailand East Asia and Pacific 18 4 Fort Lauderdale, Florida Western Hemisphere - South 13 5 Frankfurt, Germany Western Europe and Scandinavia 15...2008). Each 7 stationing plan satisfies a myriad of unit requirements, such as building and land availability. Similarly, each assignment solution...optimize the assignment of enlisted Marines to billets. EAM-GLOBAL seeks to assign the best Marine-billet fit while balancing staffing shortages
Balanced input-output assignment
Gawronski, W.; Hadaegh, F. Y.
1989-01-01
Actuator/sensor locations and balanced representations of linear systems are considered for a given set of controllability and observability grammians. The case of equally controlled and observed states is given special attention. The assignability of grammians is examined, and the conditions for their existence are presented, along with several algorithms for their determination. Although an arbitrary positive semidefinite matrix is not always assignable, the identity grammian is shown to be always assignable. The results are extended to the case of flexible structures.
Evidence of Ultrafast Charge Transfer Driven by Coherent Lattice Vibrations.
Rury, Aaron S; Sorenson, Shayne A; Dawlaty, Jahan M
2017-01-05
We report evidence that intermolecular vibrations coherently drive charge transfer between the sites of a material on ultrafast time scales. Following a nonresonant stimulated Raman pump pulse that excites the organic material quinhydrone, we observe the initial appearance of oscillations due to intermolecular lattice vibrations and then the delayed appearance of a higher-frequency oscillation that we assign to a totally symmetric intramolecular vibration. We use the coherent dynamics of the transient reflectivity signal to propose that coherence transfer drives excitation of this intramolecular vibration. Furthermore, we conclude that the dynamical frequency shift of the intramolecular vibration reports the formation of a quasi-stable charge-separated state on ultrafast time scales. We calculate model dynamics using the extended Hubbard Hamiltonian to explain coherence transfer due to vibrationally driven charge transfer. These results demonstrate that the coherent excitation of low-frequency vibrations can drive charge transfer in the solid state and control material properties.
Review of magnetostrictive vibration energy harvesters
Deng, Zhangxian; Dapino, Marcelo J.
2017-10-01
The field of energy harvesting has grown concurrently with the rapid development of portable and wireless electronics in which reliable and long-lasting power sources are required. Electrochemical batteries have a limited lifespan and require periodic recharging. In contrast, vibration energy harvesters can supply uninterrupted power by scavenging useful electrical energy from ambient structural vibrations. This article reviews the current state of vibration energy harvesters based on magnetostrictive materials, especially Terfenol-D and Galfenol. Existing magnetostrictive harvester designs are compared in terms of various performance metrics. Advanced techniques that can reduce device size and improve performance are presented. Models for magnetostrictive devices are summarized to guide future harvester designs.
张屹尚; 刘永寿; 赵彬; 翟红波
2014-01-01
针对激励与结构参数同时存在不确定性的复合随机振动系统，由随机结构无条件动力可靠度表达式出发，利用条件概率密度函数解析变换给出衡量基本随机变量对动力可靠性影响的矩独立重要性测度指标。该指标可表征不确定性随机变量对动力可靠度响应量分布的平均影响程度，可全面反映随机变量对响应分布影响。基于状态依存参数模型，提出求解矩独立重要性测度指标的态相关参数（SDP）法。利用算例分析结构动力可靠性参数的矩独立重要性测度，并与直接 Monte -Carlo 法对比。所提方法可在保证计算精度同时大幅度提高计算效率，适用于分析复合随机振动系统非线性可靠性响应。%A moment-independent importance measure index of dynamic reliability for double random vibration systems,in which the randomness of structural parameters and excitation was taken into account,was introduced to analyze the effect of input variables on dynamic reliability.Based on the expressions of unconditional dynamic reliability and conditional probability density function (PDF),the importance measure index was numerically obtained.The index can effectively describe the mean effect of the PDF on dynamic reliability from the distribution density of the basic variable.Then,on the basis of the state dependent parameter (SDP)model,the SDP method was established to estimate the defined moment-independent importance measure index.Additionally,two examples were given to illustrate the advantages of the presented method.Comparing with the direct Monte Carlo method,the results show that the established solution can considerably improve computational efficiency with acceptable precision and be suitable for analyzing non-linear dynamic reliability responses of double random vibration systems.
RELIABILITY OF LENTICULAR EXPANSION COMPENSATORS
Gabriel BURLACU,
2011-11-01
Full Text Available Axial lenticular compensators are made to take over the longitudinal heat expansion, shock , vibration and noise, made elastic connections for piping systems. In order to have a long life for installations it is necessary that all elements, including lenticular compensators, have a good reliability. This desire can be did by technology of manufactoring and assembly of compensators, the material for lenses and by maintenance.of compensator
Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter Raahave
2014-01-01
We consider the problem of assigning agents to slots on a line, where only one agent can be served at a slot and each agent prefers to be served as close as possible to his target. Our focus is on aggregate gap minimizing methods, i.e., those that minimize the total gap between targets and assigned...
Theory of vibration protection
Karnovsky, Igor A
2016-01-01
This text is an advancement of the theory of vibration protection of mechanical systems with lumped and distributed parameters. The book offers various concepts and methods of solving vibration protection problems, discusses the advantages and disadvantages of different methods, and the fields of their effective applications. Fundamental approaches of vibration protection, which are considered in this book, are the passive, parametric and optimal active vibration protection. The passive vibration protection is based on vibration isolation, vibration damping and dynamic absorbers. Parametric vibration protection theory is based on the Shchipanov-Luzin invariance principle. Optimal active vibration protection theory is based on the Pontryagin principle and the Krein moment method. The book also contains special topics such as suppression of vibrations at the source of their occurrence and the harmful influence of vibrations on humans. Numerous examples, which illustrate the theoretical ideas of each chapter, ar...
Simultaneous active and passive control for eigenstructure assignment in lightly damped systems
Richiedei, Dario; Trevisani, Alberto
2017-02-01
The assignment of the eigenstructure (i.e. eigenvalues and eigenvectors) in vibrating systems is an effective way to improve their dynamic performances. System controllability ensures that the poles of the controlled system are exactly assigned but it does not allow to assign arbitrary desired eigenvectors. To this purpose, this paper proposes a novel method for vibration control in lightly damped systems through the concurrent synthesis of passive structural modifications and active state (or state derivative) feedback control gains. Indeed, the suitable modification of the inertial and elastic parameters allows to enlarge the range of assignable eigenvectors. The problem is formulated as an optimization problem, where constraints are introduced to assure the feasibility of the physical system modifications while avoiding spillover phenomena. The experimental application to the eigenstructure assignment on a manipulator proves the method effectiveness.
An Intermolecular Vibration Model for Lattice Ice
Quinn M. Brewster
2010-06-01
Full Text Available Lattice ice with tetrahedral arrangement is studied using a modified Einstein’s model that incorporates the hindered translational and rotational vibration bands into a harmonic oscillation system. The fundamental frequencies for hindered translational and rotational vibrations are assigned based on the intermolecular vibration bands as well as thermodynamic properties from existing experimental data. Analytical forms for thermodynamic properties are available for the modified model, with three hindered translational bands at (65, 229, 229 cm-1 and three effective hindered rotational bands at 560 cm-1. The derived results are good for temperatures higher than 30 K. To improve the model below 30 K, Lorentzian broadening correction is added. This simple model helps unveil the physical picture of ice lattice vibration behavior.
Vibrational and electronic spectroscopic studies of melatonin
Singh, Gurpreet; Abbas, J. M.; Dogra, Sukh Dev; Sachdeva, Ritika; Rai, Bimal; Tripathi, S. K.; Prakash, Satya; Sathe, Vasant; Saini, G. S. S.
2014-01-01
We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm-1 regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except Nsbnd H stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of Nsbnd H stretching is due to intermolecular interactions between melatonin molecules.
SOFTWARE RELIABILITY OF PROFICIENT ENACTMENT
B.Anni Princy
2014-07-01
Full Text Available A software reliability exemplary projects snags the random process as disillusionments which were the culmination yield of two progressions: emerging faults and initial state values. The predominant classification uses the logistic analysis effort function mounting efficient software on the real time dataset. The detriments of the logistic testing were efficaciously overcome by Pareto distribution. The estimated outline ventures the resolved technique for analyzing the suitable communities and the preeminent of fit for a software reliability progress model. Its constraints are predictable to evaluate the reliability of a software system. The future process will permit for software reliability estimations that can be used both as prominence Indicator, but also for planning and controlling resources, the development times based on the onslaught assignments of the efficient computing and reliable measurement of a software system was competent.
Reliability Analysis of Mixed Component Solders under Random Vibration Load%随机振动载荷下混装组件焊点的可靠性分析
严焕斌; 吴兆华
2014-01-01
In this paper ,the modeling and simulation of mixed components are introduced .A solder and pin is transformed into a block during the modeling of the mixed components .The vibration test conditions recommended by GJB 150 .16-86 which is called EighthClassRandomVibration- JetAircraftVibrationEnvironmentisemployedtoperformrandomvibrationsimulationanalysis . The warping degree ,the region of stress concentration (weak link) ,the solder stress and strain distribution and risk solder joint po-sition of the component are analyzed .T he submodel method is used to build detailed modeling of risk zone solders and solve stress and strain values of three different types of solders .Finally ,the serive life of solders is estimated through Miner fatigue cumulative damage theory ,three band technology and three parameters S-N curve approximation formula .The results obtained from the analy-sis as following :wing pin solder’s vibration strength is the lowest and the value is 8 .54 h ,the J solder’s fatigue life is 8 .96 h ,and the BGA solder’s fatigue life is 14 .18 h .%选取混装组件进行建模仿真，建模时将混装组件中焊点和引脚等效成一个块状进行简化处理。采用GJB150.16-86中推荐的“第8类随机振动-喷气式飞机振动环境”振动试验条件进行随机振动仿真分析，分析组件的翘曲度、组件应力集中区域（薄弱环节）、组件中器件焊点应力应变分布及危险焊点位置；再运用子模型法建立危险区域焊点精细模型，利用子模型来求解3种不同类型焊点的应力应变值；最后运用M iner疲劳累积损伤理论、三带技术和三参数 S- N曲线近似公式进行不同类型焊点寿命估算。研究结果表明：翼形引脚焊点类型抗振强度最低， J型引脚焊点类型其次， BGA类鼓状焊点类型抗振强度最好；BGA类鼓状焊点振动疲劳寿命为14.18 h ，翼形焊点疲劳寿命为8.54 h ， J形焊点疲劳寿命为8.96 h。
Research of Air-Magnet Active Vibration Isolation System Based on H∞ Control
Wen Xianglong
2015-01-01
Full Text Available Considering the uncertainty of air-magnet active vibration isolation system (AMAVIS, passive vibration isolation was combined with active vibration isolation, which adopted H∞ control strategies. System identification method was used to get the channel model. By adopting mixed sensitivity design strategy, weighting functions were chosen and H∞ controller was designed. Both simulation results and experimental results show AMAVIS based on H∞ control had satisfying effect of vibration reduction in assigned frequency band.
DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM
Martin E. Cobern
2004-08-31
The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed.
DOWNHOLE VIBRATION MONITORING & CONTROL SYSTEM
Martin E. Cobern
2004-08-31
The deep hard rock drilling environment induces severe vibrations into the drillstring, which can cause reduced rates of penetration (ROP) and premature failure of the equipment. The only current means of controlling vibration under varying conditions is to change either the rotary speed or the weight-on-bit (WOB). These changes often reduce drilling efficiency. Conventional shock subs are useful in some situations, but often exacerbate the problems. The objective of this project is development of a unique system to monitor and control drilling vibrations in a ''smart'' drilling system. This system has two primary elements: (1) The first is an active vibration damper (AVD) to minimize harmful axial, lateral and torsional vibrations. The hardness of this damper will be continuously adjusted using a robust, fast-acting and reliable unique technology. (2) The second is a real-time system to monitor drillstring vibration, and related parameters. This monitor adjusts the damper according to local conditions. In some configurations, it may also send diagnostic information to the surface via real-time telemetry. The AVD is implemented in a configuration using magnetorheological (MR) fluid. By applying a current to the magnetic coils in the damper, the viscosity of the fluid can be changed rapidly, thereby altering the damping coefficient in response to the measured motion of the tool. Phase I of this program entailed modeling and design of the necessary subsystems and design, manufacture and test of a full laboratory prototype. Phase I of the project was completed by the revised end date of May 31, 2004. The objectives of this phase were met, and all prerequisites for Phase II have been completed.
A Statistical Programme Assignment Model
Rosholm, Michael; Staghøj, Jonas; Svarer, Michael
assignment mechanism, which is based on the discretionary choice of case workers. This is done in a duration model context, using the timing-of-events framework to identify causal effects. We compare different assignment mechanisms, and the results suggest that a significant reduction in the average...... duration of unemployment spells may result if a statistical programme assignment model is introduced. We discuss several issues regarding the plementation of such a system, especially the interplay between the statistical model and case workers....
Optimal actuation in vibration control
Guzzardo, C. A.; Pang, S. S.; Ram, Y. M.
2013-02-01
The paper addresses the problem of finding the optimal location of actuators and their relative gain so that the control effort in an actively controlled vibrating system is minimized. In technical terms the problem is finding the optimal input vector of unit norm that minimizes the norm of the control gain vector. This problem is addressed in the context of the active natural frequency modification problem associated with resonance avoidance in undamped systems, and in the context of the single-input-multi-output pole assignment problem for second order systems.
New principles of construction of electromechanical vibration inducers
Ashmonas, K. A. P.; Bansevichyus, R. Y.; Vaznelis, A. I.; Ragulskis, K. M.
1973-01-01
Electromechanical vibration inducers with high reliability and low noise level were created to study premature operating losses in their support bearings. An investigation was also made of the feasibility of developing stable synchronous operation of two vibrational inducers, rigidily fastened to a solid body with and without flexible suspension.
The Art of Probability Assignment
Dimitrov, Vesselin I
2012-01-01
The problem of assigning probabilities when little is known is analized in the case where the quanities of interest are physical observables, i.e. can be measured and their values expressed by numbers. It is pointed out that the assignment of probabilities based on observation is a process of inference, involving the use of Bayes' theorem and the choice of a probability prior. When a lot of data is available, the resulting probability are remarkable insensitive to the form of the prior. In the oposite case of scarse data, it is suggested that the probabilities are assigned such that they are the least sensitive to specific variations of the probability prior. In the continuous case this results in a probability assignment rule wich calls for minimizing the Fisher information subject to constraints reflecting all available information. In the discrete case, the corresponding quantity to be minimized turns out to be a Renyi distance between the original and the shifted distribution.
Reliability design method for steam turbine blades
Jinyuan SHI
2008-01-01
Based on theories of probability and statistics, and taking static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and exciting force frequencies of blades as random variables, a reliabil-ity design method for steam turbine blades is presented. The purport and calculation method for blade reliability are expounded. The distribution parameters of random variables are determined after analysis and numerical cal-culation of test data. The fatigue strength and the vibra-tion design reliability of turbine blades are determined with the aid of a probabilistic design method and by inter-ference models for stress distribution and strength distri-bution. Some blade reliability design calculation formulas for a dynamic stress design method, a safety ratio design method for fatigue strength, and a vibration reliability design method for the first and second types of tuned blades and a packet of blades on a disk connected closely, are given together with some practical examples. With these methods, the design reliability of steam turbine blades can be guaranteed in the design stage. This research may provide some scientific basis for reliability design of steam turbine blades.
Job assignment with multivariate skills
Brilon, Stefanie
2010-01-01
This paper analyzes the job assignment problem faced by a firm when workers’ skills are distributed along several dimensions and jobs require different skills to varying extent. I derive optimal assignment rules with and without slot constraints, and show that under certain circumstances workers may get promoted although in their new job they are expected to be less productive than in their old job. This can be interpreted as a version of the Peter Principle which states that workers get prom...
2017-01-17
convey any rights or permission to manufacture, use, or sell any patented invention that may relate to them. This report was cleared for public release...testing for reliability prediction of devices exhibiting multiple failure mechanisms. Also presented was an integrated accelerating and measuring ...13 Table 2 T, V, F and matrix versus measured FIT
Symmetry Beyond Perturbation Theory: Floppy Molecules and Rotation-Vibration States
Schmiedt, Hanno; Schlemmer, Stephan; Jensen, Per
2015-06-01
In the customary approach to the theoretical description of the nuclear motion in molecules, the molecule is seen as a near-static structure rotating in space. Vibrational motion causing small structural deformations induces a perturbative treatment of the rotation-vibration interaction, which fails in fluxional molecules, where all vibrational motions are large compared to the linear extension of the molecule. An example is protonated methane (CH_5^+). For this molecule, customary theory fails to simulate reliably even the low-energy spectrum. Within the traditional view of rotation and vibration being near-separable, rotational and vibrational wavefunctions can be symmetry classified separately in the molecular symmetry (MS) group. In the present contribution we discuss a fundamental group theoretical approach to the problem of determining the symmetries of molecular rotation-vibration states. We will show that all MS groups discussed so far are subgroups of the special orthogonal group in three dimensions SO(3) This leads to a group theoretical foundation of the technique of equivalent rotations. The MS group of protonated methane (G240) represents, to the best of our knowledge, the first example of an MS group which is not a subgroup of SO(3) (nor of O(3) nor of SU(2)). Because of this, a separate symmetry classification of vibrational and rotational wavefunctions becomes impossible in this MS group, consistent with the fact that a decoupling of vibrational and rotational motion is impossible. We want to discuss the consequences of this. In conclusion, we show that the prototypical floppy molecule CH_5^+ represents a new class of molecules, where usual group theoretical methods for determining selection rules and spectral assignments fail so that new methods have to be developed. P. Kumar and D. Marx, Physical Chemistry Chemical Physics 8, 573 (2006) Z. Jin, B. J. Braams, and J. M. Bowman, The Journal of Physical Chemistry A 110, 1569 (2006) A. S. Petit, J. E
2013-01-01
应用ANSYS对随机振动下商用室外机管路的响应进行分析，应用Miner线性疲劳累计损伤理论和材料的S-N曲线，估算室外机的疲劳寿命，结合正交试验表，确定商用室外机管路最佳尺寸组合，提升室外机的疲劳寿命。%In this article, the FEA software ANSYS is used to simulate the stress distribution of the outdoor unit of commercial air conditioner caused by the random vibration. The Miner’s linear fatigue accumulation rule and the S-N curve of the materials are used to estimate the fatigue life of the outdoor unit of the commercial air conditioner. The orthogonal experiment is used to analyze the optimum size of pipe structure, so as to improve the fatigue life of outdoor unit.
Conformational and Vibrational Studies of Triclosan
Özişik, Haci; Bayari, S. Haman; Saǧlam, Semran
2010-01-01
The conformational equilibrium of triclosan (5-chloro-2-(2, 4-dichlorophenoxy) phenol) have been calculated using density functional theory (DFTe/B3LYP/6-311++G(d, p)) method. Four different geometries were found to correspond to energy minimum conformations. The IR spectrum of triclosan was measured in the 4000-400 cm-1 region. We calculated the harmonic frequencies and intensities of the most stable conformers in order to assist in the assignment of the vibrational bands in the experimental spectrum. The fundamental vibrational modes were characterized depending on their total energy distribution (TED%) using scaled quantum mechanical (SQM) force field method.
Does more sophisticated modeling reduce model uncertainty? A case study on vibration predictions
Waarts, P.H.; Wit, M.S. de
2004-01-01
In this paper, the reliability of vibration predictions in civil engineering is quantified. Emphasis is laid on the vibration predictions for road- and rail traffic and vibrations from building activities such as (sheet)pile driving. Several kinds of prediction techniques were investigated: expert o
Evaluation of Automatically Assigned Job-Specific Interview Modules.
Friesen, Melissa C; Lan, Qing; Ge, Calvin; Locke, Sarah J; Hosgood, Dean; Fritschi, Lin; Sadkowsky, Troy; Chen, Yu-Cheng; Wei, Hu; Xu, Jun; Lam, Tai Hing; Kwong, Yok Lam; Chen, Kexin; Xu, Caigang; Su, Yu-Chieh; Chiu, Brian C H; Ip, Kai Ming Dennis; Purdue, Mark P; Bassig, Bryan A; Rothman, Nat; Vermeulen, Roel
2016-08-01
In community-based epidemiological studies, job- and industry-specific 'modules' are often used to systematically obtain details about the subject's work tasks. The module assignment is often made by the interviewer, who may have insufficient occupational hygiene knowledge to assign the correct module. We evaluated, in the context of a case-control study of lymphoid neoplasms in Asia ('AsiaLymph'), the performance of an algorithm that provided automatic, real-time module assignment during a computer-assisted personal interview. AsiaLymph's occupational component began with a lifetime occupational history questionnaire with free-text responses and three solvent exposure screening questions. To assign each job to one of 23 study-specific modules, an algorithm automatically searched the free-text responses to the questions 'job title' and 'product made or services provided by employer' using a list of module-specific keywords, comprising over 5800 keywords in English, Traditional and Simplified Chinese. Hierarchical decision rules were used when the keyword match triggered multiple modules. If no keyword match was identified, a generic solvent module was assigned if the subject responded 'yes' to any of the three solvent screening questions. If these question responses were all 'no', a work location module was assigned, which redirected the subject to the farming, teaching, health professional, solvent, or industry solvent modules or ended the questions for that job, depending on the location response. We conducted a reliability assessment that compared the algorithm-assigned modules to consensus module assignments made by two industrial hygienists for a subset of 1251 (of 11409) jobs selected using a stratified random selection procedure using module-specific strata. Discordant assignments between the algorithm and consensus assignments (483 jobs) were qualitatively reviewed by the hygienists to evaluate the potential information lost from missed questions with using
A Statistical Programme Assignment Model
Rosholm, Michael; Staghøj, Jonas; Svarer, Michael
When treatment effects of active labour market programmes are heterogeneous in an observable way across the population, the allocation of the unemployed into different programmes becomes a particularly important issue. In this paper, we present a statistical model designed to improve the present...... assignment mechanism, which is based on the discretionary choice of case workers. This is done in a duration model context, using the timing-of-events framework to identify causal effects. We compare different assignment mechanisms, and the results suggest that a significant reduction in the average...... duration of unemployment spells may result if a statistical programme assignment model is introduced. We discuss several issues regarding the plementation of such a system, especially the interplay between the statistical model and case workers....
Laynebaril1
2017-01-01
AC410 Unit 9 Assignment Click Link Below To Buy: http://hwcampus.com/shop/ac410-unit-9-assignment/ 18–29. The CPA firm of Carson & Boggs LLP is performing an internal control audit in accordance with PCAOB Standard No. 5. The partner in charge of the engagement has asked you to explain the process of determining which controls to test. Describe the process, presenting each of the links in this process and a short summary of how the auditors approach each of them. v ...
2010-01-01
... 7 Agriculture 7 2010-01-01 2010-01-01 false Assignment. 760.31 Section 760.31 Agriculture... Assignment. No assignment shall be made of any indemnity payment due or to come due under the regulations in this subpart. Any assignment or attempted assignment of any indemnity payment due or to come due under...
Beecher, L. C.; Williams, F. T.
1970-01-01
Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.
Control System Damps Vibrations
Kopf, E. H., Jr.; Brown, T. K.; Marsh, E. L.
1983-01-01
New control system damps vibrations in rotating equipment with help of phase-locked-loop techniques. Vibrational modes are controlled by applying suitable currents to drive motor. Control signals are derived from sensors mounted on equipment.
Vibrational frequencies and structural determination of tetraazidogermane
Jensen, James O.
2003-10-01
The vibrational frequencies and corresponding normal mode assignments of tetraazidogermane are examined theoretically using the Gaussian98 set of quantum chemistry codes. All normal modes were successfully assigned to one of seven types of motion predicted by a group theoretical analysis (NNN asymmetric stretch, NNN symmetric stretch, GeN stretch, NNN bend, GeNN bend, NGeN bend, and NGeNN torsion) utilizing the S 4 symmetry of the molecule. The molecular orbitals of Ge(N 3) 4 are examined.
Vibrational frequencies and structure determination of silylgermane
Jensen, James O.
2003-11-01
The normal mode frequencies and corresponding vibrational assignments of silylgermane are examined theoretically using the GAUSSIAN 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of seven types of motion predicted by a group theoretical analysis (SiH stretch, GeH stretch, SiGe stretch, HSiH bend, HGeH bend, SiH 3 wag/GeH 3 wag and SiGe torsion) utilizing the C3 v symmetry of the molecule. Predicted infrared and Raman intensities are presented. Molecular orbitals are presented and bonding is examined in terms of the molecular orbitals.
Who Benefits from Homework Assignments?
Ronning, Marte
2011-01-01
Using Dutch data on pupils in elementary school this paper is the first empirical study to analyze whether assigning homework has a heterogeneous impact on pupil achievement. Addressing potential biases by using a difference-in-difference approach, I find that the test score gap is larger in classes where everybody gets homework than in classes…
Assessing Contributions to Group Assignments
Johnston, Lucy; Miles, Lynden
2004-01-01
We report the use of a combination of self- and peer-assessment in an undergraduate social psychology laboratory course. Students worked in small groups on a self-directed empirical project that they each wrote up independently as a laboratory report. Marks for the written assignment were moderated by a contribution index measure based on the…
Theory Study on Structures and Vibrational Frequencies of Pyruvic acid
无
2000-01-01
Density functional theory BLYP (using Becke's and Lee-Yang-Parr's correlation functionals ), ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations were carried out to study the structure and vibrational spectra of pyruvic acid. The scaled B3LYP/6-31G* frequencies correspond well with available experimental assignment of the functional vibrational modes and the mean absolut devation is only 12.3cm-1.
Vibrational Spectra of N-Butyryl-Homoserine Lactone
Bak, Jimmy; Spanget-Larsen, Jens
in the solid state, and in liquid CCl4 solution. Quantum chemical calculations are performed in order to support the assignment of the measured vibrational bands and explain intermolecular interactions and solvent effects. The resulting designation of the reported spectral bands of C4-HSL lactone demonstrates...... spectra that resembles the measured one was possible. Here we report for the first time the key vibrational band of the monomer form....
Ramalingam, S; Jayaprakash, A; Mohan, S; Karabacak, M
2011-11-01
FT-IR and FT-Raman (4000-100 cm(-1)) spectral measurements of 3-methyl-1,2-butadiene (3M12B) have been attempted in the present work. Ab-initio HF and DFT (LSDA/B3LYP/B3PW91) calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies, IR intensities and Raman activities. Complete vibrational assignments on the observed spectra are made with vibrational frequencies obtained by HF and DFT (LSDA/B3LYP/B3PW91) at 6-31G(d,p) and 6-311G(d,p) basis sets. The results of the calculations have been used to simulate IR and Raman spectra for the molecule that showed good agreement with the observed spectra. The potential energy distribution (PED) corresponding to each of the observed frequencies are calculated which confirms the reliability and precision of the assignment and analysis of the vibrational fundamentals modes. The oscillation of vibrational frequencies of butadiene due to the couple of methyl group is also discussed. A study on the electronic properties such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The thermodynamic properties of the title compound at different temperatures reveal the correlations between standard heat capacities (C) standard entropies (S), and standard enthalpy changes (H).
Saiz, P; Rocha, R; Andreeva, J
2007-01-01
We are offering a system to track the efficiency of different components of the GRID. We can study the performance of both the WMS and the data transfers At the moment, we have set different parts of the system for ALICE, ATLAS, CMS and LHCb. None of the components that we have developed are VO specific, therefore it would be very easy to deploy them for any other VO. Our main goal is basically to improve the reliability of the GRID. The main idea is to discover as soon as possible the different problems that have happened, and inform the responsible. Since we study the jobs and transfers issued by real users, we see the same problems that users see. As a matter of fact, we see even more problems than the end user does, since we are also interested in following up the errors that GRID components can overcome by themselves (like for instance, in case of a job failure, resubmitting the job to a different site). This kind of information is very useful to site and VO administrators. They can find out the efficien...
Direm, Amani; Tursun, Mahir; Parlak, Cemal; Benali-Cherif, Nourredine
2015-08-01
The copper complex [Cu(HPrz)4]Cl2 (HPrz = Pyrazole) was synthesized and its structure was characterized by FT-IR, Raman and single-crystal X-ray diffraction (XRD) techniques. The structural conformers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the compound were examined by means of the density functional theory (DFT) method, the Becke-3-Lee-Yang-Parr (B3LYP) functional, the 6-311+G(3df,p) and lanl2dz basis sets. Reliable vibrational assignments were investigated by the potential energy distribution (PED) analysis. The compound crystallizes in the monoclinic space group C2/c with the unit cell parameters a = 13.5430 (10) Å, b = 9.1480 (10) Å, c = 14.6480 (10) Å and β = 116.7° (5). There is a good agreement between the theoretically predicted structural parameters and vibrational frequencies and those obtained experimentally. The findings of this work reveals further insight into molecular copper(II) pyrazole systems.
Scheduling Linearly Indexed Assignment Codes
Kailath, Thomas; Roychowdhury, Vwani P.
1989-05-01
It has been recently shown that linearly indexed Assignment Codes can be efficiently used for coding several problems especially in signal processing and matrix algebra. In fact, mathematical expressions for many algorithms are directly in the form of linearly indexed codes, and examples include the formulas for matrix multiplication, any m-dimensional convolution/correlation, matrix transposition, and solving matrix Lyapunov's equation. Systematic procedures for converting linearly indexed Assignment Codes to localized algorithms that are closely related to Regular Iterative Algorithms (RIAs) have also been developed. These localized algorithms can be often efficiently scheduled by modeling them as RIAs; however, it is not always efficient to do so. In this paper we shall analyze and develop systematic procedures for determining efficient schedules directly for the linearly indexed ACs and the localized algorithms. We shall also illustrate our procedures by determining schedules for examples such as matrix transposition and Gauss-Jordan elimination algorithm.
Design of Wind Turbine Vibration Monitoring System
Shoubin Wang
2013-04-01
Full Text Available In order to ensure safety of wind turbine operation and to reduce the occurrence of faults as well as to improve the reliability of wind turbine operation, a vibration monitoring for wind turbine is developed. In this paper, it analyses the enlargement of all the parts of the structure and the working mechanism, the research method of wind turbine operation vibration is introduced, with the focus being the use of the sensor principle. Finally the hardware design and software of this system is introduced and the main function of this system is described, which realizes condition monitoring of the work state of wind turbines.
CONTRACT ASSIGNMENT – THEORETICAL ASPECTS
Bogdan NAZAT
2016-12-01
Full Text Available This project aims to study in detail the theoretical aspects concerning the contract assignment, as provided by the relevant regulation, and the doctrine corresponding to old and current regulations. In this respect, this project aims to give the reader a comprehensive look on the institution in question, the regulation offered by the current Civil Code is reviewed taking into account the national and international doctrine.
Neurodynamics-Based Robust Pole Assignment for High-Order Descriptor Systems.
Le, Xinyi; Wang, Jun
2015-11-01
In this paper, a neurodynamic optimization approach is proposed for synthesizing high-order descriptor linear systems with state feedback control via robust pole assignment. With a new robustness measure serving as the objective function, the robust eigenstructure assignment problem is formulated as a pseudoconvex optimization problem. A neurodynamic optimization approach is applied and shown to be capable of maximizing the robust stability margin for high-order singular systems with guaranteed optimality and exact pole assignment. Two numerical examples and vehicle vibration control application are discussed to substantiate the efficacy of the proposed approach.
The normal modes of lattice vibrations of ice XI
Zhang, Peng; Wang, Zhe; Lu, Ying-Bo; Ding, Zheng-Wen
2016-07-01
The vibrational spectrum of ice XI at thermal wavelengths using the CASTEP code, a first-principles simulation method, is investigated. A dual-track approach is constructed to verify the validity for the computational phonon spectrum: collate the simulated spectrum with inelastic neutron scattering experiments and assign the photon scattering peaks according to the calculated normal vibration frequencies. The 33 optical normal vibrations at the Brillouin center are illustrated definitely from the ab initio outcomes. The depolarizing field effect of the hydrogen bond vibrations at frequencies of 229 cm‑1 and 310 cm‑1 is found to agree well with the LST relationship. It is a convincing evidence to manifest the LO-TO splitting of hydrogen bonds in ice crystal. We attribute the two hydrogen bond peaks to the depolarization effect and apply this viewpoint to ordinary ice phase, ice Ih, which is difficult to analyse their vibration modes due to proton disorder.
47 CFR 74.802 - Frequency assignment.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.802 Section 74.802... Frequency assignment. (a) Frequencies within the following bands may be assigned for use by low power... exceed 200 kHz. (d) Low power auxiliary licensees will not be granted exclusive frequency assignments. (e...
47 CFR 74.602 - Frequency assignment.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.602 Section 74.602... Stations § 74.602 Frequency assignment. (a) The following frequencies are available for assignment to... 2450 and 2500 MHz are also shared with other communication services and exclusive channel assignments...
5 CFR 351.705 - Administrative assignment.
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Administrative assignment. 351.705... REDUCTION IN FORCE Assignment Rights (Bump and Retreat) § 351.705 Administrative assignment. (a) An agency... cannot make an equally reasonable assignment by displacing an employee in a lower subgroup; (2) Permit an...
An algorithm for ranking assignments using reoptimization
Pedersen, Christian Roed; Nielsen, Lars Relund; Andersen, Kim Allan
2008-01-01
We consider the problem of ranking assignments according to cost in the classical linear assignment problem. An algorithm partitioning the set of possible assignments, as suggested by Murty, is presented where, for each partition, the optimal assignment is calculated using a new reoptimization...... technique. Computational results for the new algorithm are presented...
A note on ranking assignments using reoptimization
Pedersen, Christian Roed; Nielsen, L.R.; Andersen, K.A.
2005-01-01
We consider the problem of ranking assignments according to cost in the classical linear assignment problem. An algorithm partitioning the set of possible assignments, as suggested by Murty, is presented where, for each partition, the optimal assignment is calculated using a new reoptimization...
Thermal Vibrational Convection
Gershuni, G. Z.; Lyubimov, D. V.
1998-08-01
Recent increasing awareness of the ways in which vibrational effects can affect low-gravity experiments have renewed interest in the study of thermal vibrational convection across a wide range of fields. For example, in applications where vibrational effects are used to provide active control of heat and mass transfer, such as in heat exchangers, stirrers, mineral separators and crystal growth, a sound understanding of the fundamental theory is required. In Thermal Vibrational Convection, the authors present the theory of vibrational effects caused by a static gravity field, and of fluid flows which appear under vibration in fluid-filled cavities. The first part of the book discusses fluid-filled cavities where the fluid motion only appears in the presence of temperature non-uniformities, while the second considers those situations where the vibrational effects are caused by a non-uniform field. Throughout, the authors concentrate on consideration of high frequency vibrations, where averaging methods can be successfully applied in the study of the phenomena. Written by two of the pioneers in this field, Thermal Vibrational Convection will be of great interest to scientists and engineers working in the many areas that are concerned with vibration, and its effect on heat and mass transfer. These include hydrodynamics, hydro-mechanics, low gravity physics and mechanics, and geophysics. The rigorous approach adopted in presenting the theory of this fascinating and highly topical area will facilitate a greater understanding of the phenomena involved, and will lead to the development of more and better-designed experiments.
Designing for Reliability and Robustness
Svetlik, Randall G.; Moore, Cherice; Williams, Antony
2017-01-01
Long duration spaceflight has a negative effect on the human body, and exercise countermeasures are used on-board the International Space Station (ISS) to minimize bone and muscle loss, combatting these effects. Given the importance of these hardware systems to the health of the crew, this equipment must continue to be readily available. Designing spaceflight exercise hardware to meet high reliability and availability standards has proven to be challenging throughout the time the crewmembers have been living on ISS beginning in 2000. Furthermore, restoring operational capability after a failure is clearly time-critical, but can be problematic given the challenges of troubleshooting the problem from 220 miles away. Several best-practices have been leveraged in seeking to maximize availability of these exercise systems, including designing for robustness, implementing diagnostic instrumentation, relying on user feedback, and providing ample maintenance and sparing. These factors have enhanced the reliability of hardware systems, and therefore have contributed to keeping the crewmembers healthy upon return to Earth. This paper will review the failure history for three spaceflight exercise countermeasure systems identifying lessons learned that can help improve future systems. Specifically, the Treadmill with Vibration Isolation and Stabilization System (TVIS), Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), and the Advanced Resistive Exercise Device (ARED) will be reviewed, analyzed, and conclusions identified so as to provide guidance for improving future exercise hardware designs. These lessons learned, paired with thorough testing, offer a path towards reduced system down-time.
Basu, Asit P; Basu, Sujit K
1998-01-01
This volume presents recent results in reliability theory by leading experts in the world. It will prove valuable for researchers, and users of reliability theory. It consists of refereed invited papers on a broad spectrum of topics in reliability. The subjects covered include Bayesian reliability, Bayesian reliability modeling, confounding in a series system, DF tests, Edgeworth approximation to reliability, estimation under random censoring, fault tree reduction for reliability, inference about changes in hazard rates, information theory and reliability, mixture experiment, mixture of Weibul
Vibrationally Resolved Electron Transfer Rates in Solution
Spears, Kenneth G.
2002-03-01
We have re-examined our earlier report of electron transfer in the [Co(Cp)_2|V(CO)_6] radical-pair using ultrafast infrared transient absorption spectroscopy in room temperature solutions. The radical-pair is created from the [Co(Cp)_2^+|V(CO)_6^-] ion-pair by ultrafast visible charge-transfer excitation. Transient absorption experiments with ps time constants. A small ET component with a 75 ps time constant is due to some separation and reformation of the radical-pairs. Transient absorption experiments monitoring the recovery of the ion-pair state shows that both fast components are due to ET rather than some other vibrational relaxation (VR) process in the radical state. We analyze the visible charge-transfer band and assign the two fast ET decay times to two ion-pair contact geometries with absorption origins different by about 1250 ± 350 cm-1. For excitation at 800 and 700 nm the 700 fs ET lifetime depends on the vibrational quantum state of the nontotally symmetric CO stretch in the V(CO)6 radical, where the lifetime decreases by 10% for the first vibrational quantum and 45% for the second quantum. There is no quantum effect for the second ion-pair geometry with a 5 ps ET lifetime. Standard ET rate models cannot explain the rate dependence upon vibrational quantum state for a nontotally symmetric vibration, and it may arise from a breakdown of the Condon approximation. We also report rates for IVR of CO stretching modes and for VR of low frequency vibrations. At excitation wavelengths of 620 and 555 nm there is sufficient internal vibrational energy in low-frequency vibrations to cause geometric inter-conversion between energetically similar Jahn-Teller geometries in the V(CO)6 radical. This process creates a 200 fs rise time for the V(CO)6 radical species to assume a stable geometry, which requires VR of low frequency vibrations to the solvent. These results demonstrate that earlier ET measurements from our group on the same molecule had insufficient time
Vibrating fuel grapple. [LMFBR
Chertock, A.J.; Fox, J.N.; Weissinger, R.B.
A reactor refueling method is described which utilizes a vibrating fuel grapple for removing spent fuel assemblies from a reactor core. It incorporates a pneumatic vibrator in the grapple head which allows additional withdrawal capability without exceeding the allowable axial force limit. The only moving part in the vibrator is a steel ball, pneumatically driven by a gas, such as argon, around a track, with centrifugal force created by the ball being transmitted through the grapple to the assembly handling socket.
Eigenvectors of internal vibrations of C60: Theory and experiment
Heid, R.; Pintschovius, L.; Godard, J. M.
1997-09-01
We have studied the eigenvectors of all internal modes of C60 up to 75 meV by inelastic neutron scattering. The experimental data are compared in detail with a state-of-the-art ab initio theory and a phenomenological model of the vibrational spectrum of C60, respectively. We demonstrate that the momentum dependence of mode intensities obtained from measurements on single crystals as well as on powder samples represents a sensitive fingerprint of the eigenvectors which allows (i) unambiguous assignments of silent modes and (ii) discrimination of eigenvectors of modes belonging to the same symmetry class. The latter property can be used for stringent tests of theoretical models. Eigenvectors predicted by the ab initio theory are found to be in very satisfactory agreement with the experimental data, while those obtained from the phenomenological model turn out to be less reliable. We have also performed measurements to study the dispersion of the Hg(1) mode in the low-temperature phase. We found that the data can be largely, although not fully, understood on the basis of a simple van der Waals ansatz for the intermolecular interactions.
Dolmatov, E.; Zaharov, A.; Ilin, S.; Kuznetsov, I.; Nikiforov, A.
2016-11-01
The article covers a choice of main vibration parameter at an assessment of a vibration state of vertical Francis hydroturbines. At present time vibration velocity and vibration displacement are adopted as main parameters of non-rotating parts vibration in the international standard ISO 10816-5:2000 «Mechanical vibration — Evaluation of machine vibration by measurements on non-rotating parts — Part 5: Machine sets in hydraulic power generating and pumping plants» (further ISO 10816-5:2000). The hydraulic turbines refer to the slow-speed machines with rotation speed from 60 to 600 rpm (∼ 1 - 10 Hz). So maximum vibration displacements and dynamic stresses in hydraulic turbines supporting parts are in low-frequency region of vibration spectrum. In this report comparative data of hydro units supporting parts vibration velocity and vibration displacement measurements are presented. Using these data assessment of hydro units vibration state has been done. It is shown that the assessment of a hydro unit vibration state using parameter "vibration displacement" corresponds to the fundamental principles of operational reliability and fatigue strength of hydro units supporting parts. It is noted that when hydro units operate at small and partial loads with high low-frequency unsteady flow (f hydraulic turbines» which was published in 1989. In this document vibration displacement was considered as a main parameter. Evaluation of turbine vibration was performed according to the effecrive value of turbine supporting parts vibration displacement.
Vibration Analysis of Air Condition Unit on Subway
Yan Liu
2013-06-01
Full Text Available Subway system has many merits including large passenger carrying ability, high speed, strong controllability and reliability of driving. Nevertheless, subways also have brought many disadvantages for human. In many subway systems, noisy environments are clearly observed and passengers are exposed to higher noise levels than permissible limit. This study presents a study of noise and vibration of subway air condition system, so as to grasp the vibration distribution laws of the air condition system. By the tested of noise and vibration, the researcher find the sound distribution rule of air condition is very important Based on the consequence of the testing, the acceleration of air condition has little to do with the subway speed and more to do with the vibration of fan; When the train driving on the viaduct bridge, the acceleration of air condition is biggish in 125 Hz and In 50-1000 Hz the vibration of air condition is obviously. When the train running underground line, as a result of the resonance of body, air condition’s vibration is biggish in 630 Hz and the vibration is obviously in 125-1250 Hz. With the increase of the speed, the influence of the ground’s second radiation on body vibration is enhanced. The superfine gross wool which is used to air condition can achieve good results for noise reduction. This research has higher reference for the vibration and noise reduction of the subway air condition system.
Finite Element Calculation of Discrete Stratified Fluid Vibrations
Ko Ko Win
2016-01-01
Full Text Available Many publications, which consider a problem of small vibrations of an incompressible ideal fluid, completely filling the stationary cylindrical tank, have the long lists of references in the field concerned. This paper uses the finite element method to consider vibrations of three incompressible fluids, defines natural frequencies of vibrations, and builds the vibration forms of the interface surface of fluids for the double-tone vibrations. It shows how the vibration frequency depends on the ratios of vibrating fluid density and thicknesses of fluid layers and compares the numerical calculation results with the analytically obtained exact values.The paper describes a variational formulation of the problem concerning the natural vibrations of immiscible fluids and using the finite element method provides a numerical implementation to define the fixed values of the functional that meets the variational problem. The reliability of the numerical results obtained is proved by their approximation to the result of calculating frequencies derived from the solutions of the problem of natural vibrations of fluid in a cylindrical vessel with a different fluid depth. To perform all numerical calculations was used the Matlab software.
Wildlife forensic science: A review of genetic geographic origin assignment.
Ogden, Rob; Linacre, Adrian
2015-09-01
Wildlife forensic science has become a key means of enforcing legislation surrounding the illegal trade in protected and endangered species. A relatively new dimension to this area of forensic science is to determine the geographic origin of a seized sample. This review focuses on DNA testing, which relies on assignment of an unknown sample to its genetic population of origin. Key examples of this are the trade in timber, fish and ivory and these are used only to illustrate the large number of species for which this type of testing is potentially available. The role of mitochondrial and nuclear DNA markers is discussed, alongside a comparison of neutral markers with those exhibiting signatures of selection, which potentially offer much higher levels of assignment power to address specific questions. A review of assignment tests is presented along with detailed methods for evaluating error rates and considerations for marker selection. The availability and quality of reference data are of paramount importance to support assignment applications and ensure reliability of any conclusions drawn. The genetic methods discussed have been developed initially as investigative tools but comment is made regarding their use in courts. The potential to compliment DNA markers with elemental assays for greater assignment power is considered and finally recommendations are made for the future of this type of testing. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Assignment of the Raman lines in single crystal barium metaborate (beta-BaB sub 2 O sub 4)
Ney, P; Maillard, A; Polgar, K
1998-01-01
A Raman-scattering study performed on beta-BaB sub 2 O sub 4 (beta-BBO) at room temperature allows us to assign all the vibrational modes detected in the Raman spectra. The internal and external vibration modes are properly obtained by taking account of the light polarization, mode contamination and isotope effects. A correspondence between the lattice and the free-ring modes is also presented. (author)
The Random Quadratic Assignment Problem
Paul, Gerald; Shao, Jia; Stanley, H. Eugene
2011-11-01
The quadratic assignment problem, QAP, is one of the most difficult of all combinatorial optimization problems. Here, we use an abbreviated application of the statistical mechanics replica method to study the asymptotic behavior of instances in which the entries of at least one of the two matrices that specify the problem are chosen from a random distribution P. Surprisingly, the QAP has not been studied before using the replica method despite the fact that the QAP was first proposed over 50 years ago and the replica method was developed over 30 years ago. We find simple forms for C min and C max , the costs of the minimal and maximum solutions respectively. Notable features of our results are the symmetry of the results for C min and C max and their dependence on P only through its mean and standard deviation, independent of the details of P.
More General Optimal Offset Assignment
Sven Mallach
2015-06-01
Full Text Available This manuscript presents exact approaches to the general offset assignment problem arising in the address code generation phase of compilers for application-specific processors. First, integer programming models for architecture-dependent and theoretically motivated special cases of the problem are established. Then, these models are extended to provide the first widely applicable formulations for the most general problem setting, supporting processors with several address registers and complex addressing capabilities. Existing heuristics are similarly extended and practical applicability of the proposed methods is demonstrated by experimental evaluation using an established and large benchmark set. The experiments allow us to study the impact of exploiting more complex memory addressing capabilities on the address computation costs of real-world programs. We also show how to integrate operand reordering techniques for commutative instructions into existing solution approaches.
Vibrational Analysis of (SCN)2 and the Transient (SCN)2
Jensen, N. H.; Wilbrandt, Robert Walter; Pagsberg, Palle Bjørn
1979-01-01
The vibrational spectra of thiocyanogen and the transient radical anion (SCN)2− are interpreted in detail through molecular orbital and normal coordinate calculations. The results support the assignment of (SCN)2− to the anion of thiocyanogen and indicate a substantial weakening of the S–S and C...
Reference databases for taxonomic assignment in metagenomics.
Santamaria, Monica; Fosso, Bruno; Consiglio, Arianna; De Caro, Giorgio; Grillo, Giorgio; Licciulli, Flavio; Liuni, Sabino; Marzano, Marinella; Alonso-Alemany, Daniel; Valiente, Gabriel; Pesole, Graziano
2012-11-01
Metagenomics is providing an unprecedented access to the environmental microbial diversity. The amplicon-based metagenomics approach involves the PCR-targeted sequencing of a genetic locus fitting different features. Namely, it must be ubiquitous in the taxonomic range of interest, variable enough to discriminate between different species but flanked by highly conserved sequences, and of suitable size to be sequenced through next-generation platforms. The internal transcribed spacers 1 and 2 (ITS1 and ITS2) of the ribosomal DNA operon and one or more hyper-variable regions of 16S ribosomal RNA gene are typically used to identify fungal and bacterial species, respectively. In this context, reliable reference databases and taxonomies are crucial to assign amplicon sequence reads to the correct phylogenetic ranks. Several resources provide consistent phylogenetic classification of publicly available 16S ribosomal DNA sequences, whereas the state of ribosomal internal transcribed spacers reference databases is notably less advanced. In this review, we aim to give an overview of existing reference resources for both types of markers, highlighting strengths and possible shortcomings of their use for metagenomics purposes. Moreover, we present a new database, ITSoneDB, of well annotated and phylogenetically classified ITS1 sequences to be used as a reference collection in metagenomic studies of environmental fungal communities. ITSoneDB is available for download and browsing at http://itsonedb.ba.itb.cnr.it/.
Parkhurst, John T.; Fleisher, Matthew S.; Skinner, Christopher H.; Woehr, David J.; Hawthorn-Embree, Meredith L.
2011-01-01
After completing the Multidimensional Work-Ethic Profile (MWEP), 98 college students were given a 20-problem math computation assignment and instructed to stop working on the assignment after completing 10 problems. Next, they were allowed to choose to finish either the partially completed assignment that had 10 problems remaining or a new…
Parkhurst, John T.; Fleisher, Matthew S.; Skinner, Christopher H.; Woehr, David J.; Hawthorn-Embree, Meredith L.
2011-01-01
After completing the Multidimensional Work-Ethic Profile (MWEP), 98 college students were given a 20-problem math computation assignment and instructed to stop working on the assignment after completing 10 problems. Next, they were allowed to choose to finish either the partially completed assignment that had 10 problems remaining or a new…
Eugster, P.; Guerraoui, R.; Kouznetsov, P.
2001-01-01
This paper presents a new, non-binary measure of the reliability of broadcast algorithms, called Delta-Reliability. This measure quantifies the reliability of practical broadcast algorithms that, on the one hand, were devised with some form of reliability in mind, but, on the other hand, are not considered reliable according to the ``traditional'' notion of broadcast reliability [HT94]. Our specification of Delta-Reliability suggests a further step towards bridging the gap between theory and...
REN Wan-bin; CUI Li; LUO Fu-biao; ZHAI Guo-fu
2007-01-01
Published research is minimal on vibration characteristics of hermetically sealed electromagnetic relay (EMR) exposed to mechanical environment. The vibration characteristics of armature system, link contact system with electromagnetic system will cause EMR malfunction. The nonlinear dynamics model of armature systems was studied by considering electromagnetic attraction force and opposite mechanical force in this paper. Angular displacements of armature under different sinusoidal vibration conditions are solved in order to obtain the failure mode result from armature system. Vibration tests showed the presented analyzing method is suitable for EMR. The conclusions are instructive for increasing vibration resistance of armature systems of EMR, and are significant for reliability design of switch apparatus.
Reliability computation from reliability block diagrams
Chelson, P. O.; Eckstein, E. Y.
1975-01-01
Computer program computes system reliability for very general class of reliability block diagrams. Four factors are considered in calculating probability of system success: active block redundancy, standby block redundancy, partial redundancy, and presence of equivalent blocks in the diagram.
Kis, Z.; Janszky, J.; Vinogradov, An. V.; Kobayashi, T.
1996-01-01
The optical Schroedinger cat states are simple realizations of quantum states having nonclassical features. It is shown that vibrational analogues of such states can be realized in an experiment of double pulse excitation of vibrionic transitions. To track the evolution of the vibrational wave packet we derive a non-unitary time evolution operator so that calculations are made in a quasi Heisenberg picture.
Nielsen, Søren R. K.
The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 4th edition of this textbook on linear stochastic vibration...
[Vibration on agricultural tractors].
Peretti, Alessandro; Delvecchio, Simone; Bonomini, Francesco; di Bisceglie, Anita Pasqua; Colosio, Claudio
2013-01-01
In the article, details related to the diffusion of agricultural tractors in Italy are given and considerations about the effects of vibration on operators, the sources of vibration and suggestions to reduce them are presented. The acceleration values observed in Italy amongst 244 tractors and levels of worker exposure are shown by means of histograms. The relevant data variability is discussed.
Eijk, A.
2010-01-01
The methods that need to be employed to develop the better vibration guidelines to assess the integrity of a reciprocating compressor system are discussed. An R&D project of the European Forum of Reciprocating Compressors (EFRC) has been initiated to develop guidelines for vibrations in reciprocatin
Nielsen, Søren R. K.
The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 2nd edition of this textbook on linear stochastic vibration th...
Mechanical vibration and shock analysis, sinusoidal vibration
Lalanne, Christian
2014-01-01
Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m
Managing voluntary turnover through challenging assignments
Preenen, P.T.Y.; Pater, I.E. de; Vianen, A.E.M. van; Keijzer, L.
2011-01-01
This study examines employees' challenging assignments as manageable means to reduce turnover intentions, job search behaviors, and voluntary turnover. Results indicate that challenging assignments are negatively related to turnover intentions and job search behaviors and that these relationships
Vibration control in accelerators
Montag, C.
2011-01-01
In the vast majority of accelerator applications, ground vibration amplitudes are well below tolerable magnet jitter amplitudes. In these cases, it is necessary and sufficient to design a rigid magnet support structure that does not amplify ground vibration. Since accelerator beam lines are typically installed at an elevation of 1-2m above ground level, special care has to be taken in order to avoid designing a support structure that acts like an inverted pendulum with a low resonance frequency, resulting in untolerable lateral vibration amplitudes of the accelerator components when excited by either ambient ground motion or vibration sources within the accelerator itself, such as cooling water pumps or helium flow in superconducting magnets. In cases where ground motion amplitudes already exceed the required jiter tolerances, for instance in future linear colliders, passive vibration damping or active stabilization may be considered.
Vibrations of rotating machinery
Matsushita, Osami; Kanki, Hiroshi; Kobayashi, Masao; Keogh, Patrick
2017-01-01
This book opens with an explanation of the vibrations of a single degree-of-freedom (dof) system for all beginners. Subsequently, vibration analysis of multi-dof systems is explained by modal analysis. Mode synthesis modeling is then introduced for system reduction, which aids understanding in a simplified manner of how complicated rotors behave. Rotor balancing techniques are offered for rigid and flexible rotors through several examples. Consideration of gyroscopic influences on the rotordynamics is then provided and vibration evaluation of a rotor-bearing system is emphasized in terms of forward and backward whirl rotor motions through eigenvalue (natural frequency and damping ratio) analysis. In addition to these rotordynamics concerning rotating shaft vibration measured in a stationary reference frame, blade vibrations are analyzed with Coriolis forces expressed in a rotating reference frame. Other phenomena that may be assessed in stationary and rotating reference frames include stability characteristic...
Vibrational Spectroscopy of Biomembranes
Schultz, Zachary D.; Levin, Ira W.
2011-07-01
Vibrational spectroscopy, commonly associated with IR absorption and Raman scattering, has provided a powerful approach for investigating interactions between biomolecules that make up cellular membranes. Because the IR and Raman signals arise from the intrinsic properties of these molecules, vibrational spectroscopy probes the delicate interactions that regulate biomembranes with minimal perturbation. Numerous innovative measurements, including nonlinear optical processes and confined bilayer assemblies, have provided new insights into membrane behavior. In this review, we highlight the use of vibrational spectroscopy to study lipid-lipid interactions. We also examine recent work in which vibrational measurements have been used to investigate the incorporation of peptides and proteins into lipid bilayers, and we discuss the interactions of small molecules and drugs with membrane structures. Emerging techniques and measurements on intact cellular membranes provide a prospective on the future of vibrational spectroscopic studies of biomembranes.
Dynamics analysis of vibration process in Particle Impact Noise Detection
ZHANG Hui; ZHOU Chang-lei; WANG Shu-juan; ZHAI Guo-fu
2007-01-01
Particle Impact Noise Detection (PIND) test is a reliability screening technique for hermetic device that is prescribed by MIL-PRF-39016E. Some test conditions are specified, although MIL-PRF-39016E did not specify how to obtain these conditions. This paper establishes the dynamics model of vibration process based on first order mass-spring system. The corresponding Simulink model is also established to simulate vibration process in optional input excitations. The response equations are derived in sinusoidal excitations and the required electromagnetic force waves are computed in order to obtain a given vibration and shock accelerations. Last, some simulation results are given.
Vibration-free stirling cryocooler for high definition microscopy
Riabzev, S. V.; Veprik, A. M.; Vilenchik, H. S.; Pundak, N.; Castiel, E.
2009-12-01
The normal operation of high definition Scanning Electronic and Helium Ion microscope tools often relies on maintaining particular components at cryogenic temperatures. This has traditionally been accomplished by using liquid coolants such as liquid Nitrogen. This inherently limits the useful temperature range to above 77 K, produces various operational hazards and typically involves elevated ownership costs, inconvenient logistics and maintenance. Mechanical coolers, over-performing the above traditional method and capable of delivering required (even below 77 K) cooling to the above cooled components, have been well-known elsewhere for many years, but their typical drawbacks, such as high purchasing cost, cooler size, low reliability and high power consumption have so far prevented their wide-spreading. Additional critical drawback is inevitable degradation of imagery performance originated from the wideband vibration export as typical for the operation of the mechanical cooler incorporating numerous movable components. Recent advances in the development of reliable, compact, reasonably priced and dynamically quiet linear cryogenic coolers gave rise to so-called "dry cooling" technologies aimed at eventually replacing the traditional use of outdated liquid Nitrogen cooling facilities. Although much improved these newer cryogenic coolers still produce relatively high vibration export which makes them incompatible with modern high definition microscopy tools. This has motivated further research activity towards developing a vibration free closed-cycle mechanical cryocooler. The authors have successfully adapted the standard low vibration Stirling cryogenic refrigerator (Ricor model K535-LV) delivering 5 W@40 K heat lift for use in vibration-sensitive high definition microscopy. This has been achieved by using passive mechanical counterbalancing of the main portion of the low frequency vibration export in combination with an active feed-forward multi
Partial eigenvalue assignment and its stability in a time delayed system
Singh, Kumar V.; Dey, Rajeeb; Datta, Biswa N.
2014-01-01
Active vibration control strategy is an effective way to control dangerous vibrations in a structure, caused by resonance and to manipulate the dynamics of vibrational response. Implementation of this strategy requires real-time computations of two feedback control matrices such that a small amount of eigenvalues of the associated quadratic matrix pencil are replaced by suitably chosen ones while the remaining large number of eigenvalues and eigenvectors remain unchanged ensuring the no spill-over. This mathematical problem is referred to as the Quadratic Partial Eigenvalue Assignment problem. The greatest challenge there is to solve the problems using the knowledge of only a small number of eigenvalues and eigenvectors that are computable using state-of-the-art techniques. This paper generalizes the earlier work on partial assignment to constant time-delay systems. Furthermore, a posterior stability analysis is carried out to identify the ranges of the time-delay that maintains the closed-loop assignment while keeping the stability of the infinite number of eigenvalues for the time-delayed systems. The practical features of the proposed methods are that it is implemented in the second-order setting itself using only those small number of eigenvalues and the eigenvectors that are to be assigned and the no spill-over is established by means of mathematical results. The results of our numerical experiments support the validity of our proposed methods.
Attenuation of cryocooler induced vibration in spaceborne infrared payloads
Veprik, A.; Twitto, A.
2014-01-01
Recent advancement of operational responsive space programs calls for a development of compact, reliable, low power and vibration free cryogenic cooling for sophisticated infrared payloads. The refrigeration in a typical closed cycle split Stirling linear cryocooler is achieved by a cyclic compression and expansion of a gaseous working agent due to a synchronized reciprocation of electro-dynamically and pneumatically actuated compressor and expander pistons. Attenuation of the cryocooler induced vibration usually relies on the concept of actively assisted momentum cancellation. In a typical dual-piston compressor this objective is achieved by actively synchronizing the motion of oppositely moving piston assemblies; a typical single-piston expander may be counterbalanced by a motorized counter-balancer. The above approach produces complexity, weight, size, high incurred costs and affects reliability. The authors analyze the case of passive attenuation the vibration export induced by the split Stirling linear cryocooler comprised of inline mounted single-piston compressor and expander. Placement of all the moving components onto a common axis results in a single axis consolidation of vibration export and enables use of single tuned dynamic absorber and low frequency vibration mount. From theoretical analysis and full-scale testing, the performance of such vibration protection arrangement is similar to known systems of active vibration cancellation.
24 CFR 221.255 - Assignment option.
2010-04-01
... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Assignment option. 221.255 Section... Assignment option. (a) A mortgagee holding a mortgage insured pursuant to a conditional or firm commitment..., directly to the Government National Mortgage Association (GNMA). Upon such assignment, transfer and...
47 CFR 74.502 - Frequency assignment.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.502 Section 74.502... § 74.502 Frequency assignment. (a) Except as provided in NG30, broadcast auxiliary stations licensed as... Allocations. (b) The frequency band 944-952 MHz is available for assignment to aural STL and ICR stations. One...
2010-01-01
... 7 Agriculture 10 2010-01-01 2010-01-01 false Assignment. 1488.17 Section 1488.17 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF...) Miscellaneous Provisions § 1488.17 Assignment. The exporter shall not assign any claim or rights or any amounts...
24 CFR 221.770 - Assignment option.
2010-04-01
... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Assignment option. 221.770 Section... § 221.770 Assignment option. A mortgagee holding a conditional or firm commitment issued on or before... securing it, directly to the Government National Mortgage Association (GNMA). Upon such assignment...
2010-07-01
... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Assignment. 20.201 Section 20.201 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL RULES OF PRACTICE... § 20.201 Assignment. An ALJ, assigned by the Chief ALJ after receipt of the complaint, shall preside...
2010-04-01
... 25 Indians 1 2010-04-01 2010-04-01 false Assignment. 215.20 Section 215.20 Indians BUREAU OF..., QUAPAW AGENCY § 215.20 Assignment. Leases granted or approved under the regulations in this part may be... Secretary of the Interior and subject to his approval as to the terms and conditions of such assignments...
2010-10-01
... 42 Public Health 3 2010-10-01 2010-10-01 false Assignment. 414.918 Section 414.918 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE... B § 414.918 Assignment. Payment for a CAP drug may be made only on an assignment-related basis. ...
7 CFR 247.21 - Caseload assignment.
2010-01-01
... 7 Agriculture 4 2010-01-01 2010-01-01 false Caseload assignment. 247.21 Section 247.21 Agriculture... CHILD NUTRITION PROGRAMS COMMODITY SUPPLEMENTAL FOOD PROGRAM § 247.21 Caseload assignment. (a) How does... assignment of additional caseload are determined in the following manner: (i) A State agency entering its...
47 CFR 74.402 - Frequency assignment.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.402 Section 74.402....402 Frequency assignment. Operation on all channels listed in this section (except: frequencies 26.07... channels are stacked in those sections stacking is permitted, channel assignments may be made for the...
Competition Based Neural Networks for Assignment Problems
李涛; LuyuanFang
1991-01-01
Competition based neural networks have been used to solve the generalized assignment problem and the quadratic assignment problem.Both problems are very difficult and are ε approximation complete.The neural network approach has yielded highly competitive performance and good performance for the quadratic assignment problem.These neural networks are guaranteed to produce feasible solutions.
A polyhedral approach to quadratic assignment problem
Köksaldı, Ahmet Sertaç Murat
1994-01-01
Ankara : Department of Industrial Engineering and the Institute of Engineering and Sciences of Bilkent University, 1994. Thesis (Master's) -- Bilkent University, 1994. Includes bibliographical references. In this thesis, Quadratic Assignment Problem is considered. Since Quadratic Assignment Problem is JVP-bard, no polynomial time exact solution method exists. Proving optimality of solutions to Quadratic Assignment Problems has been limited to instances of small dimension. In...
7 CFR 1437.104 - Assigned production.
2010-01-01
... 7 Agriculture 10 2010-01-01 2010-01-01 false Assigned production. 1437.104 Section 1437.104... Determining Yield Coverage Using Actual Production History § 1437.104 Assigned production. (a) When determining losses under this section, assigned production will be used to offset the loss of production when...
5 CFR 870.901 - Assignments permitted.
2010-01-01
... (CONTINUED) FEDERAL EMPLOYEES' GROUP LIFE INSURANCE PROGRAM Assignments of Life Insurance § 870.901..., and compensationers. (2) An individual may assign ownership of all life insurance under this part... Benefit before assigning the remainder of his/her insurance, the amount of Basic insurance does...
The Mechanism Design Approach to Student Assignment
Pathak, Parag A.
2011-01-01
The mechanism design approach to student assignment involves the theoretical, empirical, and experimental study of systems used to allocate students into schools around the world. Recent practical experience designing systems for student assignment has raised new theoretical questions for the theory of matching and assignment. This article reviews…
Integrated assignment and path planning
Murphey, Robert A.
2005-11-01
A surge of interest in unmanned systems has exposed many new and challenging research problems across many fields of engineering and mathematics. These systems have the potential of transforming our society by replacing dangerous and dirty jobs with networks of moving machines. This vision is fundamentally separate from the modern view of robotics in that sophisticated behavior is realizable not by increasing individual vehicle complexity, but instead through collaborative teaming that relies on collective perception, abstraction, decision making, and manipulation. Obvious examples where collective robotics will make an impact include planetary exploration, space structure assembly, remote and undersea mining, hazardous material handling and clean-up, and search and rescue. Nonetheless, the phenomenon driving this technology trend is the increasing reliance of the US military on unmanned vehicles, specifically, aircraft. Only a few years ago, following years of resistance to the use of unmanned systems, the military and civilian leadership in the United States reversed itself and have recently demonstrated surprisingly broad acceptance of increasingly pervasive use of unmanned platforms in defense surveillance, and even attack. However, as rapidly as unmanned systems have gained acceptance, the defense research community has discovered the technical pitfalls that lie ahead, especially for operating collective groups of unmanned platforms. A great deal of talent and energy has been devoted to solving these technical problems, which tend to fall into two categories: resource allocation of vehicles to objectives, and path planning of vehicle trajectories. An extensive amount of research has been conducted in each direction, yet, surprisingly, very little work has considered the integrated problem of assignment and path planning. This dissertation presents a framework for studying integrated assignment and path planning and then moves on to suggest an exact
Huynh, Tri H V; Shim, Irene; Bohr, Henrik; Abrahamsen, Bjarke; Nielsen, Birgitte; Jensen, Anders A; Bunch, Lennart
2012-06-14
The excitatory amino acid transporters (EAATs) play essential roles in regulating the synaptic concentration of the neurotransmitter glutamate in the mammalian central nervous system. To date, five subtypes have been identified, named EAAT1-5 in humans, and GLAST, GLT-1, EAAC1, EAAT4, and EAAT5 in rodents, respectively. In this paper, we present the design, synthesis, and pharmacological evaluation of seven 7-N-substituted analogues of UCPH-101/102. Analogue 9 inhibited EAAT1 in the micromolar range (IC(50) value 20 μM), whereas analogues 8 and 10 were inactive (IC(50) values >100 μM). The diastereomeric pairs 11a/11b and 12a/12b were separated by HPLC and the absolute configuration assigned by VCD technique in combination with ab initio Hartree-Fock calculations. Analogues 11a (RS-isomer) and 12b (RR-isomer) inhibited EAAT1 (IC(50) values 5.5 and 3.8 μM, respectively), whereas analogues 11b (SS-isomer) and 12a (SR-isomer) failed to inhibit EAAT1 uptake (IC(50) values >300 μM).
Vibrational Spectra and Quantum Calculations of Ethylbenzene
Jian Wang; Xue-jun Qiu; Yan-mei Wang; Song Zhang; Bing Zhang
2012-01-01
Normal vibrations of ethylbenzene in the first excited state have been studied using resonant two-photon ionization spectroscopy.The band origin of ethylbenzene of S1←S0 transition appeared at 37586 cm-1.A vibrational spectrum of 2000 cm-1 above the band origin in the first excited state has been obtained.Several chain torsions and normal vibrations are obtained in the spectrum.The energies of the first excited state are calculated by the time-dependent density function theory and configuration interaction singles (CIS) methods with various basis sets.The optimized structures and vibrational frequencies of the S0 and S1 states are calculated using Hartree-Fock and CIS methods with 6-311++G(2d,2p) basis set.The calculated geometric structures in the S0 and S1 states are gauche conformations that the symmetric plane of ethyl group is perpendicular to the ring plane.All the observed spectral bands have been successfully assigned with the help of our calculations.
Power Quality and Reliability Project
Attia, John O.
2001-01-01
One area where universities and industry can link is in the area of power systems reliability and quality - key concepts in the commercial, industrial and public sector engineering environments. Prairie View A&M University (PVAMU) has established a collaborative relationship with the University of'Texas at Arlington (UTA), NASA/Johnson Space Center (JSC), and EP&C Engineering and Technology Group (EP&C) a small disadvantage business that specializes in power quality and engineering services. The primary goal of this collaboration is to facilitate the development and implementation of a Strategic Integrated power/Systems Reliability and Curriculum Enhancement Program. The objectives of first phase of this work are: (a) to develop a course in power quality and reliability, (b) to use the campus of Prairie View A&M University as a laboratory for the study of systems reliability and quality issues, (c) to provide students with NASA/EPC shadowing and Internship experience. In this work, a course, titled "Reliability Analysis of Electrical Facilities" was developed and taught for two semesters. About thirty seven has benefited directly from this course. A laboratory accompanying the course was also developed. Four facilities at Prairie View A&M University were surveyed. Some tests that were performed are (i) earth-ground testing, (ii) voltage, amperage and harmonics of various panels in the buildings, (iii) checking the wire sizes to see if they were the right size for the load that they were carrying, (iv) vibration tests to test the status of the engines or chillers and water pumps, (v) infrared testing to the test arcing or misfiring of electrical or mechanical systems.
Reliability-based design optimization for nonlinear energy harvesters
Seong, Sumin; Lee, Soobum; Hu, Chao
2015-03-01
The power output of a vibration energy harvesting device is highly sensitive to uncertainties in materials, manufacturing, and operating conditions. Although the use of a nonlinear spring (e.g., snap-through mechanism) in energy harvesting device has been reported to reduce the sensitivity of power output with respect to the excitation frequency, the nonlinear spring characteristic remains significantly sensitive and it causes unreliable power generation. In this paper, we present a reliability-based design optimization (RBDO) study of vibration energy harvesters. For a nonlinear harvester, a purely mechanical nonlinear spring design implemented in the middle of cantilever beam harvester is considered in the study. This design has the curved section in the center of beam that causes bi-stable configuration. When vibrating, the inertia of the tip mass activates the curved shell to cause snap-through buckling and make the nature of vibration nonlinear. In this paper, deterministic optimization (DO) is performed to obtain deterministic optimum of linear and nonlinear energy harvester configuration. As a result of the deterministic optimization, an optimum bi-stable vibration configuration of nonlinear harvester can be obtained for reliable power generation despite uncertainty on input vibration condition. For the linear harvester, RBDO is additionally performed to find the optimum design that satisfies a target reliability on power generation, while accounting for uncertainty in material properties and geometric parameters.
Automatic Assessment of Programming assignment
Surendra Gupta
2012-01-01
Full Text Available In today’s world study of computer’s language is more important. Effective and good programming skills are need full all computer science students. They can be master in programming, only through intensive exercise practices. Due to day by day increasing number of students in the class, the assessment of programming exercises leads to extensive workload for teacher/instructor, particularly if it has to be carried out manually. In this paper, we propose an automatic assessment system for programming assignments, using verification program with random inputs. One of the most important properties of a program is that, it carries out its intended function. The intended function of a program or part of a program can be verified by using inverse function’s verification program. For checking intended functionality and evaluation of a program, we have used verification program. This assessment system has been tested on basic C programming courses, and results shows that it can work well in basic programming exercises, with some initial promising results
Verweij, Jan F.
1993-01-01
Several issue's regarding VLSI reliability research in Europe are discussed. Organizations involved in stimulating the activities on reliability by exchanging information or supporting research programs are described. Within one such program, ESPRIT, a technical interest group on IC reliability was
Vibrations and hydrogen bonding in porphycene.
Gawinkowski, Sylwester; Walewski, Łukasz; Vdovin, Alexander; Slenczka, Alkwin; Rols, Stephane; Johnson, Mark R; Lesyng, Bogdan; Waluk, Jacek
2012-04-28
Combined use of IR, Raman, neutron scattering and fluorescence measurements for porphycene isolated in helium nanodroplets, supersonic jet and cryogenic matrices, as well as for solid and liquid solutions, resulted in the assignments of almost all of 108 fundamental vibrations. The puzzling feature of porphycene is the apparent lack of the N-H stretching band in the IR spectrum, predicted to be the strongest of all bands by standard harmonic calculations. Theoretical modeling of the IR spectra, based on ab initio molecular dynamics simulations, reveals that the N-H stretching mode should appear as an extremely broad band in the 2250-3000 cm(-1) region. Coupling of the N-H stretching vibration to other modes is discussed in the context of multidimensional character of intramolecular double hydrogen transfer in porphycene. The analysis can be generalized to other strongly hydrogen-bonded systems. This journal is © the Owner Societies 2012
Trabia, M.B.; Kiley, M.; Cardle, J.; Joseph, M.
1991-07-01
The Waste Package Project Research Team, at UNLV, has four general required tasks. Task one is the management, quality assurance, and overview of the research that is performed under the cooperative agreement. Task two is the structural analysis of spent fuel and high level waste. Task three is an American Society of Mechanical Engineers (ASME) Pressure Vessel Code review for waste package application. Finally, task four is waste package labeling. This report includes preliminary information about task three (ASME Pressure Vessel Code review for Waste package Application). The first objective is to compile a list of the ASME Pressure Vessel Code that can be applied to waste package containers design and manufacturing processes. The second objective is to explore the use of these applicable codes to the preliminary waste package container designs. The final objective is to perform a library search for reliability and/or failure rates data on low pressure, low temperature, containers and casks with long design lives.
Stereospecific assignments in proteins using exact NOEs
Orts, Julien; Vögeli, Beat; Riek, Roland, E-mail: roland.riek@phys.chem.ethz.ch [Swiss Federal Institute of Technology, Laboratory of Physical Chemistry (Switzerland); Güntert, Peter, E-mail: guentert@em.uni-frankfurt.de [Goethe University Frankfurt am Main, Center for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry (Germany)
2013-10-18
Recently developed methods to measure distances in proteins with high accuracy by “exact” nuclear Overhauser effects (eNOEs) make it possible to determine stereospecific assignments, which are particularly important to fully exploit the accuracy of the eNOE distance measurements. Stereospecific assignments are determined by comparing the eNOE-derived distances to protein structure bundles calculated without stereospecific assignments, or an independently determined crystal structure. The absolute and relative CYANA target function difference upon swapping the stereospecific assignment of a diastereotopic group yields the respective stereospecific assignment. We applied the method to the eNOE data set that has recently been obtained for the third immunoglobulin-binding domain of protein G (GB3). The 884 eNOEs provide relevant data for 47 of the total of 75 diastereotopic groups. Stereospecific assignments could be established for 45 diastereotopic groups (96 %) using the X-ray structure, or for 27 diastereotopic groups (57 %) using structures calculated with the eNOE data set without stereospecific assignments, all of which are in agreement with those determined previously. The latter case is relevant for structure determinations based on eNOEs. The accuracy of the eNOE distance measurements is crucial for making stereospecific assignments because applying the same method to the traditional NOE data set for GB3 with imprecise upper distance bounds yields only 13 correct stereospecific assignments using the X-ray structure or 2 correct stereospecific assignments using NMR structures calculated without stereospecific assignments.
DFT studies on the vibrational and electronic spectra of acetylsalicylic acid
Ye, Yunfeng; Tang, Guodong; Han, Yonghong; Culnane, Lance F.; Zhao, Jianyin; Zhang, Yu
2016-05-01
The following is a theoretical and experimental study on the vibrational and electronic properties of acetylsalicylic acid (ASA). Vibrational information was obtained by FT-IR and Raman spectroscopy which agree well with harmonic vibrational frequency calculations. The calculations were carried out using density functional theory B3LYP methods with 6-311G** and LANL2DZ basis sets. The vibrational assignments were calculated by Gaussview. Absorption UV-Vis experiments of ASA reveal three maximum peaks at 203, 224 and 277 nm, which are in agreement with calculated electronic transitions using TD-B3LYP/6-311G**.
Torsional and Bending Vibration Measurement on Rotors Using Laser Technology
MILES, T. J.; LUCAS, M.; HALLIWELL, N. A.; ROTHBERG, S. J.
1999-09-01
Based on the principles of laser Doppler velocimetry, the laser torsional vibrometer (LTV) was developed for non-contact measurement of torsional oscillation of rotating shafts, offering significant advantages over conventional techniques. This paper describes comprehensive theory to account for the sensitivity of the LTV's measurements to shaft motion in all degrees of freedom. The optical geometry of the LTV offers inherent immunity to translational motion of the target shaft, either axial or radial. However, its measurements are sensitive to angular lateral vibration of the shaft. The significance of this sensitivity is compared with the instrument noise floor and typical torsional and lateral vibration levels. Optimum alignments of the instrument are then specified to ensure effective immunity to all lateral motion in typical applications. To overcome this problem more reliably, a new technique is proposed permitting unambiguous measurement of pure torsional vibration in situations where use of a single LTV demonstrates unacceptable sensitivity to angular lateral vibrations. Practical application of this technology is demonstrated with torsional vibration measurements from a diesel engine crankshaft. Simultaneously, previously unattained measurements of shaft bending vibration measurements are made. The first bending mode of the crankshaft was identified and its vibration amplitude and damping estimated. This application of laser vibrometry for non-contact measurements of shaft vibration represents a further step forward in the use of this technology for machinery diagnostics.
Lanzani, Guglielmo; De Silvestri, Sandro
2007-01-01
Vibrational spectroscopy is a powerful investigation tool for a wide class of materials covering diverse areas in physics, chemistry and biology. The continuous development in the laser field regarding ultrashort pulse generation has led to the possibility of producing light pulses that can follow vibrational motion coupled to the electronic transitions in molecules and solids in real time. Aimed at researchers and graduate students using vibrational spectroscopy, this book provides both introductory chapters as well as more advanced contents reporting on recent progress. It also provides a good starting point for scientists seeking a sound introduction to ultrafast optics and spectroscopic techniques.
Vibrational spectra study on quinolones antibiotics
Wang, Yu; Yu, Ke; Wang, Sihuan
2006-09-01
In order to be able to fully understand and easily identify the quilonoles, we collected IR and Raman spectra of six quinolones, and attempted to assign the attribution of the observed frequencies and their association with specific modes of vibration. According to the structure, the compounds were divided into the groups, and the similarities and differences were further studied by comparing. The result of the study shows that the frequency and intensity are comparable to the corresponding structure. The spectra not only have the commonness but also the individualities.
Vibrational spectra of pilocarpine hydrochloride crystals
Bento, R.R.F. [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Inst. de Fisica; Freire, P.T.C. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Fisica]. E-mail: tarso@fisica.ufc.br; Teixeira, A.M.R.; Silva, J.H. [Universidade Regional do Cariri, Crato, CE (Brazil). Dept. Ciencias Fisicas e Biologicas; Lima Junior, J.A. [Universidade Estadual do Ceara (UECE), Limoeiro do Norte, CE (Brazil); Oliveira, M.C.F. de; Andrade-Neto, M. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica; Romero, N.R. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Farmacia; Pontes, F.M. [Universidade Estadual Paulista, Bauru, SP (Brazil). Faculdade de Ciencias
2009-03-15
Pilocarpine is a natural substance with potential application in the treatment of several diseases. In this work Fourier Transform (FT)-Raman spectrum and the Fourier Transform infra red (FT-IR) spectrum of pilocarpine hydrochloride C{sub 11} H{sub 17} N{sub 2} O{sup +}{sub 2} .Cl{sup -1} were investigated at 300 K. Vibrational wavenumber and wave vector have been predicted using density functional theory (B3LYP) calculations with the 6-31 G(d,p) basis set. A comparison with experiment allowed to assign most of the normal modes of the crystal. (author)
An Investigation of the Partial-Assignment Completion Effect on Students' Assignment Choice Behavior
Hawthorn-Embree, Meredith L.; Skinner, Christopher H.; Parkhurst, John; Conley, Elisha
2011-01-01
This study was designed to investigate the partial assignment completion effect. Seventh-grade students were given a math assignment. After working for 5 min, they were interrupted and their partially completed assignments were collected. About 20 min later, students were given their partially completed assignment and a new, control assignment…
An Investigation of the Partial-Assignment Completion Effect on Students' Assignment Choice Behavior
Hawthorn-Embree, Meredith L.; Skinner, Christopher H.; Parkhurst, John; Conley, Elisha
2011-01-01
This study was designed to investigate the partial assignment completion effect. Seventh-grade students were given a math assignment. After working for 5 min, they were interrupted and their partially completed assignments were collected. About 20 min later, students were given their partially completed assignment and a new, control assignment…
Bai, Zheng-Jian; Yang, Jin-Ku; Datta, Biswa Nath
2016-12-01
In this paper, we consider the robust partial quadratic eigenvalue assignment problem in vibration by active feedback control. Based on the receptance measurements and the system matrices, we propose an optimization method for the robust and minimum norm partial quadratic eigenvalue assignment problem. We provide a new cost function and the closed-loop eigenvalue sensitivity and the feedback norms can be minimized simultaneously. Our method is also extended to the case of time delay between measurements of state and actuation of control. Numerical tests demonstrate the effectiveness of our method.
Vibrating wire alignment technique
Xiao-Long, Wang; lei, Wu; Chun-Hua, Li
2013-01-01
Vibrating wire alignment technique is a kind of method which through measuring the spatial distribution of magnetic field to do the alignment and it can achieve very high alignment accuracy. Vibrating wire alignment technique can be applied for magnet fiducialization and accelerator straight section components alignment, it is a necessary supplement for conventional alignment method. This article will systematically expound the international research achievements of vibrating wire alignment technique, including vibrating wire model analysis, system frequency calculation, wire sag calculation and the relation between wire amplitude and magnetic induction intensity. On the basis of model analysis this article will introduce the alignment method which based on magnetic field measurement and the alignment method which based on amplitude and phase measurement. Finally, some basic questions will be discussed and the solutions will be given.
Vibration enhanced quantum transport
Semião, F L; Milburn, G J
2009-01-01
In this paper, we study the role of a collective vibrational motion in the phenomenon of electronic energy transfer (EET) between chromophores with different electronic transition frequencies. Previous experimental work on EET in conjugated polymer samples has suggested that the common structural framework of the macromolecule introduce correlations in the energy gap fluctuations which cause coherent EET. We present a simple model describing the coupling between the chromophores and a common vibrational mode, and find that vibration can indeed lead to an enhancement in the transport of excitations across the quantum network. Furthermore, in our model phase information is partially retained in the transfer process from a donor to an acceptor, as experimentally demonstrated in the conjugated polymer system. Consequently, this mechanism of vibration enhanced quantum transport might find applications in quantum information transfer of qubit states or entanglement.
NIF Ambient Vibration Measurements
Noble, C.R.; Hoehler, M.S., S.C. Sommer
1999-11-29
LLNL has an ongoing research and development project that includes developing data acquisition systems with remote wireless communication for monitoring the vibrations of large civil engineering structures. In order to establish the capability of performing remote sensing over an extended period of time, the researchers needed to apply this technology to a real structure. The construction of the National Ignition Facility provided an opportunity to test the data acquisition system on a large structure to monitor whether the facility is remaining within the strict ambient vibration guidelines. This document will briefly discuss the NIF ambient vibration requirements and summarize the vibration measurements performed during the Spring and Summer of 1999. In addition, a brief description of the sensors and the data acquisition systems will be provided in Appendix B.
NIF Ambient Vibration Measurements
Noble, C.R.; Hoehler, M.S., S.C. Sommer
1999-11-29
LLNL has an ongoing research and development project that includes developing data acquisition systems with remote wireless communication for monitoring the vibrations of large civil engineering structures. In order to establish the capability of performing remote sensing over an extended period of time, the researchers needed to apply this technology to a real structure. The construction of the National Ignition Facility provided an opportunity to test the data acquisition system on a large structure to monitor whether the facility is remaining within the strict ambient vibration guidelines. This document will briefly discuss the NIF ambient vibration requirements and summarize the vibration measurements performed during the Spring and Summer of 1999. In addition, a brief description of the sensors and the data acquisition systems will be provided in Appendix B.
Philip J. Reid
2009-09-21
The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.
Vibration sensation as an indicator of surgical anesthesia following brachial plexus block
Seema Jindal
2016-01-01
Conclusions: Vibration sense serves as a reliable indicator for the onset of surgical anesthesia following brachial plexus block. Vibration sense testing with 128 Hz Rydel–Seiffer tuning fork along with motor power assessment should be used as an objective tool to assess the onset of surgical anesthesia following brachial plexus block.
Reliability Generalization: "Lapsus Linguae"
Smith, Julie M.
2011-01-01
This study examines the proposed Reliability Generalization (RG) method for studying reliability. RG employs the application of meta-analytic techniques similar to those used in validity generalization studies to examine reliability coefficients. This study explains why RG does not provide a proper research method for the study of reliability,…
Vibrational spectroscopic studies of Isoleucine by quantum chemical calculations.
Moorthi, P P; Gunasekaran, S; Ramkumaar, G R
2014-04-24
In this work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of Isoleucine (2-Amino-3-methylpentanoic acid). The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments, thermodynamics properties, NBO analyses, NMR chemical shifts and ultraviolet-visible spectral interpretation of Isoleucine have been studied by performing MP2 and DFT/cc-pVDZ level of theory. The FTIR, FT-Raman spectra were recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1) respectively. The UV-visible absorption spectra of the compound were recorded in the range of 200-800 nm. Computational calculations at MP2 and B3LYP level with basis set of cc-pVDZ is employed in complete assignments of Isoleucine molecule on the basis of the potential energy distribution (PED) of the vibrational modes, calculated using VEDA-4 program. The calculated wavenumbers are compared with the experimental values. The difference between the observed and calculated wavenumber values of most of the fundamentals is very small. (13)C and (1)H nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method and compared with experimental results. The formation of hydrogen bond was investigated in terms of the charge density by the NBO calculations. Based on the UV spectra and TD-DFT calculations, the electronic structure and the assignments of the absorption bands were carried out. Besides, molecular electrostatic potential (MEP) were investigated using theoretical calculations.
Structural safety criteria for blasting vibration based on wavelet packet energy spectra
Zhong Guosheng; Li Jiang; Zhao Kui
2011-01-01
Given multi-resolution decomposition of wavelet packet transforms, wavelet packet frequency band energy has been deduced from different bands of blasting vibration signals. Our deduction reflects the total effect of all three key elements (intensity, frequency and duration of vibration) of blasting vibration.We considered and discuss the dynamic response of structures and the effect of inherent characteristics of controlled structures to blasting vibration. Frequency band response coefficients for controlled structures by blasting vibration have been obtained. We established multi-factor blasting vibration safety criteria, referred to as response energy criteria. These criteria reflect the total effect of intensity,frequency and duration of vibration and the inherent characteristics (natural frequency and damping ratio) of dynamic responses from controlled structures themselves. Feasibility and reliability of the criteria are validated by an example.
Job assignments, intrinsic motivation and explicit incentives
Nafziger, Julia
2008-01-01
This paper considers the interplay of job assignments with the intrinsic and extrinsic motivation of an agent. Job assignments influence the self confidence of the agent, and thereby his intrinsic motivation. Monetary reward allow the principal to complement intrinsic motivation with extrinsic incentives. The main result is that the principal chooses an inefficient job assignment rule to enhance the agent's intrinsic motivation even though she can motivate him with monetary rewards. This show...
The Kinetics of Chirality Assignment in Catalytic Single Walled Carbon Nanotube Growth
Xu, Ziwei; Yan, Tianying; Ding, Feng
2014-01-01
Chirality-selected single-walled carbon nanotubes (SWCNTs) ensure a great potential of building ~1 nm sized electronics. However, the reliable method for chirality-selected SWCNT is still pending. Here we present a theoretical study on the SWCNT's chirality assignment and control during the catalytic growth. This study reveals that the chirality of a SWCNT is determined by the kinetic incorporation of the pentagon formation during SWCNT nucleation. Therefore, chirality is randomly assigned on...
Cemal Parlak
2012-08-01
Full Text Available The normal mode frequencies and corresponding vibrational assignments, 1H and 13C NMR chemical shifts and structural parameters (bond lengths, bond and dihedral angles of 2-[(1E-2-aza-2-(5-methyl(2-pyridylethenyl]-4-bromobenzen-1-ol (2mpe-4bb Schiff base compound have been theoretically examined by means of Hartree-Fock (HF and Becke-3-Lee-Yang-Parr (B3LYP density functional methods with 6-31G(d and 6-311++G(d,p basis sets. Furthermore, reliable vibrational assignments have made on the basis of potential energy distribution (PED calculated and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO of 2mpe-4bb have been predicted. Theoretical results have been successfully compared with available experimental data in the literature. Regarding the calculations, 2mpe-4bb prefers enol-imine form and DFT method is superior to HF approach except for predicting bond lengths.DOI: http://dx.doi.org/10.4314/bcse.v26i2.11
Fachina, Rafael; da Silva, Antônio; Falcão, William; Montagner, Paulo; Borin, João; Minozzo, Fábio; Falcão, Diego; Vancini, Rodrigo; Poston, Brach; de Lira, Claudio
2013-01-01
Purpose: To quantify creatine kinase (CK) activity changes across time following an acute bout of whole-body vibration (WBV) and determine the association between changes in CK activity and jumping performance. Method: Twenty-six elite young basketball players were assigned to 3 groups: 36-Hz and 46-Hz vibration groups (G36 and G46, respectively)…
Regular vibrational state progressions at the dissociation limit of SCCl2.
Chowdary, Praveen D; Gruebele, Martin
2009-01-14
We observe sharp features in the vibrational spectrum of SCCl(2) at and above its two lowest-lying dissociation limits. Highly regular vibrational progressions persist at dissociation, as in some smaller molecules studied previously by others. Nearly all of the SCCl(2) transitions studied by stimulated emission pumping can be assigned and fitted by a simple effective Hamiltonian without resonance terms, up to a total vibrational excitation of 36 quanta. The character of the highly excited vibrational wave functions is not normal mode-like, but it nonetheless arises gradually from the normal modes as the energy increases. The number of sharp vibrational features observed matches a scaling model that predicts localization of nearly all vibrational states near dissociation as the size of a polyatomic molecule increases.
Yin Luo
2012-01-01
Full Text Available Traditional pump scheduling models neglect the operation reliability which directly relates with the unscheduled maintenance cost and the wear cost during the operation. Just for this, based on the assumption that the vibration directly relates with the operation reliability and the degree of wear, it could express the operation reliability as the normalization of the vibration level. The characteristic of the vibration with the operation point was studied, it could be concluded that idealized flow versus vibration plot should be a distinct bathtub shape. There is a narrow sweet spot (80 to 100 percent BEP to obtain low vibration levels in this shape, and the vibration also follows similar law with the square of the rotation speed without resonance phenomena. Then, the operation reliability could be modeled as the function of the capacity and rotation speed of the pump and add this function to the traditional model to form the new. And contrast with the tradition method, the result shown that the new model could fix the result produced by the traditional, make the pump operate in low vibration, then the operation reliability could increase and the maintenance cost could decrease.
Observation of vibrational overtones by single molecule resonant photodissociation
Khanyile, Ncamiso B; Brown, Kenneth R
2015-01-01
Coulomb crystals composed of atomic ions and molecular ions are an ideal system for performing high-precision spectroscopy with applications in astrochemistry and fundamental physics. Here we show that this same system can be coupled with a broadband laser to discover new molecular transitions. We use three-ion chains of Ca$^{+}$ and CaH$^{+}$ to observe vibrational transitions via resonance enhanced multiphoton dissociation detected by Ca$^{+}$ fluorescence. Based on theoretical calculations, we assign the observed peaks to the transition from the ground vibrational state, $\
[Lattice vibration of Sr3TaGa3Si2O14 single crystal].
Yang, Hong; Lu, Gui-Wu; Yu, Ying-Hui; Li, Ying-Feng; Wang, Zeng-Mei
2008-03-01
Based on the space group theory, the normal vibration modes of Sr3 TaGa3Si2O14 (STGS) single crystal were predicted, and the Raman scattering intensities of non-polar and polar modes were calculated. The Raman spectrum of STGS crystal was measured, and lattice vibration modes of STGS crystal were assigned. For symmetry species A1, six typical Raman-active optical modes have been recorded at 126, 245, 557, 604, 896 and 991 cm(-1), respectively. It is easy to assign the mode of 126 cm(-1) as the relative translation between SiO4, Sr and the TaO6. The mode 245 cm(-1) corresponds to the twisting vibration of SiO4 correlating with the Sr-TaO6-Sr stretching vibration. The mode 557 cm(-1) was assigned as the O-Ta-O stretching vibration, while the mode 604 cm(-1) as the O-Ga-O stretching vibration. The band at 896 cm(-1) in the Raman spectrum was assigned to be the O-Si-O stretching vibration of the two SiO4 tetrahedra in the primitive cell of STGS single crystal. Meanwhile, the band at 991 cm(-1) in the Raman spectrum was assigned to be the Si-O stretching vibration of the two SiO4 tetrahedra in the primitive cell of STGS single crystal. The layer structure of STGS crystal was identified by both theory study and Raman spectroscopy experiment results. The small anisotropy and piezoelectric modulus of STGS crystal were ascribed to the weak distortion of decahedral unit.
Free vibration and transverse stresses of viscoelastic laminated plates
Ming-yong HU; An-wen WANG
2009-01-01
Based on Reddy's layerwise theory, the governing equations for dynamic response of viscoelastic laminated plate are derived by using the quadratic interpolation function for displacement in the direction of plate thickness. Vibration frequencies and loss factors are calculated for flee vibration of simply supported viscoelastic sandwich plate, showing good agreement with the results in the literature. Harmonious transverse stresses can be obtained. The results show that the transverse shear stresses are the main factor to the delamination of viscoelastic laminated plate in lower-frequency free vibra-tion, and the transverse normal stress is the main one in higher-frequency free vibration. Relationship between the modulus of viscoelastic materials and transverse stress is an-alyzed. Ratio between the transverse stress's maximum value and the in-plane stress's maximum-value is obtained. The results show that the proposed method, and the adopted equations and programs are reliable.
Stereovision vibration measurement test of a masonry building model
Shan, Baohua; Gao, Yunli; Shen, Yu
2016-04-01
To monitor 3D deformations of structural vibration response, a stereovision-based 3D deformation measurement method is proposed in paper. The world coordinate system is established on structural surface, and 3D displacement equations of structural vibration response are acquired through coordinate transformation. The algorithms of edge detection, center fitting and matching constraint are developed for circular target. A shaking table test of a masonry building model under Taft and El Centro earthquake at different acceleration peak is performed in lab, 3D displacement time histories of the model are acquired by the integrated stereovision measurement system. In-plane displacement curves obtained by two methods show good agreement, this suggests that the proposed method is reliable for monitoring structural vibration response. Out-of-plane displacement curves indicate that the proposed method is feasible and useful for monitoring 3D deformations of vibration response.
Structural health monitoring with a wireless vibration sensor network
Basten, T.G.H.; Sas, P; Schiphorst, F.B.A.; Jonckheere, S.; Moens, D.
2012-01-01
Advanced maintenance strategies for infrastructure assets such as bridges or off shore wind turbines require actual and reliable information of the maintenance status. Structural health monitoring based on vibration sensing can help in supplying the input needed for structural health monitoring appl
Structural health monitoring with a wireless vibration sensor network
Basten, T.G.H.; Sas, P; Schiphorst, F.B.A.; Jonckheere, S.; Moens, D.
2012-01-01
Advanced maintenance strategies for infrastructure assets such as bridges or off shore wind turbines require actual and reliable information of the maintenance status. Structural health monitoring based on vibration sensing can help in supplying the input needed for structural health monitoring
Structural health monitoring with a wireless vibration sensor network
Basten, T.G.H.; Schiphorst, F.B.A.
2012-01-01
Advanced maintenance strategies for infrastructure assets such as bridges or off shore wind turbines require actual and reliable information of the maintenance status. Structural health monitoring based on vibration sensing can help in supplying the input needed for structural health monitoring appl
Assuring reliability program effectiveness.
Ball, L. W.
1973-01-01
An attempt is made to provide simple identification and description of techniques that have proved to be most useful either in developing a new product or in improving reliability of an established product. The first reliability task is obtaining and organizing parts failure rate data. Other tasks are parts screening, tabulation of general failure rates, preventive maintenance, prediction of new product reliability, and statistical demonstration of achieved reliability. Five principal tasks for improving reliability involve the physics of failure research, derating of internal stresses, control of external stresses, functional redundancy, and failure effects control. A final task is the training and motivation of reliability specialist engineers.
The Accelerator Reliability Forum
Lüdeke, Andreas; Giachino, R
2014-01-01
A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.
47 CFR 74.103 - Frequency assignment.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.103 Section 74.103 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO....103 Frequency assignment. (a) Frequencies allocated to broadcasting and the various categories of...
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Assignment. 725.26 Section 725.26 Energy DEPARTMENT OF ENERGY PERMITS FOR ACCESS TO RESTRICTED DATA Permits § 725.26 Assignment. An access permit is nontransferable and nonassignable. ...
47 CFR 80.509 - Frequency assignment.
2010-10-01
... 47 Telecommunication 5 2010-10-01 2010-10-01 false Frequency assignment. 80.509 Section 80.509 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Private Coast Stations and Marine Utility Stations § 80.509 Frequency assignment...
Assignment procedure biases in randomized policy experiments
Aldashev, Gani; Kirchsteiger, Georg; Sebald, Alexander Christopher
2017-01-01
’s propensity to act reciprocally. When people are motivated by reciprocity, the choice of assignment procedure influences the RCTs’ findings. We show that even credible and explicit randomization procedures do not guarantee an unbiased prediction of the impact of policy interventions; however, they minimize...... any bias relative to other less transparent assignment procedures....
47 CFR 80.511 - Assignment limitations.
2010-10-01
... 47 Telecommunication 5 2010-10-01 2010-10-01 false Assignment limitations. 80.511 Section 80.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Private Coast Stations and Marine Utility Stations § 80.511 Assignment limitations. (a...
47 CFR 74.1202 - Frequency assignment.
2010-10-01
... 47 Telecommunication 4 2010-10-01 2010-10-01 false Frequency assignment. 74.1202 Section 74.1202 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... FM Broadcast Booster Stations § 74.1202 Frequency assignment. (a) An applicant for a new FM broadcast...
48 CFR 208.7002 - Assignment authority.
2010-10-01
... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Assignment authority. 208..., DEPARTMENT OF DEFENSE ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Coordinated Acquisition 208.7002 Assignment authority. (a) Under the DoD Coordinated Acquisition Program,...
On the Bicriterion Multi Modal Assignment Problem
Pedersen, Christian Roed; Nielsen, L.R.; Andersen, K.A.
2005-01-01
We consider the bicriterion multi modal assignment problem which is a new generalization of the classical linear assignment problem. A two-phase solution method using an effective ranking scheme is presented. The algorithm is valid for generating all nondominated criterion points...
Detecting Plagiarism in MS Access Assignments
Singh, Anil
2013-01-01
Assurance of individual effort from students in computer-based assignments is a challenge. Due to digitization, students can easily use a copy of their friend's work and submit it as their own. Plagiarism in assignments puts students who cheat at par with those who work honestly and this compromises the learning evaluation process. Using a…
7 CFR 601.1 - Functions assigned.
2010-01-01
... 7 Agriculture 6 2010-01-01 2010-01-01 false Functions assigned. 601.1 Section 601.1 Agriculture... AGRICULTURE GENERAL FUNCTIONS § 601.1 Functions assigned. The Natural Resources Conservation Service (NRCS) is... conserve, improve, and sustain natural resources. The following functions support the mission. (a)...
Stress Assignment in Reading Italian Polysyllabic Pseudowords
Sulpizio, Simone; Arduino, Lisa S.; Paizi, Despina; Burani, Cristina
2013-01-01
In 4 naming experiments we investigated how Italian readers assign stress to pseudowords. We assessed whether participants assign stress following distributional information such as stress neighborhood (the proportion and number of existent words sharing orthographic ending and stress pattern) and whether such distributional information affects…
Maximizing Completion and Comprehension of Reading Assignments
Owen, Leanne R.
The author presents self-report data from students in three upper-level undergraduate courses to illustrate the comparative effectiveness of different out-of-class assessment approaches in promoting completion and comprehension of reading assignments. Students reported agreeing or strongly agreeing that all three assignments motivated them to…
Effects of Individualized Assignments on Biology Achievement.
Kremer, Philip L.
1983-01-01
Compared detailed (favoring field dependence and induction) and nondetailed (favoring field dependence and deduction) assignments on biology achievement of grade 10 male students (N=95) over a seven-month period. Detailed assignments, employing pictorial and verbal block diagrams and high structure, significantly enhanced learning among some…
A Role-Based Fuzzy Assignment Model
ZUO Bao-he; FENG Shan
2002-01-01
It's very important to dynamically assign the tasks to corresponding actors in workflow management system, especially in complex applications. This improves the flexibility of workflow systems.In this paper, a role-based workflow model with fuzzy optimized intelligent assignment is proposed and applied in the investment management system. A groupware-based software model is also proposed.
33 CFR 401.61 - Assigned frequencies.
2010-07-01
... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Assigned frequencies. 401.61 Section 401.61 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT... frequencies. The Seaway stations operate on the following assigned VHF frequencies: 156.8 MHz—(channel...
Optimization of Rated Officer Staff Assignments
2007-06-01
determinant +1, -1 or 0, which holds for the assignment problem ( Bazaraa et al., 1990). The Unimodularity Theorem states for an integer matrix A with...Prentice-Hall, 1993. 2. Air Force Instruction 36-2110, Assignments, 20 April 2005. 3. Bazaraa , Mokhtar S., Jarvis, John J. and Sherali, Hanif D
Online Discussion Assignments Improve Students' Class Preparation
Lineweaver, Tara T.
2010-01-01
To increase the number of students who read the text before class and to promote student interaction centering on text material, I developed an online discussion assignment as a required component of a cognitive psychology course. Across 2 studies, this assignment had a limited effect on examination performance, but students completing online…
Stress Assignment in Reading Italian Polysyllabic Pseudowords
Sulpizio, Simone; Arduino, Lisa S.; Paizi, Despina; Burani, Cristina
2013-01-01
In 4 naming experiments we investigated how Italian readers assign stress to pseudowords. We assessed whether participants assign stress following distributional information such as stress neighborhood (the proportion and number of existent words sharing orthographic ending and stress pattern) and whether such distributional information affects…
A Model of Hierarchical Key Assignment Scheme
ZHANG Zhigang; ZHAO Jing; XU Maozhi
2006-01-01
A model of the hierarchical key assignment scheme is approached in this paper, which can be used with any cryptography algorithm. Besides, the optimal dynamic control property of a hierarchical key assignment scheme will be defined in this paper. Also, our scheme model will meet this property.
Detecting Plagiarism in MS Access Assignments
Singh, Anil
2013-01-01
Assurance of individual effort from students in computer-based assignments is a challenge. Due to digitization, students can easily use a copy of their friend's work and submit it as their own. Plagiarism in assignments puts students who cheat at par with those who work honestly and this compromises the learning evaluation process. Using a…
Discriminant Kernel Assignment for Image Coding.
Deng, Yue; Zhao, Yanyu; Ren, Zhiquan; Kong, Youyong; Bao, Feng; Dai, Qionghai
2017-06-01
This paper proposes discriminant kernel assignment (DKA) in the bag-of-features framework for image representation. DKA slightly modifies existing kernel assignment to learn width-variant Gaussian kernel functions to perform discriminant local feature assignment. When directly applying gradient-descent method to solve DKA, the optimization may contain multiple time-consuming reassignment implementations in iterations. Accordingly, we introduce a more practical way to locally linearize the DKA objective and the difficult task is cast as a sequence of easier ones. Since DKA only focuses on the feature assignment part, it seamlessly collaborates with other discriminative learning approaches, e.g., discriminant dictionary learning or multiple kernel learning, for even better performances. Experimental evaluations on multiple benchmark datasets verify that DKA outperforms other image assignment approaches and exhibits significant efficiency in feature coding.
Airport Gate Assignment: New Model and Implementation
Li, Chendong
2008-01-01
Airport gate assignment is of great importance in airport operations. In this paper, we study the Airport Gate Assignment Problem (AGAP), propose a new model and implement the model with Optimization Programming language (OPL). With the objective to minimize the number of conflicts of any two adjacent aircrafts assigned to the same gate, we build a mathematical model with logical constraints and the binary constraints, which can provide an efficient evaluation criterion for the Airlines to estimate the current gate assignment. To illustrate the feasibility of the model we construct experiments with the data obtained from Continental Airlines, Houston Gorge Bush Intercontinental Airport IAH, which indicate that our model is both energetic and effective. Moreover, we interpret experimental results, which further demonstrate that our proposed model can provide a powerful tool for airline companies to estimate the efficiency of their current work of gate assignment.
Enlightenment on Computer Network Reliability From Transportation Network Reliability
Hu Wenjun; Zhou Xizhao
2011-01-01
Referring to transportation network reliability problem, five new computer network reliability definitions are proposed and discussed. They are computer network connectivity reliability, computer network time reliability, computer network capacity reliability, computer network behavior reliability and computer network potential reliability. Finally strategies are suggested to enhance network reliability.
Theoretical rotation-vibration spectrum of thioformaldehyde
Yachmenev, Andrey [Department of Physics and Astronomy, University College London, London, WC1E 6BT (United Kingdom); Polyak, Iakov; Thiel, Walter [Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D–45470 Mülheim an der Ruhr (Germany)
2013-11-28
We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H{sub 2}CS. It covers 41 809 rovibrational levels for states up to J{sub max} = 30 with vibrational band origins up to 5000 cm{sup −1} and provides the energies and line intensities for 547 926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.
Pott, J.-U.
2011-09-01
MPIA is the PI institute of the MCAO-supported Fizeau imager LINC-NIRVANA at the LBT, and a partner of the E-ELT first light NIR imager MICADO (both SCAO and MCAO assisted). LINC-NIRVANA is a true pathfinder for future ELT-AO imagers both in terms of size and technology. I will present our vibration control strategies, involving accelerometer based real-time vibration measurements, feedforward and feedback optical path control, predictive filtering, vibration sensitive active control of actuators, and the development of a dynamical model of the entire telescope. Our experiences, made with LINC-NIRVANA, will be fed into the MICADO structural AO design to reach highest on-sky sensitivity.
Vibrational spectroscopic characterization of fluoroquinolones
Neugebauer, U.; Szeghalmi, A.; Schmitt, M.; Kiefer, W.; Popp, J.; Holzgrabe, U.
2005-05-01
Quinolones are important gyrase inhibitors. Even though they are used as active agents in many antibiotics, the detailed mechanism of action on a molecular level is so far not known. It is of greatest interest to shed light on this drug-target interaction to provide useful information in the fight against growing resistances and obtain new insights for the development of new powerful drugs. To reach this goal, on a first step it is essential to understand the structural characteristics of the drugs and the effects that are caused by the environment in detail. In this work we report on Raman spectroscopical investigations of a variety of gyrase inhibitors (nalidixic acid, oxolinic acid, cinoxacin, flumequine, norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, enoxacin, sarafloxacin and moxifloxacin) by means of micro-Raman spectroscopy excited with various excitation wavelengths, both in the off-resonance region (532, 633, 830 and 1064 nm) and in the resonance region (resonance Raman spectroscopy at 244, 257 and 275 nm). Furthermore DFT calculations were performed to assign the vibrational modes, as well as for an identification of intramolecular hydrogen bonding motifs. The effect of small changes in the drug environment was studied by adding successively small amounts of water until physiological low concentrations of the drugs in aqueous solution were obtained. At these low concentrations resonance Raman spectroscopy proved to be a useful and sensitive technique. Supplementary information was obtained from IR and UV/vis spectroscopy.
Interpretation of Nitroindolinospirobenzothiopyran Vibrational Spectra
Gladkov, L. L.; Khamchukov, Yu. D.; Lyubimov, A. V.
2016-05-01
The structures of four possible stereoisomers of the closed form of photochromic nitroindolinospirobenzothiopyran (NISTP) {1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzothiopyran-2,2'-(2H)-indoline]} were determined by the DFT method. The geometry of the most stable isomer was defined. Nitro-substitution changes mainly the lengths of bonds formed by S and N with spiro-atom Cs. According to the calculations, the CsS bond changes most and lengthens by 0.019 Å. It is shown that the S atom has large displacement amplitudes in normal modes assigned to Raman lines at 230, 285, 360, and 575 cm-1 and weak IR bands at 467 and 577 cm-1. Oscillations involving the nitro group are very active in Raman and IR spectra. Their frequencies are slightly lower than similar frequencies of nitrobenzene and nitroindolinospirobenzopyran, indicating a higher degree of vibrational coupling of the NO2 group with the NISTP molecular skeleton.
Random vibration analysis of switching apparatus based on Monte Carlo method
ZHAI Guo-fu; CHEN Ying-hua; REN Wan-bin
2007-01-01
The performance in vibration environment of switching apparatus containing mechanical contact is an important element when judging the apparatus's reliability. A piecewise linear two-degrees-of-freedom mathematical model considering contact loss was built in this work, and the vibration performance of the model under random external Gaussian white noise excitation was investigated by using Monte Carlo simulation in Matlab/Simulink. Simulation showed that the spectral content and statistical characters of the contact force coincided strongly with reality. The random vibration character of the contact system was solved using time (numerical) domain simulation in this paper. Conclusions reached here are of great importance for reliability design of switching apparatus.
Human Reliability Program Overview
Bodin, Michael
2012-09-25
This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.
Power electronics reliability analysis.
Smith, Mark A.; Atcitty, Stanley
2009-12-01
This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.
Reliability of procedures used for scaling loudness
Jesteadt, Walt; Joshi, Suyash Narendra
2013-01-01
(ME, MP, CLS; MP, ME, CLS; CLS, ME, MP; CLS, MP, ME), and the order was reversed on the second visit. This design made it possible to compare the reliability of estimates of the slope of the loudness function across procedures in the same listeners. The ME data were well fitted by an inflected...... exponential (INEX) function, but a modified power law was used to obtain slope estimates for both ME and MP. ME and CLS were more reliable than MP. CLS results were consistent across groups, but ME and MP results differed across groups in a way that suggested influence of experience with CLS. Although CLS...... results were the most reproducible, they do not provide direct information about the slope of the loudness function because the numbers assigned to CLS categories are arbitrary. This problem can be corrected by using data from the other procedures to assign numbers that are proportional to loudness...
Kaliski, S
2013-01-01
This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth
Thomsen, Jon Juel
dynamical phenomena that can be encountered in engineering and scientific practice. It progresses steadily from linear vibration theory over various levels of nonlinearity to bifurcation analysis, global dynamics and chaotic vibrations. It trains the student to analyze simple models, recognize nonlinear...... phenomena and work with advanced tools such as perturbation analysis and bifurcation analysis. Explaining theory in terms of relevant examples from real systems, this book is user-friendly and meets the increasing interest in non-linear dynamics in mechanical/structural engineering and applied mathematics...
Berg, Melanie; LaBel, Kenneth A.
2016-01-01
This presentation focuses on reliability and trust for the users portion of the FPGA design flow. It is assumed that the manufacturer prior to hand-off to the user tests FPGA internal components. The objective is to present the challenges of creating reliable and trusted designs. The following will be addressed: What makes a design vulnerable to functional flaws (reliability) or attackers (trust)? What are the challenges for verifying a reliable design versus a trusted design?
Viking Lander reliability program
Pilny, M. J.
1978-01-01
The Viking Lander reliability program is reviewed with attention given to the development of the reliability program requirements, reliability program management, documents evaluation, failure modes evaluation, production variation control, failure reporting and correction, and the parts program. Lander hardware failures which have occurred during the mission are listed.
Vibration Propagation in Spider Webs
Hatton, Ross; Otto, Andrew; Elias, Damian
Due to their poor eyesight, spiders rely on web vibrations for situational awareness. Web-borne vibrations are used to determine the location of prey, predators, and potential mates. The influence of web geometry and composition on web vibrations is important for understanding spider's behavior and ecology. Past studies on web vibrations have experimentally measured the frequency response of web geometries by removing threads from existing webs. The full influence of web structure and tension distribution on vibration transmission; however, has not been addressed in prior work. We have constructed physical artificial webs and computer models to better understand the effect of web structure on vibration transmission. These models provide insight into the propagation of vibrations through the webs, the frequency response of the bare web, and the influence of the spider's mass and stiffness on the vibration transmission patterns. Funded by NSF-1504428.
Vibrational frequencies and structural determinations of 1,1-dicyanocyclopropane
Jensen, James O.
2003-12-01
The vibrational frequencies and corresponding normal mode assignments of 1,1-dicyanocyclopropane are examined theoretically using the Gaussian98 set of quantum chemistry codes. All normal modes were successfully assigned to one nine types of motion predicted by a group theoretical analysis (C-H stretch, CN stretch, C-C stretch, C-CN bend, C-C-C bend, CH 2 scissors, CH 2 wag, CH 2 rock, CH 2 twist) utilizing the C2 v symmetry of the molecule. The molecular orbitals of 1,1-dicyanocyclopropane are also examined.
On the Bicriterion Multi Modal Assignment Problem
Pedersen, Christian Roed; Nielsen, L.R.; Andersen, K.A.
2005-01-01
We consider the bicriterion multi modal assignment problem which is a new generalization of the classical linear assignment problem. A two-phase solution method using an effective ranking scheme is presented. The algorithm is valid for generating all nondominated criterion points...... or an approximation. Extensive computational results are conducted on a large library of test instances to test the performance of the algorithm and to identify hard test instances. Also, test results of the algorithm applied to the bicriterion assignment problem is given. Here our algorithm outperforms all...
Protein secondary structure: category assignment and predictability
Andersen, Claus A.; Bohr, Henrik; Brunak, Søren
2001-01-01
In the last decade, the prediction of protein secondary structure has been optimized using essentially one and the same assignment scheme known as DSSP. We present here a different scheme, which is more predictable. This scheme predicts directly the hydrogen bonds, which stabilize the secondary...... structures. Single sequence prediction of the new three category assignment gives an overall prediction improvement of 3.1% and 5.1%, compared to the DSSP assignment and schemes where the helix category consists of a-helix and 3(10)-helix, respectively. These results were achieved using a standard feed...
Dynamic Assignment in Microsimulations of Pedestrians
Kretz, Tobias; Hofsäß, Ingmar; Leonhardt, Axel
2014-01-01
A generic method for dynamic assignment used with microsimulation of pedestrian dynamics is introduced. As pedestrians - unlike vehicles - do not move on a network, but on areas they in principle can choose among an infinite number of routes. To apply assignment algorithms one has to select for each OD pair a finite (realistically a small) number of relevant representatives from these routes. This geometric task is the main focus of this contribution. The main task is to find for an OD pair the relevant routes to be used with common assignment methods. The method is demonstrated for one single OD pair and exemplified with an example.
The Assignment Game : The Reduced Game
Owen, Guillermo
1992-01-01
Let v be an assignment game. For a given reference payoff vector (x; y), and a coalition S, bargaining within the coalition can be represented by either the reduced game or the derived game. It is known that the reduced game need not be an assignment game (in fact, it need not be super additive) while the derived game is another assignment game, with modified reservation prices. We prove that, when the reference vector is in the core of the game, the derived game is the super additive cover o...
The Assignment Game : The Reduced Game
Owen, Guillermo
1992-01-01
Let v be an assignment game. For a given reference payoff vector (x; y), and a coalition S, bargaining within the coalition can be represented by either the reduced game or the derived game. It is known that the reduced game need not be an assignment game (in fact, it need not be super additive) while the derived game is another assignment game, with modified reservation prices. We prove that, when the reference vector is in the core of the game, the derived game is the super additive cover o...
A vibrational spectroscopic study of the copper bearing silicate mineral luddenite.
Frost, Ray L; López, Andrés; Xi, Yunfei; Scholz, Ricardo
2015-02-25
The molecular structure of the copper-lead silicate mineral luddenite has been analysed using vibrational spectroscopy. The mineral is only one of many silicate minerals containing copper. The intense Raman band at 978 cm(-1) is assigned to the ν1 (A1g) symmetric stretching vibration of Si5O14 units. Raman bands at 1122, 1148 and 1160 cm(-1) are attributed to the ν3 SiO4 antisymmetric stretching vibrations. The bands in the 678-799 cm(-1) are assigned to OSiO bending modes of the (SiO3)n chains. Raman bands at 3317 and 3329 cm(-1) are attributed to water stretching bands. Bands at 3595 and 3629 cm(-1) are associated with the stretching vibrations of hydroxyl units suggesting that hydroxyl units exist in the structure of luddenite.
Fault diagnosis of the rolling bearing with optical fiber Bragg grating vibration sensor
Wei, Peng; Dai, Zejing; Zheng, Leilei; Li, Ming
2016-10-01
Fault diagnosis of the rolling bearing means a lot for property and life safety. In this paper the Fiber Bragg Grating (FBG) vibration sensor and resonance demodulation technology are used in the fault diagnosis of the rolling bearing. Traditionally, the vibration signals are measured by the resistance strain gauge, accelerometer, etc. But those traditional electronic sensors are usually influenced by the industry electromagnetic noise. But the FBG vibration sensor is totally different. It has a lot of advantages such as small volume, light weight, easy connection and so on. And the high industry electromagnetic noise means nothing to the FBG sensors. In this paper, we use the FBG vibration and temperature sensors to measure the fast strain and temperature signal of the rolling bearing. In order to extract the fault signals from strong background noise, the resonant demodulation technology is used to analyze and process the vibration signals collected by the FBG sensors. In order to verify the reliability of the FBG vibration sensor and resonance demodulation technology applied in the fault diagnosis of the rolling bearing, several experiments are done. Five FBG vibration sensors are attached on the different parts of the rolling bearing to verify its function and its influence on the fault diagnosis of the rolling bearing. The results of the experiments show that the FBG vibration sensor method could be used in fault diagnosis of the rolling bearing. The repetitive experiments show the reliability of the FBG vibration sensors method.
Electronic and vibrational spectra of some rare earth trifluoromethanesulfonates crystals
Paul, P.; Ghosh, M.; Neogy, D.; Mallick, P. K.
2011-01-01
The Raman and infrared spectra of some rare earth (dysprosium and terbium) trifluoromethanesulfonates crystals have been analyzed. Different vibrational frequencies of trifluoromethanesulfonate ions (CF 3SO 3-) are identified and assigned to different vibrations of the SO 3 and CF 3 groups. Electronic transitions of R 3+ ions (R = Dy, Tb) in these salts have been assigned to transitions from the ground to different energy levels of the ground multiplet. The electronic energy levels of the rare earth ions are also determined theoretically with the help of single electron crystal field theory. They are found to yield results not only in good agreement with the observed spectral data but also in good conformity with those obtained previously from magnetic measurements.
Vibrational spectra and DFT calculations of sonderianin diterpene
Oliveira, I. M. M.; Santos, H. S.; Sena, D. M.; Cruz, B. G.; Teixeira, A. M. R.; Freire, P. T. C.; Braz-Filho, R.; Sousa, J. W.; Albuquerque, M. R. J. R.; Bandeira, P. N.; Bernardino, A. C. S. S.; Gusmão, G. O. M.; Bento, R. R. F.
2015-11-01
In the present study, the natural product sonderianin diterpene (C21H26O4), a diterpenoid isolated from Croton blanchetianus, with potential application in the drug industry, was characterized by nuclear magnetic resonance, infrared and Raman spectroscopy. Vibrational spectra were supported by Density Functional Theory calculations. Infrared and Raman spectra of sonderianin were recorded at ambient temperature in the regions from 400 cm-1 to 3600 cm-1 and from 40 cm-1 to 3500 cm-1, respectively. DFT calculations with the hybrid functional B3LYP and the basis set 6-31 G(d,p) were performed with the purpose of obtaining information on the structural and vibrational properties of this organic compound. A comparison with experimental spectra allowed us to assign all of the normal modes of the crystal. The assignment of the normal modes was carried out by means of potential energy distribution.
General principles of vibrational spectroscopies
Weckhuysen, B.M.; Schoonheydt, R.A.
2000-01-01
Atoms in molecules and solids do not remain in fixed relative positions, but vibrate about some mean position. This vibrational motion is quantized and at room temperature, most of the molecules in a given sample are in their lowest vibrational state. Absorption of electromagnetic radiation with
Vibration characteristics of ultrasonic complex vibration for hole machining
Asami, Takuya; Miura, Hikaru
2012-05-01
Complex vibration sources that use diagonal slits as a longitudinal-torsional vibration converter have been applied to ultrasonic motors, ultrasonic rock drilling, and ultrasonic welding. However, there are few examples of the application of these sources to ultrasonic machining in combination with an abrasive. Accordingly, a new method has been developed for machining of holes in brittle materials by using the ultrasonic longitudinal and torsional vibration of a hollow-type stepped horn with a diagonal slit vibration converter. In this paper, we compared vibration of a uniform rod and a hollow-type stepped horn, both with diagonal slits, when the conditions of the diagonal slits are constant.
Vibration Sensitive Keystroke Analysis
Lopatka, M.; Peetz, M.-H.; van Erp, M.; Stehouwer, H.; van Zaanen, M.
2009-01-01
We present a novel method for performing non-invasive biometric analysis on habitual keystroke patterns using a vibration-based feature space. With the increasing availability of 3-D accelerometer chips in laptop computers, conventional methods using time vectors may be augmented using a distinct fe
Development of vibrating insoles
Hijmans, J.M.; Geertzen, J.H.B.; Schokker, B.; Postema, K.
2007-01-01
The objective of this study was to describe the development of vibrating insoles. Insoles, providing a subsensory mechanical noise signal to the plantar side of the feet, may improve balance in healthy young and older people and in patients with stroke or diabetic neuropathy. This study describes th
Minaeva, V A; Minaev, B F; Hovorun, D M
2008-01-01
The structure of estrogen receptors and their interaction with 17beta-estradiol and estriol are of particular interest today because the treatment of breast cancer and the cause of the disease are intricately linked to the activity of the estrogen receptor and the normal blood serum level of these hormones. Molecular geometry and vibration frequencies of these steroid hormones are calculated by density functional theory with the B3LYP/ 6-31G** approximation. Intensities of infrared absorption and Raman spectra for estradiol are in an agreement with the experiment data. The assignments of all vibrational bands in the spectra of these hormones are presented on the basis of quantum chemical calculations of frequencies and normal modes. For the large number of bands such an assignment is made for the first time. The analysis of infrared spectra of both hormones indicates some nontrivial structure-spectra correlations. A series of specific vibrations is predicted in the low-frequency region of the IR spectra; their role in hormone-receptor interaction and in energy transfer processes are discussed. The search of the optimized geometrical structure by minimization of the total energy gradient is accompanied by the second derivatives calculation; diagonalization of the Hessian matrix leads finally to solution of vibration problem. The 17beta-estradiol molecule consists of 44 atoms and has 126 normal modes of internal vibrations. All these normal modes are presented together with their analysis and comparison with experimental data. From this comparison we have obtained an assignment of all absorption IR bands of 17beta-estradiol recorded earlier in KBr. For all stretching vibrations our assignment is in agreement with the previous one, obtained on the basis of the empirical rules. Direct DFT calculation of vibrational frequencies cannot provide a 100% agreement with the experimental IR spectra and scaling factors in the range of 0.95-0.97 are used in order to fit
Theoretical prediction on vibrational spectra of [Ar…Ar-H]+
LI; Wei(李巍); ZHAO; Xinsheng(赵新生)
2003-01-01
Centrosymmetric linear [Ar-H-Ar]+ and asymmetric linear [Ar…Ar-H]+ are two stable configurations of [Ar2H]+. Based on the global potential energy surface of [Ar2H]+ provided by our group recently, we calculated the vibrational spectra of [Ar…Ar-H]+ with total angular momentum J = 0 by time-dependent quantum mechanical method, and the influence of quantum tunneling effect on vibrational spectra was found. With the help of the observation on the eigenstate functions and the modified potential energy surface, assignments were made to the spectra. The strong coupling between the excited bending mode of [Ar-H-Ar]+ and the vibrational states of [Ar…Ar-H]+ was discussed.
5 CFR 870.902 - Making an assignment.
2010-01-01
... assignment. (a) To assign insurance, an insured individual must complete an approved assignment form. Only the insured individual can make an assignment; no one can assign on behalf of an insured individual... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Making an assignment. 870.902 Section...
The effects of vibration-reducing gloves on finger vibration.
Welcome, Daniel E; Dong, Ren G; Xu, Xueyan S; Warren, Christopher; McDowell, Thomas W
2014-01-01
Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed.
Crosstalk-Aware Routing Resource Assignment
Hai-Long Yao; Yi-Ci Cai; Qiang Zhou; Xian-Long Hong
2005-01-01
Crosstalk noise is one of the emerging issues in deep sub-micrometer technology which causes many undesired effects on the circuit performance. In this paper, a Crosstalk-Aware Routing Resource Assignment (CARRA) algorithm is proposed, which integrates the routing layers and tracks to address the crosstalk noise issue during the track/layer assignment stage. The CARRA problem is formulated as a weighted bipartite matching problem and solved using the linear assignment algorithm. The crosstalk risks between nets are represented by an undirected graph and the maximum number of the concurrent crosstalk risking nets is computed as the max clique of the graph. Then the nets in each max clique are assigned to disadjacent tracks. Thus the crosstalk noise can be avoided based on the clique concept. The algorithm is tested on IBM benchmarks and the experimental results show that it can improve the final routing layout a lot with little loss of the completion rate.
A new routing assignment model for Internet
无
2001-01-01
This paper builds a new traffic assignment model for Internet. The routing policy based on this model can realize load splitting in a network automatically, which overcomes the shortcoming of OSPF and satisfies the load balancing requirement of IETF.
Vibrational spectra and normal coordinate analysis on structure of chlorambucil and thioguanine
S Gunasekaran; S Kumaresan; R Arun Balaji; G Anand; S Seshadri
2008-12-01
A normal coordinate analysis on chlorambucil and thioguanine has been carried out with a set of symmetry coordinates following Wilson's – matrix method. The potential constants evaluated for these molecules are found to be in good agreement with literature values thereby confirming the vibrational assignments. To check whether the chosen set of vibrational frequencies contribute maximum to the potential energy associated with the normal coordinates of the molecule, the potential energy distribution has been evaluated.
Hyogo, Ryosuke; Nakamura, Atsushi; Okuda, Hidekazu; Wakamatsu, Kazumasa; Ito, Shosuke; Sota, Takayuki
2011-12-01
Mid-infrared vibrational spectroscopic study has been made on 5,6-dihydroxyindole (DHI) and DHI-derived eumelanin. It has been revealed for DHI monomer that measured infrared absorption spectrum is well reproduced by that predicted from ab initio calculations. Thus, vibrational modes of DHI monomer causing dominant absorption bands have been successfully assigned. It has been also reconfirmed that DHI-derived eumelanin includes indolequinone and/or quinone methide units in addition to DHI units.
Active vibration control of structures undergoing bending vibrations
Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor)
1995-01-01
An active vibration control subassembly for a structure (such as a jet engine duct or a washing machine panel) undergoing bending vibrations caused by a source (such as the clothes agitator of the washing machine) independent of the subassembly. A piezoceramic actuator plate is vibratable by an applied electric AC signal. The plate is connected to the structure such that vibrations in the plate induced by the AC signal cause canceling bending vibrations in the structure and such that the plate is compressively pre-stressed along the structure when the structure is free of any bending vibrations. The compressive prestressing increases the amplitude of the canceling bending vibrations before the critical tensile stress level of the plate is reached. Preferably, a positive electric DC bias is also applied to the plate in its poling direction.
A new algorithm for pole assignment of single-input linear systems using state feedback
QIAN Jiang; CHENG Mingsong; XU Shufang
2005-01-01
In this paper we present a new algorithm for the single-input pole assignment problem using state feedback. This algorithm is based on the Schur decomposition of the closed-loop system matrix, and the numerically stable unitary transformations are used whenever possible, and hence it is numerically reliable.The good numerical behavior of this algorithm is also illustrated by numerical examples.
Competitive Traffic Assignment in Road Networks
Krylatov Alexander Y.
2016-09-01
Full Text Available Recently in-vehicle route guidance and information systems are rapidly developing. Such systems are expected to reduce congestion in an urban traffic area. This social benefit is believed to be reached by imposing the route choices on the network users that lead to the system optimum traffic assignment. However, guidance service could be offered by different competitive business companies. Then route choices of different mutually independent groups of users may reject traffic assignment from the system optimum state. In this paper, a game theoretic approach is shown to be very efficient to formalize competitive traffic assignment problem with various groups of users in the form of non-cooperative network game with the Nash equilibrium search. The relationships between the Wardrop’s system optimum associated with the traffic assignment problem and the Nash equilibrium associated with the competitive traffic assignment problem are investigated. Moreover, some related aspects of the Nash equilibrium and the Wardrop’s user equilibrium assignments are also discussed.
Guicheteau, Jason; Argue, Leanne; Hyre, Aaron; Jacobson, Michele; Christesen, Steven D.
2006-05-01
Raman and surface-enhanced Raman spectroscopy (SERS) studies of bacteria have reported a wide range of vibrational mode assignments associated with biological material. We present Raman and SER spectra of the amino acids phenylalanine, tyrosine, tryptophan, glutamine, cysteine, alanine, proline, methionine, asparagine, threonine, valine, glycine, serine, leucine, isoleucine, aspartic acid and glutamic acid and the nucleic acid bases adenosine, guanosine, thymidine, and uridine to better characterize biological vibrational mode assignments for bacterial target identification. We also report spectra of the bacteria Bacillus globigii, Pantoea agglomerans, and Yersinia rhodei along with band assignments determined from the reference spectra obtained.
Vendrell, Oriol; Gatti, Fabien; Meyer, Hans-Dieter
2007-01-01
the fundamentals and several overtones of the vibrational motion are computed. The spectrum of H5O2+ is shaped to a large extent by couplings of the proton-transfer motion to large amplitude fluxional motions of the water molecules, water bending and water-water stretch motions. These couplings are identified...... and discussed, and the corresponding spectral lines are assigned. The large couplings featured by H5O2+ do not hinder, however, to describe the coupled vibrational motion by well defined simple types of vibration (stretching, bending; etc.) based on well defined modes of vibration, in terms of which...
Improved Active Vibration Isolation Systems
无
2007-01-01
The control force, feedback gain, and actuator stroke of several active vibration isolation systems were analyzed based on a single-layer active vibration isolation system. The analysis shows that the feedback gain and actuator stroke cannot be selected independently and the active isolation system design must make a compromise between the feedback gain and actuator stroke. The performance of active isolation systems can be improved by the joint vibration reduction using an active vibration isolation system with an adaptive dynamic vibration absorber. The results show that the joint vibration reduction method can successfully avoid the compromise between the feedback gain and actuator stroke. The control force and the object vibration amplitude are also greatly reduced.
Animal Communications Through Seismic Vibrations
Hill, Peggy (University of Tulsa)
2001-05-02
Substrate vibration has been important to animals as a channel of communication for millions of years, but our literature on vibration in this context of biologically relevant information is only decades old. The jaw mechanism of the earliest land vertebrates allowed them to perceive substrate vibrations as their heads lay on the ground long before airborne sounds could be heard. Although the exact mechanism of vibration production and the precise nature of the wave produced are not always understood, recent development of affordable instrumentation to detect and measure vibrations has allowed researchers to answer increasingly sophisticated questions about how animals send and receive vibration signals. We now know that vibration provides information used in predator defense, prey detection, recruitment to food, mate choice, intrasexual competition, and maternal/brood social interactions in a variety of insect orders, spiders, crabs, scorpions, chameleons, frogs, golden moles, mole rats, kangaroos rats, wallabies, elephants and bison.
CO2 laser photoacoustic spectra and vibrational modes of heroin, morphine and narcotine
R L Prasad; S N Thakur; G C Bhar
2002-09-01
Heroin, morphine and narcotine are very large molecules having 50, 40 and 53 atoms respectively. Moderately high resolution photoacoustic (PA) spectra have been recorded in 9.6 m and 10.6 m regions of CO2 laser. It is very difﬁcult to assign the modes of vibrations for PA bands by comparison with conventional low resolution IR spectra. The ab initio quantum chemical calculations were used for determining the molecular geometries and normal mode frequencies of vibrations of these molecules for assignments of PA spectra.
Characterization of a novel instrument for vibration exercise.
Xu, L; Rabotti, C; Mischi, M
2012-01-01
Vibration exercise (VE) has been suggested as an effective option to improve muscle strength and power performance. Several studies link the effects of vibration training to enhanced neuromuscular stimulation and typically to involuntary reflex mechanisms. However, the underlying mechanisms are still unclear and information for the most appropriate vibration training protocols is limited. This study proposes to realize a new vibration exercise system for the biceps brachii. Amplitude, frequency, and baseline of the vibrating load, which is generated by an electromechanical actuator, can be adjusted dynamically by a feedback control loop. A second-order model is employed to identify the relation between the mechanical load and the input voltage driving the actuator. An adaptive normalized least mean square algorithm is proposed to remove the motion artifacts from the measured electromyography (EMG) data. Our results show a high correlation (0.99) between the second-order model fit and the measured data, permitting accurate control on the supplied load for vibrations up to 80 Hz. Furthermore, preliminary validation with 4 volunteers showed an excellent performance in the motion artifact removal, enabling reliable evaluation of the neuromuscular activation.
Shen, Shixin (Cindy); House, Ronald A.
2017-01-01
Résumé Objectif Permettre aux médecins de famille de comprendre l’épidémiologie, la pathogenèse, les symptômes, le diagnostic et la prise en charge de la maladie des vibrations, une maladie professionnelle importante et courante au Canada. Sources d’information Une recherche a été effectuée sur MEDLINE afin de relever les recherches et comptes rendus portant sur la maladie des vibrations. Une recherche a été effectuée sur Google dans le but d’obtenir la littérature grise qui convient au contexte canadien. D’autres références ont été tirées des articles relevés. Message principal La maladie des vibrations est une maladie professionnelle répandue touchant les travailleurs de diverses industries qui utilisent des outils vibrants. La maladie est cependant sous-diagnostiquée au Canada. Elle compte 3 éléments : vasculaire, sous la forme d’un phénomène de Raynaud secondaire; neurosensoriel; et musculosquelettique. Aux stades les plus avancés, la maladie des vibrations entraîne une invalidité importante et une piètre qualité de vie. Son diagnostic exige une anamnèse minutieuse, en particulier des antécédents professionnels, un examen physique, des analyses de laboratoire afin d’éliminer les autres diagnostics, et la recommandation en médecine du travail aux fins d’investigations plus poussées. La prise en charge consiste à réduire l’exposition aux vibrations, éviter les températures froides, abandonner le tabac et administrer des médicaments. Conclusion Pour assurer un diagnostic rapide de la maladie des vibrations et améliorer le pronostic et la qualité de vie, les médecins de famille devraient connaître cette maladie professionnelle courante, et pouvoir obtenir les détails pertinents durant l’anamnèse, recommander les patients aux cliniques de médecine du travail et débuter les demandes d’indemnisation de manière appropriée. PMID:28292812
Łodyga, Wiesław; Makarewicz, Jan
2012-05-01
Geometries, anharmonic vibrations, and torsion-wagging (TW) multiplets of hydrazine and its deuterated species are studied using high-level ab initio methods employing the second-order Møller-Plesset perturbation theory (MP2) as well as the coupled cluster singles and doubles model including connected triple corrections, CCSD(T), in conjunction with extended basis sets containing diffuse and core functions. To describe the splitting patterns caused by tunneling in TW states, the 3D potential energy surface (PES) for the large-amplitude TW modes is constructed. Stationary points in the 3D PES, including equivalent local minima and saddle points are characterized. Using this 3D PES, a flexible Hamiltonian is built numerically and then employed to solve the vibrational problem for TW coupled motion. The calculated ground state rav structure is expected to be more reliable than the experimental one that has been determined using a simplified structural model. The calculated fundamental frequencies allowed resolution of the assignment problems discussed earlier in the literature. The determined energy barriers, including the contributions from the small-amplitude vibrations, to the tunneling of the symmetric and antisymmetric wagging mode of 1997 cm-1 and 3454 cm-1, respectively, are in reasonable agreement with the empirical estimates of 2072 cm-1 and 3312 cm-1, respectively [W. Łodyga et al. J. Mol. Spectrosc. 183, 374 (1997), 10.1006/jmsp.1997.7271]. However, the empirical torsion barrier of 934 cm-1 appears to be overestimated. The ab initio calculations yield two torsion barriers: cis and trans of 744 cm-1 and 2706 cm-1, respectively. The multiplets of the excited torsion states are predicted from the refined 3D PES.
Reliability and safety engineering
Verma, Ajit Kumar; Karanki, Durga Rao
2016-01-01
Reliability and safety are core issues that must be addressed throughout the life cycle of engineering systems. Reliability and Safety Engineering presents an overview of the basic concepts, together with simple and practical illustrations. The authors present reliability terminology in various engineering fields, viz.,electronics engineering, software engineering, mechanical engineering, structural engineering and power systems engineering. The book describes the latest applications in the area of probabilistic safety assessment, such as technical specification optimization, risk monitoring and risk informed in-service inspection. Reliability and safety studies must, inevitably, deal with uncertainty, so the book includes uncertainty propagation methods: Monte Carlo simulation, fuzzy arithmetic, Dempster-Shafer theory and probability bounds. Reliability and Safety Engineering also highlights advances in system reliability and safety assessment including dynamic system modeling and uncertainty management. Cas...
Tuttle, William D.; Gardner, Adrian M.; Whalley, Laura E.; Wright, Timothy G.
2017-06-01
A study of the vibration and vibration-torsion levels of para-fluorotoluene in the 580-830 cm-1 region is presented, where a number of features are located whose identity is complicated by interactions and overlap. We examine this region with a view to ascertaining the assignments of the bands; in particular, identifying those that arise from interactions involving various zero-order states (ZOSs) involving both vibrations and torsions. Resonance-enhanced multiphoton ionization (REMPI) is employed to identify the wavenumbers of the relevant transitions, and subsequently zero-kinetic-energy (ZEKE) spectra are recorded to assign the various eigenstates. In some cases, a set of ZEKE spectra are recorded across the wavenumber range of a REMPI feature, and we construct what we term a two-dimensional ZEKE (2D-ZEKE) spectrum, which allows the changing ZOS contributions to the eigenstates to be ascertained. Assignment of the observed bands is aided by quantum chemical calculations and all b1 and a2 symmetry vibrational wavenumbers are now determined in the S1 state and cation, as well as those of the D10 vibration. We also compare to the activity seen in the corresponding S1 ← S0 spectrum of para-difluorobenzene.
The structure and the Raman vibrational spectrum of the beryllium aquacation.
Rozmanov, Dmitry A; Sizova, Olga V; Skripkin, Mikhail Yu; Burkov, Kim A
2005-11-01
The experimental Raman vibrational spectrum of the 5.94 m water solution of the beryllium(II) chloride has been acquired. Theoretical frequencies, infrared and Raman intensities of the vibrational spectrum of the beryllium cation tetrahydrate have been calculated by means of quantum chemical approach. The peaks of the experimental spectrum have been assigned on the basis of the results of the quantum-chemical calculations. It has been shown that the hydrating surrounding of the aquacation increases effectively the frequency of the beryllium-oxygen stretching vibration by 16% in comparison with the free complex.
Translational vibrations between chains of hydrogen-bonded molecules in solid-state aspirin form I
Takahashi, Masae; Ishikawa, Yoichi
2013-06-01
We perform dispersion-corrected first-principles calculations, and far-infrared (terahertz) spectroscopic experiments at 4 K, to examine translational vibrations between chains of hydrogen-bonded molecules in solid-state aspirin form I. The calculated frequencies and relative intensities reproduce the observed spectrum to accuracy of 11 cm-1 or less. The stronger one of the two peaks assigned to the translational mode includes the stretching vibration of the weak hydrogen bond between the acetyl groups of a neighboring one-dimensional chain. The calculation of aspirin form II performed for comparison gives the stretching vibration of the weak hydrogen bond in one-dimensional chain.
Measurement System Reliability Assessment
Kłos Ryszard
2015-06-01
Full Text Available Decision-making in problem situations is based on up-to-date and reliable information. A great deal of information is subject to rapid changes, hence it may be outdated or manipulated and enforce erroneous decisions. It is crucial to have the possibility to assess the obtained information. In order to ensure its reliability it is best to obtain it with an own measurement process. In such a case, conducting assessment of measurement system reliability seems to be crucial. The article describes general approach to assessing reliability of measurement systems.
Dai, Honghua; Smirnov, Evgueni
2012-01-01
Reliable Knowledge Discovery focuses on theory, methods, and techniques for RKDD, a new sub-field of KDD. It studies the theory and methods to assure the reliability and trustworthiness of discovered knowledge and to maintain the stability and consistency of knowledge discovery processes. RKDD has a broad spectrum of applications, especially in critical domains like medicine, finance, and military. Reliable Knowledge Discovery also presents methods and techniques for designing robust knowledge-discovery processes. Approaches to assessing the reliability of the discovered knowledge are introduc
Kopáček Jaroslav
2016-01-01
Full Text Available This paper focuses on the importance of detection reliability, especially in complex fluid systems for demanding production technology. The initial criterion for assessing the reliability is the failure of object (element, which is seen as a random variable and their data (values can be processed using by the mathematical methods of theory probability and statistics. They are defined the basic indicators of reliability and their applications in calculations of serial, parallel and backed-up systems. For illustration, there are calculation examples of indicators of reliability for various elements of the system and for the selected pneumatic circuit.
Circuit design for reliability
Cao, Yu; Wirth, Gilson
2015-01-01
This book presents physical understanding, modeling and simulation, on-chip characterization, layout solutions, and design techniques that are effective to enhance the reliability of various circuit units. The authors provide readers with techniques for state of the art and future technologies, ranging from technology modeling, fault detection and analysis, circuit hardening, and reliability management. Provides comprehensive review on various reliability mechanisms at sub-45nm nodes; Describes practical modeling and characterization techniques for reliability; Includes thorough presentation of robust design techniques for major VLSI design units; Promotes physical understanding with first-principle simulations.
Harmonic Analysis of Vibrations of 4-Chloro-2-Fluroaniline: A Scaled Quantum Mechanical approach
G. RAJA
2013-06-01
Full Text Available The FT-IR and Raman spectra of 4-Chloro-2-Fluroaniline (4C2FA were measured. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT and standard B3LYP/6-311+G** basis set combination. The vibrational spectra were interpreted, with the aid of normal coordinate analysis based on a scaled quantum mechanical (SQM force field. The infrared and Raman spectra were also predicted from the calculated intensities. Comparison of simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes. Unambiguous vibrational assignment of all the fundamentals was made using the total energy distribution (TED.
Hydroelastic Vibrations of Ships
Jensen, Jørgen Juncher; Folsø, Rasmus
2002-01-01
A formula for the necessary hull girder bending stiffness required to avoid serious springing vibrations is derived. The expression takes into account the zero crossing period of the waves, the ship speed and main dimensions. For whipping vibrations the probability of exceedance for the combined...... wave- and whipping induced bending moment is derived under the assumption that the maximum peak value in a whipping sequence occurs simultaneously with a peak in sagging wave-induced bending moment, but that the magnitudes of these two peaks are statistically independent. The expression can be written...... as the usual Rayleigh distribution for the wave response multiplied by a factor independent of the significant wave height. Finally, the springing and whipping predictions are compared with model test results....
Laser induced structural vibration
Koss, L. L.; Tobin, R. C.
1983-01-01
A technique is described for exciting structural vibration by using a focussed laser beam to vaporize material from a target attached to the structure. The rapid ejection of material results in an impulsive reaction to the target which is transmitted to the structure. The method has been studied with a Nd: glass laser, operated in the long pulse mode, in combination with a bismuth target attached in turn to a ballistic pendulum and cantilever beam. The specific mechanical energy was found to be proportional to the laser pulse energy raised to a power in the range 2.5-2.9. The highest efficiency of energy transfer achieved for the first vibrational mode of the cantilever was about 2 millipercent for the maximum laser pulse energy used, 1.5 J, the signal to noise ratio then being about 40 dB.
Effect of vibration on forward split flexibility and pain perception in young male gymnasts.
Sands, William A; McNeal, Jeni R; Stone, Michael H; Haff, G Gregory; Kinser, Ann M
2008-12-01
Serious stretching in many sports involves discomfort and is often an early ceiling on improvements. To continue investigation of the use of vibration to enhance acute range of motion while assessing the influence of vibration and stretching on pressure-to-pain threshold perception. Ten young male gymnasts were assessed for split range of motion. One side split was randomly assigned as the experimental condition, and the other side split was assigned as the control. Both side splits were performed on a vibration device; the experimental condition had the device turned on and the control condition was performed with the device turned off. In addition, the athletes were assessed for pressure-to-pain transition using an algometer on the biceps femoris (stretched muscle) and vastus lateralis (nonstretched muscle) bilaterally. Pre-post difference scores between the vibrated split (most improved) and the nonvibrated split were statistically different (P=.001, 95% confidence interval of the difference 2.3 to 5.8 cm). Following the stretching protocol, the force values for the pressure-to-pain threshold comparing the vibrated and nonvibrated biceps femoris muscle were not statistically different. The nonstretched vastus lateralis muscle also showed no statistical difference in pressure-to-pain threshold between the vibration and nonvibration conditions. This study showed that vibration improved split range of motion over stretching alone, but did not show a difference in pressure-to-pain perception in either the stretched or nonstretched muscles.
Vibrational stability of graphene
Yangfan Hu
2013-05-01
Full Text Available The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP models. Compared with three-dimensional (3-D materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202. This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC, defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D materials.
Vibration Induced Microfluidic Atomization
Yeo, Leslie; Qi, Aisha; Friend, James
2008-11-01
We demonstrate rapid generation of micron aerosol droplets in a microfluidic device in which a fluid drop is exposed to surface vibration as it sits atop a piezoelectric substrate. Little, however, is understood about the processes by which these droplets form due to the complex hydrodynamic processes that occur across widely varying length and time scales. Through experiments, scaling theory and numerical modelling, we elucidate the interfacial destabilization mechanisms that lead to droplet formation. Droplets form due to the axisymmetric break-up of cylindrical liquid jets ejected as a consequence of interfacial destabilization. Their 10 μm size correlates with the jet radius and the instability wavelength, both determined from a viscous-capillary dominant force balance and confirmed through a numerical solution. With the exception of drops that spread into thin films with thicknesses on the order of the boundary layer dimension, the free surface is always observed to vibrate at the capillary-viscous resonance frequency despite the surface vibration frequency being several orders larger. This is contrary to common assumptions used in deriving subharmonic models resulting in a Mathieu equation, which has commonly led to spurious predictions in the droplet size.
Katarina Anthony
2015-01-01
In preparation for the civil engineering work on the HL-LHC, vibration measurements were carried out at the LHC’s Point 1 last month. These measurements will help evaluate how civil engineering work could impact the beam, and will provide crucial details about the site’s geological make-up before construction begins. A seismic truck at Point 1 generated wave-like vibrations measured by EN/MME. From carrying out R&D to produce state-of-the-art magnets to developing innovative, robust materials capable of withstanding beam impact, the HL-LHC is a multi-faceted project involving many groups and teams across CERN’s departments. It was in this framework that the project management mandated CERN's Mechanical and Materials Engineering (EN/MME) group to measure the propagation of vibrations around Point 1. Their question: can civil engineering work for the HL-LHC – the bulk of which is scheduled for LS2 – begin while the LHC is running? Alth...
High-Pressure Crystal Structure, Lattice Vibrations, and Band Structure of BiSbO4.
Errandonea, Daniel; Muñoz, Alfonso; Rodríguez-Hernández, Placida; Gomis, Oscar; Achary, S Nagabhusan; Popescu, Catalin; Patwe, Sadeque J; Tyagi, Avesh K
2016-05-16
The high-pressure crystal structure, lattice-vibrations, and electronic band structure of BiSbO4 were studied by ab initio simulations. We also performed Raman spectroscopy, infrared spectroscopy, and diffuse-reflectance measurements, as well as synchrotron powder X-ray diffraction. High-pressure X-ray diffraction measurements show that the crystal structure of BiSbO4 remains stable up to at least 70 GPa, unlike other known MTO4-type ternary oxides. These experiments also give information on the pressure dependence of the unit-cell parameters. Calculations properly describe the crystal structure of BiSbO4 and the changes induced by pressure on it. They also predict a possible high-pressure phase. A room-temperature pressure-volume equation of state is determined, and the effect of pressure on the coordination polyhedron of Bi and Sb is discussed. Raman- and infrared-active phonons were measured and calculated. In particular, calculations provide assignments for all the vibrational modes as well as their pressure dependence. In addition, the band structure and electronic density of states under pressure were also calculated. The calculations combined with the optical measurements allow us to conclude that BiSbO4 is an indirect-gap semiconductor, with an electronic band gap of 2.9(1) eV. Finally, the isothermal compressibility tensor for BiSbO4 is given at 1.8 GPa. The experimental (theoretical) data revealed that the direction of maximum compressibility is in the (0 1 0) plane at ∼33° (38°) to the c-axis and 47° (42°) to the a-axis. The reliability of the reported results is supported by the consistency between experiments and calculations.
de Brevern Alexandre G
2005-09-01
Full Text Available Abstract Background A number of methods are now available to perform automatic assignment of periodic secondary structures from atomic coordinates, based on different characteristics of the secondary structures. In general these methods exhibit a broad consensus as to the location of most helix and strand core segments in protein structures. However the termini of the segments are often ill-defined and it is difficult to decide unambiguously which residues at the edge of the segments have to be included. In addition, there is a "twilight zone" where secondary structure segments depart significantly from the idealized models of Pauling and Corey. For these segments, one has to decide whether the observed structural variations are merely distorsions or whether they constitute a break in the secondary structure. Methods To address these problems, we have developed a method for secondary structure assignment, called KAKSI. Assignments made by KAKSI are compared with assignments given by DSSP, STRIDE, XTLSSTR, PSEA and SECSTR, as well as secondary structures found in PDB files, on 4 datasets (X-ray structures with different resolution range, NMR structures. Results A detailed comparison of KAKSI assignments with those of STRIDE and PSEA reveals that KAKSI assigns slightly longer helices and strands than STRIDE in case of one-to-one correspondence between the segments. However, KAKSI tends also to favor the assignment of several short helices when STRIDE and PSEA assign longer, kinked, helices. Helices assigned by KAKSI have geometrical characteristics close to those described in the PDB. They are more linear than helices assigned by other methods. The same tendency to split long segments is observed for strands, although less systematically. We present a number of cases of secondary structure assignments that illustrate this behavior. Conclusion Our method provides valuable assignments which favor the regularity of secondary structure segments.
argosy B6029 full course latest 2015 winters [all assignments and Assignment discussion
Laynebaril
2017-01-01
argosy B6029 full course latest 2015 winters [all assignments and Assignment discussion ] Click Link Below To Buy: http://hwcampus.com/shop/b6029-full-course/ Assignment 2: Discussion—Competitive Advantage and Globalization Competitive advantage implies the creation of a system that has a unique advantage over competitors. With the advent of globalization, the competition has become stronger and can be located anywhere in the world. The idea behind competitive adv...
Grouping puts figure-ground assignment in context by constraining propagation of edge-assignment
Brooks, Joseph L.; Driver, Jon
2010-01-01
Figure-ground organization involves assignment of edges to a figural shape on one or the other side of each dividing edge. Established visual cues for edge-assignment primarily concern relatively local rather than contextual factors. Here we show that assignment for a locally-unbiased edge can be affected by assignment of a remote contextual edge that has its own locally-biased assignment. We find that such propagation of edge-assignment from the biased remote context occurs only when the biased and unbiased edges are grouped. This new principle, whereby grouping constrains propagation of figural edge-assignment, emerges from both subjective reports and from an objective short-term edge-matching task. It generalizes from moving displays involving grouping by common fate and collinearity, to static displays with grouping by similarity of edge-contrast polarity, or apparent occlusion. Our results identify a new contextual influence upon edge-assignment. They also identify a new mechanistic relation between grouping and figure-ground processes, whereby grouping between remote elements can constrain propagation of edge-assignment between those elements. PMID:20436200
Assignment of fields from particles to mesh
Duque, Daniel
2016-01-01
In Computational Fluid Dynamics there have been many attempts to combine the power of a fixed mesh on which to carry out spatial calculations with that of a set of particles that moves following the velocity field. These ideas indeed go back to Particle-in-Cell methods, proposed about 60 years ago. Of course, some procedure is needed to transfer field information between particles and mesh. There are many possible choices for this "assignment", or "projection". Several requirements may guide this choice. Two well-known ones are conservativity and stability, which apply to volume integrals of the fields. An additional one is here considered: preservation of information. This means that mesh interpolation, followed by mesh assignment, should leave the field values invariant. The resulting methods are termed "mass" assignments due to their strong similarities with the Finite Element Method. We test several procedures, including the well-known FLIP, on three scenarios: simple 1D convection, 2D convection of Zales...
Reasoning about Assignments in Recursive Data Structures
Tamalet, Alejandro; Madlener, Ken
This paper presents a framework to reason about the effects of assignments in recursive data structures. We define an operational semantics for a core language based on Meyer's ideas for a semantics for the object-oriented language Eiffel. A series of field accesses, e.g. f1 • f2 • ··· • fn , can be seen as a path on the heap. We provide rules that describe how these multidot expressions are affected by an assignment. Using multidot expressions to construct an abstraction of a list, we show the correctness of a list reversal algorithm. This approach does not require induction and the reasoning about the assignments is encapsulated in the mentioned rules. We also discuss how to use this approach when working with other data structures and how it compares to the inductive approach. The framework, rules and examples have been formalised and proven correct using the PVS proof assistant.
Demand assignment in the ACTS LBR system
Palmer, Larry C.; White, Lawrence W.
1990-05-01
On the Advanced Communications Technology Satellite (ACTS) being developed at NASA Lewis, low-burst-rate (LBR) traffic stations will access the ACTS multibeam package via two hopping beams that can be directed at certain areas in the continental U.S. An onboard baseband processor (BBP) demodulates uplink traffic, switches it between uplink and downlink beams at baseband, and then remodulates it for retransmission at 20 GHz. This study describes the demand-assigned operation of the ACTS LBR system, where the onboard switch is remote from both traffic stations and master control station (MCS). Network control uses inbound and outbound orderwire channels and a BBP control channel, allowing the MCS to coordinate assignment of individual 64-kb/s spacecraft channels. Models are developed to simulate the dynamics of the assignment process and verify the call blocking behavior, to predict control channel loads, and to evaluate algorithms for burst time plan rearrangement.
A tracked approach for automated NMR assignments in proteins (TATAPRO)
Atreya, H.S.; Sahu, S.C.; Chary, K.V.R.; Govil, Girjesh [Tata Institute of Fundamental Research, Department of Chemical Sciences (India)
2000-06-15
experimental data on a calcium binding protein from Entamoeba histolytica (Eh-CaBP, 15 kDa) having substantial internal sequence homology and using published data on four other proteins in the molecular weight range of 18-42 kDa. In all the cases, nearly complete sequence specific resonance assignments (> 95%) are obtained. Furthermore, the reliability of the program has been tested by deleting sets of chemical shifts randomly from the master{sub l}ist created for the test proteins.
Driel, W.D. van; Yuan, C.A.; Koh, S.; Zhang, G.Q.
2011-01-01
This paper presents our effort to predict the system reliability of Solid State Lighting (SSL) applications. A SSL system is composed of a LED engine with micro-electronic driver(s) that supplies power to the optic design. Knowledge of system level reliability is not only a challenging scientific ex
Principles of Bridge Reliability
Thoft-Christensen, Palle; Nowak, Andrzej S.
The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...
Improving machinery reliability
Bloch, Heinz P
1998-01-01
This totally revised, updated and expanded edition provides proven techniques and procedures that extend machinery life, reduce maintenance costs, and achieve optimum machinery reliability. This essential text clearly describes the reliability improvement and failure avoidance steps practiced by best-of-class process plants in the U.S. and Europe.
Hawaii Electric System Reliability
Loose, Verne William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Silva Monroy, Cesar Augusto [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2012-08-01
This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers’ views of reliability “worth” and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers’ views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.
Hawaii electric system reliability.
Silva Monroy, Cesar Augusto; Loose, Verne William
2012-09-01
This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.
A vibrational spectroscopic study of the phosphate mineral whiteite CaMn++Mg2Al2(PO4)4(OH)2 8(H2O).
Frost, Ray L.; Sholz, Ricardo Augusto; López, Andrés; Xi, Yunfei
2014-01-01
Vibrational spectroscopy enables subtle details of the molecular structure of whiteite to be determined. Single crystals of a pure phase from a Brazilian pegmatite were used. The infrared and Raman spectroscopy were applied to compare the molecular structure of whiteite with that of other phosphate minerals. The Raman spectrum of whiteite shows an intense band at 972 cm_1 assigned to the m1 PO3_ 4 symmetric stretching vibrations. The low intensity Raman bands at 1076 and 1173 cm_1 are assigne...
Writing Assignments that Promote Active Learning
Narayanan, M.
2014-12-01
Encourage students to write a detailed, analytical report correlating classroom discussions to an important historical event or a current event. Motivate students interview an expert from industry on a topic that was discussed in class. Ask the students to submit a report with supporting sketches, drawings, circuit diagrams and graphs. Propose that the students generate a complete a set of reading responses pertaining to an assigned topic. Require each student to bring in one comment or one question about an assigned reading. The assignment should be a recent publication in an appropriate journal. Have the students conduct a web search on an assigned topic. Ask them to generate a set of ideas that can relate to classroom discussions. Provide the students with a study guide. The study guide should provide about 10 or 15 short topics. Quiz the students on one or two of the topics. Encourage the students to design or develop some creative real-world examples based on a chapter discussed or a topic of interest. Require that students originate, develop, support and defend a viewpoint using a specifically assigned material. Make the students practice using or utilizing a set of new technical terms they have encountered in an assigned chapter. Have students develop original examples explaining the different terms. Ask the students to select one important terminology from the previous classroom discussions. Encourage the students to explain why they selected that particular word. Ask them to talk about the importance of the terminology from the point of view of their educational objectives and future career. Angelo, T. A. (1991). Ten easy pieces: Assessing higher learning in four dimensions. In T. A. Angelo (Ed.), Classroom research: Early lessons from success (pp. 17-31). New Directions for Teaching and Learning, No. 46. San Francisco: Jossey-Bass.
Pei, Yan-Ling; Wu, Zhi-Sheng; Shi, Xin-Yuan; Zhou, Lu-Wei; Qiao, Yan-Jiang
2014-09-01
The present paper firstly reviewed the research progress and main methods of NIR spectral assignment coupled with our research results. Principal component analysis was focused on characteristic signal extraction to reflect spectral differences. Partial least squares method was concerned with variable selection to discover characteristic absorption band. Two-dimensional correlation spectroscopy was mainly adopted for spectral assignment. Autocorrelation peaks were obtained from spectral changes, which were disturbed by external factors, such as concentration, temperature and pressure. Density functional theory was used to calculate energy from substance structure to establish the relationship between molecular energy and spectra change. Based on the above reviewed method, taking a NIR spectral assignment of chlorogenic acid as example, a reliable spectral assignment for critical quality attributes of Chinese materia medica (CMM) was established using deuterium technology and spectral variable selection. The result demonstrated the assignment consistency according to spectral features of different concentrations of chlorogenic acid and variable selection region of online NIR model in extract process. Although spectral assignment was initial using an active pharmaceutical ingredient, it is meaningful to look forward to the futurity of the complex components in CMM. Therefore, it provided methodology for NIR spectral assignment of critical quality attributes in CMM.
Algora, Carlos; Espinet-Gonzalez, Pilar; Vazquez, Manuel; Bosco, Nick; Miller, David; Kurtz, Sarah; Rubio, Francisca; McConnell,Robert
2016-04-15
This chapter describes the accumulated knowledge on CPV reliability with its fundamentals and qualification. It explains the reliability of solar cells, modules (including optics) and plants. The chapter discusses the statistical distributions, namely exponential, normal and Weibull. The reliability of solar cells includes: namely the issues in accelerated aging tests in CPV solar cells, types of failure and failures in real time operation. The chapter explores the accelerated life tests, namely qualitative life tests (mainly HALT) and quantitative accelerated life tests (QALT). It examines other well proven and experienced PV cells and/or semiconductor devices, which share similar semiconductor materials, manufacturing techniques or operating conditions, namely, III-V space solar cells and light emitting diodes (LEDs). It addresses each of the identified reliability issues and presents the current state of the art knowledge for their testing and evaluation. Finally, the chapter summarizes the CPV qualification and reliability standards.
The Wiener maximum quadratic assignment problem
Cela, Eranda; Woeginger, Gerhard J
2011-01-01
We investigate a special case of the maximum quadratic assignment problem where one matrix is a product matrix and the other matrix is the distance matrix of a one-dimensional point set. We show that this special case, which we call the Wiener maximum quadratic assignment problem, is NP-hard in the ordinary sense and solvable in pseudo-polynomial time. Our approach also yields a polynomial time solution for the following problem from chemical graph theory: Find a tree that maximizes the Wiener index among all trees with a prescribed degree sequence. This settles an open problem from the literature.
Evolving Networks with Nonlinear Assignment of Weight
TANG Chao; TANG Yi
2006-01-01
We propose a weighted evolving network model in which the underlying topological structure is still driven by the degree according to the preferential attachment rule while the weight assigned to the newly established edges is dependent on the degree in a nonlinear form. By varying the parameter α that controls the function determining the assignment of weight, a wide variety of power-law behaviours of the total weight distributions as well as the diversity of the weight distributions of edges are displayed. Variation of correlation and heterogeneity in the network is illustrated as well.
AC410 Unit 2 Homework Assignment
Laynebaril1
2017-01-01
AC410 Unit 2 Homework Assignment Click Link Below To Buy: http://hwcampus.com/shop/ac410-unit-2-homework-assignment/ 3-31 Ron Barber, CPA, is auditing the financial statements of DGF, Inc., a publicly held company. During the course of the audit, Barber discovered that DGF has been making illegal bribes to foreign government officials to obtain business, and he reported the matter to senior management and the board of directors of DGF. Required: If management a...
Storage assignment problem in flexible manufacturing
Abdel-Hamid, A.
1994-12-31
In this talk some results of a joint project with industry that had the aim to speed up the operation of an automatic storage device of a flexible manufacturing system is presented. One of the aspects that influence this speed is the technique used to solve the problem of assigning containers with different sizes to storage locations of an automatic storage system (storage assignment problem, shortly, SAP). Both off-line and on line computational studies of various solution techniques (heuristics, a cutting plane algorithm) to solve SAP are reported. These studies show that under heavy load conditions a considerable speed up of the system can be achieved.
Manganese Oxidation State Assignment for Manganese Catalase.
Beal, Nathan J; O'Malley, Patrick J
2016-04-06
The oxidation state assignment of the manganese ions present in the superoxidized manganese (III/IV) catalase active site is determined by comparing experimental and broken symmetry density functional theory calculated (14)N, (17)O, and (1)H hyperfine couplings. Experimental results have been interpreted to indicate that the substrate water is coordinated to the Mn(III) ion. However, by calculating hyperfine couplings for both scenarios we show that water is coordinated to the Mn(IV) ion and that the assigned oxidation states of the two manganese ions present in the site are the opposite of that previously proposed based on experimental measurements alone.
Experimenting with Request Assignment Simulator (RAS
R. Arokia Paul Rajan
2014-11-01
Full Text Available There is no existence of dedicated simulators on the Internet that studies the impact of load balancing principles of the cloud architectures. Request Assignment Simulator (RAS is a customizable, visual tool that helps to understand the request assignment to the resources based on the load balancing principles. We have designed this simulator to fit into Infrastructure as a Service (IaaS cloud model. In this paper, we present a working manual useful for the conduct of experiment with RAS. The objective of this paper is to instill the user to understand the pertinent parameters in the cloud, their metrics, load balancing principles, and their impact on the performance.
Competition assignment problem algorithm based on Hungarian method
KONG Chao; REN Yongtai; GE Huiling; DENG Hualing
2007-01-01
Traditional Hungarian method can only solve standard assignment problems, while can not solve competition assignment problems. This article emphatically discussed the difference between standard assignment problems and competition assignment problems. The kinds of competition assignment problem algorithms based on Hungarian method and the solutions of them were studied.
VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS
Smirnov Vladimir Alexandrovich
2012-10-01
Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.
Further developments in material properties determined by vibration analysis
Nielsen, Lauge Fuglsang; Andreasen, Lotte; Seifert, Mette
1997-01-01
have been studied by testing a number of building materials. The method has been PC-integrated with the Brüel & Kjær's type 3550 vibration equipment - and special user menus have been developed to facilitate handling of the method in practice. Limits on range of test frequencies applied are discussed...... with respect to configurations of vibration equipment and shapes of test specimens used. Sensitivity studies have been made to identify sources of errors which may disturb the reliability of the method used in practice. Practical aspects with respect to test set-ups are considered in these studies - as well......A method was described in Materialnyt 1 (1995) on "Material properties determined by vibration analysis". This new method of materials testing has been further developed as the result of research at the Building Materials Laboratory, Technical University of Denmark.Practical aspects of the method...
Grey forecasting model for active vibration control systems
Lihua, Zou; Suliang, Dai; Butterworth, John; Ma, Xing; Dong, Bo; Liu, Aiping
2009-05-01
Based on the grey theory, a GM(1,1) forecasting model and an optimal GM(1,1) forecasting model are developed and assessed for use in active vibration control systems for earthquake response mitigation. After deriving equations for forecasting the control state vector, design procedures for an optimal active control method are proposed. Features of the resulting vibration control and the influence on it of time-delay based on different sampling intervals of seismic ground motion are analysed. The numerical results show that the forecasting models based on the grey theory are reliable and practical in structural vibration control fields. Compared with the grey forecasting model, the optimal forecasting model is more efficient in reducing the influences of time-delay and disturbance errors.
Koroleva, L. A.; Tyulin, V. I.; Matveev, V. K.; Pentin, Yu. A.
2012-04-01
The assignments of absorption bands of the vibrational structure of the UV spectrum are compared with the assignments of bands obtained by the CRDS method in a supersonic jet from the time of laser radiation damping for the trans isomer of acrolein in the excited ( S 1) electronic state. The ν00 trans = 25861 cm-1 values and fundamental frequencies, including torsional vibration frequency, obtained by the two methods were found to coincide in the excited electronic state ( S 1) for this isomer. The assignments of several absorption bands of the vibrational structure of the spectrum obtained by the CRDS method were changed. Changes in the assignment of (0-v') transition bands of the torsional vibration of the trans isomer in the Deslandres table from the ν00 trans trans origin allowed the table to be extended to high quantum numbers v'. The torsional vibration frequencies up to v' = 5 were found to be close to the frequencies found by analyzing the vibrational structure of the UV spectrum and calculated quantum-mechanically. The coincidence of the barrier to internal rotation (the cis-trans transition) in the one-dimensional model with that calculated quantum-mechanically using the two-dimensional model corresponds to a planar structure of the acrolein molecule in the excited ( S 1) electronic state.
A Joint Link and Channel Assignment Routing Scheme for Cognitive Radio Networks
H.S.Zhao
2013-12-01
Full Text Available Cognitive radio (CR is a promising technology that enables opportunistic utilization of the temporarily vacant spectrum to mitigate the spectrum scarcity in wireless communications. Since secondary users (SUs should vacate the channel in use immediately after detecting the reappearances of primary users (PUs in cognitive radio networks (CRNs, the route reliability is a distinctive challenge for routing in CRNs. Furthermore, the throughput requirement of an SU session should be satisfied and it is always preferable to select a route with less negative influence on other current or latish sessions. To account for the route reliability challenge, we study the joint link and channel assignment routing problem for CRNs. It is formulated in a form of integer nonlinear programming (INLP, which is NP-hard, with the objective of minimizing the interference of a new route to other routes while providing route reliability and throughput guarantee. An on-demand route discovery algorithm is proposed to find reliable candidate paths, while a joint link and channel assignment routing algorithm with sequentially-connected-link coordination is proposed to choose the near-optimal route for improving the route reliability and minimizing negative influence. Simulation results demonstrate that the proposed algorithm achieves considerable improvement over existing schemes in both route reliability and throughput.
48 CFR 211.274-5 - Policy for assignment of Government-assigned serial numbers.
2010-10-01
... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Policy for assignment of... DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE ACQUISITION PLANNING DESCRIBING AGENCY NEEDS Using and Maintaining Requirements Documents 211.274-5 Policy for assignment of...
Smith, Matthew W.; Dallmeyer, Ian; Johnson, Timothy J.; Brauer, Carolyn S.; McEwen, Jean-Sabin; Espinal, Juan F.; Garcia-Perez, Manuel
2016-04-01
Raman spectroscopy is a powerful tool for the characterization of many carbon 27 species. The complex heterogeneous nature of chars and activated carbons has confounded 28 complete analysis due to the additional shoulders observed on the D-band and high intensity 29 valley between the D and G-bands. In this paper the effects of various vacancy and substitution 30 defects have been systematically analyzed via molecular modeling using density functional 31 theory (DFT) and how this is manifested in the calculated gas-phase Raman spectra. The 32 accuracy of these calculations was validated by comparison with (solid-phase) experimental 33 spectra, with a small correction factor being applied to improve the accuracy of frequency 34 predictions. The spectroscopic effects on the char species are best understood in terms of a 35 reduced symmetry as compared to a “parent” coronene molecule. Based upon the simulation 36 results, the shoulder observed in chars near 1200 cm-1 has been assigned to the totally symmetric 37 A1g vibrations of various small polyaromatic hydrocarbons (PAH) as well as those containing 38 rings of seven or more carbons. Intensity between 1400 cm-1 and 1450 cm-1 is assigned to A1g 39 type vibrations present in small PAHs and especially those containing cyclopentane rings. 40 Finally, band intensity between 1500 cm-1 and 1550 cm-1 is ascribed to predominately E2g 41 vibrational modes in strained PAH systems. A total of ten potential bands have been assigned 42 between 1000 cm-1 and 1800 cm-1. These fitting parameters have been used to deconvolute a 43 thermoseries of cellulose chars produced by pyrolysis at 300-700 °C. The results of the 44 deconvolution show consistent growth of PAH clusters with temperature, development of non-45 benzyl rings as temperature increases and loss of oxygenated features between 400 °C and 46 600 °C
Structural Encoding of Static Single Assignment Form
Gal, Andreas; Probst, Christian; Franz, Michael
2005-01-01
Static Single Assignment (SSA) form is often used as an intermediate representation during code optimization in Java Virtual Machines. Recently, SSA has successfully been used for bytecode verification. However, constructing SSA at the code consumer is costly. SSAbased mobile code transport formats...
Tabu search for target-radar assignment
Hindsberger, Magnus; Vidal, Rene Victor Valqui
2000-01-01
In the paper the problem of assigning air-defense illumination radars to enemy targets is presented. A tabu search metaheuristic solution is described and the results achieved are compared to those of other heuristic approaches, implementation and experimental aspects are discussed. It is argued...
Strategy-Proof Assignment Of Multiple Resources
Erlanson, Albin; Szwagrzak, Karol
2015-01-01
We examine the strategy-proof allocation of multiple resources; an application is the assignment of packages of tasks, workloads, and compensations among the members of an organization. In the domain of multidimensional single-peaked preferences, we find that any allocation mechanism obtained...
Dynamic traffic assignment on parallel computers
Nagel, K.; Frye, R.; Jakob, R.; Rickert, M.; Stretz, P.
1998-12-01
The authors describe part of the current framework of the TRANSIMS traffic research project at the Los Alamos National Laboratory. It includes parallel implementations of a route planner and a microscopic traffic simulation model. They present performance figures and results of an offline load-balancing scheme used in one of the iterative re-planning runs required for dynamic route assignment.
Test-assignment: a quadratic coloring problem
Duives, Jelle; Lodi, Andrea; Malaguti, Enrico
2013-01-01
We consider the problem of assigning the test variants of a written exam to the desks of a classroom in such a way that desks that are close-by receive different variants. The problem is a generalization of the Vertex Coloring and we model it as a binary quadratic problem. Exact solution methods bas
Experimental results on quadratic assignment problem
N.P. Nikolov
1999-08-01
Full Text Available The paper presents experimental results on quadratic assignment problem. The "scanning area" method formulated for radioelectronic equipment design is applied. For all more complex tests ours results are better or coincident with the ones known in literature. Conclusion concerning the effectiveness of method are given.
School Assignment, School Choice and Social Mobility
Burgess, Simon; Briggs, Adam
2010-01-01
We estimate the chances of poor and non-poor children getting places in good schools, analysing the relationship between poverty, location and school assignment. Our dataset allows us to measure location and distance very precisely. The simple unconditional difference in probabilities of attending a good school is substantial. We run an analysis…
Assessing the Assignment Policy for Army Women
2007-01-01
General surgeon 61K Thoracic surgeon 61L Plastic surgeon 61M Orthopedic surgeon 61N Flight surgeon 61P Physiatrist 61Q Radiation oncologist 61R Diagnostic... veterinarian (immaterial) Branch 65, Army Medical Specialist Corps 65A Occupational therapy Table C.3—Continued 100 Assessing the Assignment Policy for Army
On Online Assignments in a Calculus Class
Jungic, Veselin; Kent, Deborah; Menz, Petra
2012-01-01
In this paper, we describe our experience with the creation and utilization of online assignments for several calculus classes at Simon Fraser University (SFU). We present our findings regarding available software by considering the needs and perspectives of the instructors, students, and administrators. We provide a list of questions that guide…
Radio labeling with pre-assigned frequencies
Bodlaender, H.L.; Broersma, H.J.; Fomin, F.V.; Pyatkin, A.V.; Woeginer, G.J.
2007-01-01
A radio labeling of a graph G is an assignment of pairwise distinct, positive integer labels to the vertices of G such that labels of adjacent vertices differ by at least 2. The radio labeling problem (RL) consists in determining a radio labeling that minimizes the maximum label that is used (the so
Improving Marine Corps Assignment of SDAP Levels
2013-03-01
Advisor William R. Gates, Dean Graduate School of Business and Public Policy iv THIS PAGE INTENTIONALLY LEFT BLANK v ABSTRACT The...normally covered through TAD funds, COLA, BAH, and BAS, but not SDAP. 9 Information Paper, SDAP...Lien, and Dave Gregory. Evaluation of the Assignment Incentive Pay (AIP) System. Alexandria: CNA, June 2004. Greene, William . Econometric Analysis
Incentivized optimal advert assignment via utility decomposition
Kelly, F.; Key, P.; Walton, N.
2014-01-01
We consider a large-scale Ad-auction where adverts are assigned over a potentially infinite number of searches. We capture the intrinsic asymmetries in information between advertisers, the advert platform and the space of searches: advertisers know and can optimize the average performance of their a
Accounting for Sustainability: An Active Learning Assignment
Gusc, Joanna; van Veen-Dirks, Paula
2017-01-01
Purpose: Sustainability is one of the newer topics in the accounting courses taught in university teaching programs. The active learning assignment as described in this paper was developed for use in an accounting course in an undergraduate program. The aim was to enhance teaching about sustainability within such a course. The purpose of this…
A Literature Assignment with a Civic Emphasis.
Brough, Barbara L.
1989-01-01
Describes how students wrestled with an assignment that asked them to name their heroes or heroines, compare them to "Beowulf," and defend their choices in writing and class discussion. Tells how students gained insight into their community and the ways in which people make it better. (MG)
Writing Assignments Based on Literary Works.
Matthews, Dorothy, Ed.
1985-01-01
The literature selections serving as the basis for writing assignments in the articles in this journal issue range from time-honored English classics ("Beowulf,""Sir Gawain and the Green Knight") and American standards ("A Farewell to Arms,""The Scarlet Letter") to contemporary fiction. The articles deal with works by women writers (Shirley…
Credit assignment during movement reinforcement learning.
Dam, Gregory; Kording, Konrad; Wei, Kunlin
2013-01-01
We often need to learn how to move based on a single performance measure that reflects the overall success of our movements. However, movements have many properties, such as their trajectories, speeds and timing of end-points, thus the brain needs to decide which properties of movements should be improved; it needs to solve the credit assignment problem. Currently, little is known about how humans solve credit assignment problems in the context of reinforcement learning. Here we tested how human participants solve such problems during a trajectory-learning task. Without an explicitly-defined target movement, participants made hand reaches and received monetary rewards as feedback on a trial-by-trial basis. The curvature and direction of the attempted reach trajectories determined the monetary rewards received in a manner that can be manipulated experimentally. Based on the history of action-reward pairs, participants quickly solved the credit assignment problem and learned the implicit payoff function. A Bayesian credit-assignment model with built-in forgetting accurately predicts their trial-by-trial learning.
Incentivized optimal advert assignment via utility decomposition
Kelly, F.; Key, P.; Walton, N.
2014-01-01
We consider a large-scale Ad-auction where adverts are assigned over a potentially infinite number of searches. We capture the intrinsic asymmetries in information between advertisers, the advert platform and the space of searches: advertisers know and can optimize the average performance of their a
Tabu search for target-radar assignment
Hindsberger, Magnus; Vidal, Rene Victor Valqui
2000-01-01
In the paper the problem of assigning air-defense illumination radars to enemy targets is presented. A tabu search metaheuristic solution is described and the results achieved are compared to those of other heuristic approaches, implementation and experimental aspects are discussed. It is argued...... that tabu search could be used in near real-time decision making systems...
Accounting for Sustainability: An Active Learning Assignment
Gusc, Joanna; van Veen-Dirks, Paula
2017-01-01
Purpose: Sustainability is one of the newer topics in the accounting courses taught in university teaching programs. The active learning assignment as described in this paper was developed for use in an accounting course in an undergraduate program. The aim was to enhance teaching about sustainability within such a course. The purpose of this…
Politics, Internet Assignments, and Civic Knowledge.
May, Vaughn
2000-01-01
Describes how one professor of American government fights the apathy and cynicism of college students toward politics by using the Internet to help students more fairly appraise the workings of the American political system. One assignment has students research and manage a particular public policy initiative through visits to Web sites…
Feedback for Web-based Assignments.
Collis, Betty; De Boer, W.; Slotman, K.
2001-01-01
Discusses a concept used at the University of Twente based on increased flexibility in learning options and the active student in which there are assignments submitted and monitored via a Web-based course management system. Outlines conceptual aspects of feedback as part of the assessment process, particularly feedback supported by a Web-based…
Locomotive Assignment Optimization Including Train Delays
Sandra Kasalica
2013-10-01
Full Text Available Intention– Cyclic locomotive assignment planning is a specific type of organization of locomotive usage, and in fact, it means putting the complete workload to a closed chain, which is repeated periodically. The concept of cyclic locomotive assignment planning type organization in the area of train traction has proven in practice as the best one, but as it is made for in-advance defined timetable and without considering the stochastic nature of the timetable realization process, it leads to incompatibility in using locomotives. Methodology – Methodology defined in this paper contains: research of train delays on the Serbian Railways and Montenegrin Railways networks, analysis of the real system organization of locomotive usage in conditions of train delays, theoretical thesis of solving the problem of optimal cyclic locomotive assignment planning in conditions of train delays, designing of a model with algorithms, preparing the software package, testing the model and program with results, as well as the conclusions drawn from the complete research project. Results– The optimization model of cyclic locomotive assignment planning during the process of making timetable including train delays has been defined. Conclusion –The obtained results have shown as expected, that the larger delays of trains required a larger number of locomotives. However, by using this model it is possible to optimize the required number of locomotives, taking into account the real time delays of trains.
12 CFR 25.28 - Assigned ratings.
2010-01-01
... on the bank's performance under the lending, investment and service tests, the community development..., investment, and service tests. The OCC assigns a rating for a bank assessed under the lending, investment, and service tests in accordance with the following principles: (1) A bank that receives...
Semi-infinite assignment and transportation games
Sánchez-Soriano, Joaqu´ın; Llorca, Navidad; Tijs, Stef; Timmer, Judith; Goberna, Miguel A.; López, Marco A.
2001-01-01
Games corresponding to semi-infinite transportation and related assignment situations are studied. In a semi-infinite transportation situation, one aims at maximizing the profit from the transportation of a certain good from a finite number of suppliers to an infinite number of demanders. An assignm
Teaching Historical Analysis through Creative Writing Assignments
Peterson, Janine Larmon; Graham, Lea
2015-01-01
Incorporating creative writing exercises in history courses can heighten students' critical reading and analytical skills in an active learning model. We identify and define two types of possible assignments that use model texts as their locus: centripetal, which focuses on specific context and disciplinary terms, and centrifugal, which address…
Democratization of Learning through Thematic Assignment
Medellu, Christophil S.; Lumingkewas, S.; Walangitan, J. F.
2015-01-01
This article describes the results of research on learning democratization in Sangihe. This study is the first year of a five-year plan. Long-term goal of this research is to create the democratic science learning in schools. Democratic learning model was developed through thematic assignment, involving the participation of parents and…
Generalised Assignment Matrix Methodology in Linear Programming
Jerome, Lawrence
2012-01-01
Discrete Mathematics instructors and students have long been struggling with various labelling and scanning algorithms for solving many important problems. This paper shows how to solve a wide variety of Discrete Mathematics and OR problems using assignment matrices and linear programming, specifically using Excel Solvers although the same…
Radio labeling with pre-assigned frequencies
Bodlaender, H.L.; Broersma, H.J.; Fomin, F.V.; Pyatkin, A.V.; Woeginer, G.J.
2002-01-01
A radio labeling of a graph G is an assignment of pairwise distinct, positive integer labels to the vertices of G such that labels of adjacent vertices differ by at least 2. The radio labeling problem (RL) consists in determining a radio labeling that minimizes the maximum label that is used (the
Radio labeling with pre-assigned frequencies
Bodlaender, H.L.; Broersma, Haitze J.; Fomin, F.V.; Pyatkin, A.V.; Woeginger, Gerhard
2002-01-01
A radio labeling of a graph $G$ is an assignment of pairwise distinct, positive integer labels to the vertices of $G$ such that labels of adjacent vertices differ by at least $2$. The radio labeling problem (\\mbox{\\sc RL}) consists in determining a radio labeling that minimizes the maximum label
Computer analysis of railcar vibrations
Vlaminck, R. R.
1975-01-01
Computer models and techniques for calculating railcar vibrations are discussed along with criteria for vehicle ride optimization. The effect on vibration of car body structural dynamics, suspension system parameters, vehicle geometry, and wheel and rail excitation are presented. Ride quality vibration data collected on the state-of-the-art car and standard light rail vehicle is compared to computer predictions. The results show that computer analysis of the vehicle can be performed for relatively low cost in short periods of time. The analysis permits optimization of the design as it progresses and minimizes the possibility of excessive vibration on production vehicles.
Dynamical flexibility of discretecontinuous vibrating mechatronic system
A. Buchacz
2008-06-01
Full Text Available Purpose: The application of approximate method for solving the task of assignment the frequency-modal analysis and characteristics of flexibly vibrating mechatronic system, because for considered case of boundary conditions exact and approximate methods for the coordinates are equivalent.Design/methodology/approach: Formulate and solve the problem in the form of a set of differential equations of motion and state equations of the considered mechatronic model of an object Galerkin’s method was used. The considered flexibly vibrating mechanical system is a continuous beam, clamped at one of its ends. An integral part of the mechatronic system is a transducer perfectly bonded to the beam surface.Findings: The parameters of the transducer exert an important influence on the values of natural frequencies and on the form of the characteristics of the discussed mechatronic system.Research limitations/implications: The linear mechanical subsystem and linear electrical subsystem of the mechatronic system were analyzed and the theory Euler-Bernoulli is used for the beam; however, this approach is sufficient for such systems.Practical implications: Global approach is presented in the domain of frequency spectrum analysis. The methods of analysis and the obtained results my give grounds for designing and investigating this type of mechatronic systems.Originality/value: The mechatronic system created from mechanical and electric subsystems with electromechanical bondage has been considered. This approach is different from those considered so far.
Vibrational Spectroscopy of PTSA—Doped Polyaniline
Arora, Manju; Gupta, S. K.
2008-11-01
Infrared transmittance spectra of polyaniline emeraldine base (EB) form and its different PTSA (p-toulene sulphonic acid) concentration doped samples were measured in 4000-400 cm-1 region at ambient temperature to reveal the polymeric chain oligomeric unit, interaction of sulphonate ions with these chains and effect of its concentration. The vibrational peaks of benzenoid (B) ring, quinoid (Q) ring, their combination modes and semiquinone units in PTSA doped emeraldine salts (PTSA:ES) are observed and assigned by using Oligomer Compound Approach. The para-substitution of B rings is confirmed by the appearance of B ring C-H out-of-plane deformation mode as a medium intensity band at 827 cm-1 in EB and at 824 cm-1 in ES:PTSA salts. The out-of-plane wagging mode of five adjacent hydrogen in end capped phenyl group due to conformational deformation of rings in polymeric chain is obtained as very weak bands at 712 and 682 cm-1 in EB and PTSA doped salts. These studies showed that B4Q1 is the basic oligomeric unit in polymer chain formation with their ends capped with phenyl rings. The strong and broad sulphonate ion stretching vibration and C-H bending of Q ring is observed at 1120 cm-1 due to the high degree of electron delocalization in PANI polymeric chain. On increasing PTSA concentration minor variations in intensity and position of peaks were observed.
Puzzarini, Cristina [Dipartimento di Chimica " Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo, E-mail: cristina.puzzarini@unibo.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)
2014-04-20
In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm{sup –1} for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%-3%, and 3%-4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for identification of oxirane in Titan's atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz).
Photovoltaic system reliability
Maish, A.B.; Atcitty, C. [Sandia National Labs., NM (United States); Greenberg, D. [Ascension Technology, Inc., Lincoln Center, MA (United States)] [and others
1997-10-01
This paper discusses the reliability of several photovoltaic projects including SMUD`s PV Pioneer project, various projects monitored by Ascension Technology, and the Colorado Parks project. System times-to-failure range from 1 to 16 years, and maintenance costs range from 1 to 16 cents per kilowatt-hour. Factors contributing to the reliability of these systems are discussed, and practices are recommended that can be applied to future projects. This paper also discusses the methodology used to collect and analyze PV system reliability data.
Structural Reliability Methods
Ditlevsen, Ove Dalager; Madsen, H. O.
of structural reliability, including the theoretical basis for these methods. Partial safety factor codes under current practice are briefly introduced and discussed. A probabilistic code format for obtaining a formal reliability evaluation system that catches the most essential features of the nature......The structural reliability methods quantitatively treat the uncertainty of predicting the behaviour and properties of a structure given the uncertain properties of its geometry, materials, and the actions it is supposed to withstand. This book addresses the probabilistic methods for evaluation...
Pole Assignment for Second-Order Systems
CHU, E. K.
2002-01-01
This paper contains some results for pole assignment problems for the second-order system M ẍ(t)+D ẋ(t)+K x (t)=B u (t) . Specifically, Algorithm 0 constructs feedback matrices F1 and F2 such that the closed-loop quadratic pencil Pc( λ)= λ2M+ λ ( D+ BF2)+( K+ BF1) has a desired set of eigenvalues and the associated eigenvectors are well-conditioned. The method is a modification of the SVD-based method proposed by Juang and Maghami [1, 2] which is a second-order adaptation of the well-known robust eigenvalue assignment method by Kautsky et al. [3] for first-order systems. Robustness is achieved by minimising some not-so-well-known condition numbers of the eigenvalues of the closed-loop second-order pencil. We next consider the partial pole assignment problem. In 1997, Datta, Elhay and Ram proposed three biorthogonality relations for eigenvectors of symmetric definite quadratic pencils [4]. One of these relations was used to derive an explicit solution to the partial pole assignment problem by state feedback for the related single-input symmetric definite second-order control system. The solution shed new light on the stabilisation and control of large flexible space structures, for which only one small subset of the spectrum needs to be reassigned while retaining the complementary part of the spectrum. In this paper, the method has been generalised for multi-input and non-symmetric quadratic pencils. Finally, we discuss briefly the output feedback pole assignment problem.
Chaotic vortex induced vibrations
Zhao, J.; Sheridan, J. [Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria 3800 (Australia); Leontini, J. S. [Department of Mechanical and Product Design Engineering, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Lo Jacono, D. [Institut de Mécanique des Fluides de Toulouse (IMFT), CNRS, UPS and Université de Toulouse, 31400 Toulouse (France)
2014-12-15
This study investigates the nature of the dynamic response of an elastically mounted cylinder immersed in a free stream. A novel method is utilized, where the motion of the body during a free vibration experiment is accurately recorded, and then a second experiment is conducted where the cylinder is externally forced to follow this recorded trajectory. Generally, the flow response during both experiments is identical. However, particular regimes exist where the flow response is significantly different. This is taken as evidence of chaos in these regimes.
Anharmonic vibrations in nuclei
Fallot, M; Andrés, M V; Catara, F; Lanza, E G; Scarpaci, J A; Chomaz, Ph.
2003-01-01
In this letter, we show that the non-linearitites of large amplitude motions in atomic nuclei induce giant quadrupole and monopole vibrations. As a consequence, the main source of anharmonicity is the coupling with configurations including one of these two giant resonances on top of any state. Two-phonon energies are often lowered by one or two MeV because of the large matrix elements with such three phonon configurations. These effects are studied in two nuclei, 40Ca and 208Pb.
Lattice Vibrations in Chlorobenzenes:
Reynolds, P. A.; Kjems, Jørgen; White, J. W.
1974-01-01
Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... by consideration of electrostatic forces or by further anisotropy in the dispersion forces not described in the atom‐atom model. Anharmonic effects are shown to be large, but the dominant features in the temperature variation of frequencies are describable by a quasiharmonic model....
Jönsson, Jeppe; Hansen, Lars Pilegaard
1994-01-01
Human motion can cause various types of periodic or transient dynamic loads. The periodic loads are mainly due to jumping, running, dancing, walking and body rocking. Transient loads primarily result from single impulse loads, such as jumping and falling from elevated positions. The response...... concerned with spectator-induced vertical vibrations on grandstands. The idea is to use impulse response analysis and base the load description on the load impulse. If the method is feasable, it could be used in connection with the formulation of requirements in building codes. During the last two decades...
Haoyun Tang
2016-01-01
Full Text Available The irregular wave condition, especially the oblique irregular wave condition, is the actual circumstances when trimaran is sailing in sea. In order to identify the characteristic of the wave-induced hydroelastic vibration in irregular waves, as well as investigate the change of vibration in different oblique irregular wave conditions, trimaran model tests were conducted to measure vibrations, wave impact, and motion under different azimuth and wave height. The vibration on main hull, side hull, and cross-desk is measured and analyzed separately to observe the influence of irregular wave in different structural parts. The longitudinal vibration, transverse vibration, and torsion are also included in the model tests measurement to investigate the relationship between these vibration deformation components and parameters of the irregular waves. The wave-induced hydroelastic vibrations and whipping effect is extracted and analyzed to find influence of whipping and springing on the total vibration. Based on the analysis, the dangerous positions and the critical waves condition is introduced to ensure that the subsequent structural strength assessment is more reliable.
Large scale application of vibration sensors for fan monitoring at commercial layer hen houses.
Chen, Yan; Ni, Ji-Qin; Diehl, Claude A; Heber, Albert J; Bogan, Bill W; Chai, Li-Long
2010-01-01
Continuously monitoring the operation of each individual fan can significantly improve the measurement quality of aerial pollutant emissions from animal buildings that have a large number of fans. To monitor the fan operation by detecting the fan vibration is a relatively new technique. A low-cost electronic vibration sensor was developed and commercialized. However, its large scale application has not yet been evaluated. This paper presents long-term performance results of this vibration sensor at two large commercial layer houses. Vibration sensors were installed on 164 fans of 130 cm diameter to continuously monitor the fan on/off status for two years. The performance of the vibration sensors was compared with fan rotational speed (FRS) sensors. The vibration sensors exhibited quick response and high sensitivity to fan operations and therefore satisfied the general requirements of air quality research. The study proved that detecting fan vibration was an effective method to monitor the on/off status of a large number of single-speed fans. The vibration sensor itself was $2 more expensive than a magnetic proximity FRS sensor but the overall cost including installation and data acquisition hardware was $77 less expensive than the FRS sensor. A total of nine vibration sensors failed during the study and the failure rate was related to the batches of product. A few sensors also exhibited unsteady sensitivity. As a new product, the quality of the sensor should be improved to make it more reliable and acceptable.
An equipment test for grading lumber by transverse vibration technique
Marcelo Rodrigo Carreira
2008-08-01
Full Text Available Due to the great variability of its mechanical properties, the rational use of lumber for structural purposes is directly conditioned to its grading. There are several techniques available for grading structural lumber. The most relevant one is the transverse vibration technique which obtained reliable results in non-destructive evaluation of lumber. The purpose of this work is to present the bases for the mechanical grading of lumber and the results of the calibration test of the frst transverse vibration equipment developed in Brazil. In this research 30 beams of cupiúba (Goupia glabra with nominal dimensions of 5 cm X 10 cm X 300 cm, were used. The tests were accomplished at the Wood and Timber Structures Laboratory (LaMEM of the University of São Paulo (USP. The results showed a strong correlation between the elasticity modulus measured by the static bending test and the one obtained with the transverse vibration equipment, showing the high reliability of the vibration method for the grading of structural lumber. A determination coeffcient (R² of 0.896 was obtained with the Brazilian equipment, showing that it can be used in the grading of lumber.
Localization of Vibrating Noise Sources in Nuclear Reactor Cores
Hultqvist, Pontus
2004-09-01
In this thesis the possibility of locating vibrating noise sources in a nuclear reactor core from the neutron noise has been investigated using different localization methods. The influence of the vibrating noise source has been considered to be a small perturbation of the neutron flux inside the reactor. Linear perturbation theory has been used to construct the theoretical framework upon which the localization methods are based. Two different cases have been considered: one where a one-dimensional one-group model has been used and another where a two-dimensional two-energy group noise simulator has been used. In the first case only one localization method is able to determine the position with good accuracy. This localization method is based on finding roots of an equation and is sensitive to other perturbations of the neutron flux. It will therefore work better with the assistance of approximative methods that reconstruct the noise source to determine if the results are reliable or not. In the two-dimensional case the results are more promising. There are several different localization techniques that reproduce both the vibrating noise source position and the direction of vibration with enough precision. The approximate methods that reconstruct the noise source are substantially better and are able to support the root finding method in a more constructive way. By combining the methods, the results will be more reliable.
Vibration analysis of a bearing integrated sensor module
Suryavanshi, Abhijit P.; Gao, Robert X.
2001-12-01
Implementing a reliable condition monitoring system for bearing fault diagnosis and prognosis poses a big challenge to the industry. This challenge stems from the fact that bearing failure is statistical in nature, and thus contains elements of uncertainty and unpredictability. To achieve high accuracy in bearing diagnosis in spite of this inherent variance, reliable data acquisition and analysis techniques are needed. This paper focuses on the vibration analysis of a wireless transmitter module with an integrated sensor that is embedded into the bearing outer raceway for high signal-to-noise ratio data acquisition. A mechatronic design of the sensor module under severe space constraints is presented. The paper also analyses an optimizing scheme for the placement of sensor module substrate supports to reduce vibration transmitted from the bearing to the on-board electronics.
Off-axis Modal Active Vibration Control Of Rotational Vibrations
Babakhani, B.; de Vries, Theodorus J.A.; van Amerongen, J.
Collocated active vibration control is an effective and robustly stable way of adding damping to the performance limiting vibrations of a plant. Besides the physical parameters of the Active Damping Unit (ADU) containing the collocated actuator and sensor, its location with respect to the
Vibrational relaxation and vibrational cooling in low temperature molecular crystals
Hill, Jeffrey R.; Chronister, Eric L.; Chang, Ta-Chau; Kim, Hackjin; Postlewaite, Jay C.; Dlott, Dana D.
1988-01-01
The processes of vibrational relaxation (VR) and vibrational cooling (VC) are investigated in low temperature crystals of complex molecules, specifically benzene, naphthalene, anthracene, and durene. In the VR process, a vibration is deexcited, while VC consists of many sequential and parallel VR steps which return the crystal to thermal equilibrium. A theoretical model is developed which relates the VR rate to the excess vibrational energy, the molecular structure, and the crystal structure. Specific relations are derived for the vibrational lifetime T1 in each of three regimes of excess vibrational energy. The regimes are the following: Low frequency regime I where VR occurs by emission of two phonons, intermediate frequency regime II where VR occurs by emission of one phonon and one vibration, and high frequency regime III where VR occurs by evolution into a dense bath of vibrational combinations. The VR rate in each regime depends on a particular multiphonon density of states and a few averaged anharmonic coefficients. The appropriate densities of states are calculated from spectroscopic data, and together with available VR data and new infrared and ps Raman data, the values of the anharmonic coefficients are determined for each material. The relationship between these parameters and the material properties is discussed. We then describe VC in a master equation formalism. The transition rate matrix for naphthalene is found using the empirically determined parameters of the above model, and the time dependent redistribution in each mode is calculated.
Tamo, F O Waffeu; Motapon, O; Altevogt, S; Andrianarijaona, V M; Grieser, M; Lammich, L; Lestinsky, M; Motsch, M; Nevo, I; Novotny, S; Orlov, D A; Pedersen, H B; Schwalm, D; Sprenger, F; Urbain, X; Weigel, U; Wolf, A; Schneider, I F
2011-01-01
The collision-energy resolved rate coefficient for dissociative recombination of HD+ ions in the vibrational ground state is measured using the photocathode electron target at the heavy-ion storage ring TSR. Rydberg resonances associated with ro-vibrational excitation of the HD+ core are scanned as a function of the electron collision energy with an instrumental broadening below 1 meV in the low-energy limit. The measurement is compared to calculations using multichannel quantum defect theory, accounting for rotational structure and interactions and considering the six lowest rotational energy levels as initial ionic states. Using thermal equilibrium level populations at 300 K to approximate the experimental conditions, close correspondence between calculated and measured structures is found up to the first vibrational excitation threshold of the cations near 0.24 eV. Detailed assignments, including naturally broadened and overlapping Rydberg resonances, are performed for all structures up to 0.024 eV. Resona...
N. A. Nayak
1960-05-01
Full Text Available The reliability aspect of electronic equipment's is discussed. To obtain optimum results, close cooperation between the components engineer, the design engineer and the production engineer is suggested.
Reliability prediction techniques
Whittaker, B.; Worthington, B.; Lord, J.F.; Pinkard, D.
1986-01-01
The paper demonstrates the feasibility of applying reliability assessment techniques to mining equipment. A number of techniques are identified and described and examples of their use in assessing mining equipment are given. These techniques include: reliability prediction; failure analysis; design audit; maintainability; availability and the life cycle costing. Specific conclusions regarding the usefulness of each technique are outlined. The choice of techniques depends upon both the type of equipment being assessed and its stage of development, with numerical prediction best suited for electronic equipment and fault analysis and design audit suited to mechanical equipment. Reliability assessments involve much detailed and time consuming work but it has been demonstrated that the resulting reliability improvements lead to savings in service costs which more than offset the cost of the evaluation.
The rating reliability calculator
Solomon David J
2004-04-01
Full Text Available Abstract Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program.
Reliability of power connections
BRAUNOVIC Milenko
2007-01-01
Despite the use of various preventive maintenance measures, there are still a number of problem areas that can adversely affect system reliability. Also, economical constraints have pushed the designs of power connections closer to the limits allowed by the existing standards. The major parameters influencing the reliability and life of Al-Al and Al-Cu connections are identified. The effectiveness of various palliative measures is determined and the misconceptions about their effectiveness are dealt in detail.
Assignment and Correspondence Tracking System - Tactical / Operational Reporting
Social Security Administration — Reporting data store for the Assignment and Correspondence Tracking System (ACT). ACT automates the assignment and tracking of correspondence processing within the...
Multidisciplinary System Reliability Analysis
Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)
2001-01-01
The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code, developed under the leadership of NASA Glenn Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multidisciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.
Sensitivity Analysis of Component Reliability
ZhenhuaGe
2004-01-01
In a system, Every component has its unique position within system and its unique failure characteristics. When a component's reliability is changed, its effect on system reliability is not equal. Component reliability sensitivity is a measure of effect on system reliability while a component's reliability is changed. In this paper, the definition and relative matrix of component reliability sensitivity is proposed, and some of their characteristics are analyzed. All these will help us to analyse or improve the system reliability.
ZHOU,Zheng-Yu(周正宇); CHENG,Xue-Li(程学礼); GUO,Li(郭丽)
2002-01-01
On the basis of the computed results got by the Gaussian 94 package at B3LYP/6-311 + +G * * level, the reaction mechanism of CH3O radical with CO has been investigated thoroughly via the vibrational model analysis. And the relationships among the reactants, eight transition states, four intermediates and various products involved this multichannel reaction are elucidated. The vibrational mode analysis shows that the reaction mechanism is reliable.
Free Vibration Analysis of Laminated Composite Beams Using Differential Quadrature Method
冯丽娟; 钟宏志; 郝照平; 吴德隆
2002-01-01
A higher-order theory for laminated composite beams is used to study the free vibration of laminated composite beams, and the differential quadrature method is employed to obtain the numerical solution of the governing differential equations. Free vibration analysis of beams with rectangular cross-section for various combinations of end conditions is studied. The results show that the differential quadrature method is reliable and accurate compared with other available results.
Periodic material-based vibration isolation for satellites
Xinnan Liu
2016-01-01
Full Text Available The vibration environment of a satellite is very severe during launch. Isolating the satellitevibrations during launch will significantly enhance reliability and lifespan, and reduce the weight of satellite structure and manufacturing cost. Guided by the recent advances in solid-state physics research, a new type of satellite vibration isolator is proposed by usingperiodic material that is hence called periodic isolator. The periodic isolator possesses a unique dynamic property, i.e., frequency band gaps. External vibrations with frequencies falling in the frequency band gaps of the periodic isolator are to be isolated. Using the elastodynamics and the Bloch-Floquet theorem, the frequency band gaps of periodic isolators are determined. A parametric study is conducted to provide guidelines for the design of periodic isolators. Based on these analytical results, a finite element model of a micro-satellite with a set of designed periodic isolators is built to show the feasibility of vibration isolation. The periodic isolator is found to be a multi-directional isolator that provides vibration isolation in the three directions.
Vibrational study of a nucleoside analogue with antiviral activity, 5-chloro-2'-deoxyuridine, CDU.
Bailey, L; Navarro, R; Hernanz, A
1999-01-01
The experimental FTIR and FT-Raman spectra of 5-chloro-2'-deoxyuridine have been assigned on the basis of normal coordinate analyses, in the light of observed and calculated wavenumbers and isotopic shifts. The results indicate that virtually all normal modes of IDU involve some degree of vibrational coupling between the chlorouracil base and the deoxyribose moiety.
Active Blade Vibration Control Being Developed and Tested
Johnson, Dexter
2003-01-01
Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.
Adaptive-passive vibration control systems for industrial applications
Mayer, D.; Pfeiffer, T.; Vrbata, J.; Melz, T.
2015-04-01
Tuned vibration absorbers have become common for passive vibration reduction in many industrial applications. Lightly damped absorbers (also called neutralizers) can be used to suppress narrowband disturbances by tuning them to the excitation frequency. If the resonance is adapted in-operation, the performance of those devices can be significantly enhanced, or inertial mass can be decreased. However, the integration of actuators, sensors and control electronics into the system raises new design challenges. In this work, the development of adaptive-passive systems for vibration reduction at an industrial scale is presented. As an example, vibration reduction of a ship engine was studied in a full scale test. Simulations were used to study the feasibility and evaluate the system concept at an early stage. Several ways to adjust the resonance of the neutralizer were evaluated, including piezoelectric actuation and common mechatronic drives. Prototypes were implemented and tested. Since vibration absorbers suffer from high dynamic loads, reliability tests were used to assess the long-term behavior under operational conditions and to improve the components. It was proved that the adaptive systems are capable to withstand the mechanical loads in an industrial application. Also a control strategy had to be implemented in order to track the excitation frequency. The most mature concepts were integrated into the full scale test. An imbalance exciter was used to simulate the engine vibrations at a realistic level experimentally. The neutralizers were tested at varying excitation frequencies to evaluate the tracking capabilities of the control system. It was proved that a significant vibration reduction is possible.
Daniel Zurita-Millán
2016-01-01
Full Text Available Vibration monitoring plays a key role in the industrial machinery reliability since it allows enhancing the performance of the machinery under supervision through the detection of failure modes. Thus, vibration monitoring schemes that give information regarding future condition, that is, prognosis approaches, are of growing interest for the scientific and industrial communities. This work proposes a vibration signal prognosis methodology, applied to a rotating electromechanical system and its associated kinematic chain. The method combines the adaptability of neurofuzzy modeling with a signal decomposition strategy to model the patterns of the vibrations signal under different fault scenarios. The model tuning is performed by means of Genetic Algorithms along with a correlation based interval selection procedure. The performance and effectiveness of the proposed method are validated experimentally with an electromechanical test bench containing a kinematic chain. The results of the study indicate the suitability of the method for vibration forecasting in complex electromechanical systems and their associated kinematic chains.
Gear noise, vibration, and diagnostic studies at NASA Lewis Research Center
Zakrajsek, J. J.; Oswald, F. B.; Townsend, D. P.; Coy, J. J.
1990-01-01
The NASA Lewis Research Center and the U.S. Army Aviation Systems Command are involved in a joint research program to advance the technology of rotorcraft transmissions. This program consists of analytical as well as experimental efforts to achieve the overall goals of reducing weight, noise, and vibration, while increasing life and reliability. Recent analytical activities are highlighted in the areas of gear noise, vibration, and diagnostics performed in-house and through NASA and U.S. Army sponsored grants and contracts. These activities include studies of gear tooth profiles to reduce transmission error and vibration as well as gear housing and rotordynamic modeling to reduce structural vibration and transmission and noise radiation, and basic research into current gear failure diagnostic methodologies. Results of these activities are presented along with an overview of near-term research plans in the gear noise, vibration, and diagnostics area.
Dynamic Assessment of Vibration of Tooth Modification Gearbox Using Grey Bootstrap Method
Hui-liang Wang
2015-01-01
Full Text Available The correlation analysis between gear modification and vibration characteristics of transmission system was difficult to quantify; a novel small sample vibration of gearbox prediction method based on grey system theory and bootstrap theory was presented. The method characterized vibration base feature of tooth modification gearbox by developing dynamic uncertainty, estimated true value, and systematic error measure, and these parameters could indirectly dynamically evaluate the effect of tooth modification. The method can evaluate the vibration signal of gearbox with installation of no tooth modification gear and topological modification gear, respectively, considering that 100% reliability is the constraints condition and minimum average uncertainty is the target value. Computer simulation and experiment results showed that vibration amplitude of gearbox was decreased partly due to topological tooth modification, and each value of average dynamic uncertainty, mean true value, and systematic error measure was smaller than the no tooth modification value. The study provided an important guide for tooth modification, dynamic performance optimization.
An Assessment of Blasting Vibrations: A Case Study on Quarry Operation
Alessandro Giraudi
2009-01-01
Full Text Available Problem statement: One of the major environmental concerns related to blasting operation in mining and civil engineering projects is ground vibration. Approach: This study presented an assessment of ground vibrations caused by the blasting experiments at a marlstone quarry in northern Italy. The primary goal of this study was to determine the vibration level in order to protect dwelling area adjacent to the quarry. Based on the data obtained from the field, a new equation for the level of ground vibrations was proposed. Results: A comparative analysis between the results obtained by the new equation and common empirical predictors currently used in blasting practice was also carried out. Conclusion: Results indicated that a new equation may be used as a reliable predictor of the vibration level for the studied quarry.
The Teacher-Teacher Reliability of the CRI and ERI.
Christine, Charles T.; And Others
Thirty-two children aged 7 to 12 participated in a study to determine the reliability of the Ekwall Reading Inventory (ERI) and the Classroom Reading Inventory (CRI). The children were randomly assigned to take one of the two inventories, which were administered by four different specially trained teachers. The study used a test-retest design, in…
Interrater Reliability of a Team-Scored Electronic Portfolio
Yao, Yuankun; Foster, Karen; Aldrich, Jennifer
2009-01-01
This study applied generalizability theory to investigate the interrater reliability of a team-scored electronic portfolio required for initial teacher certification. The sample consisted of 31 preservice teacher portfolios which were assigned to three groups of portfolio review teams. The review teams, which had received several rounds of…
Vibrations and Stability: Solved Problems
Thomsen, Jon Juel
Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003.......Worked out solutions for exercise problems in J. J. Thomsen 'Vibrations and Stability: Advanced Theory, Analysis, and Tools', Springer, Berlin - Heidelberg, 2003....
Studies Of Vibrations In Gearboxes
Choy, Fred K.; Ruan, Yeefeng F.; Tu, Yu K.; Zakrajsek, James J.; Oswald, Fred B.; Coy, John J.; Townsend, Dennis P.
1994-01-01
Three NASA technical memorandums summarize studies of vibrations in gearboxes. Directed toward understanding and reducing gearbox noise caused by coupling of vibrations from meshing gears, through gear shafts and their bearings, to surfaces of gearbox housings. Practical systems in which understanding and reduction of gearbox noise beneficial include helicopter, car, and truck transmissions; stationary geared systems; and gear-driven actuator systems.
Online Assignment Algorithms for Dynamic Bipartite Graphs
Sahai, Ankur
2011-01-01
This paper analyzes the problem of assigning weights to edges incrementally in a dynamic complete bipartite graph consisting of producer and consumer nodes. The objective is to minimize the overall cost while satisfying certain constraints. The cost and constraints are functions of attributes of the edges, nodes and online service requests. Novelty of this work is that it models real-time distributed resource allocation using an approach to solve this theoretical problem. This paper studies variants of this assignment problem where the edges, producers and consumers can disappear and reappear or their attributes can change over time. Primal-Dual algorithms are used for solving these problems and their competitive ratios are evaluated.
Weekly Fleet Assignment Model and Algorithm
ZHU Xing-hui; ZHU Jin-fu; GONG Zai-wu
2007-01-01
A 0-1 integer programming model for weekly fleet assignment was put forward based on linear network and weekly flight scheduling in China. In this model, the objective function is to maximize the total profit of fleet assignment, subject to the constraints of coverage, aircraft flow balance, fleet size, aircraft availability, aircraft usage, flight restriction, aircraft seat capacity,and stopover. Then the branch-and-bound algorithm based on special ordered set was applied to solve the model. At last, a realworld case study on an airline with 5 fleets, 48 aircrafts and 1 786 flight legs indicated that the profit increase was $1591276 one week and the running time was no more than 4 min, which shows that the model and algorithm are fairly good for domestic airline.
Assigning cause for sudden unexpected infant death.
Hunt, Carl E; Darnall, Robert A; McEntire, Betty L; Hyma, Bruce A
2015-06-01
We have reached a conundrum in assigning cause of death for sudden unexpected infant deaths. We summarize the discordant perspectives and approaches and how they have occurred, and recommend a pathway toward improved consistency. This lack of consistency affects pediatricians and other health care professionals, scientific investigators, medical examiners and coroners, law enforcement agencies, families, and support or advocacy groups. We recommend that an interdisciplinary international committee be organized to review current approaches for assigning cause of death, and to identify a consensus strategy for improving consistency. This effort will need to encompass intrinsic risk factors or infant vulnerability in addition to known environmental risk factors including unsafe sleep settings, and must be sufficiently flexible to accommodate a progressively expanding knowledge base.
Speeding up sequence specific assignment of IDPs
Bermel, Wolfgang [Bruker BioSpin GmbH (Germany); Bertini, Ivano, E-mail: ivanobertini@cerm.unifi.it; Felli, Isabella C.; Gonnelli, Leonardo [CERM, University of Florence (Italy); Kozminski, Wiktor [University of Warsaw, Faculty of Chemistry (Poland); Piai, Alessandro; Pierattelli, Roberta [CERM, University of Florence (Italy); Stanek, Jan [University of Warsaw, Faculty of Chemistry (Poland)
2012-08-15
The characterization of intrinsically disordered proteins (IDPs) by NMR spectroscopy is made difficult by the extensive spectral overlaps. To overcome the intrinsic low-resolution of the spectra the introduction of high-dimensionality experiments is essential. We present here a set of high-resolution experiments based on direct {sup 13}C-detection which proved useful in the assignment of {alpha}-synuclein, a paradigmatic IDP. In particular, we describe the implementation of 4D HCBCACON, HCCCON, HCBCANCO, 4/5D HNCACON and HNCANCO and 3/4D HCANCACO experiments, specifically tailored for spin system identification and backbone resonances sequential assignment. The use of non-uniform-sampling in the indirect dimension and of the H-flip approach to achieve longitudinal relaxation enhancement rendered the experiments very practical.