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Sample records for semi-empirical calculation pre-equilibrium

  1. An Effect of Spin Distributions in the Pre-Equilibrium Process on Cross-Section Calculations

    Science.gov (United States)

    Kawano, Toshihiko; Chadwick, Mark B.

    2004-10-01

    An interpretation of surrogate nuclear reaction measurements requires a modeling of reaction process. It is often assumed that the dominant process is a compound reaction, and the Hauser-Feshbach statistical model is used to calculate decay of intermediate compound state. When the incident energy is high, a pre-equilibrium particle emission occurs before the composite system equilibrates, and this changes the spin distribution of compound nucleus slightly. In the classical framework such as the exciton model it is impossible to calculate the spin distribution of pre-equilibrium process, however, quantum mechanical approaches --- FKK, TUL, NWY --- can give it. We calculate the quantum mechanical pre-equilibrium theory to estimate the spin-distribution of the doorway state, and investigate how this distribution is important for the surrogate reaction technique. The calculated spin-distribution of the pre-equilibrium process is combined with the GNASH compound reaction calculation, and compare with experimental data of γ-ray production cross section using GEANIE at LANSCE for Zr isotopes.

  2. Equilibrium and pre-equilibrium calculations of cross-sections of (p ...

    Indian Academy of Sciences (India)

    Equilibrium and pre-equilibrium calculations of cross-sections of (, ) reactions on 89Y, 90Zr and 94Mo targets used for the production of 89Zr, 90Nb and 94Tc ... Bülent Ecevit University, 67100 Zonguldak, Turkey; Faculty of Arts and Science, Department of Physics, Osmaniye Korkut Ata University, Osmaniye, Turkey ...

  3. Resonance Raman investigation and semi-empirical calculation of the natural carotenoid bixin

    Science.gov (United States)

    de Oliveira, Luiz F. C.; Dantas, Sócrates O.; Velozo, Eudes S.; Santos, Paulo S.; Ribeiro, Mauro C. C.

    1997-11-01

    A detailed resonance Raman investigation of the natural carotenoid bixin (6,6'-diapo-ψ-ψ'-carotenedioic acid monomethyl ester) was undertaken in chloroform solution. The excitation profiles of four fundamentals, one overtone and one combination band were obtained and calculated by the transform method within the standard assumptions. A simple model of displaced harmonic oscillators reproduced the profiles satisfactorily, in contrast to the more elaborate models previously used in the case of 1,3,5-hexatriene. In addition, the time-dependent formalism was used to reproduce the optical absorption spectrum of bixin, and together with the transform method, to calculate the displacement parameters. Use was made of semi-empirical calculations via MOPAC6 and ZINDO to gain further insight into the bond length variations in the excited electronic state.

  4. Electro-Absorption Spectroscopy and Semi-Empirical Molecular Orbital Calculations of Polar Retinoid Analogues

    Science.gov (United States)

    Hashimoto, Hideki; Hattori, Kingo; Yamada, Takashi; Kobayashi, Takayoshi

    2001-08-01

    Nonlinear polarizabilities of a series of polar retinoid analogues were determined experimentally by means of electro-absorption (Stark) spectroscopy. The dependence of the magnitude of nonlinear polarizabilities on polyene chain-lengths as well as on the strength of electron-accepting groups was systematically compared. Semi-empirical molecular orbital calculations using AM1 Hamiltonian (MNDO-AM1 method) could quantitatively predict the second (β) and the third (γ) order nonlinear polarizabilities of the present set of molecules except for the γ value of C20BDCInd. The real and imaginary parts of χ(3)(-ω0,0,ω) spectra were calculated in order to account the figure of merit of the third-order nonlinear optical material.

  5. Investigation of diazepam drug using thermal analyses, mass spectrometry and semi-empirical MO calculation

    Science.gov (United States)

    Zayed, M. A.; Fahmey, M. A.; Hawash, M. F.

    2005-03-01

    In the present work diazepam (Dz) drug was investigated using thermal analyses (TA) measurements (TG/DTG) in comparison with EI mass spectral (MS) fragmentation at 70 and 20 eV. Semi-empirical MO calculations, MNDO procedure, have been carried out on diazepam both as neutral molecule and the corresponding positively charged molecular ion. These include molecular geometry, bond order, charge distribution, heats of formation and ionization energy. Thermogravimetric and kinetic analysis, reveal a high response of the drug to the temperature variation with very fast rate. It is completely decomposed in the temperature range between 204 and 340 °C with average kinetic energy (KE) at 164.69 kJ mol -1. On the other hand, diazepam can easily fragmented at low energy after ionization by electron energy at 9.56 eV. The losses of CO gas molecules followed by chlorine gas from the entity of diazepam (both neutral and charged molecular ion) as the best selected pathway were observed in both mass spectra (MS) and thermal analyses (TA). MNDO calculation was applied to declare both TA and MS observations.

  6. Investigation of naproxen drug using mass spectrometry, thermal analyses and semi-empirical molecular orbital calculation

    Directory of Open Access Journals (Sweden)

    M.A. Zayed

    2017-03-01

    Full Text Available Naproxen (C14H14O3 is a non-steroidal anti-inflammatory drug (NSAID. It is important to investigate its structure to know the active groups and weak bonds responsible for medical activity. In the present study, naproxen was investigated by mass spectrometry (MS, thermal analysis (TA measurements (TG/DTG and DTA and confirmed by semi empirical molecular orbital (MO calculation, using PM3 procedure. These calculations included, bond length, bond order, bond strain, partial charge distribution, ionization energy and heat of formation (ΔHf. The mass spectra and thermal analysis fragmentation pathways were proposed and compared to select the most suitable scheme representing the correct fragmentation pathway of the drug in both techniques. The PM3 procedure reveals that the primary cleavage site of the charged molecule is the rupture of the COOH group (lowest bond order and high strain which followed by CH3 loss of the methoxy group. Thermal analysis of the neutral drug reveals a high response to the temperature variation with very fast rate. It decomposed in several sequential steps in the temperature range 80–400 °C. These mass losses appear as two endothermic and one exothermic peaks which required energy values of 255.42, 10.67 and 371.49 J g−1 respectively. The initial thermal ruptures are similar to that obtained by mass spectral fragmentation (COOH rupture. It was followed by the loss of the methyl group and finally by ethylene loss. Therefore, comparison between MS and TA helps in selection of the proper pathway representing its fragmentation. This comparison is successfully confirmed by MO-calculation.

  7. Pre-Equilibrium Emission in Differential Cross-Section Calculations and Analysis of Experimental Data for 232Th

    Science.gov (United States)

    Tel, E.; Demirkol, I.; Arasoğlu, A.; Şarer, B.

    In this study, neutron-emission spectra produced by (n,xn) reactions on nuclei 232Th have been calculated. Angle-integrated cross-sections in neutron induced reactions on targets 232Th have been calculated at the bombarding energies from 2 MeV to 18 MeV. We have investigated multiple pre-equilibrium matrix element constant from internal transition for 232Th (n,xn) neutron emission spectra. In the calculations, the geometry dependent hybrid model and the cascade exciton model including the effects of pre-equilibrium have been used. Pre-equilibrium direct effects have been examined by using full exciton model. In addition, we have described how multiple pre-equilibrium emissions can be included in the Feshbach-Kerman-Koonin (FKK) fully quantum-mechanical theory. By analyzing (n,xn) reaction on 232Th, with the incident energy from 2 MeV to 18 MeV, the importance of multiple pre-equilibrium emission can be seen clearly. All calculated results have been compared with experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.

  8. Semi-empirical method for calculating the activation energies of the unimolecular thermal decomposition of vinyl ethers

    Science.gov (United States)

    Sargsyan, G. N.; Shakhrokh, B.; Harutyunyan, A. B.

    2015-02-01

    A semi-empirical method is proposed for calculating the activation energy of the unimolecular decomposition of complex compounds using the example of vinyl (ethyl, propyl, and butyl) ethers. The method is based on the concept of the formation of intramolecular hydrogen bonds and the possibility of calculating the energy of deformation of ether molecules upon activation, resulting in the potential surface of the transition state undergoing distortion and the transfer of a hydrogen atom from an alkyl group to a vinyl group. The energy of deformation is calculated using the Mathcad 2001i and MM2 computer programs.

  9. Thermodynamic entropy of organic oxidation in the water environment: experimental evaluation compared to semi-empirical calculation.

    Science.gov (United States)

    Luo, Li; Wang, Xiaochang C; Ngo, Huu Hao; Guo, Wenshan

    2016-11-01

    Residual organic matters in the secondary effluent are usually less biodegradable in terms of the total organic carbon content, and when discharged into a receiving water body, their further decomposition most likely mainly occurs due to chemical oxidation. Using this scenario, a semi-empirical method was previously developed to calculate the thermodynamic entropy of organic oxidation to quantitatively evaluate the impact of organic discharge on the water environment. In this study, the relationship between the entropy increase (ΔSC) and excess organic mass (ΔTOC) was experimentally verified via combustion heat measurement using typical organic chemicals and mixtures. For individual organic chemicals, a linear relationship was detected between ΔSC and ΔTOC with the same proportionality coefficient, 54.0 kJ/g, determined in the previous semi-empirical relationship. For the organic mixtures, a linear relationship was also identified; however, the proportionality coefficient was 69.2 kJ/g, indicating an approximately 28 % increase in the oxidation heat required to decompose the same organic mass. This increase in energy can likely be attributed to the synergistic effects of hydrogen bonding, hydrophobic interactions, π-π interactions, and van der Waals interactions between functional groups of different organic compounds. Intermolecular interactions may result in 17-32 % more dissociation energy for organic mixtures compared to the organic components' chemical structures. Because organics discharged into a water body are always a mixture of organic compounds, the proportionality coefficient obtained using organic mixtures should be adopted to modify the previously proposed semi-empirical equation.

  10. Calculation of bulk etch rate’s semi-empirical equation for polymer track membranes in stationary and dynamic modes

    Directory of Open Access Journals (Sweden)

    A. Mashentseva

    2013-05-01

    Full Text Available One of the most urgent and extremely social problems in environmental safeties area in Kazakhstan is providing the population of all regions of the country with quality drinking water. Development of filter elements based on nuclear track-etch membranes may be considered as one of best solutions this problem. The values of bulk etch rate and activation energy were calculated in view the effect of temperature, alkaline solution concentration as well as stirring effect. The semi-empirical equation of the bulk etch rate for PET track membranes was calculated. As a result of theoretical and experimental studies a semi-empirical equation of the bulk etch rate VB=3.4∙1012∙C2.07∙exp(-0.825/kT for 12 microns PET film, irradiated by ions 84Kr15+ (energy of 1.75 MeV/nucleon at the heavy ion accelerator DC-60 in Astana branch of the INP NNC RK, was obtained. 

  11. Furanose C-C-linked γ-lactones: a combined ESI FTICR MS and semi-empirical calculations study.

    Science.gov (United States)

    Madeira, Paulo J Amorim; Xavier, Nuno M; Rauter, Amélia P; Florêncio, M Helena

    2010-10-01

    Sugars that incorporate the unsaturated carbonyl motif have become important synthetic targets not only as a result of their potential biological properties but also as precursors in the synthesis of many bioactive products. Moreover, little is known about the influence of the γ-lactone moiety in the fragmentation pattern of furanose rings. Therefore, two α,β-unsaturated γ-lactones (butenolides) and two β-hydroxy γ-lactones, C-C linked to a furanose ring were studied using electrospray ionization FTICR mass spectrometry. The behaviour of the protonated and sodiated forms of the compounds under study has been compared considering their structural features. Fragmentation mechanisms were established and ion structures were proposed taking into account the MS(2) and MS(3) experiments, accurate mass measurements and semi-empirical calculations. These inexpensive methods proved to be a valuable resource for proposing protonation sites and for the establishment of fragmentation pathways. Copyright © 2010 John Wiley & Sons, Ltd.

  12. Ab initio calculation of UV-absorption spectra of chlorophyll a: Comparison study between RHF/CIS, TDDFT, and semi-empirical methods

    CERN Document Server

    Suendo, Veinardi

    2011-01-01

    Chlorophyll a is one the most abundant pigment on Earth, which is responsible for trapping the light energy to perform the photosynthesis process in green plants. This molecule is a metal-complex compound that consists of a porphyrins ring with high symmetry that acts as ligands with magnesium as the central ion. Chlorophyll a has been studied for many years from different point of views for both experimental and theoretical interests. In this study, the restricted Hartree-Fock configuration interaction single (RHF/CIS), time-dependent density functional theory (TDDFT) and some semi-empirical methods (CNDO/s and ZINDO) calculations were carried out and compared to reconstruct the UV-Vis absorption spectra of chlorophyll a. In some extend, the calculation results based on a single molecule calculation were succeeded to reconstruct the absorption spectra but required to be scaling and broaden to match the experimental one. Different computational methods (ab initio and semi-empirical) exhibits the differences i...

  13. Ab initio calculation of UV-absorption spectra of chlorophyll a: Comparison study between RHF/CIS, TDDFT, and semi-empirical methods

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    Veinardi Suendo

    2012-07-01

    Full Text Available Chlorophyll a is one the most abundant pigment on Earth that responsible for trapping the light energy to perform photosynthesis in green plants. This molecule has been studied for many years from different point of views in both experimental and theoretical interests. In this study, the restricted Hartree-Fock configuration interaction single (RHF/CIS, time-dependent density functional theory (TDDFT and several semi-empirical methods (CNDO/s and ZINDO calculations were carried out to reconstruct the UV-Vis absorption spectra of chlorophyll a. In some extend, the calculation results based on single molecule approach were succeeded to reconstruct the absorption spectra but required to be rescaled to fit the experimental one. In general, the semi-empirical methods provide better energy scaling factor that closer to unity. However, they lack of vertical transition fine features with respect to the spectrum obtained experimentally. Here, the ab initio calculations provide more complete features, especially the TDDFT at high level of basis sets that also has a good accuracy in the transition energies. The contribution of ground states and excited states orbitals in the main vertical transitions is discussed based on delocalization nature of the wavefunctions and the presence of solvent through polarizable continuum model (PCM.

  14. Semi empirical formula to calculate MSP of relativistic electrons in the range of 940 keV–1020 keV

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    S. Ramesh Babu

    2016-01-01

    Full Text Available A semi empirical formula has been obtained to calculate the Mass stopping power (MSP of relativistic electrons in the energy range of 950 keV–1050 keV, for any material of atomic number or Zeff ranging from 10–82. The MSP of 942 keV and 1016 keV internal conversion electrons of Bi207 are obtained by allowing them to pass through the targets of atomic numbers 13, 29, 47, 50, 79 and 82. The energies of the incident and transmitted electrons are measured using a Si(Li detector coupled to 8 K multi channel analyzer and the MSP has been determined from the measured incident and transmitted energies. The resultant variation of MSP with the atomic number of the material is plotted and best fitted to a first order exponential equation. The results predicted by this semi empirical formula are compared with the NIST-ESTAR database & Batra's formula and found to be in good agreement. Application of this formula to calculate the MSP and effective atomic number of any biological sample or compound is discussed.

  15. Quantitative structure-activity relationship (QSAR) for a series of novel cannabinoid derivatives using descriptors derived from semi-empirical quantum-chemical calculations.

    Science.gov (United States)

    Ferreira, Antonio M; Krishnamurthy, Mathangi; Moore, Bob M; Finkelstein, David; Bashford, Donald

    2009-03-15

    Recent work implicating the cannabinoid receptors in a wide range of human pathologies has intensified the need for reliable QSAR models for drug discovery and lead optimization. Predicting the ligand selectivity of the cannabinoid CB(1) and CB(2) receptors in the absence of generally accepted models for their structures requires a ligand-based approach, which makes such studies ideally suited for quantum-chemical treatments. We present a QSAR model for ligand-receptor interactions based on quantum-chemical descriptors (an eQSAR) obtained from PM3 semi-empirical calculations for a series of phenyl-substituted cannabinoids based on a ligand with known in vivo activity against glioma [Duntsch, C.; Divi, M. K.; Jones, T.; Zhou, Q.; Krishnamurthy, M.; Boehm, P.; Wood, G.; Sills, A.; Moore. B. M., II. J. Neuro-Oncol., 2006, 77, 143] and a set of structurally similar adamantyl-substituted cannabinoids. A good model for CB(2) inhibition (R(2)=0.78) has been developed requiring only four explanatory variables derived from semi-empirical results. The role of the ligand dipole moment is discussed and we propose that the CB(2) binding pocket likely possesses a significant electric field. Describing the affinities with respect to the CB(1) receptor was not possible with the current set of ligands and descriptors, although the attempt highlighted some important points regarding the development of QSAR models.

  16. A semi-empirical method for calculating the pitching moment of bodies of revolution at low Mach numbers

    Science.gov (United States)

    Hopkins, Edward J

    1951-01-01

    A semiempirical method, in which potential theory is arbitrarily combined with an approximate viscous theory, for calculating the aerodynamic pitching moments for bodies of revolution is presented. The method can also be used for calculating the lift and drag forces. The calculated and experimental force and moment characteristics of 15 bodies of revolution are compared.

  17. Semi-empirical calculations of radiative decay rates in Mo II. A comparison between oscillator strength parametrization and core-polarization-corrected relativistic Hartree-Fock approaches

    Science.gov (United States)

    Bouazza, Safa; Palmeri, Patrick; Quinet, Pascal

    2017-09-01

    We present a semi-empirical determination of Mo II radiative parameters in a wide wavelength range 1716-8789 Å. Our fitting procedure to experimental oscillator strengths available in the literature permits us to provide reliable values for a large number of Mo II lines, predicting previously unmeasured oscillator strengths of lines involving 4d45p and 4d35s5p odd-parity configurations. The extracted transition radial integral values are compared with ab-initio calculations: on average they are 0.88 times the values obtained with the basic pseudo-relativistic Hartree Fock method and they agree well when core polarization effects are included. When making a survey of our present and previous studies and including also those given in the literature we observe as general trends a decreasing of transition radial integral values with filling nd shells of the same principal quantum numbers for ndk(n + 1)s → ndk(n + 1)p transitions.

  18. A CALCULATION OF SEMI-EMPIRICAL ONE-ELECTRON WAVE FUNCTIONS FOR MULTI-ELECTRON ATOMS USED FOR ELEMENTARY PROCESS SIMULATION IN NONLOCAL PLASMA

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    M. V. Tchernycheva

    2017-01-01

    Full Text Available Subject of Research. The paper deals with development outcomes for creation method of one-electron wave functions of complex atoms, relatively simple, symmetrical for all atom electrons and free from hard computations. The accuracy and resource intensity of the approach are focused on systematic calculations of cross sections and rate constants of elementary processes of inelastic collisions of atoms or molecules with electrons (ionization, excitation, excitation transfer, and others. Method. The method is based on a set of two iterative processes. At the first iteration step the Schrödinger equation was solved numerically for the radial parts of the electron wave functions in the potential of the atomic core self-consistent field. At the second iteration step the new approximationfor the atomic core field is created that uses found solutions for all one-electron wave functions. The solution optimization for described multiparameter problem is achieved by the use of genetic algorithm. The suitability of the developed method was verified by comparing the calculation results with numerous data on the energies of atoms in the ground and excited states. Main Results. We have created the run-time version of the program for creation of sets of one-electron wave functions and calculation of the cross sections and constants of collisional transition rates in the first Born approximation. The priori available information about binding energies of the electrons for any many-particle system for creation of semi-empirical refined solutions for the one-electron wave functions can be considered at any step of this procedure. Practical Relevance. The proposed solution enables a simple and rapid preparation of input data for the numerical simulation of nonlocal gas discharge plasma. The approach is focused on the calculation of discharges in complex gas mixtures requiring inclusion in the model of a large number of elementary collisional and radiation

  19. Nuclear binding energy using semi empirical mass formula

    Energy Technology Data Exchange (ETDEWEB)

    Ankita,, E-mail: ankitagoyal@gmail.com; Suthar, B. [Department of Physics, Govt. Engineering College, Bikaner-334004 Rajasthan (India)

    2016-05-06

    In the present communication, semi empirical mass formula using the liquid drop model has been presented. Nuclear binding energies are calculated using semi empirical mass formula with various constants given by different researchers. We also compare these calculated values with experimental data and comparative study for finding suitable constants is added using the error plot. The study is extended to find the more suitable constant to reduce the error.

  20. Calculation of pre-equilibrium effects in neutron-induced cross section on 32,34S isotopes using the EMPIRE 3.2 code

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    Yettou Leila

    2015-01-01

    Full Text Available In this study, a new version EMPIRE 3.2 code was used in the cross section calculations of (n,p reactions and in the calculation of proton emission spectra produced by (n,xp reactions. Exciton model predictions combined with the Kalbach angular distribution systematics were used and some parameters such as those of mean free path, cluster emission in terms of Iwamoto-Harada model, optical model potentials of Morillon for neutrons and protons in the energy range up to 20 MeV, level density for spherical nuclei of Gilbert-Cameron model and width fluctuation correction in terms of compound nucleus have been investigated our calculations. The excitation functions and the proton emission spectra for 32,34S nuclei were calculated, discussed and found in good agreement with available experimental data.

  1. Semi-Empirical Aeroacoustic Noise Prediction Code for Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, P.; Migliore, P.

    2003-12-01

    A series of semi-empirical aeroacoustic noise prediction subroutines was written and incorporated into the National Renewable Energy Laboratory's (NREL's) aeroelastic simulation code: FAST[1]. The subroutines predict six different forms of aerodynamically produced noise that were superimposed to calculate the total aeroacoustic signature of an operating wind turbine. This report explains how the code was written, what validation against test data was performed, and how a user can implement the code to predict noise for any given turbine design.

  2. β-Lactam antibiotics. Spectroscopy and molecular orbital (MO) calculations . Part I: IR studies of complexation in penicillin-transition metal ion systems and semi-empirical PM3 calculations on simple model compounds

    Science.gov (United States)

    Kupka, Teobald

    1997-12-01

    IR studies were preformed to determine possible transition metal ion binding sites of penicillin. the observed changes in spectral position and shape of characteristic IR bands of cloxacillin in the presence of transition metal ions (both in solutions and in the solid state) indicate formation of M-L complexes with engagement of -COO - and/or -CONH- functional groups. The small shift of νCO towards higher frequencies rules out direct M-L interaction via β-lactam carbonyl. PM3 calculations on simple model compounds (substituted formamide, cyclic ketones, lactams and substituted monocyclic β-lactams) have been performed. All structures were fully optimized and the calculated bond lengths, angles, heats of formation and CO stretching frequencies were discussed to determine the β-lactam binding sites and to explain its susceptibility towards nucleophilic attack (hydrolysis in vitro) and biological activity. The relative changes of calculated values were critically compared with available experimental data and same correlation between structural parameters and in vivo activity was shown.

  3. Effect of pre-equilibrium spin distribution on neutron induced {sup 150}Sm cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Dashdorj, D.; Mitchell, G.E. [North Carolina State University, Raleigh, NC (United States); Dashdorj, D.; Becker, J.A.; Agvaanluvsan, U.; Wu, C.Y.; Younes, W. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Kawano, T.; Chadwick, M.; Devlin, M.; Fotiades, N.; Nelson, R.O. [3 Los Alamos National Laboratory, Los Alamos, NM (United States); Mitchell, G.E. [Triangle Univ. Nuclear Laboratory, Durham, NC (United States); Cooper, J.R. [USEC Inc., Piketon, OH (United States); Garrett, P.E. [Guelph Univ., Ontario (Canada); Kunieda, S. [Japan Atomic Energy Agency, Tokai, Naka, Ibaraki (Japan)

    2008-07-01

    Prompt {gamma}-ray production cross section measurements were made as a function of incident neutron energy (E{sub n} = 1 to 35 MeV) on an enriched (95.6%) {sup 150}Sm sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Above En {approx} 8 MeV the pre-equilibrium reaction process dominates the inelastic reaction. The spin distribution transferred in pre-equilibrium neutron-induced reactions was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK). These pre-equilibrium spin distributions were incorporated into the Hauser-Feshbach statistical reaction code GNASH and the {gamma}-ray production cross sections were calculated and compared with experimental data. Neutron inelastic scattering populates {sup 150}Sm excited states either by (1) forming the compound nucleus {sup 151}Sm{sup *} and decaying by neutron emission, or (2) by the incoming neutron transferring energy to create a particle-hole pair, and thus initiating the pre-equilibrium process. These two processes produce rather different spin distributions: the momentum transfer via the pre-equilibrium process tends to be smaller than in the compound reaction. This difference in the spin population has a significant impact on the {gamma}-ray de-excitation cascade and therefore in the partial {gamma}-ray cross sections. The difference in the calculated partial {gamma}-ray cross sections using spin distributions with and without pre-equilibrium effects was significant, e.g., for the 558-keV transition between 8{sup +} and 6{sup +} states the calculated partial {gamma}-ray production cross sections changed by 70% at E{sub n} equals 20 MeV with inclusion of the spin distribution of pre-equilibrium process. (authors)

  4. Effect of pre-equilibrium spin distribution on neutron-induced reaction cross sections

    Science.gov (United States)

    Dashdorj, D.; Mitchell, G. E.; Becker, J. A.; Chadwick, M. B.; Devlin, M.; Fotiades, N.; Kawano, T.; Nelson, R. O.; Wu, C. Y.; Garrett, P. E.; Kunieda, S.

    2008-04-01

    Cross section measurements were made of prompt gamma-ray production as a function of neutron energy using the germanium array for neutron induced excitations (GEANIE) at LANSCE. Measuring the prompt reaction gamma rays as a function of incident neutron energy provides more precise understanding of the spins populated by the pre-equilibrium reaction. The effect of the spin distribution in pre-equilibrium reactions has been investigated using the GNASH reaction code. Widely used classical theories such as the exciton model usually assume that the spin distribution of the pre-equilibrium reaction is the same as the spin distribution of the compound nucleus reaction mechanism. In the present approach, the pre-equilibrium reaction spin distribution was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK). This pre-equilibrium spin distribution was incorporated into the GNASH code and the gamma-ray production cross sections were calculated and compared with experimental data. Spin distributions peak at lower spin when calculated with the FKK formulation than with the Compound Nuclear theory. The measured partial gamma-ray cross sections reflect this spin difference. Realistic treatment of the spin distribution improves the accuracy of calculations of gamma-ray production cross sections.

  5. Electron scattering on molecules: search for semi-empirical indications

    Science.gov (United States)

    Fedus, Kamil; Karwasz, Grzegorz P.

    2017-06-01

    Reliable cross-sections for electron-molecule collisions are urgently needed for numerical modeling of various processes important from technological point of view. Unfortunately, a significant progress in theory and experiment over the last decade is not usually accompanied by the convergence of cross-sections measured at different laboratories and calculated with different methods. Moreover the most advanced contemporary theories involve such large basis sets and complicated equations that they are not easily applied to each specific molecule for which data are needed. For these reasons the search for semi-empirical indications in angular and energy dependencies of scattering cross-section becomes important. In this paper we make a brief review of the applicability of the Born-dipole approximation for elastic, rotational, vibrational and ionization processes that can occur during electron-molecule collisions. We take into account the most recent experimental findings as the reference points. Contribution to the Topical Issue "Atomic and Molecular Data and Their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, and Grzegorz Karwasz.

  6. The relationship between the semi-empirical and the embedded ...

    African Journals Online (AJOL)

    The connection established between the semi-empirical tight-binding potential and embedded atom model was employed to simulate the properties of the fcc metals. The attractive part of the potentials is of the form of the nth power dependence on the effective coordination (or second moment of the local density of states) ...

  7. Effect of pre-equilibrium spin distribution on neutron induced 150Sm cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Dashdorj, D; Kawano, T; Mitchell, G E; Becker, J A; Agvaanluvsan, U; Chadwick, M; Cooper, J; Devlin, M; Fotiades, N; Garrett, P E; Kunieda, S; Nelson, R O; Wu, C Y; Younes, W

    2007-04-16

    Prompt {gamma}-ray production cross section measurements were made as a function of incident neutron energy (En = 1 to 35 MeV) on an enriched (95.6%) {sup 150}Sm sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center (LANSCE) facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Above E{sub n} {approx} 8 MeV the pre-equilibrium reaction process dominates the inelastic reaction. The spin distribution transferred in pre-equilibrium neutron-induced reactions was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK). These preequilibrium spin distributions were incorporated into the Hauser-Feshbach statistical reaction code GNASH and the {gamma}-ray production cross sections were calculated and compared with experimental data. Neutron inelastic scattering populates 150Sm excited states either by (1) forming the compound nucleus {sup 151}Sm* and decaying by neutron emission, or (2) by the incoming neutron transferring energy to create a particle-hole pair, and thus initiating the pre-equilibrium process. These two processes produce rather different spin distributions: the momentum transfer via the pre-equilibrium process tends to be smaller than in the compound reaction. This difference in the spin population has a significant impact on the {gamma}-ray de-excitation cascade and therefore in the partial {gamma}-ray cross sections. The difference in the partial {gamma}-ray cross sections using spin distributions with and without preequilibrium effects was significant, e.g., for the 558-keV transition between 8{sup +} and 6{sup +} states the calculated partial {gamma}-ray production cross sections changed by 70% at E{sub n} = 20 MeV with inclusion of the spin distribution of pre-equilibrium process.

  8. Data mining of Ti-Al semi-empirical parameters for developing reduced order models

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Scott R. [Department of Materials Science and Engineering and Institute for Combinatorial Discovery, Iowa State University, Ames, IA 50011 (United States); Aourag, Hafid [Department of Physics, University Abou Bakr Belkaid, Tlemcen 13000 (Algeria); Rajan, Krishna, E-mail: krajan@iastate.ed [Department of Materials Science and Engineering and Institute for Combinatorial Discovery, Iowa State University, Ames, IA 50011 (United States)

    2011-05-15

    A focus of materials design is determining the minimum amount of information necessary to fully describe a system, thus reducing the number of empirical results required and simplifying the data analysis. Screening descriptors calculated through a semi-empirical model, we demonstrate how an informatics-based analysis can be used to address this issue with no prior assumptions. We have developed a unique approach for identifying the minimum number of descriptors necessary to capture all the information of a system. Using Ti-Al alloys of varying compositions and crystal chemistries as the test bed, 5 of the 21 original descriptors from electronic structure calculations are found to capture all the information from the calculation, thereby reducing the structure-chemistry-property search space. Additionally, by combining electronic structure calculations with data mining, we classify the systems by chemistries and structures, based on the electronic structure inputs, and thereby rank the impact of change in chemistry and crystal structure on the electronic structure. -- Research Highlights: {yields} We developed an informatics-based methodology to minimize the necessary information. {yields} We applied this methodology to descriptors from semi-empirical calculations. {yields} We developed a validation approach for maintaining information from screening. {yields} We classified intermetallics and identified patterns of composition and structure.

  9. Research on the quantum multistep theory for pre-equilibrium nuclear reaction

    CERN Document Server

    Su Zong Di; Abdurixit, A; Wang Shu Nuan; Li Bao Xian; Huang Zhong; Liu Jian Feng; Zhang Benai; Zhu Yao Yin; Li Zhi Wen

    2002-01-01

    The Feshbach-Kerman-Koonin (FKK) quantum multistep theory of the pre-equilibrium reaction is further improved and perfected. A unified description for the multistep compound (MSC) process of the pre-equilibrium reaction and the compound nucleus (CN) process of full equilibrium reaction can be presented. This formula can integrate MSC and CN theories with the optical model and Hauser-Feshbach formula, and can get self-consistent expression. In multistep direct (MSD) process of the pre-equilibrium reaction, the mu-step cross section can be expressed by the convolution of mu one-step cross section. And the one step cross section for continuum can be written as the product of an averaged DWBA matrix element and the state density. For calculating the multistep direct reaction cross section, two methods, the state densities and full microscopic model, are used and compared. Some typical experiments are analyzed by using the work mentioned above. The calculated results are reasonable and in good agreement with the e...

  10. Semi-Empirical Predictions on the Structure and Properties of ent-Kaurenoic Acid and Derivatives

    Directory of Open Access Journals (Sweden)

    Jose Isagani B. Janairo

    2011-01-01

    Full Text Available The physicochemical properties of ent- kaurenoic acid model derivatives, which possibly influence its therapeutic application, were calculated. Results revealed that the molecule possess favourable attributes which renders it possible to be considered as a drug lead only that its very hydrophobic nature can result to poor bioavailabilty, low absorption and poor systemic circulation. In silico simulations revealed that this setback can be overcome by introduction of hydroxyl group to the tertiary carbon of ent-kaurenoic acid employing m-CPBA catalyzed hydroxylation, thus, unleashing its full drug potency. Moreover, molecular similarity analyses derived from semi-empirical calculations between ent-kaurenoic acid and a set of kaurane diterpenoids showed differences in hydrophobic complementarity, size and electronic properties despite possessing nearly identical molecular frameworks, thus, arriving in a generalization for their observed mechanistic differences on acting on different targets.

  11. Holocene sea level, a semi-empirical contemplation

    Science.gov (United States)

    Bittermann, Klaus; Kemp, Andrew; Vermeer, Martin; Rahmstorf, Stefan

    2017-04-01

    Holocene eustatic sea level from approximately -10,000-1800 CE was characterized by an increase of about 60 m, with the rate progressively slowing down until sea level almost stabilizes between 500-1800 CE. Global and northern-hemisphere temperatures rose from the last glacial termination until the 'Holocene Optimum'. From there, up to the start of the recent anthropogenic rise, they almost steadily decline. How are the sea-level and temperature evolutions linked? We investigate this with a semi-empirical sea-level model. We found that, due to the nature of Milankovitch forcing, northern-hemisphere temperature (we used the Greenland temperature by Vinther et al., 2009) is a better model driver than global mean temperature because the evolving mass of northern-hemisphere land ice was the dominant cause of Holocene global sea-level trends. The adjustment timescale for this contribution is 1200 years (900-1500 years; 90% confidence interval). To fit the observed sea-level history, the model requires a small additional constant rate (Bittermann 2016). This rate turns out to be of the same order of magnitude as reconstructions of Antarctic sea-level contributions (Briggs et al. 2014, Golledge et al. 2014). In reality this contribution is unlikely to be constant but rather has a dominant timescale that is large compared to the time considered. We thus propose that Holocene sea level can be described by a linear combination of a temperature driven rate, which becomes negative in the late Holocene (as Northern Hemisphere ice masses are diminished), and a positive, approximately constant term (possibly from Antarctica), which starts to dominate from the middle of the Holocene until the start of industrialization. Bibliography: Bittermann, K. 2016. Semi-empirical sea-level modelling. PhD Thesis University of Potsdam. Briggs, R.D., Pollard, D., & Tarasov, L. 2014. A data-constrained large ensemble analysis of Antarctic evolution since the Eemian. Quaternary science reviews

  12. Pre-equilibrium (exciton) model and the heavy-ion reactions with cluster emission

    CERN Document Server

    Betak, E

    2015-01-01

    We bring the possibility to include the cluster emission into the statistical pre-equilibrium (exciton) model enlarged for considering also the heavy ion collisions. At this moment, the calculations have been done without treatment of angular momentum variables, but all the approach can be straightforwardly applied to heavy-ion reactions with cluster emission including the angular momentum variables. The direct motivation of this paper is a possibility of producing the superdeformed nuclei, which are easier to be detected in heavy-ion reactions than in those induced by light projectiles (nucleons, deuterons, $\\alpha$-particles).

  13. Comparison of transition densities in the DDHMS model of pre-equilibrium emission

    Energy Technology Data Exchange (ETDEWEB)

    Brito, L.; Carlson, B. V. [Depto. de Física, Instituto Tecnológico de Aeronáutica, São José dos Campos, SP (Brazil)

    2014-11-11

    The DDHMS (double differential hybrid Monte Carlo simulation) model treats nucleon-induced pre-equilibrium reactions as a series of particle-particle and particle-hole interactions in the space of energy and angle. This work compares spectra obtained within the model using diferent approximations to the density of accessible states. The calculations are performed with the EMPIRE reaction model code, a modular system containing several nuclear reaction models that permits a fairly complete descritpion of the reaction, from elastic scattering and absorption through the pre-equilbrium stage to the final decay by statistical emission.

  14. Application of a semi-empirical model for the evaluation of transmission properties of barite mortar.

    Science.gov (United States)

    Santos, Josilene C; Tomal, Alessandra; Mariano, Leandro; Costa, Paulo R

    2015-06-01

    The aim of this study was to estimate barite mortar attenuation curves using X-ray spectra weighted by a workload distribution. A semi-empirical model was used for the evaluation of transmission properties of this material. Since ambient dose equivalent, H(⁎)(10), is the radiation quantity adopted by IAEA for dose assessment, the variation of the H(⁎)(10) as a function of barite mortar thickness was calculated using primary experimental spectra. A CdTe detector was used for the measurement of these spectra. The resulting spectra were adopted for estimating the optimized thickness of protective barrier needed for shielding an area in an X-ray imaging facility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The density of available states of the DDHMS pre-equilibrium model

    Directory of Open Access Journals (Sweden)

    Mega D.F.

    2012-02-01

    Full Text Available Griffin's exciton model of pre-equilibrium emission and Blann's hybrid model have proven extremely successful in describing the energy dependence and, to a certain extent the angular dependence, of nucleon and composite particle emission in preequilibrium reactions. However, the conceptual basis of these models was called into question by Bisplinghoff already some time ago. In response to Bisplinghoff, Blann proposed the hybrid Monte Carlo simulation model (HMS, which uses only the densities of available states for creation and decay of single particle-hole pairs. The model was later extended, in collaboration with Chadwick, to the double-differential HMS, which we call the DDHMS. This extension is based on the Chadwick-Obložinský prescription for pproximating the energy-angular distribution of available two-particle-one-hole states. Here, we show how this distribution can be calculated exactly.

  16. Assessment of semi-empirical potentials for the U-Si system

    Energy Technology Data Exchange (ETDEWEB)

    Baskes, Michael I. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Andersson, Anders David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-03

    Accident tolerant fuels (ATF) are being developed in response to the Fukushima Daiichi accident in Japan. One of the options being pursued is U-Si fuels, such as the U3Si2 and U3Si5 compounds, which benefit from high thermal conductivity (metallic) compared to the UO2 fuel (semi-conductor) used in current Light Water Reactors (LWRs). The U-Si fuels also have higher fissile density. In order to perform meaningful engineering scale nuclear fuel performance simulations, the material properties of the fuel, including the response to irradiation environments, must be known. Unfortunately, the data available for U-Si fuels are rather limited, in particular for the temperature range where LWRs would operate. The ATF HIP is using multi-scale modeling and simulations to address this knowledge gap. Even though Density Functional Theory (DFT) calculations can provide useful answers to a subset of problems, they are computationally too costly for many others, including properties governing microstructure evolution and irradiation effects. For the latter, semi-empirical potentials are typically used. Unfortunately, there is currently no potential for the U-Si system. In this brief report we present initial results from the development of a U-Si semi-empirical potential based on the Modified Embedded Atom Method (MEAM). The potential should reproduce relevant parts of the U-Si phase diagram as well as defect properties important in irradiation environments. This work also serves as an assessment of the general challenges associated with the U-Si system, which will be valuable for the efforts to develop a U-Si Tersoff potential undertaken by Idaho National Laboratory (also part of the ATF HIP). Going forward the main potential development activity will reside at INL and the work presented here is meant to provide input data and guidelines for that activity. The main focus of our work is on the U3Si2 and U3Si5

  17. A Semi-Empirical Emissivity Model for use in Passive Microwave Precipitation Retrievals Over Land

    Science.gov (United States)

    Ringerud, S.; Kummerow, C. D.; Peters-Lidard, C. D.

    2013-12-01

    The upcoming NASA Global Precipitation Measurement Mission (GPM) offers the opportunity for greatly increased understanding of global rainfall and the hydrologic cycle. The GPM algorithm team has made improvement in passive microwave remote sensing of precipitation over land a priority for this mission, and developed a framework allowing for algorithm advancement for individual land surface types as new techniques are developed. An accurate understanding of land surface emissivity in terms of associated surface properties is necessary for any physically-based retrieval scheme over land. This is a complex problem for passive microwave sensors, as the emissivity of land surfaces in the microwave region is large and dynamic, making it difficult to distinguish hydrometeor signal from the highly variable surface emission. In an effort to understand and model the surface emissivity, a semi-empirical technique is developed and tested over the US Southern Great Plains (SGP) area. A physical model is used to calculate emissivity at the 10 GHz frequency, combining contributions from the underlying soil as well as vegetation layers, including the dielectric and roughness effects of each medium. Radiative transfer through each layer is calculated. Adjustments are added for post-precipitation surface water emissivity effects on both the soil and water-coated vegetation. A 5-year dataset of retrieved emissivities from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is employed for calculation of a robust set of channel covariances. These covariances, combined with the modeled 10 GHz emissivities, provide emissivity values for each AMSR-E channel, which are then used to compute top of the atmosphere brightness temperatures (TBs). Initial results comparing these calculated TBs to observed values show correlations of 0.87-0.97, with the lowest correlations appearing in the highest frequencies of the microwave window region. Such a modeling system could

  18. QSAR Analysis of Benzothiazole Derivatives of Antimalarial Compounds Based On AM1 Semi-Empirical Method

    Directory of Open Access Journals (Sweden)

    Ruslin Hadanu

    2015-03-01

    Full Text Available Quantitative Structure and Activity Relationship (QSAR analysis of 13 benzothiazoles derivatives compound as antimalarial compounds have been performed using electronic descriptor of the atomic net charges (q, dipole moment (μ, ELUMO, EHOMO and polarizability (α. The electronic structures as descriptors were calculated through HyperChem for Windows 7.0 using AM1 semi-empirical method. The descriptors were obtained through molecules modeling to get the most stable structure after geometry optimization step. The antimalarial activity (IC50 were taken from literature. The best model of QSAR model was determined by multiple linear regression approach and giving equation of QSAR: Log IC50 = 23.527 + 4.024 (qC4 + 273.416 (qC5 + 141.663 (qC6 – 0.567 (ELUMO – 3.878 (EHOMO– 2.096 (α. The equation was significant on the 95% level with statistical parameters: n = 13, r = 0.994, r2 = 0.987, SE = 0.094, Fcalc/Ftable = 11.212, and gave the PRESS = 0.348. Its means that there were only a relatively few deviations between the experimental and theoretical data of antimalarial activity.

  19. A semi-empirical approach to determine gamma activities (Bqkg{sup -1}) in environmental cylindrical samples

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, Daniel Francisco [Universidad Simon Bolivar (USB), Apartado 89000, Caracas (Venezuela)], E-mail: palacios@usb.ve; Alfonso, Juan A. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 21827, Caracas (Venezuela); Barros, Haydn [Universidad Simon Bolivar (USB), Apartado 89000, Caracas (Venezuela); LaBrecque, John J.; Perez, Karla [Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 21827, Caracas (Venezuela); Lossada, Marian R. [Direccion de Investigacion y Postgrado, Universidad Maritima del Caribe (UMC), Caracas (Venezuela)

    2008-01-15

    A semi-empirical method to determine radionuclide concentrations in large environmental samples without the use of reference material and avoiding the typical complexity of Monte-Carlo codes is proposed. The calculation of full-energy peak efficiencies was carried out from a relative efficiency curve (obtained from the gamma spectra data), and the geometric (simulated by Monte-Carlo), absorption, sample and intrinsic efficiencies for energies between 130 and 3000 keV. The absorption and sample efficiencies were determined from the mass absorption coefficients, whereas the intrinsic efficiency was approximated by an empirical function. The deviations between calculated and experimental efficiencies for a reference material in most cases are less than 10%. Radionuclide activities in marine sediment samples calculated by the proposed method and by the experimental comparative method were not significantly different. This new method can be used for routine environmental monitoring when uncertainties up to 10% are acceptable.

  20. Intermolecular interactions in the condensed phase: Evaluation of semi-empirical quantum mechanical methods

    Science.gov (United States)

    Christensen, Anders S.; Kromann, Jimmy C.; Jensen, Jan H.; Cui, Qiang

    2017-10-01

    To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy in solution is computed via a thermodynamic cycle that integrates dimer binding energy in the gas phase at the coupled cluster level and solute-solvent interaction with density functional theory; the estimated uncertainty of such calculated interaction energy is ±1.5 kcal/mol. The dataset is used to benchmark the performance of a set of semi-empirical quantum mechanical (SQM) methods that include DFTB3-D3, DFTB3/CPE-D3, OM2-D3, PM6-D3, PM6-D3H+, and PM7 as well as the HF-3c method. We find that while all tested SQM methods tend to underestimate binding energies in the gas phase with a root-mean-squared error (RMSE) of 2-5 kcal/mol, they overestimate binding energies in the solution phase with an RMSE of 3-4 kcal/mol, with the exception of DFTB3/CPE-D3 and OM2-D3, for which the systematic deviation is less pronounced. In addition, we find that HF-3c systematically overestimates binding energies in both gas and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need to be treated in a balanced fashion.

  1. A semi-empirical model for predicting crown diameter of cedrela ...

    African Journals Online (AJOL)

    A semi-empirical model relating age and breast height has been developed to predict individual tree crown diameter for Cedrela odorata (L) plantation in the moist evergreen forest zones of Ghana. The model was based on field records of 269 trees, and could determine the crown cover dynamics, forecast time of canopy ...

  2. History of the solar particle event radiation doses on-board aeroplanes using a semi-empirical model and Concorde measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lantos, P.; Fuller, N

    2003-07-01

    Measurements during solar particle events with dosemeters flying permanently on-board Concorde are used to develop a semi-empirical model, called SiGLE. The model is intended to calculate, for a given flight plan, the dose equivalent received during a solar particle event observed with ground-based neutron monitors. It is successfully in operation in the SIEVERT computerised system intended to improve monitoring of radiation dose received by aircrews, in application to a European Directive. The semi-empirical model is applied to evaluate, for most exposed routes, the radiation doses corresponding to the GLEs observed since 1942 with ion chambers or neutron monitors. The results for the largest GLEs observed in the past are discussed in terms of radiation risk, and guidelines are suggested concerning possible alerts to the aeroplanes in case of events of exceptional magnitude. (author)

  3. Clustering Pre-equilibrium Model Analysis for Nucleon-induced Alpha-particle Spectra up to 200 MeV

    Directory of Open Access Journals (Sweden)

    Watanabe Y.

    2012-02-01

    Full Text Available The clustering exciton model of Iwamoto and Harada is applied to the analysis of pre-equilibrium (N, xα energy spectra for medium-to-heavy nuclei up to 200 MeV. In this work, we calculate alpha-particle formation factors without any approximations that appear in the original model. The clustering process is also considered in both the primary and second pre-equilibrium emissions. We optimize the exciton and the clustering model parameters simultaneously by looking at the experimental (N, xN and (N, xα energy spectra. The experimental alpha-particle spectra are well reproduced with a unique set of clustering model parameters, which is independent of incident neutrons/protons. The present analysis also implies that the clustering model parameter is not so different between the medium and heavy nuclei. Our calculations reproduce experimental data generally well up to the incident energy of ~150 MeV, but underestimations are seen above this energy.

  4. Equilibrium and pre-equilibrium emissions in proton-induced ...

    Indian Academy of Sciences (India)

    transmutation rates, nuclear heating, radiation damage etc. The proton-induced nuclear reaction cross-section data are very important for the production of medical radioisotopes using cyclotrons [2–5]. Nuclear data evaluation is generally carried out on the basis of experimental data and theoretical model calculations.

  5. Systematic study of neutron capture including the compound, pre-equilibrium, and direct mechanisms

    Science.gov (United States)

    Xu, Y.; Goriely, S.; Koning, A. J.; Hilaire, S.

    2014-08-01

    The neutron capture reaction is investigated. The three major reaction mechanisms, namely, compound-nucleus capture (CNC), pre-equilibrium capture (PEC), and direct capture (DIC), are considered on the basis of the Hauser-Feshbach model, the exciton model, and potential model, respectively. The three mechanisms are treated simultaneously and consistently, i.e, they are obtained on the basis of the same nuclear ingredients, such as the optical potential and nuclear-level densities. In this framework, the three components are calculated on the same footing and represent partial fluxes of the same total reaction cross section. The total neutron-capture cross sections and astrophysical reaction rates are calculated within the updated modern reaction code talys for about 8000 nuclei with 8≤Z≤110 lying between the proton and neutron drip lines. The nuclear-structure ingredients involved in the calculation are determined from experimental data whenever available and, if not, from global microscopic nuclear models. For the targets with mass number A >26, a fair agreement between the computed total-capture cross sections and experimental data is found but, for the lightest nuclei, only the predicted DIC cross sections reproduce the experimental results satisfactorily. Significant and even dominant contribution to the total reaction rate comes from the DIC component for neutron-rich nuclei, especially in the Z =50-70 region. The impact of the newly determined reaction rates on the r process abundances resulting from the ejection of matter in neutrino-driven winds or the decompression of neutron star matter is investigated.

  6. Simulation of Strong Ground Motion of the 2009 Bhutan Earthquake Using Modified Semi-Empirical Technique

    Science.gov (United States)

    Sandeep; Joshi, A.; Lal, Sohan; Kumar, Parveen; Sah, S. K.; Vandana; Kamal

    2017-09-01

    On 21st September 2009 an earthquake of magnitude (M w 6.1) occurred in the East Bhutan. This earthquake caused serious damage to the residential area and was widely felt in the Bhutan Himalaya and its adjoining area. We estimated the source model of this earthquake using modified semi empirical technique. In the rupture plane, several locations of nucleation point have been considered and finalised based on the minimum root mean square error of waveform comparison. In the present work observed and simulated waveforms has been compared at all the eight stations. Comparison of horizontal components of actual and simulated records at these stations confirms the estimated parameters of final rupture model and efficacy of the modified semi-empirical technique (Joshi et al., Nat Hazards 64:1029-1054, 2012b) of strong ground motion simulation.

  7. Aeroelastic loads prediction for an arrow wing. Task 2: Evaluation of semi-empirical methods

    Science.gov (United States)

    Wery, A. C.; Kulfan, R. M.; Manro, M. E.

    1983-01-01

    The development and evaluation of a semi empirical method to predict pressure distributions on a deformed wing by using an experimental data base in addition to a linear potential flow solution is described. The experimental data accounts for the effects of aeroelasticity by relating the pressures to a parameter which is influenced by the deflected shape. Several parameters were examined before the net leading edge suction coefficient was selected as the best.

  8. Permeability-driven selection in a semi-empirical protocell model

    DEFF Research Database (Denmark)

    Piedrafita, Gabriel; Monnard, Pierre-Alain; Mavelli, Fabio

    2017-01-01

    , together with plausible synthetic pathways that might have led, abiotically, to such a minimalist scenario. However, in addition to molecular kinetics or molecular evolutionary dynamics, other physical and chemical constraints (like compartmentalization, differential diffusion, selective transport, osmotic...... their 'system-level' implications. In particular, an experimental study on the permeability of prebiotic vesicle membranes composed of binary lipid mixtures allows us to construct a semi-empirical model where protocells are able to reproduce and undergo an evolutionary process based on their coupling...

  9. Test/semi-empirical analysis of a carbon/epoxy fabric stiffened panel

    Science.gov (United States)

    Spier, E. E.; Anderson, J. A.

    1990-01-01

    The purpose of this work-in-progress is to present a semi-empirical analysis method developed to predict the buckling and crippling loads of carbon/epoxy fabric blade stiffened panels in compression. This is a hand analysis method comprised of well known, accepted techniques, logical engineering judgements, and experimental data that results in conservative solutions. In order to verify this method, a stiffened panel was fabricated and tested. Both the best and analysis results are presented.

  10. Pre-equilibrium effects in charge-asymmetric low-energy reactions

    Directory of Open Access Journals (Sweden)

    H. Zheng

    2017-06-01

    Full Text Available We study the pre-equilibrium dipole response in the charge-asymmetric reaction Sn132+Ni58 at Elab=10 MeV/A, within a semi-classical transport model employing effective interactions for the nuclear mean-field. In particular, we adopt the recently introduced SAMi-J Skyrme interactions, whose parameters are specifically tuned to improve the description of spin–isospin properties of nuclei. Within the same framework, we also discuss pre-equilibrium nucleon emission. Our results show that both mechanisms, i.e., pre-equilibrium dipole oscillations and nucleon emission, are sensitive to the symmetry energy below the saturation density ρ0 (in the range 0.6ρ0−ρ0, to the momentum dependence of the mean-field potential and to the nucleon–nucleon cross section. Finally, a correlation analysis is applied to examine the impact of the model parameters on observables of experimental interest.

  11. 16O+65Cu and 19F+62Ni at 16 AMeV reaction mechanisms comparison: Pre-equilibrium vs. clustering

    Science.gov (United States)

    Mabiala, J.; Fabris, D.; Gramegna, F.; Marchi, T.; Cicerchia, M.; Cinausero, M.; Degerlier, M.; Fotina, O. V.; Kravchuk, V. L.; D'Agostino, M.; Morelli, L.; Baiocco, G.; Bruno, M.; Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Olmi, A.; Pasquali, G.; Piantelli, S.; Poggi, G.; Valdré, S.; Vardaci, E.

    2017-11-01

    Cluster structure effects in nuclei have been investigated looking to the pre-equilibrium particles emitted in the ^{16} O+ ^{65} Cu and ^{19} F+ ^{62} Ni reactions at the same beam velocity of 16 AMeV which lead to the same ^{81} Rb* compound nucleus. Despite the slight difference in excitation energies, the same fast emission should be expected from the two systems; unless major effects induced by the projectile's cluster structure, which should influence the pre-equilibrium α -particle production during the non-equilibrium stage, are present. The experimental data have been collected with the GARFIELD+RCo apparatus at Laboratori Nazionali di Legnaro. In this contribution we report on the preliminary spectra of light-charged particles, obtained in coincidence with evaporation residues, and their comparison with the results obtained from model calculations.

  12. Study of the terahertz spectra of crystalline materials using NDDO semi-empirical methods: polyethylene, poly(vinylidene fluoride) form II and $\\alpha$-D-glucose

    CERN Document Server

    Chamorro-Posada, P

    2016-01-01

    Semi-empirical quantum chemistry methods offer a very interesting compromise between accuracy and computational load. In order to assess the performance of NDDO methods in the interpretation of terahertz spectra, the low frequency vibration modes of three crystalline materials, namely, polyethylene, poly(vinylidene fluoride) form II and $\\alpha$-D-glucose have been studied using the PM6 and PM7 Hamiltonians and the results have been compared with the experimental data and former calculations. The results show good qualitative or semi-quantitative agreement with the experimentally observed terahertz spectra.

  13. A semi-empirical potential for the statics and dynamics of covalent carbon systems

    Science.gov (United States)

    Burgos, E.; Halac, E.; Bonadeo, H.

    1998-12-01

    The statics and dynamics of different carbon crystals and compounds were studied using a semi-empirical potential, of the form proposed by Tersoff with the addition of a torsion-like term, proposed to overcome the inadequacy of the original potential to describe the dynamics of these systems. The potential parameters were refined by fitting the observed properties of graphite and diamond; the r.m.s. deviations for the vibrational frequencies were reduced by a factor of about 3. The potential is applied to systems not included in the fit, yielding excellent agreement with experimental data on Lonsdaleite and fullerenes.

  14. Soil Moisture Estimate Under Forest Using a Semi-Empirical Model at P-Band

    Science.gov (United States)

    Truong-Loi, My-Linh; Saatchi, Sassan; Jaruwatanadilok, Sermsak

    2013-01-01

    Here we present the result of a semi-empirical inversion model for soil moisture retrieval using the three backscattering coefficients: sigma(sub HH), sigma(sub VV) and sigma(sub HV). In this paper we focus on the soil moisture estimate and use the biomass as an ancillary parameter estimated automatically from the algorithm and used as a validation parameter, We will first remind the model analytical formulation. Then we will sow some results obtained with real SAR data and compare them to ground estimates.

  15. Estimation of Aboveground Biomass in Alpine Forests: A Semi-Empirical Approach Considering Canopy Transparency Derived from Airborne LiDAR Data

    Directory of Open Access Journals (Sweden)

    Martin Rutzinger

    2010-12-01

    Full Text Available In this study, a semi-empirical model that was originally developed for stem volume estimation is used for aboveground biomass (AGB estimation of a spruce dominated alpine forest. The reference AGB of the available sample plots is calculated from forest inventory data by means of biomass expansion factors. Furthermore, the semi-empirical model is extended by three different canopy transparency parameters derived from airborne LiDAR data. These parameters have not been considered for stem volume estimation until now and are introduced in order to investigate the behavior of the model concerning AGB estimation. The developed additional input parameters are based on the assumption that transparency of vegetation can be measured by determining the penetration of the laser beams through the canopy. These parameters are calculated for every single point within the 3D point cloud in order to consider the varying properties of the vegetation in an appropriate way. Exploratory Data Analysis (EDA is performed to evaluate the influence of the additional LiDAR derived canopy transparency parameters for AGB estimation. The study is carried out in a 560 km2 alpine area in Austria, where reference forest inventory data and LiDAR data are available. The investigations show that the introduction of the canopy transparency parameters does not change the results significantly according to R2 (R2 = 0.70 to R2 = 0.71 in comparison to the results derived from, the semi-empirical model, which was originally developed for stem volume estimation.

  16. Models of direct reactions and quantum pre-equilibrium for nucleon scattering on spherical nuclei; Modeles de reactions directes et de pre-equilibre quantique pour la diffusion de nucleons sur des noyaux spheriques

    Energy Technology Data Exchange (ETDEWEB)

    Dupuis, M.

    2006-01-15

    When a nucleon collides with a target nucleus, several reactions may occur: elastic and inelastic scatterings, charge exchange... In order to describe these reactions, different models are involved: the direct reactions, pre-equilibrium and compound nucleus models. Our goal is to study, within a quantum framework and without any adjustable parameter, the direct and pre-equilibrium reactions for nucleons scatterings off double closed-shell nuclei. We first consider direct reactions: we are studying nucleon scattering with the Melbourne G-matrix, which represents the interaction between the projectile and one target nucleon, and with random phase approximation (RPA) wave functions which describe all target states. This is a fully microscopic approach since no adjustable parameters are involved. A second part is dedicated to the study of nucleon inelastic scattering for large energy transfer which necessarily involves the pre-equilibrium mechanism. Several models have been developed in the past to deal with pre-equilibrium. They start from the Born expansion of the transition amplitude which is associated to the inelastic process and they use several approximations which have not yet been tested. We have achieved some comparisons between second order cross sections which have been calculated with and without these approximations. Our results allow us to criticize some of these approximations and give several directions to improve the quantum pre-equilibrium models. (author)

  17. Production of isomers by neutron-induced inelastic scattering on 193Ir and influence of spin distribution in the pre-equilibrium process

    Science.gov (United States)

    Kawano, Toshihiko; Talou, Patrick; Chadwick, Mark B.

    2006-06-01

    We present calculations of the production cross-section of isomeric-state for 193Ir. The isomer was produced by neutron inelastic scattering, and several γ-ray production cross-sections were measured at LANSCE with the GEANIE detector. The total isomer production cross-section is then inferred by combining the experimental data with the GNASH statistical model calculations. The spin distribution is calculated with the Feshbach-Kerman-Koonin (FKK) quantum mechanical pre-equilibrium theory, and it is incorporated with the GNASH results. We found that the inclusion of FKK has a significant impact on the isomer production cross-sections at high energies.

  18. Production of isomers by neutron-induced inelastic scattering on {sup 193}Ir and influence of spin distribution in the pre-equilibrium process

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko [Los Alamos National Laboratory, NM 87545 (United States)]. E-mail: kawano@lanl.gov; Talou, Patrick [Los Alamos National Laboratory, NM 87545 (United States); Chadwick, Mark B. [Los Alamos National Laboratory, NM 87545 (United States)

    2006-06-23

    We present calculations of the production cross-section of isomeric-state for {sup 193}Ir. The isomer was produced by neutron inelastic scattering, and several {gamma}-ray production cross-sections were measured at LANSCE with the GEANIE detector. The total isomer production cross-section is then inferred by combining the experimental data with the GNASH statistical model calculations. The spin distribution is calculated with the Feshbach-Kerman-Koonin (FKK) quantum mechanical pre-equilibrium theory, and it is incorporated with the GNASH results. We found that the inclusion of FKK has a significant impact on the isomer production cross-sections at high energies.

  19. Heavy quark diffusion in the pre-equilibrium stage of heavy ion collisions

    Science.gov (United States)

    Das, Santosh K.; Ruggieri, Marco; Mazumder, Surasree; Greco, Vincenzo; Alam, Jan-e.

    2015-09-01

    The drag and diffusion coefficients of heavy quarks (HQs) have been evaluated in the pre-equilibrium phase of the evolving fireball produced in heavy ion collisions at relativistic heavy ion collider and Large Hadron Collider energies. KLN and classical Yang-Mills spectra have been used for describing the momentum distributions of the gluons produced just after the collisions but before they thermalize. The interaction of the HQs with these gluons has been treated within the framework of perturbative quantum chromodynamics. We have observed that the HQs are dragged almost equally by the kinetically equilibrated and out-of-equilibrium gluonic systems. We have also noticed that the HQ diffusion in the pre-equilibrium gluonic phase is as fast as in the kinetically equilibrated gluons. Moreover, the diffusion is faster in the pre-equilibrium phase than in the chemically equilibrated quark-gluon plasma. These findings may have significant impact on the analysis of experimental results on the elliptic flow and the high momentum suppression of the open charm and beauty hadrons.

  20. Aircraft directional stability and vertical tail design: A review of semi-empirical methods

    Science.gov (United States)

    Ciliberti, Danilo; Della Vecchia, Pierluigi; Nicolosi, Fabrizio; De Marco, Agostino

    2017-11-01

    Aircraft directional stability and control are related to vertical tail design. The safety, performance, and flight qualities of an aircraft also depend on a correct empennage sizing. Specifically, the vertical tail is responsible for the aircraft yaw stability and control. If these characteristics are not well balanced, the entire aircraft design may fail. Stability and control are often evaluated, especially in the preliminary design phase, with semi-empirical methods, which are based on the results of experimental investigations performed in the past decades, and occasionally are merged with data provided by theoretical assumptions. This paper reviews the standard semi-empirical methods usually applied in the estimation of airplane directional stability derivatives in preliminary design, highlighting the advantages and drawbacks of these approaches that were developed from wind tunnel tests performed mainly on fighter airplane configurations of the first decades of the past century, and discussing their applicability on current transport aircraft configurations. Recent investigations made by the authors have shown the limit of these methods, proving the existence of aerodynamic interference effects in sideslip conditions which are not adequately considered in classical formulations. The article continues with a concise review of the numerical methods for aerodynamics and their applicability in aircraft design, highlighting how Reynolds-Averaged Navier-Stokes (RANS) solvers are well-suited to attain reliable results in attached flow conditions, with reasonable computational times. From the results of RANS simulations on a modular model of a representative regional turboprop airplane layout, the authors have developed a modern method to evaluate the vertical tail and fuselage contributions to aircraft directional stability. The investigation on the modular model has permitted an effective analysis of the aerodynamic interference effects by moving, changing, and

  1. Equilibrium and pre-equilibrium calculations of cross-sections of (p ...

    Indian Academy of Sciences (India)

    2013-02-01

    ). [25] W D Myers and W J Swiatecki, Ark. Fysik 36, 343 (1967). [26] R Capote, E Herrera, E Kabin, R Lopez and V Osorio, Proc. XVII International Symposium on Nuclear Physis (Gaussig, GDR, November 1987), edited D ...

  2. A simple semi-empirical model for predicting missing carbon monoxide concentrations

    Science.gov (United States)

    Dirks, Kim N.; Johns, Murray D.; Hay, John E.; Sturman, Andrew P.

    Carbon monoxide monitoring using continuous samplers is carried out in most major urban centres in the world and generally forms the basis for air quality assessments. Such assessments become less reliable as the proportion of data missing due to equipment failure and periods of calibration increases. This paper presents a semi-empirical model for the prediction of atmospheric carbon monoxide concentrations near roads for the purpose of interpolating missing data without the need for any traffic or emissions information. The model produces reliable predictions while remaining computationally simple by being site-specifically optimized. The model was developed for, and evaluated at, both a suburban site and an inner city site in Hamilton, New Zealand. Model performance statistics were found to be significantly better than other simple methods of interpolation with little additional computational complexity.

  3. Investigation of 14-15 MeV ( n, t) Reaction Cross-sections by Using New Evaluated Empirical and Semi-empirical Systematic Formulas

    Science.gov (United States)

    Tel, E.; Aydın, A.; Kaplan, A.; Şarer, B.

    2008-09-01

    In the hybrid reactor, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study we have investigated asymmetry term effect for the ( n, t) reaction cross-sections at 14-15 neutron incident energy. It has been discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained empirical and semi-empirical formulas by fitting two parameter for ( n, t) reactions were given. All calculated results have been compared with the experimental data and the other semi-empirical formulas.

  4. Potentiometric and semi-empirical quantum chemical studies on liquid–liquid micro-extraction of 4-tert-butylphenol with trioctyl phosphate clusters

    Directory of Open Access Journals (Sweden)

    Xiurong Zhu

    2017-05-01

    Full Text Available In the present paper, the liquid–liquid micro extraction of 4-tert-butylphenol from aqueous solution to trioctyl phosphate organic phase in carbon paste electrode was studied by potentiometry and semi-empirical quantum chemistry with MOPAC2009. The extraction dynamic process was monitored by open circuit potential method, which follows an exponential association function with the apparent first extraction kinetic rate constant of 0.01685 s−1. The Nernstian plot of potential difference of the open circuit potentials against logarithm of 4-tert-butylphenol concentration at 500 s extraction time gives a slope of 0.01382, and indicates that 3 or 4 of 4-tert-butylphenol molecules can be extracted by one cluster of trioctyl phosphate dimer. This equation can also serve as working curve for the determination of 4-tert-butylphenol in the concentration range of 1.0 × 10−4–5.0 × 10−7 M with detection limit of 5.0 × 10−7 M (n = 3, ratio of signal/noise = 3. The semi-empirical quantum chemical calculation offers a thermodynamic evidence for the molecular mechanism of the liquid–liquid micro extraction of 4-tert-butylphenol from aqueous solution to trioctyl phosphate cluster.

  5. Semi-empirical relationship between the hardness, grain size and mean free path of WC-Co

    CSIR Research Space (South Africa)

    Makhele-Lekala, L

    2001-01-01

    Full Text Available , was subsequently derived. The results obtained from this model were in good agreement with those of the empirical formula and like the empirical formula, did not reproduce high hardness values of other researchers. Thus, the model was modified by introducing semi-empirical...

  6. Interface of the polarizable continuum model of solvation with semi-empirical methods in the GAMESS program

    DEFF Research Database (Denmark)

    Svendsen, Casper Steinmann; Blædel, Kristoffer L.; Christensen, Anders Steen

    2013-01-01

    An interface between semi-empirical methods and the polarized continuum model (PCM) of solvation successfully implemented into GAMESS following the approach by Chudinov et al (Chem. Phys. 1992, 160, 41). The interface includes energy gradients and is parallelized. For large molecules...

  7. Statistical iterative material image reconstruction for spectral CT using a semi-empirical forward model

    Science.gov (United States)

    Mechlem, Korbinian; Ehn, Sebastian; Sellerer, Thorsten; Pfeiffer, Franz; Noël, Peter B.

    2017-03-01

    In spectral computed tomography (spectral CT), the additional information about the energy dependence of attenuation coefficients can be exploited to generate material selective images. These images have found applications in various areas such as artifact reduction, quantitative imaging or clinical diagnosis. However, significant noise amplification on material decomposed images remains a fundamental problem of spectral CT. Most spectral CT algorithms separate the process of material decomposition and image reconstruction. Separating these steps is suboptimal because the full statistical information contained in the spectral tomographic measurements cannot be exploited. Statistical iterative reconstruction (SIR) techniques provide an alternative, mathematically elegant approach to obtaining material selective images with improved tradeoffs between noise and resolution. Furthermore, image reconstruction and material decomposition can be performed jointly. This is accomplished by a forward model which directly connects the (expected) spectral projection measurements and the material selective images. To obtain this forward model, detailed knowledge of the different photon energy spectra and the detector response was assumed in previous work. However, accurately determining the spectrum is often difficult in practice. In this work, a new algorithm for statistical iterative material decomposition is presented. It uses a semi-empirical forward model which relies on simple calibration measurements. Furthermore, an efficient optimization algorithm based on separable surrogate functions is employed. This partially negates one of the major shortcomings of SIR, namely high computational cost and long reconstruction times. Numerical simulations and real experiments show strongly improved image quality and reduced statistical bias compared to projection-based material decomposition.

  8. Technical Note: SWIFT - a fast semi-empirical model for polar stratospheric ozone loss

    Science.gov (United States)

    Rex, M.; Kremser, S.; Huck, P.; Bodeker, G.; Wohltmann, I.; Santee, M. L.; Bernath, P.

    2014-07-01

    An extremely fast model to estimate the degree of stratospheric ozone depletion during polar winters is described. It is based on a set of coupled differential equations that simulate the seasonal evolution of vortex-averaged hydrogen chloride (HCl), nitric acid (HNO3), chlorine nitrate (ClONO2), active forms of chlorine (ClOx = Cl + ClO + 2 ClOOCl) and ozone (O3) on isentropic levels within the polar vortices. Terms in these equations account for the chemical and physical processes driving the time rate of change of these species. Eight empirical fit coefficients associated with these terms are derived by iteratively fitting the equations to vortex-averaged satellite-based measurements of HCl, HNO3 and ClONO2 and observationally derived ozone loss rates. The system of differential equations is not stiff and can be solved with a time step of one day, allowing many years to be processed per second on a standard PC. The inputs required are the daily fractions of the vortex area covered by polar stratospheric clouds and the fractions of the vortex area exposed to sunlight. The resultant model, SWIFT (Semi-empirical Weighted Iterative Fit Technique), provides a fast yet accurate method to simulate ozone loss rates in polar regions. SWIFT's capabilities are demonstrated by comparing measured and modeled total ozone loss outside of the training period.

  9. The effect of electrodes on 11 acene molecular spin valve: Semi-empirical study

    Science.gov (United States)

    Aadhityan, A.; Preferencial Kala, C.; John Thiruvadigal, D.

    2017-10-01

    A new revolution in electronics is molecular spintronics, with the contemporary evolution of the two novel disciplines of spintronics and molecular electronics. The key point is the creation of molecular spin valve which consists of a diamagnetic molecule in between two magnetic leads. In this paper, non-equilibrium Green's function (NEGF) combined with Extended Huckel Theory (EHT); a semi-empirical approach is used to analyse the electron transport characteristics of 11 acene molecular spin valve. We examine the spin-dependence transport on 11 acene molecular junction with various semi-infinite electrodes as Iron, Cobalt and Nickel. To analyse the spin-dependence transport properties the left and right electrodes are joined to the central region in parallel and anti-parallel configurations. We computed spin polarised device density of states, projected device density of states of carbon and the electrode element, and transmission of these devices. The results demonstrate that the effect of electrodes modifying the spin-dependence behaviours of these systems in a controlled way. In Parallel and anti-parallel configuration the separation of spin up and spin down is lager in the case of iron electrode than nickel and cobalt electrodes. It shows that iron is the best electrode for 11 acene spin valve device. Our theoretical results are reasonably impressive and trigger our motivation for comprehending the transport properties of these molecular-sized contacts.

  10. Development of Semi-Empirical Damping Equation for Baffled Tank with Oblate Spheroidal Dome

    Science.gov (United States)

    Yang, H. Q.; West, Jeff; Brodnick, Jacob; Eberhart, Chad

    2016-01-01

    Propellant slosh is a potential source of disturbance that can significantly impact the stability of space vehicles. The slosh dynamics are typically represented by a mechanical model of a spring-mass-damper. This mechanical model is then included in the equation of motion of the entire vehicle for Guidance, Navigation and Control analysis. The typical parameters required by the mechanical model include natural frequency of the slosh, slosh mass, slosh mass center location, and the critical damping ratio. A fundamental study has been undertaken at NASA MSFC to understand the fluid damping physics from a ring baffle in the barrel section of a propellant tank. An asymptotic damping equation and CFD blended equation have been derived by NASA MSFC team to complement the popularly used Miles equation at different flow regimes. The new development has found success in providing a nonlinear damping model for the Space Launch System. The purpose of this study is to further extend the semi-empirical damping equations into the oblate spheroidal dome section of the propellant tanks. First, previous experimental data from the spherical baffled tank are collected and analyzed. Several methods of taking the dome curvature effect, including a generalized Miles equation, area projection method, and equalized fill height method, are assessed. CFD simulation is used to shed light on the interaction of vorticity around the baffle with the locally curved wall and liquid-gas interface. The final damping equation will be validated by a recent subscale test with an oblate spheroidal dome conducted at NASA MSFC.

  11. Semi-empirical mixed statistical flood forecasting for the Mekong River

    Science.gov (United States)

    Khurram Shahzad, Muhammad; Ihringer, Jürgen; Plate, Erich J.

    2010-05-01

    An ongoing study for improving flood forecasting for the Mekong River by data based modeling by mix of statistical methods and semi-empirical approach has yielded intermediate results, which reduced forecasting errors of previous forecasting models. In contrast to deterministic or semi-deterministic approach, the procedure is adopted to build the physical reality based semi-empirical model from the available data set. The forecast in data scarce basin like Mekong always remained a challenge for hydrologists where with the River of total length of 4000 km and 795000 Sq.km area of catchment has only 32 rainfall gauging stations and 8 runoff gauges in its key contributing catchments with consistent data. Therefore, simple rainfall runoff modeling module is developed for the estimation of inflows contributed by lateral catchments along the River Mekong and added into pre-developed runoff routing algorithm. The simple 3 parameter Nash-cascade model is applied in non-linear mode with varying runoff coefficients (RC). These runoff coefficients were pre-computed by multiple linear auto-regressions algorithms. It has been found that runoff coefficients increase along the flood season from its onset in May to end in October. However this increase was found highly dependent on previous month's RC values. This RC dependency on previous months is exploited to develop multiple linear regressions for estimation of forthcoming month RC's. These pre-computed monthly RC's were used in Nash-cascade to estimate runoff temporal distribution from daily areal average incremental rainfall for each sub-catchment. The algorithm was developed to give flood forecast at 4 points in middle Mekong River starting from N.Phanom in Lao-PDR to Stung Treng in Cambodia. There are a total of 4 sub-catchments which contribute runoff into the main Mekong River from its travel along these points. Separate rainfall-runoff Nash-cascade models were developed and added into routing algorithm to compute 1 to 5

  12. A Semi-Empirical Model for Tilted-Gun Planar Magnetron Sputtering Accounting for Chimney Shadowing

    Science.gov (United States)

    Bunn, J. K.; Metting, C. J.; Hattrick-Simpers, J.

    2015-01-01

    Integrated computational materials engineering (ICME) approaches to composition and thickness profiles of sputtered thin-film samples are the key to expediting materials exploration for these materials. Here, an ICME-based semi-empirical approach to modeling the thickness of thin-film samples deposited via magnetron sputtering is developed. Using Yamamura's dimensionless differential angular sputtering yield and a measured deposition rate at a point in space for a single experimental condition, the model predicts the deposition profile from planar DC sputtering sources. The model includes corrections for off-center, tilted gun geometries as well as shadowing effects from gun chimneys used in most state-of-the-art sputtering systems. The modeling algorithm was validated by comparing its results with experimental deposition rates obtained from a sputtering system utilizing sources with a multi-piece chimney assembly that consists of a lower ground shield and a removable gas chimney. Simulations were performed for gun-tilts ranging from 0° to 31.3° from the vertical with and without the gas chimney installed. The results for the predicted and experimental angular dependence of the sputtering deposition rate were found to have an average magnitude of relative error of for a 0°-31.3° gun-tilt range without the gas chimney, and for a 17.7°-31.3° gun-tilt range with the gas chimney. The continuum nature of the model renders this approach reverse-optimizable, providing a rapid tool for assisting in the understanding of the synthesis-composition-property space of novel materials.

  13. Calculations of Excitation Functions of Some Structural Fusion Materials for ( n, t) Reactions up to 50 MeV Energy

    Science.gov (United States)

    Tel, E.; Durgu, C.; Aktı, N. N.; Okuducu, Ş.

    2010-06-01

    Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of ( n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. In this study, ( n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al( n, t)25Mg, 51V( n, t)49Ti, 52Cr( n, t)50V, 55Mn( n, t)53Cr and 56Fe( n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, we have calculated ( n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results are discussed and compared with the experimental data taken from the literature.

  14. Pre-equilibrium Longitudinal Flow in the IP-Glasma Framework for Pb+Pb Collisions at the LHC

    Science.gov (United States)

    McDonald, Scott; Shen, Chun; Fillion-Gourdeau, François; Jeon, Sangyong; Gale, Charles

    2017-08-01

    In this work, we debut a new implementation of IP-Glasma and quantify the pre-equilibrium longitudinal flow in the IP-Glasma framework. The saturation physics based IP-Glasma model naturally provides a non-zero initial longitudinal flow through its pre-equilibrium Yang-Mills evolution. A hybrid IP-Glasma+MUSIC+UrQMD frame-work is employed to test this new implementation against experimental data and to make further predictions about hadronic flow observables in Pb+Pb collisions at 5.02 TeV. Finally, the non-zero pre-equilibrium longitudinal flow of the IP-Glasma model is quantified, and its origin is briefly discussed.

  15. Application of the Semi-Empirical Force-Limiting Approach for the CoNNeCT SCAN Testbed

    Science.gov (United States)

    Staab, Lucas D.; McNelis, Mark E.; Akers, James C.; Suarez, Vicente J.; Jones, Trevor M.

    2012-01-01

    The semi-empirical force-limiting vibration method was developed and implemented for payload testing to limit the structural impedance mismatch (high force) that occurs during shaker vibration testing. The method has since been extended for use in analytical models. The Space Communications and Navigation Testbed (SCAN Testbed), known at NASA as, the Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT), project utilized force-limiting testing and analysis following the semi-empirical approach. This paper presents the steps in performing a force-limiting analysis and then compares the results to test data recovered during the CoNNeCT force-limiting random vibration qualification test that took place at NASA Glenn Research Center (GRC) in the Structural Dynamics Laboratory (SDL) December 19, 2010 to January 7, 2011. A compilation of lessons learned and considerations for future force-limiting tests is also included.

  16. Quantitative structure-cytotoxicity relationship analysis of betulinic acid and its derivatives by semi-empirical molecular-orbital method.

    Science.gov (United States)

    Ishihara, Mariko; Sakagami, Hiroshi; Liu, Wing-Keung

    2005-01-01

    A semi-empirical molecular-orbital method (CAChe) demonstrates that the cytotoxicity of betulinic acid derivatives can be predicted by several physical parameters (such as heat of formation, hydrophobicity (log P), watersolubility, ionization potential, electron affinity, dipole moment), but not by molecular size (maximum length and width). The present study demonstrates how this method can be applied to estimate the cytotoxic activity of structurally-related compounds.

  17. Global Estimation of Soil Nitrous Oxide Emission Using a Semi-Empirical Model and a Global Dataset

    Science.gov (United States)

    Hashimoto, S.

    2015-12-01

    Nitrous oxide (N2O) flux is one of the major greenhouse gas fluxes from terrestrial ecosystems. N2O is produced as a by-product of the transformations of nitrogen in the soil and is generally released from the soil surface to the atmosphere. The purpose of this study is to provide a data-oriented global estimate of N2O flux from the soil. In this study, a semi-empirical model was developed by modifying a model for soil CO2 flux (Raich et al. 2002). The model consists of the functions of nitrogen, air temperature, and precipitation. The parameters of the functions were determined using a global dataset of N2O emission (Stehfest and Bouwman 2006) through the Bayesian approach. The function of nitrogen is a function of carbon to nitrogen ratio. For agricultural land use, the effect of nitrogen fertilizer was also incorporated in the function of nitrogen. The model was applied at a spatial resolution of 5 min and at a monthly time resolution. Preliminary calculation revealed that the total amount of N2O emission was 10 Tg N yr-1. The upland natural land was the major source of N2O emission, followed by the upland agricultural land. Latitudinally, the flux was high at 30°N-40°N and 10°S-10°N. The major contribution to the peak at 30°N-40°N was by the upland agricultural land and that to the peak around the equator was by the upland natural land. The monthly flux showed a clear seasonality, and it was the highest and lowest in August and February, respectively. The global scale seasonality was mainly contributed by the N2O flux from the upland agricultural land in the northern mid-latitude. This study provides data-oriented spatiotemporal distribution of soil N2O flux, and I hope that these data will be used for a benchmark and constraint of process-based modeling.

  18. Semi-empirical model for the assessment of railway ballast using GPR

    Science.gov (United States)

    Giulia Brancadoro, Maria; Benedetto, Andrea

    2017-04-01

    Over time, railways have become a very competitive mean of transportation, especially for long distances. In order to ensure high level of safety, comfort and regularity of transportation, an efficient maintenance of the railway track-bed is crucial. In fact, the cyclic loads passing on the rails produce a progressive deterioration of railway ballast beneath the sleepers, and a breakdown of its particles that causes a general decrease of railway performances. This work aims at proposing a semi-empirical model for the characterisation of railway ballast grading, through the spectral analysis of Ground-Penetrating Radar (GPR) signal. To this effect, a theoretical study has been preliminary conducted to investigate the propagation and scattering phenomena of the electromagnetic waves within a ballast layer. To confirm the theoretical assumptions, high-frequency GPR signals have been both collected in laboratory and virtual environment. Concerning the latter, progressively more complex numerical domains have been designed and subjected to synthetic GPR test, by a Finite Different Time Domain (FTDT) procedure, run in GPR Max 2D simulator. As first simulation steps, ballast aggregates simplified through circles have been accounted for, with increasing values of radius. Subsequently, real-scale scenarios characterized by multi-size ballast particles, consistent with three different grain size distribution from railway network standards, have been reproduced by the employment of Random Sequential Adsorption - RSA algorithm. As far as the laboratory procedures, real GPR tests have been carried out on an experimental framework purposely set up, and composed of a methacrylate tank filled up with limestone-derived railway ballast. The ballast aggregates grading has been retrieved by means of an automatic image analysis algorithm, run on the lateral sight of the transparent tank. Through their spectral analysis, an empirical relationship between the position of the amplitude

  19. The Equilibrium and Pre-equilibrium Triton Emission Spectra of Some Target Nuclei for ( n, xt) Reactions up to 45 MeV Energy

    Science.gov (United States)

    Tel, E.; Kaplan, A.; Aydın, A.; Özkorucuklu, S.; Büyükuslu, H.; Yıldırım, G.

    2010-08-01

    Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, working out the systematics of ( n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, ( n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

  20. Validation of Empirical and Semi-empirical Net Radiation Models versus Observed Data for Cold Semi-arid Climate Condition

    Directory of Open Access Journals (Sweden)

    aliakbar sabziparvar

    2017-03-01

    climatology station of Bu-Ali Sina University. This experiment was performed for the cold semi-arid site of Hamedan (Iran. The study site (Hamedan is a mountainous research station (1860 meters above sea-level which is located at the eastern side of central Zagros Mountain Range. The net radiation fluxes were measured by four SW (300-2800 nm and LW (4500-42000 nm.Hukseflux Thermal Sensors mounted on an automatic logger system. The logger reported four upward and downward solar components in every 8-minute intervals. In this study, total daily net radiation was estimated by 12 empirical and semi-empirical Rn models including: Basic Regression Models (BRM, Extended Regression Models (ERM, Linacre, Berliand, Wright and FAO-56 Penman-Monteith. The model performances were evaluated by R2, RMSE, MBE and MPE criteria and the best model was selected accordingly. Results and Discussion: In this research, the model calculations were done for seasonal and annual time scales. The results indicate that Basic Regression Model Rn(BRM-4 performs the best estimates in spring time. Further, for summer and autumn seasons, Rn (BRM-3 was superior for the cold semi-arid climate of Hamedan. Therefore, with the exception of winter, the BRM models performed the best estimates. Unlike the other seasons, for winter, Irmak presented the most accurate results. This is due to the fact that net radiation as estimates by Irmak Model is mainly dependent on daily maximum (Tmax and minimum temperatures. For Irmak model, as the Tmax is increased, Rn will be reduced proportionally. For this reason, Irmak does not perform good estimates for warm months. In annual time scale, the Basic Regression Model of Rn (BRM-3 presented the most accurate estimates of net radiation. The study of Monteith and Szeicz (1961and MirgaloyBayat (2011 also showed that Rn (BRM-3 model can generated the best Rn estimate in annual scale for mountain regions. Conclusion: Unlike the recommendation of FAO for using Penman-Monteith and

  1. Semi-empirical prediction of moisture build-up in an electronic enclosure using analysis of variance (ANOVA)

    DEFF Research Database (Denmark)

    Shojaee Nasirabadi, Parizad; Conseil, Helene; Mohanty, Sankhya

    2016-01-01

    and temperature are studied. A set of experiments are done based on a fractional factorial design in order to estimate the time constant for moisture transfer into the enclosure by fitting the experimental data to an analytical quasi-steady-state model. According to the statistical analysis, temperature...... and the opening length are found as the most significant factors. Based on analysis of variance of the derived time constants, a semi-empirical regression model is proposed to predict the moisture transfer time constant with an adjusted R2 of 0.98; which demonstrated that the model can be used for estimation...

  2. Clustering in light nuclei and their effects on fusion and pre - equilibrium processes.

    Science.gov (United States)

    Gramegna, Fabiana; Cicerchia, Magda; Fabris, Daniela; Marchi, Tommaso; Cinausero, Marco; Degerlier, Meltem; Mabiala, Justin; Mantovani, Giorgia; Morelli, Luca; D'Agostino, Michela; Bruno, Mauro; Barlini, Sandro; Bini, Maurizio; Pasquali, Gabriele; Piantelli, Silvia; Casini, Giovanni; Pastore, Giuseppe; Gruyer, Diego; Ottanelli, Pietro; Valdré, Simone; Gelli, Nicla; Olmi, Alessandro; Poggi, Giacomo; Vardaci, Emanuele; Lombardo, Ivano; Dell'Aquila, Daniele; Leoni, Silvia; Cieplicka-Orynczak, Natalya; Fornal, Bogdan; Mengoni, Daniele; Collazuol, Gianmaria; Caciolli, Antonio; Colonna, Maria; Ono, Akira; Baiocco, Giorgio

    2017-11-01

    The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1-5]. The NUCL-EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion-evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited 24Mg system have been studied through two different reactions, 12C (95 MeV)+ 12C and 14N (80.7 MeV)+ 10B, which have been used to produce fused systems with nearly the same mass and excitation energy ( 60 MeV). In particular, even the de-excitation of the Hoyle state in 12C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems 18O+28Si, 16O+30Si and 19F+27Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI++ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions.

  3. Semi-empirical models for polarized reflectance of land surfaces: Intercomparison using space-borne POLDER measurements

    Science.gov (United States)

    Yang, Bin; Zhao, Haimeng; Chen, Wei

    2017-11-01

    In this paper, six semi-empirical bidirectional polarization distribution functions (BPDF) models for polarized reflectance of land surfaces (Nadal-Bréon model, Waquet model, Maignan model, Litvinov model, Diner model and Xie-Cheng model) were quantitatively intercompared using the recently released database of representative BPDFs generated from POLDER measurements over a wide range of surface types at global scale. The intercomparison technique involved two strategies: one for fitting and the other for priori modeling. Our results suggest that (1) Nadal-Bréon model and Litvinov model provide best fits to the POLDER measurements with average RMSEs equal to 0.174% and 0.173%, respectively; (2) as for priori modeling, Xie-Cheng model performs best among these models as its average RMSE is 0.249%, indicating the corresponding surface-type-based free parameters can be used for a priori model of surface polarized reflectance; (3) despite the semi-empirical models cannot estimate negative polarized reflectance at backward scattering direction, impact of negative polarized reflectance on fitting and priori modeling is negligible. The results provide a priori knowledge of the model performances over various surface types and can be applied to future researches of land optical properties and aerosol parameters retrieval over land surfaces.

  4. Semi-Empirical Calibration of the Integral Equation Model for Co-Polarized L-Band Backscattering

    Directory of Open Access Journals (Sweden)

    Nicolas Baghdadi

    2015-10-01

    Full Text Available The objective of this paper is to extend the semi-empirical calibration of the backscattering Integral Equation Model (IEM initially proposed for Synthetic Aperture Radar (SAR data at C- and X-bands to SAR data at L-band. A large dataset of radar signal and in situ measurements (soil moisture and surface roughness over bare soil surfaces were used. This dataset was collected over numerous agricultural study sites in France, Luxembourg, Belgium, Germany and Italy using various SAR sensors (AIRSAR, SIR-C, JERS-1, PALSAR-1, ESAR. Results showed slightly better simulations with exponential autocorrelation function than with Gaussian function and with HH than with VV. Using the exponential autocorrelation function, the mean difference between experimental data and Integral Equation Model (IEM simulations is +0.4 dB in HH and −1.2 dB in VV with a Root Mean Square Error (RMSE about 3.5 dB. In order to improve the modeling results of the IEM for a better use in the inversion of SAR data, a semi-empirical calibration of the IEM was performed at L-band in replacing the correlation length derived from field experiments by a fitting parameter. Better agreement was observed between the backscattering coefficient provided by the SAR and that simulated by the calibrated version of the IEM (RMSE about 2.2 dB.

  5. A semi-empirical model for the estimation of maximum horizontal displacement due to liquefaction-induced lateral spreading

    Science.gov (United States)

    Faris, Allison T.; Seed, Raymond B.; Kayen, Robert E.; Wu, Jiaer

    2006-01-01

    During the 1906 San Francisco Earthquake, liquefaction-induced lateral spreading and resultant ground displacements damaged bridges, buried utilities, and lifelines, conventional structures, and other developed works. This paper presents an improved engineering tool for the prediction of maximum displacement due to liquefaction-induced lateral spreading. A semi-empirical approach is employed, combining mechanistic understanding and data from laboratory testing with data and lessons from full-scale earthquake field case histories. The principle of strain potential index, based primary on correlation of cyclic simple shear laboratory testing results with in-situ Standard Penetration Test (SPT) results, is used as an index to characterized the deformation potential of soils after they liquefy. A Bayesian probabilistic approach is adopted for development of the final predictive model, in order to take fullest advantage of the data available and to deal with the inherent uncertainties intrinstiic to the back-analyses of field case histories. A case history from the 1906 San Francisco Earthquake is utilized to demonstrate the ability of the resultant semi-empirical model to estimate maximum horizontal displacement due to liquefaction-induced lateral spreading.

  6. A semi-empirical formula for calculation of absolute cross sections for ionization and excitation of atoms by electrons

    NARCIS (Netherlands)

    Vriens, L.

    A simple analytical expression for the absolute ionization and (optically allowed) excitation cross sections, as a function of the electron energy, is “derived”. In this expression there are two parameters. The first one is proportional to the optical oscillator strength and the second one is

  7. The Dependence of Convective Core Overshooting on Stellar Mass: A Semi-empirical Determination Using the Diffusive Approach with Two Different Element Mixtures

    Science.gov (United States)

    Claret, Antonio; Torres, Guillermo

    2017-11-01

    Convective core overshooting has a strong influence on the evolution of stars of moderate and high mass. Studies of double-lined eclipsing binaries and stellar oscillations have renewed interest in the possible dependence of overshooting on stellar mass, which has been poorly constrained by observations so far. Here, we have used a sample of 29 well-studied double-lined eclipsing binaries in key locations of the H–R diagram to establish the explicit dependence of {f}{ov} on mass, where {f}{ov} is the free parameter in the diffusive approximation to overshooting. Measurements of the masses, radii, and temperatures of the binary components were compared against stellar evolution calculations based on the MESA code to infer semi-empirical values of {f}{ov} for each component. We find a clear mass-dependence such that {f}{ov} rises sharply from zero in the range 1.2{--}2.0 {M}ȯ , and levels off thereafter up to the 4.4 {M}ȯ limit of our sample. Tests with two different element mixtures indicate the trend is the same, and we find it to also be qualitatively similar to the one established in our previous study with the classical step-function implementation of overshooting characterized by the free parameter {α }{ov}. Based on these measurements, we infer an approximate relationship between the two overshooting parameters of {α }{ov}/{f}{ov}=11.36+/- 0.22, with a possible dependence on stellar properties.

  8. Measurement and correlation study of silymarin solubility in supercritical carbon dioxide with and without a cosolvent using semi-empirical models and back-propagation artificial neural networks

    Directory of Open Access Journals (Sweden)

    Gang Yang

    2017-09-01

    Full Text Available The solubility data of compounds in supercritical fluids and the correlation between the experimental solubility data and predicted solubility data are crucial to the development of supercritical technologies. In the present work, the solubility data of silymarin (SM in both pure supercritical carbon dioxide (SCCO2 and SCCO2 with added cosolvent was measured at temperatures ranging from 308 to 338 K and pressures from 8 to 22 MPa. The experimental data were fit with three semi-empirical density-based models (Chrastil, Bartle and Mendez-Santiago and Teja models and a back-propagation artificial neural networks (BPANN model. Interaction parameters for the models were obtained and the percentage of average absolute relative deviation (AARD% in each calculation was determined. The correlation results were in good agreement with the experimental data. A comparison among the four models revealed that the experimental solubility data were more fit with the BPANN model with AARDs ranging from 1.14% to 2.15% for silymarin in pure SCCO2 and with added cosolvent. The results provide fundamental data for designing the extraction of SM or the preparation of its particle using SCCO2 techniques.

  9. A semi-empirical model for predicting the effect of changes in traffic flow patterns on carbon monoxide concentrations

    Science.gov (United States)

    Dirks, Kim N.; Johns, Murray D.; Hay, John E.; Sturman, Andrew P.

    A simple semi-empirical model for predicting the effect of changes in traffic flow patterns on carbon monoxide concentrations is presented. The traffic component of the model requires average vehicle emission rate estimates for a range of driving conditions, as well as traffic flow data for the site of interest. The dispersion component of the model is based on a modified empirically optimised box model requiring only wind speed and direction information. The model is evaluated at a suburban site in Hamilton, New Zealand. Despite the simplicity of the model, produces reliable concentration predictions when tested on days with significantly different traffic flow patterns from those days with which the optimum model parameters were evaluated.

  10. A Semi-Empirical Formula of the Dependence of the Fluorescence Intensity of Naphthalene on Temperature and the Oxygen Concentration

    Science.gov (United States)

    An, B.; Wang, Z.-G.; Yang, L.-C.; Li, X.-P.

    2017-09-01

    Two-ring aromatics, such as naphthalene, are important fluorescent components of kerosene in the planar laser-induced fluorescent (PLIF) technique. Quantifying measurements of kerosene vapor concentrations by PLIF require a prior knowledge of the fluorescence intensity of naphthalene over a wide temperature and oxygen concentration range. To promote the application of PLIF, a semi-empirical formula based on the collision theory and experimental data at the laser wavelength of 266 nm and a pressure of 0.1 MPa is established to predict the fluorescence intensity of naphthalene at different temperatures and oxygen concentrations. This formula takes vibrational states, temperature, and oxygen quenching into account. Verified by published experimental data, the formula can predict the fluorescence intensity of naphthalene with an error less than 9%.

  11. Semi-empirical Algorithm for the Retrieval of Ecology-Relevant Water Constituents in Various Aquatic Environments

    Directory of Open Access Journals (Sweden)

    Robert Shuchman

    2009-03-01

    Full Text Available An advanced operational semi-empirical algorithm for processing satellite remote sensing data in the visible region is described. Based on the Levenberg-Marquardt multivariate optimization procedure, the algorithm is developed for retrieving major water colour producing agents: chlorophyll-a, suspended minerals and dissolved organics. Two assurance units incorporated by the algorithm are intended to flag pixels with inaccurate atmospheric correction and specific hydro-optical properties not covered by the applied hydro-optical model. The hydro-optical model is a set of spectral cross-sections of absorption and backscattering of the colour producing agents. The combination of the optimization procedure and a replaceable hydro-optical model makes the developed algorithm not specific to a particular satellite sensor or a water body. The algorithm performance efficiency is amply illustrated for SeaWiFS, MODIS and MERIS images over a variety of water bodies.

  12. New semi-empirical formula for α-decay half-lives of the heavy and superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Manjunatha, H.C. [Government College for Women, Department of Physics, Kolar, Karnataka (India); Sridhar, K.N. [Government First Grade College, Department of Physics, Kolar, Karnataka (India)

    2017-07-15

    We have succesfully formulated the semi-empirical formula for α-decay half-lives of heavy and superheavy nuclei for different isotopes of the wide atomic-number range 94 < Z < 136. We have considered 2627 isotopes of heavy and superheavy nuclei for the fitting. The value produced by the present formula is compared with that of experiments and other eleven models, i.e. ImSahu, Sahu, Royer10, VS2, UNIV2, SemFIS2, WKB. Sahu16, Densov, VSS and Royer formula. This formula is exclusively for heavy and superheavy nuclei. α-decay is one of the dominant decay mode of superheavy nucleus. By identifying the α-decay mode superheavy nuclei can be detected. This formula helps in predicting the α-decay chains of superheavy nuclei. (orig.)

  13. A semi-empirical effective medium theory for metals and alloys

    DEFF Research Database (Denmark)

    Jacobsen, Karsten wedel; Stoltze, Per; Nørskov, Jens kehlet

    1996-01-01

    A detailed derivation of the simplest form of the effective medium theory for bonding in metallic systems is presented, and parameters for the fee metals Ni, Pd, Pt, Cu, Ag and Au are given. The derivation of parameters is discussed in detail to show how new parameterizations can be made....... The method and the parameterization is tested for a number of surface and bulk problems. In particular we present calculations of the energetics of metal atoms deposited on metal surfaces. The calculated energies include heats of adsorption, energies of overlayers, both pseudomorphic and relaxed, as well...

  14. Comparing Band Ratio, Semi-Empirical, and Modified Gaussian Models in Predicting Cyanobacterial Pigments in Eutrophic Inland Waters

    Science.gov (United States)

    Robertson, A. L.; Lin, L.; Tedesco, L.; Wilson, J.; Soyeux, E.

    2008-12-01

    Cyanobacteria are known to produce toxins harmful to humans and compounds that alter the taste/odor of water. Monitoring cyanobacteria is of interest to surface water managers because eutrophication of these surface water bodies are common thus increasing the chances of cyanobacterial blooms. Traditionally cyanobacteria are remotely sensed using the spectral properties of the two pigments: chlorophyll a (Chl-a), indicative of all algal and cyanobacteria species, and phycocyanin (PC), specific to cyanobacteria in most freshwater systems. Initial algorithms identifying cyanobacterial pigments used ratios of reflectance at specific wavelengths. In an effort to increase transferability between different systems researchers have included optical properties of water and water constituents to build semi-empirical models. Recently researchers have applied a curve-fitting, modified Gaussian model (MGM), to predict these cyanobacterial pigments. To determine the best performing algorithm this study compares the performance of 4 band ratio, 4 semi-empirical, and 2 modified Gaussian models in predicting PC and Chl-a on three central Indiana reservoirs (Eagle Creek, Geist, Morse). For each of these reservoirs, spectral data were collected with three different sensors (boat-based: ASD Fieldspec, Ocean Optics USB4000; Ariel: AISA Eagle) over a three year period (2005-2007), and water samples concomitant with these spectra were analyzed for concentration of the two pigments and other water constituents. Comparison shows that a model using the MGM strength at 620 nm from a 2005 Morse Reservoir ASD Fieldspec data set shows that the MGM has the best transferability to a 2006 Morse Reservoir ASD Fieldspec data set in predicting phycocyanin (R2 = 0.77; RMSE= 52.45 ppb), and a band ratio model published by Mittenzwey et al. 1991 has the best transferability in predicting chlorophyll a (R2 = 0.74; RMSE 16.31=ppb).

  15. SWIFT: Semi-empirical and numerically efficient stratospheric ozone chemistry for global climate models

    OpenAIRE

    Kreyling, Daniel; Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2015-01-01

    The SWIFT model is a fast yet accurate chemistry scheme for calculating the chemistry of stratospheric ozone. It is mainly intended for use in Global Climate Models (GCMs), Chemistry Climate Models (CCMs) and Earth System Models (ESMs). For computing time reasons these models often do not employ full stratospheric chem- istry modules, but use prescribed ozone instead. This can lead to insufficient representation between stratosphere and troposphere. The SWIFT stratospheric ozone chem...

  16. Estimation of Leaf Area Index Using DEIMOS-1 Data: Application and Transferability of a Semi-Empirical Relationship between two Agricultural Areas

    Directory of Open Access Journals (Sweden)

    Guido D'Urso

    2013-03-01

    Full Text Available This work evaluates different procedures for the application of a semi-empirical model to derive time-series of Leaf Area Index (LAI maps in operation frameworks. For demonstration, multi-temporal observations of DEIMOS-1 satellite sensor data were used. The datasets were acquired during the 2012 growing season over two agricultural regions in Southern Italy and Eastern Austria (eight and five multi-temporal acquisitions, respectively. Contemporaneous field estimates of LAI (74 and 55 measurements, respectively were collected using an indirect method (LAI-2000 over a range of LAI values and crop types. The atmospherically corrected reflectance in red and near-infrared spectral bands was used to calculate the Weighted Difference Vegetation Index (WDVI and to establish a relationship between LAI and WDVI based on the CLAIR model. Bootstrapping approaches were used to validate the models and to calculate the Root Mean Square Error (RMSE and the coefficient of determination (R2 between measured and predicted LAI, as well as corresponding confidence intervals. The most suitable approach, which at the same time had the minimum requirements for fieldwork, resulted in a RMSE of 0.407 and R2 of 0.88 for Italy and a RMSE of 0.86 and R2 of 0.64 for the Austrian test site. Considering this procedure, we also evaluated the transferability of the local CLAIR model parameters between the two test sites observing no significant decrease in estimation accuracies. Additionally, we investigated two other statistical methods to estimate LAI based on: (a Support Vector Machine (SVM and (b Random Forest (RF regressions. Though the accuracy was comparable to the CLAIR model for each test site, we observed severe limitations in the transferability of these statistical methods between test sites with an increase in RMSE up to 24.5% for RF and 38.9% for SVM.

  17. Semi-empirical method for estimating the performance of direct gain passive solar heated buildings

    Energy Technology Data Exchange (ETDEWEB)

    Wray, W.O.; Balcomb, J.D.; McFarland, R.D.

    1979-01-01

    The sunspot code for performance analysis of direct gain passive solar heated buildings is used to calculate the annual solar fraction for two representative designs in ten American cities. The two representative designs involve a single thermal storage mass configuration which is evaluated with and without night insulation. In both cases the solar aperture is double glazed. The results of the detailed thermal network calculations are then correlated using the monthly solar load ratio method which has already been successfully applied to the analysis of both active solar heated buildings and passive thermal storage wall systems. The method is based on a correlation between the monthly solar heating fraction and the monthly solar load ratio. The monthly solar load ratio is defined as the ratio of the monthly solar energy transmitted through the glazing aperture to the building's monthly thermal load. The procedure using the monthly method for any location is discussed in detail. In addition, a table of annual performance results for 84 cities is presented, enabling the designer to bypass the monthly method for these locations.

  18. Semi-Empirical Prediction of Aircraft Low-Speed Aerodynamic Characteristics

    Science.gov (United States)

    Olson, Erik D.

    2015-01-01

    This paper lays out a comprehensive methodology for computing a low-speed, high-lift polar, without requiring additional details about the aircraft design beyond what is typically available at the conceptual design stage. Introducing low-order, physics-based aerodynamic analyses allows the methodology to be more applicable to unconventional aircraft concepts than traditional, fully-empirical methods. The methodology uses empirical relationships for flap lift effectiveness, chord extension, drag-coefficient increment and maximum lift coefficient of various types of flap systems as a function of flap deflection, and combines these increments with the characteristics of the unflapped airfoils. Once the aerodynamic characteristics of the flapped sections are known, a vortex-lattice analysis calculates the three-dimensional lift, drag and moment coefficients of the whole aircraft configuration. This paper details the results of two validation cases: a supercritical airfoil model with several types of flaps; and a 12-foot, full-span aircraft model with slats and double-slotted flaps.

  19. Empirical phylogenies and species abundance distributions are consistent with pre-equilibrium dynamics of neutral community models with gene flow

    KAUST Repository

    Bonnet-Lebrun, Anne-Sophie

    2017-03-17

    Community characteristics reflect past ecological and evolutionary dynamics. Here, we investigate whether it is possible to obtain realistically shaped modelled communities - i.e., with phylogenetic trees and species abundance distributions shaped similarly to typical empirical bird and mammal communities - from neutral community models. To test the effect of gene flow, we contrasted two spatially explicit individual-based neutral models: one with protracted speciation, delayed by gene flow, and one with point mutation speciation, unaffected by gene flow. The former produced more realistic communities (shape of phylogenetic tree and species-abundance distribution), consistent with gene flow being a key process in macro-evolutionary dynamics. Earlier models struggled to capture the empirically observed branching tempo in phylogenetic trees, as measured by the gamma statistic. We show that the low gamma values typical of empirical trees can be obtained in models with protracted speciation, in pre-equilibrium communities developing from an initially abundant and widespread species. This was even more so in communities sampled incompletely, particularly if the unknown species are the youngest. Overall, our results demonstrate that the characteristics of empirical communities that we have studied can, to a large extent, be explained through a purely neutral model under pre-equilibrium conditions. This article is protected by copyright. All rights reserved.

  20. Discussion on climate oscillations: CMIP5 general circulation models versus a semi empirical harmonic model based on astronomical cycles

    CERN Document Server

    Scafetta, Nicola

    2013-01-01

    Power spectra of global surface temperature (GST) records reveal major periodicities at about 9.1, 10-11, 19-22 and 59-62 years. The Coupled Model Intercomparison Project 5 (CMIP5) general circulation models (GCMs), to be used in the IPCC (2013), are analyzed and found not able to reconstruct this variability. From 2000 to 2013.5 a GST plateau is observed while the GCMs predicted a warming rate of about 2 K/century. In contrast, the hypothesis that the climate is regulated by specific natural oscillations more accurately fits the GST records at multiple time scales. The climate sensitivity to CO2 doubling should be reduced by half, e.g. from the IPCC-2007 2.0-4.5 K range to 1.0-2.3 K with 1.5 C median. Also modern paleoclimatic temperature reconstructions yield the same conclusion. The observed natural oscillations could be driven by astronomical forcings. Herein I propose a semi empirical climate model made of six specific astronomical oscillations as constructors of the natural climate variability spanning ...

  1. Basis material decomposition in spectral CT using a semi-empirical, polychromatic adaption of the Beer-Lambert model

    Science.gov (United States)

    Ehn, S.; Sellerer, T.; Mechlem, K.; Fehringer, A.; Epple, M.; Herzen, J.; Pfeiffer, F.; Noël, P. B.

    2017-01-01

    Following the development of energy-sensitive photon-counting detectors using high-Z sensor materials, application of spectral x-ray imaging methods to clinical practice comes into reach. However, these detectors require extensive calibration efforts in order to perform spectral imaging tasks like basis material decomposition. In this paper, we report a novel approach to basis material decomposition that utilizes a semi-empirical estimator for the number of photons registered in distinct energy bins in the presence of beam-hardening effects which can be termed as a polychromatic Beer-Lambert model. A maximum-likelihood estimator is applied to the model in order to obtain estimates of the underlying sample composition. Using a Monte-Carlo simulation of a typical clinical CT acquisition, the performance of the proposed estimator was evaluated. The estimator is shown to be unbiased and efficient according to the Cramér-Rao lower bound. In particular, the estimator is capable of operating with a minimum number of calibration measurements. Good results were obtained after calibration using less than 10 samples of known composition in a two-material attenuation basis. This opens up the possibility for fast re-calibration in the clinical routine which is considered an advantage of the proposed method over other implementations reported in the literature.

  2. Semi-Empirical Validation of the Cross-Band Relative Absorption Technique for the Measurement of Molecular Mixing Ratios

    Science.gov (United States)

    Pliutau, Denis; Prasad, Narasimha S

    2013-01-01

    Studies were performed to carry out semi-empirical validation of a new measurement approach we propose for molecular mixing ratios determination. The approach is based on relative measurements in bands of O2 and other molecules and as such may be best described as cross band relative absorption (CoBRA). . The current validation studies rely upon well verified and established theoretical and experimental databases, satellite data assimilations and modeling codes such as HITRAN, line-by-line radiative transfer model (LBLRTM), and the modern-era retrospective analysis for research and applications (MERRA). The approach holds promise for atmospheric mixing ratio measurements of CO2 and a variety of other molecules currently under investigation for several future satellite lidar missions. One of the advantages of the method is a significant reduction of the temperature sensitivity uncertainties which is illustrated with application to the ASCENDS mission for the measurement of CO2 mixing ratios (XCO2). Additional advantages of the method include the possibility to closely match cross-band weighting function combinations which is harder to achieve using conventional differential absorption techniques and the potential for additional corrections for water vapor and other interferences without using the data from numerical weather prediction (NWP) models.

  3. Neutron skin effect of some Mo isotopes in pre-equilibrium reactions

    Indian Academy of Sciences (India)

    In 2008, Tel et al sug- gested that the initial neutron and proton exciton numbers for nucleon-induced PEQ re- actions could be calculated from the neutron and proton densities by using an effective nucleon–nucleon interaction with Skyrme force. This new method, taking into account single-particle wave functions, allows an ...

  4. A new semi-empirical kinetic method for the determination of ion exchange constants for the counterions of cationic micelles.

    Science.gov (United States)

    Khan, M Niyaz

    2010-09-15

    A new method, based upon semi-empirical kinetic approach, for the determination of ion exchange constant for ion exchange processes occurring between counterions at the cationic micellar surface is described in this review article. Basically, the method involves a reaction kinetic probe which gives observed pseudo-first-order rate constants (k(obs)) for a nucleophilic substitution reaction between the nonionic and anionic reactants (R and S) in the presence of a constant concentration of both reactants as well as cationic micelles and varying concentrations of an inert inorganic or organic salt (MX). The observed data (k(obs), versus [MX]) fit satisfactorily (in terms of residual errors) to an empirical equation which could be derived from an equation explaining the mechanism of the reaction of the kinetic probe in terms of pseudophase micellar (PM) model coupled with another empirical equation. This (another) empirical equation explains the effect of [MX] on cationic micellar binding constant (K(S)) of the anionic reactant (say S) and gives an empirical constant, K(X/S). The magnitude of K(X/S) is the measure of the ability of X(-) to expel S(-) from a cationic micellar pseudophase to the bulk aqueous phase through ion exchange X(-)/S(-). The values of K(X/S) and K(Y/S) (where Y(-) is another inert counterion) give the ion exchange constant, K(X)(Y) (=K(X)/K(Y) where K(X) and K(Y) represent cationic micellar binding constants of X(-) and Y(-), respectively). The suitability of this method is demonstrated by the use of three different reaction kinetic probes and various MX. Copyright 2010 Elsevier B.V. All rights reserved.

  5. Semi-empirical lake level (SELL) model for mapping lake water depths from partially clouded satellite data

    Science.gov (United States)

    Velpuri, N.; Senay, G. B.

    2011-12-01

    Information on the variability in surface water is critical to understand the impact of climate change and global water cycle. Surface water features such as lakes, or reservoirs can affect local weather and regional climate. Hence, there is a widespread demand for accurate and quantitative global observations of surface water variability. Satellite imagery provides a direct way to monitor variations in surface water. However, estimating accurate surface area from satellite imagery can be a problem due to clouds. Hence, the use of optical imagery for operational implementation has been a challenge for monitoring variations in surface water. In this research, a semi-empirical lake level (SELL) model is developed to derive lake/reservoir water levels from partially covered satellite imagery. SRTM elevation combined with bathymetry was used to derive the relationships between lake depth vs. surface area and shore line (L). Using these relationships, lake level/depth (D) was estimated from the surface area (A) and/or shore line (L) delineated from Landsat and MODIS data. The SELL model was applied on Lake Turkana, one of the rift valley lakes in East Africa. First, Lake Turkana water levels were delineated using cloud-free or partially clouded Landsat and MODIS imagery over 1993-2009 and 2002-2009 time periods respectively. Historic lake depths were derived using 1972-1992 Landsat imagery. Lake depths delineated using this approach were validated using TOPEX/Poseidon/Jason satellite altimetry data. It was found that lake depths derived using SELL model matched reasonably well with the satellite altimetry data. The approach presented in this research can be used to (a) simulate lake water level variations in data scarce regions (b) increase the frequency of observation in regions where cloud cover is a problem (c) operationally monitor lake water levels in ungauged basins (d) derive historic lake level information using satellite data.

  6. Measurement of polarization curve and development of a unique semi-empirical model for description of PEMFC and DMFC performances

    Directory of Open Access Journals (Sweden)

    M. SHAKERI

    2011-06-01

    Full Text Available In this study, a single polymer electrolyte membrane fuel cell (PEMFC in H2/ /O2 form with an effective dimension of 5 cm5 cm as well as a single direct methanol fuel cell (DMFC with a dimension of 10 cm10 cm were fabricated. In an existing test station, the voltage-current density performances of the fabricated PEMFC and DMFC were examined under various operating conditions. As expected, DMFC showed a lower electrical performance which can be attributed to the slower methanol oxidation rate in comparison to the hydrogen oxidation. The results obtained from the cell operation indicated that the temperature has a great effect on the cell performance. At 60 C, the best power output was obtained for PEMFC. There was a drop in the cell voltage beyond 60 C, which can be attributed to the reduction of water content inside the membrane. For DMFC, the maximum power output resulted at 64 C. Increasing oxygen stoichiometry and total cell pressure had a marginal effect on the cell performance. The results also revealed that the cell performance improved by increasing pressure differences between the anode and cathode. A unified semi-empirical thermodynamic based model was developed to describe the cell voltage as a function of current density for both kinds of fuel cells. The model equation parameters were obtained through a nonlinear fit to the experimental data. There was a good agreement between the experimental data and the model predicted cell performance for both types of fuel cells.

  7. Reactions forming C(0,+)n=2,10, Cn=2,4H(0,+) and C3H(0,+) in the gas phase: semi empirical branching ratios

    OpenAIRE

    Chabot, M.; Beroff, K.; Gratier, P.; Jallat, A.; Wakelam, V.

    2013-01-01

    The aim of this paper is to provide a new set of branching ratios for interstellar and planetary chemical networks based on a semi empirical model. We applied, instead of zero order theory (i.e. only the most exoergic decaying channel is considered), a statistical microcanonical model based on the construction of breakdown curves and using experimental high velocity collision branching ratios for their parametriza- tion. We applied the model to ion-molecule, neutral-neutral, and ion-pair reac...

  8. New Evaluated Semi-Empirical Formula Using Optical Model for 14-15 MeV ( n, t) Reaction Cross Sections

    Science.gov (United States)

    Tel, E.; Durgu, C.; Aydın, A.; Bölükdemir, M. H.; Kaplan, A.; Okuducu, Ş.

    2009-12-01

    In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using optical model for ( n, t) reactions at 14-15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the ( n, t) reaction cross-sections. We have obtained new coefficients for the ( n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting two parameters for the ( n, t) reaction cross-sections at 14-15 MeV. We have discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained cross-section formulas

  9. A semi-empirical approach for the modelling and analysis of microvibration sources on-board spacecraft

    Science.gov (United States)

    Addari, Daniele

    The term microvibrations generally refers to accelerations in the order of micro-gs and which manifest in a bandwidth from a few Hz up to say 500-1000 Hz. The need to accurately characterise this small disturbances acting on-board modern satellites, thus allowing the design of dedicated minimisation and control systems, is nowadays a major concern for the success of some space missions. The main issues related to microvibrations are the feasibility to analytically describe the microvibration sources using a series of analysis tools and test experiments and the prediction of how the dynamics of the microvibration sources couple with those of the satellite structure. In this thesis, a methodology to facilitate the modelling of these phenomena is described. Two aspects are investigated: the characterisation of the microvibration sources with a semi-empirical procedure which allows derivation of the dynamic mass properties of the source, also including the gyroscopic effect, with a significantly simpler test configuration and lower computational effort compared to traditional approaches; and the modelling of the coupled dynamics when the source is mounted on a representative supporting structure of a spacecraft, including the passive and active effects of the source, which allows prediction of the structure response at any location. The methodology has been defined conducting an extensive study, both experimental and numerical, on a reaction wheel assembly, as this is usually identified as the main contributory factor among all microvibration sources. The contributions to the state-of-the-art made during this work include: i) the development of a cantilever configured reaction wheel analytical model able to reproduce all the configurations in which the mechanism may operate and inclusive of the gyroscopic effect; ii) the reformulation of the coupling theory which allows retrieving the dynamic mass of a microvibration source over a wide range of frequencies and speeds

  10. A simple semi-empirical approach to model thickness of ash-deposits for different eruption scenarios

    Directory of Open Access Journals (Sweden)

    A. O. González-Mellado

    2010-11-01

    Full Text Available The impact of ash-fall on people, buildings, crops, water resources, and infrastructure depends on several factors such as the thickness of the deposits, grain size distribution and others. Preparedness against tephra falls over large regions around an active volcano requires an understanding of all processes controlling those factors, and a working model capable of predicting at least some of them. However, the complexity of tephra dispersion and sedimentation makes the search of an integral solution an almost unapproachable problem in the absence of highly efficient computing facilities due to the large number of equations and unknown parameters that control the process. An alternative attempt is made here to address the problem of modeling the thickness of ash deposits as a primary impact factor that can be easily communicated to the public and decision-makers. We develop a semi-empirical inversion model to estimate the thickness of non-compacted deposits produced by an explosive eruption around a volcano in the distance range 4–150 km from the eruptive source.

    The model was elaborated from the analysis of the geometric distribution of deposit thickness of 14 world-wide well-documented eruptions. The model was initially developed to depict deposits of potential eruptions of Popocatépetl and Colima volcanoes in México, but it can be applied to any volcano. It has been designed to provide planners and Civil Protection authorities of an accurate perception of the ash-fall deposit thickness that may be expected for different eruption scenarios. The model needs to be fed with a few easy-to-obtain parameters, namely, height of the eruptive column, duration of the explosive phase, and wind speed and direction, and its simplicity allows it to run in any platform, including a personal computers and even a notebook. The results may be represented as tables, two dimensional thickness-distance plots, or isopach maps using any available

  11. Semi-empirical spectrophotometric (SESp) method for the indirect determination of the ratio of cationic micellar binding constants of counterions X⁻ and Br⁻(K(X)/K(Br)).

    Science.gov (United States)

    Khan, Mohammad Niyaz; Yusof, Nor Saadah Mohd; Razak, Norazizah Abdul

    2013-01-01

    The semi-empirical spectrophotometric (SESp) method, for the indirect determination of ion exchange constants (K(X)(Br)) of ion exchange processes occurring between counterions (X⁻ and Br⁻) at the cationic micellar surface, is described in this article. The method uses an anionic spectrophotometric probe molecule, N-(2-methoxyphenyl)phthalamate ion (1⁻), which measures the effects of varying concentrations of inert inorganic or organic salt (Na(v)X, v = 1, 2) on absorbance, (A(ob)) at 310 nm, of samples containing constant concentrations of 1⁻, NaOH and cationic micelles. The observed data fit satisfactorily to an empirical equation which gives the values of two empirical constants. These empirical constants lead to the determination of K(X)(Br) (= K(X)/K(Br) with K(X) and K(Br) representing cationic micellar binding constants of counterions X and Br⁻). This method gives values of K(X)(Br) for both moderately hydrophobic and hydrophilic X⁻. The values of K(X)(Br), obtained by using this method, are comparable with the corresponding values of K(X)(Br), obtained by the use of semi-empirical kinetic (SEK) method, for different moderately hydrophobic X. The values of K(X)(Br) for X = Cl⁻ and 2,6-Cl₂C6H₃CO₂⁻, obtained by the use of SESp and SEK methods, are similar to those obtained by the use of other different conventional methods.

  12. EVALUATION OF NEUTRON SCATTERING CORRECTION USING THE SEMI-EMPIRICAL METHOD AND THE SHADOW-CONE METHOD FOR THE NEUTRON FIELD OF THE KOREA ATOMIC ENERGY RESEARCH INSTITUTE.

    Science.gov (United States)

    Lee, Seung Kyu; Kim, Sang I; Lee, Jungil; Chang, Insu; Kim, Jang-Lyul; Kim, Hyoungtaek; Kim, Min Chae; Kim, Bong-Hwan

    2017-10-19

    When neutron survey metres are calibrated in neutron fields, the results for room- and air-scattered neutrons vary according to the distance from the source and the size, shape and construction of the neutron calibration room. ISO 8529-2 recommends four approaches for correcting these effects: the shadow-cone method, semi-empirical method, generalised fit method and reduced-fitting method. In this study, neutron scattering effects are evaluated and compared using the shadow-cone and semi-empirical methods for the neutron field of the Korea Atomic Energy Research Institute (KAERI). The neutron field is constructed using a 252Cf neutron source positioned in the centre of the neutron calibration room. To compare the neutron scattering effects using the two correction methods, measurements and simulations are performed using respectively KAERI's Bonner sphere spectrometer (BBS) and Monte Carlo N-Particle code at twenty different positions. Neutron spectra are measured by a europium-activated lithium iodide [6LiI(Eu)] scintillator in combination with the BBS. The calibration factors obtained using each methods show good agreement within 1.1%. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Combined semi-empirical screening and design of experiments (DOE) approach to identify candidate formulations of a lyophilized live attenuated tetravalent viral vaccine candidate.

    Science.gov (United States)

    Patel, Ashaben; Erb, Steven M; Strange, Linda; Shukla, Ravi S; Kumru, Ozan S; Smith, Lee; Nelson, Paul; Joshi, Sangeeta B; Livengood, Jill A; Volkin, David B

    2017-05-12

    A combination experimental approach, utilizing semi-empirical excipient screening followed by statistical modeling using design of experiments (DOE), was undertaken to identify stabilizing candidate formulations for a lyophilized live attenuated Flavivirus vaccine candidate. Various potential pharmaceutical compounds used in either marketed or investigative live attenuated viral vaccine formulations were first identified. The ability of additives from different categories of excipients, either alone or in combination, were then evaluated for their ability to stabilize virus against freeze-thaw, freeze-drying, and accelerated storage (25°C) stresses by measuring infectious virus titer. An exploratory data analysis and predictive DOE modeling approach was subsequently undertaken to gain a better understanding of the interplay between the key excipients and stability of virus as well as to determine which combinations were interacting to improve virus stability. The lead excipient combinations were identified and tested for stabilizing effects using a tetravalent mixture of viruses in accelerated and real time (2-8°C) stability studies. This work demonstrates the utility of combining semi-empirical excipient screening and DOE experimental design strategies in the formulation development of lyophilized live attenuated viral vaccine candidates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Determination of the solvent density profiles across mesopores of silica-C18 bonded phases in contact with acetonitrile/water mixtures: A semi-empirical approach.

    Science.gov (United States)

    Gritti, Fabrice

    2015-09-04

    The local volume fractions of water, acetonitrile, and C18-bonded chains across the 96Åmesopores of 5μm Symmetry particles were determined semi-empirically. The semi-empirical approach was based on previous molecular dynamics studies, which provided relevant mathematical expressions for the density profiles of C18 chains and water molecules, and on minor disturbance experiments, which measured the excess amount of acetonitrile adsorbed in the pores of Symmetry-C18 particles. The pore walls of the Symmetry-C18 material were in thermodynamic equilibrium with a series of binary mixtures of water and acetonitrile. The results show that C18 chains are mostly solvated by acetonitrile molecules, water is excluded from the C18-bonded layer, and acetonitrile concentrates across a 15-25Åthick interface region between the C18 layer and the bulk phase. These actual density profiles are expected to have a direct impact on the retention behaviour of charged, polar, and neutral analytes in RPLC. They also provide clues to predict the local mobility of analytes inside the pores and a sound physico-chemical description of the phenomenon of surface diffusion observed in RPLC. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Kinetic calibration using dominant pre-equilibrium desorption for on-site and in vivo sampling by solid-phase microextraction.

    Science.gov (United States)

    Zhou, Simon Ningsun; Zhao, Wennan; Pawliszyn, Janusz

    2008-01-15

    A new kinetic calibration was developed using dominant pre-equilibrium desorption by solid-phase microextracton. The calibration was based on isotropism between absorption and desorption, which was proved theoretically and experimentally in an aqueous solution and semisolid matrix. This approach allows for the calibration of absorption using desorption to compensate for matrix effects. Moreover, concentration profiles are initially proposed to verify isotropism between the absorption and desorption, while providing a linear approach to obtain time constants for the purpose of quantitative analysis. This linear approach is more convenient, robust, and accurate than the nonlinear version with the previously used time profiles. Furthermore, the target analytes are used as the internal standards; thus, radioactive or deuterated internal standards are not necessary. In addition, dominant pre-equilibrium desorption utilizes the pre-equilibrium approach and offers a shorter sample preparation time, which is typically suitable for in vivo sampling. This kinetic calibration method was successfully applied to prepare samples of polycyclic aromatic hydrocarbons in a flow-through system and in vivo pesticide sampling in a jade plant (Crassula ovata).

  16. A semi-empirical model for the complete orientation dependence of the growth rate for vapor phase epitaxy - Chloride VPE of GaAs

    Science.gov (United States)

    Seidel-Salinas, L. K.; Jones, S. H.; Duva, J. M.

    1992-01-01

    A semi-empirical model has been developed to determine the complete crystallographic orientation dependence of the growth rate for vapor phase epitaxy (VPE). Previous researchers have been able to determine this dependence for a limited range of orientations; however, our model yields relative growth rate information for any orientation. This model for diamond and zincblende structure materials is based on experimental growth rate data, gas phase diffusion, and surface reactions. Data for GaAs chloride VPE is used to illustrate the model. The resulting growth rate polar diagrams are used in conjunction with Wulff constructions to simulate epitaxial layer shapes as grown on patterned substrates. In general, this model can be applied to a variety of materials and vapor phase epitaxy systems.

  17. Pharmacological Classification and Activity Evaluation of Furan and Thiophene Amide Derivatives Applying Semi-Empirical ab initio Molecular Modeling Methods

    Directory of Open Access Journals (Sweden)

    Leszek Bober

    2012-05-01

    Full Text Available Pharmacological and physicochemical classification of the furan and thiophene amide derivatives by multiple regression analysis and partial least square (PLS based on semi-empirical ab initio molecular modeling studies and high-performance liquid chromatography (HPLC retention data is proposed. Structural parameters obtained from the PCM (Polarizable Continuum Model method and the literature values of biological activity (antiproliferative for the A431 cells expressed as LD50 of the examined furan and thiophene derivatives was used to search for relationships. It was tested how variable molecular modeling conditions considered together, with or without HPLC retention data, allow evaluation of the structural recognition of furan and thiophene derivatives with respect to their pharmacological properties.

  18. Modeling of the phase equilibria of polystyrene in methylcyclohexane with semi-empirical quantum mechanical methods I

    DEFF Research Database (Denmark)

    Wilczura-Wachnik, H.; Jonsdottir, Svava Osk

    2003-01-01

    A method for calculating interaction parameters traditionally used in phase-equilibrium computations in low-molecular systems has been extended for the prediction of solvent activities of aromatic polymer solutions (polystyrene+methylcyclohexane). Using ethylbenzene as a model compound for the re......A method for calculating interaction parameters traditionally used in phase-equilibrium computations in low-molecular systems has been extended for the prediction of solvent activities of aromatic polymer solutions (polystyrene+methylcyclohexane). Using ethylbenzene as a model compound...... energies are determined for three molecular pairs, the solvent and the model molecule, two solvent molecules and two model molecules, and used to calculated UNIQUAC interaction parameters, a(ij) and a(ji). Using these parameters, the solvent activities of the polystyrene 90,000 amu+methylcyclohexane system...

  19. Evaluation of characteristic-to-total spectrum ratio: Comparison between experimental and a semi-empirical model.

    Science.gov (United States)

    Lopez Gonzales, A H; Tomal, A; Costa, P R

    2015-06-01

    Primary X-ray spectra were measured in the range of 80-150kV in order to validate a computer program based on a semiempirical model. The ratio between the characteristic and total air Kerma was considered to compare computed results and experimental data. Results show that the experimental spectra have higher first HVL and mean energy than the calculated ones. The ratios between the characteristic and total air Kerma for calculated spectra are in good agreement with experimental results for all filtrations used. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. A semi-empirical approximation of static hysteresis for high flux densities in highly grain-oriented silicon iron

    Science.gov (United States)

    Carrander, C.; Engdahl, G.

    2017-10-01

    In calculations and simulations regarding magnetic materials, it is important to have a have an accurate model of the hysteresis loop. The major loop, in particular, is used in many simulations. However, it is generally not possible to measure the true major loop, and it must therefore be approximated using a minor loop. There are several methods available for approximating magnetization curves, but they are primarily designed for paramagnetic materials, and are poorly suited to the highly grain-oriented steels used in modern transformers. Therefore, we propose two expressions for approximating the magnetization curves of grain-oriented silicon-iron steels. Both methods give close agreement with measurements and can be extrapolated to in order to describe the major loop.

  1. Pre-equilibrium solid-phase microextraction of free analyte in complex samples: correction for mass transfer variation from protein binding and matrix tortuosity.

    Science.gov (United States)

    Zhang, Xu; Oakes, Ken D; Hoque, Md Ehsanul; Luong, Di; Metcalfe, Chris D; Pawliszyn, Janusz; Servos, Mark R

    2011-05-01

    The accurate measurement of free analyte concentrations within complex sample matrixes by pre-equilibrium solid-phase microextraction (SPME) has proven challenging due to variations in mass uptake kinetics. For the first time, the effects of the sample binding matrix and tortuosity on the kinetics of analyte extraction (from the sample to the SPME fiber) are demonstrated to be quantitatively symmetrical with those of the desorption of preloaded deuterated standards (from the fiber to the sample matrix). Consequently, kinetic calibration methods can be employed to correct for variation in SPME sampling kinetics, facilitating the application of pre-equilibrium SPME within complex sample systems. This approach was applied ex vivo to measure pharmaceuticals in fish muscle tissues, with results consistent with those obtained from equilibrium SPME and microdialysis. The developed method has the inherent advantages of being more accurate, precise, and reproducible, thus providing the framework for applications where rapid measurement of free analyte concentrations (within complicated sample matrixes such as biological tissues, sediment, and surface water) are required.

  2. Determination of Equations of State for AlF3 and AlI3: Semi-empirical Modeling of Extreme Condition Halide Chemistry

    Science.gov (United States)

    Zaug, Joseph; Stavrou, Elissaios; Bastea, Sorin; Goncharov, Alexander; Crowhurst, Jonathon; Roberts, Sarah; Plaue, Jonathan; Carter, Jeffrey; Armstrong, Michael

    2013-06-01

    Pressure dependent angle-dispersive x-ray powder diffraction measurements of alpha-phase aluminum trifluoride (alpha-AlF3) and separately, aluminum triiodide (AlI3) were conducted using a diamond-anvil cell. Results at 295 K extend to 50 GPa. The equations of state of AlF3 and AlI3 were determined through refinements of collected x-ray patterns. The respective bulk moduli and corresponding pressure derivatives using multiple orders of the Birch-Murngahan, Ff, and Gg EoS models will be discussed. Aluminum trifluoride exhibits no pressure induced structural phase transition while the triiodide data reveal a second-order iso-structural rearrangement: Applied stress transformed a monoclinicly distorted face centered cubic (FCC) structure into a perfect FCC structure. Results from semi-empirical thermochemical computations of energetic materials formulated with fluorine containing reactants will be presented. This work was performed under the auspices of the U.S. Department of Energy jointly by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. On-line monitoring of vacuum drying of theophylline using NIR spectroscopy: solid-state transitions, water content and semi-empirical modeling.

    Science.gov (United States)

    Amira, Touil; Roman, Peczalski; Fethi, Zagrouba

    2016-11-01

    The aim of this work was to monitor in-line and at a real time, the solid-state forms during pharmaceuticals manufacturing. It concerns the dehydration behavior and the solid-state transitions of theophylline in an agitated vacuum contact dryer. First, a near infrared spectroscopy (NIRS) method was performed using a reflectance diffuse probe to measure the in-line and in-situ exact composition of the mixture of different forms of theophylline and water content during drying. A multivariate modeling has been investigated to build a robust model which can predict four components at the same time during drying process. The XRPD analysis was used as a reference method in the process of calibration of NIRS. The indicators of the accuracy in quantitative spectral analysis confirm the robustness of the model and the efficiency of the method of calibration. Second, the kinetics of solid state transformations were investigated. It was shown that the dehydration advanced first by the formation of the metastable anhydrate and after a lag time of the stable one. Once the stable form appeared, formation of the metastable form came to an end. The temperature was found out to be the main factor controlling the overall process rate but also the final contents of the stable and metastable anhydrates for the considered dryer and operating conditions range. Finally, a semi-empirical drying model was proposed and significant quantitative differences were found, particularly at the product temperature which was probably caused by the excessive simplicity of the model.

  4. Pre-equilibrium emission and clustering in medium-mass nuclei: 46Ti from 16O + 30Si, 18O + 28Si, 19F + 27Al

    Science.gov (United States)

    Cicerchia, M.; Marchi, T.; Gramegna, F.; Cinausero, M.; Mabiala, J.; Fabris, D.; Caciolli, A.; Collazzuol, G.; Mengoni, D.; Degerlier, M.; Morelli, L.; Bruno, M.; D'Agostino, M.; Barlini, S.; Bini, M.; Pasquali, G.; Piantelli, S.; Casini, G.; Pastore, G.; Gruyer, D.; Ottanelli, P.; Valdrè, S.; Gelli, N.; Olmi, A.; Poggi, G.; Vardaci, E.; Lombardo, I.; Dell'Aquila, D.; Leoni, S.; Cieplicka, N.; Fornal, B.

    2017-06-01

    The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is interesting to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions. The NUCL-EX collaboration (INFN, Italy) is carrying out a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei. For this purpose, a comparative study of the three nuclear reactions: 16O + 30Si, 18O + 28Si and 19F + 27Al, has been recently carried out using the GARFIELD+RCo 4π setup. After a general introduction on the experimental campaign, the preliminary results for the three systems are presented.

  5. A revised calculational model for fission

    Energy Technology Data Exchange (ETDEWEB)

    Atchison, F.

    1998-09-01

    A semi-empirical parametrization has been developed to calculate the fission contribution to evaporative de-excitation of nuclei with a very wide range of charge, mass and excitation-energy and also the nuclear states of the scission products. The calculational model reproduces measured values (cross-sections, mass distributions, etc.) for a wide range of fissioning systems: Nuclei from Ta to Cf, interactions involving nucleons up to medium energy and light ions. (author)

  6. Neutron induced reactions of ^150Sm and influence of spin distribution in the pre-equilibrium process

    Science.gov (United States)

    Dashdorj, D.; Mitchell, G. E.; Agvaanluvsan, U.; Becker, J. A.; Cooper, J. R.; Garrett, P. E.; Wu, C. Y.; Younes, W.; Kawano, T.; Chadwick, M.; Devlin, M.; Fotiades, N.; Nelson, R. O.

    2006-10-01

    Cross-section measurements were made of prompt γ-ray production as a function of incident neutron energy (En = 1 to 35 MeV) on an enriched (95.6%) ^150Sm sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center facility. The prompt-reaction γ rays were detected with the large-scale Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The preequilibrium reaction process is important at high energies. The spin distribution transferred in preequilibrium neutron-induced reactions was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK). These preequilibrium spin distributions were incorporated into a new version of the Hauser-Feshbach statistical reaction code GNASH and the γ-ray production cross sections were calculated and compared with experimental data. The difference in the partial γ-ray cross sections using spin distributions with and without preequilibrium effects will be discussed.

  7. Low velocity impact response of carbon fiber laminates fabricated by pulsed infusion: A review of damage investigation and semi-empirical models validation

    Science.gov (United States)

    Antonucci, V.; Caputo, F.; Ferraro, P.; Langella, A.; Lopresto, V.; Pagliarulo, V.; Ricciardi, M. R.; Riccio, A.; Toscano, C.

    2016-02-01

    The research reported in this paper was aimed mainly to investigate the different NDE techniques on specimens made by a new process labeled as "pulsed infusion", very crucial for voids content under critical loading conditions. The impact load, in fact, is critical for composite laminates due to their anisotropy, in particular in extreme temperature conditions due to their brittleness. An additional and very relevant aim was to collect a large number of experimental results to supply useful information for the numerical models needed to simulate the dynamic behavior of composite laminates. At the aim to investigate the response under dynamic loads of laminates fabricated by a new vacuum assisted technology labeled as "pulsed infusion", rectangular carbon fiber composite specimens were subjected to low velocity impact tests. Experimental tests up to complete penetration and at different energy levels, were carried out by a modular falling weight tower. All the parameters related to the phenomenon, like penetration energy, maximum force and indentation depths, were used to validate existing semi-empirical and numerical models. The largely used ultra sound technique (US) was adopted to investigate the delamination together with the thermo graphic technique. The results of the measurements were compared with data obtained on the same specimens by holographic analysis (ESPI). One of the scope was to investigate the crucial internal impact damage and assess the ability of an unconventional ND system (ESPI) in giving right information about non-visual damage generated inside composite laminates subjected to dynamic loads. Moreover, some of the specimens were cut to allow the fractographic analysis. The efficiency of the above mentioned new fabrication technology was studied also comparing the results with measurements from literature on impacted autoclave cured laminates. By the comparison between the results, good agreements were found denoting the efficiency and the

  8. Semi-empirical simulation of thermoluminescent response under different filter geometries; Simulacao semi-empirica da resposta termoluminescente sob diferentes geometrias de filtro

    Energy Technology Data Exchange (ETDEWEB)

    Shammas, Gabriel Issa Jabra

    2006-07-01

    Many thermoluminescent materials has been developed and used for photon personal dosimetry but no one has all desired characteristics alone. These characteristics include robustness, high sensitivity, energy photon independence, large range of photon energy detection, good reproducibility, small fading and simple glow curve with peaks above 150 deg C. Calcium Sulfate Dysprosium doped (CaSO{sub 4}:Dy) phosphor Thermoluminescent Dosimeter (TLD) has been used by many laboratories, mainly in Brazil and India. Another interesting phosphor is Calcium Fluoride (CaF{sub 2}). These phosphor advantages begin to be more required and its disadvantages have became more apparent, in a global market more and more competitive. These phosphors are used in environmental and area monitoring, once they present more sensibility than other phosphors, like LiF:Mg. Theirs mainly disadvantage is a strong energetic dependence response, which must be corrected for theirs application in the field, where photon radiation is unknown a priori. An interesting way do make this correction in orthogonal incidence of the radiation on the phosphor is to interject a plane leaked filter between the beam and the phosphor. In order to reduce the energetic dependence on any incidence angle, reducing the field dose measurement uncertainty too, this work presents a simulation study on spherical filter geometries. It was simulated photon irradiations with Gamma rays of {sup 60}Co and x-rays of 33; 48 and 118 keV, on many incidence angles from zero to ninety degrees. These semi-empirical computational simulations using finite differences in three dimensions were done in spherical coordinates. The results pointed out the best filter thicknesses and widths, in order to optimize the correction on energetic dependence. (author)

  9. Through-Flow Calculations in Axial Turbomachinery

    Science.gov (United States)

    1976-10-01

    Glassman , Lewis Research Center, NASA SP-290, 1973. 3. Dzung, L.S.: Schaufelgitter mit dicker Hinterkante, Technical Note BBC, (unpublished) 4...of peak efficiency was taken from - Warner L.S. : ASME Paper 61-WA-37 - Glassman A.J. : NASA TN-D-6702 The method for computing incidence losses is...devise more intelligent ý , flow models whicn will enable us to do semi-empirical simpler calculations. One of the things that I have in mind and has not

  10. Development of new model for high explosives detonation parameters calculation

    Directory of Open Access Journals (Sweden)

    Jeremić Radun

    2012-01-01

    Full Text Available The simple semi-empirical model for calculation of detonation pressure and velocity for CHNO explosives has been developed, which is based on experimental values of detonation parameters. Model uses Avakyan’s method for determination of detonation products' chemical composition, and is applicable in wide range of densities. Compared with the well-known Kamlet's method and numerical model of detonation based on BKW EOS, the calculated values from proposed model have significantly better accuracy.

  11. Semi-empirical long-term cycle life model coupled with an electrolyte depletion function for large-format graphite/LiFePO4 lithium-ion batteries

    Science.gov (United States)

    Park, Joonam; Appiah, Williams Agyei; Byun, Seoungwoo; Jin, Dahee; Ryou, Myung-Hyun; Lee, Yong Min

    2017-10-01

    To overcome the limitation of simple empirical cycle life models based on only equivalent circuits, we attempt to couple a conventional empirical capacity loss model with Newman's porous composite electrode model, which contains both electrochemical reaction kinetics and material/charge balances. In addition, an electrolyte depletion function is newly introduced to simulate a sudden capacity drop at the end of cycling, which is frequently observed in real lithium-ion batteries (LIBs). When simulated electrochemical properties are compared with experimental data obtained with 20 Ah-level graphite/LiFePO4 LIB cells, our semi-empirical model is sufficiently accurate to predict a voltage profile having a low standard deviation of 0.0035 V, even at 5C. Additionally, our model can provide broad cycle life color maps under different c-rate and depth-of-discharge operating conditions. Thus, this semi-empirical model with an electrolyte depletion function will be a promising platform to predict long-term cycle lives of large-format LIB cells under various operating conditions.

  12. Semi-empirical correlation for binary interaction parameters of the Peng–Robinson equation of state with the van der Waals mixing rules for the prediction of high-pressure vapor–liquid equilibrium

    Directory of Open Access Journals (Sweden)

    Seif-Eddeen K. Fateen

    2013-03-01

    Full Text Available Peng–Robinson equation of state is widely used with the classical van der Waals mixing rules to predict vapor liquid equilibria for systems containing hydrocarbons and related compounds. This model requires good values of the binary interaction parameter kij. In this work, we developed a semi-empirical correlation for kij partly based on the Huron–Vidal mixing rules. We obtained values for the adjustable parameters of the developed formula for over 60 binary systems and over 10 categories of components. The predictions of the new equation system were slightly better than the constant-kij model in most cases, except for 10 systems whose predictions were considerably improved with the new correlation.

  13. A Computational Study of the Tensile and Compressive Properties of Ordered Polymers via the Austin Model 1 (AM1) Semi-Empirical Molecular Orbital Method

    Science.gov (United States)

    1988-10-01

    by the facility with which it may be submitted to calculation (1]. Adolphe Quetelet 1796-1874 Adolphe Quetelet’s words turned out to be prophetic...modeling of polymer solutions with computational chemistry techniques is still in the future. REFERENCES 1. A. Quetelet , Instructions Populaires sur le

  14. Reaction cross section calculation of some alkaline earth elements

    Science.gov (United States)

    Tel, Eyyup; Kavun, Yusuf; Sarpün, Ismail Hakki

    2017-09-01

    Reaction cross section knowledge is crucial to application nuclear physics such as medical imaging, radiation shielding and material evaluations. Nuclear reaction codes can be used if the experimental data are unavailable or are improbably to be produced because of the experimental trouble. In this study, there action cross sections of some target alkaline earth elements have been calculated by using pre-equilibrium and equilibrium nuclear reaction models for nucleon induced reactions. While these calculations, the Hybrid Model, the Geometry Dependent Hybrid Model, the Full Exciton Model, the Cascade Exciton Model for pre-equilibrium reactions and the Weisskopf-Ewing Model for equilibrium reactions have been used. The calculated cross sections have been discussed and compared with the experimental data taken from Experimental Nuclear Reaction Data library.

  15. Quantitative structure-cytotoxicity relationship of newly synthesised trihaloacetylazulenes determined by a semi-empirical molecular-orbital method (PM5).

    Science.gov (United States)

    Ishihara, Mariko; Wakabayashi, Hidetsugu; Motohashi, Noboru; Sakagami, Hiroshi

    2011-02-01

    In order to extend the search for tumour-targeting compounds, this study performed a quantitative structure-activity relationship (QSAR) analysis of 26 newly synthesised trihaloacetylazulenes. The value of 50% cytotoxic concentration (CC(50)) of trihaloacetylazulenes against human oral squamous cell carcinoma (HSC-2, HSC-3, HSC-4) and human promyelocytic leukaemia (HL-60) cell lines was calculated from the dose-response curve by the MTT method. CONFLEX/CAChe PM5 was used for the calculation of 11 physico-chemical features for each compound. When all 26 compounds were analysed together, the CC(50) values correlated well with the dipole moment, the lowest unoccupied molecular orbital energy and the reactivity index, and somewhat with the heat of formation, the stability of hydration and the absolute electron negativity, but not with other features. When these 26 compounds were separated into two groups with or without substituents of the 7-membered ring, the correlation coefficient was increased. When the 26 compounds were separated into a different set of two groups with different halogen atoms in the 5-membered ring, no improvement of correlation coefficient was observed. The present study suggests that appropriate grouping of test compounds may further increase the correlation coefficient. The QSAR approach was useful in the design of azulene compounds that are expected to show higher potency.

  16. A Semi-Empirical Excess Pressure Equation for CO{sub 2}-H{sub 2}O fluids at 400 C, 0--400 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Blencoe, J.G.; Anovitz, L.M.; Singh, J.

    1999-09-12

    Highly accurate and precise density data for CO{sub 2}-H{sub 2}O mixtures at 400 C 10-400 MPa, were used to develop a modified, B-truncated virial equation for excess pressure (P{sup ex}). This function and empirical equations of state for H{sub 2}O and CO{sub 2} accurately represent the experimentally determined densities, and interpolate smoothly between data points. Integrating the P{sub ex} expression with respect to molar volume yields an equation for excess Helmholta free energy, which can be used to calculate other excess properties of interest. The P{sup ex} modeling method has important advantages over more conventional, alternative approaches.

  17. Semi-empirical thermospheric modeling: the new NASA Marchall Engineering Thermosphere model - version 2.0 (MET-V2.0)

    Science.gov (United States)

    Owens, J.; Vaughan, W.

    The use of thermospheric density models in the prediction of atmospheric drag (the major perturbation for orbiting spacecraft) is of great importance. Issues for which these predictions are key considerations include prediction and statistical confidence of satellite orbital lifetime estimates, orbital insertion altitudes, orbit determination and tracking, attitude dynamics, and re-entry prediction. Logistics planning through attitude control requirements and re-boost planning are also influenced by future orbital altitude density estimates. This paper describes the new NASA Marshall Engineering Thermosphere Model-Version 2.0 (MET-V 2.0), and the history associated with its development. This model is used by a number of aerospace organizations. The model computes the total mass density, temperature, and individual species number densities for altitudes between 90 and 2500 km as a function of latitude, longitude, time, and solar and geomagnetic activity. Using current or past observations of solar radio flux and geomagnetic activity as inputs to the MET-V2.0 model will produce thermospheric density estimates with an accuracy of about 15 percent. However, as with all other thermospheric density models, using future estimates of these solar and geomagnetic input values from generally accepted statistical models (no physical solar model is available for use currently) will result in significantly (order of magnitude effects) reduced accuracy for the calculated thermospheric density values.

  18. Determination of the semi-empiric relationship among the physical density, the concentration and rate between hydrogen and manganese atoms, and a manganese sulfate solution; Determinacao da relacao semi-empirica entre a densidade fisica, concentracao e razao entre atomos de hidrogenio e manganes em uma solucao de sulfato de manganes

    Energy Technology Data Exchange (ETDEWEB)

    Bittencourt, Guilherme Rodrigues [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil). PIBIC; Castro, Leonardo Curvello de; Pereira, Walsan W.; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Dantas, Maria Leticia [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes (LNMRI). Lab. de Neutrons

    2009-07-01

    The bath of a manganese sulfate (BMS) is a system for absolute standardization of the neutron sources. This work establishes a functional relationship based on semi-empirical methods for the theoretical prediction of physical density values, concentration and rate between the hydrogen and manganese atoms presents in the solution of the BMS

  19. Semi-empirical chemical model for indirect advanced oxidation of Acid Orange 7 using an unmodified carbon fabric cathode for H2O2 production in an electrochemical reactor.

    Science.gov (United States)

    Ramírez, B; Rondán, V; Ortiz-Hernández, L; Silva-Martínez, S; Alvarez-Gallegos, A

    2016-04-15

    A commercial Unidirectional Carbon Fabric piece was used to design an electrode for the cathodic O2 reduction reaction in a divided (by a Nafion(®) 117 membrane) parallel plate reactor. The anode was a commercial stainless steel mesh. Under this approach it is feasible to produce H2O2 at low energy (2.08 kWh kg(-1) H2O2) in low ionic acidic medium. In the catholyte side the H2O2 can be activated with Fe(2+) to develop the Fenton reagent. It was found that Acid Orange 7 (AO7) indirect oxidation (in the concentration range of 0.12-0.24 mM) by Fenton chemistry follows a first order kinetic equation. The energy required for 0.24 mM AO7 degradation is 1.04 kWhm(-3). From each experimental AO7 oxidation the main parameters (a, mM and k, min(-1)) of the first order kinetic equation are obtained. These parameters can be correlated with AO7 concentration in the concentration range studied. Based on this method a semi-empirical chemical model was developed to predict the AO7 abatement, by means of Fenton chemistry. Good AO7 oxidation predictions can be made in the concentration range studied. A detailed discussion of the energy required for oxidizing AO7 and the accuracy of the chemical model to predict its oxidation is included in this paper. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Semi-empirical crack tip analysis

    Science.gov (United States)

    Chudnovsky, A.; Ben Ouezdon, M.

    1988-01-01

    Experimentally observed crack opening displacements are employed as the solution of the multiple crack interaction problem. Then the near and far fields are reconstructed analytically by means of the double layer potential technqiue. Evaluation of the effective stress intensity factor resulting from the interaction of the main crack and its surrounding crazes in addition to the remotely applied load is presented as an illustrative example. It is shown that crazing (as well as microcracking) may constitute an alternative mechanism to Dugdale-Berenblatt models responsible for the cancellation of the singularity at the crack tip.

  1. Fast-neutron induced pre-equilibrium reactions on 55Mn and 63,65Cu at energies up to 40 MeV

    CERN Document Server

    Avrigeanu, M; Filatenkov, A A; Forrest, R A; Herman, M; Köning, A J; Plompen, A J M; Roman, F L; Avrigeanu, V

    2007-01-01

    Excitation functions were measured for the $^{55}$Mn(n,2n)$^{54}$Mn, $^{55}$Mn(n,$\\alpha$)$^{52}$V, $^{63}$Cu(n,$\\alpha$)$^{60}$Co, $^{65}$Cu(n,2n)$^{64}$Cu, and $^{65}$Cu(n,p)$^{65}$Ni reactions from 13.47 to 14.83 MeV. The experimental cross sections are compared with the results of calculations including all activation channels for the stable isotopes of Mn and Cu, for neutron incident energies up to 50 MeV. Within the energy range up to 20 MeV the model calculations are most sensitive to the parameters related to nuclei in the early stages of the reaction, while the model assumptions are better established by analysis of the data in the energy range 20-40 MeV. While the present analysis has taken advantage of both a new set of accurate measured cross sections around 14 MeV and the larger data basis fortunately available between 20 and 40 MeV for the Mn and Cu isotopes, the need of additional measurements below as well as above 40 MeV is pointed out. Keywords: 55Mn, 63,65Cu, E$\\leq$40 MeV, Neutron activati...

  2. Pre-equilibrium parton dynamics: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin-Nian [ed.

    1993-12-31

    This report contains papers on the following topics: parton production and evolution; QCD transport theory; interference in the medium; QCD and phase transition; and future heavy ion experiments. This papers have been indexed separately elsewhere on the data base.

  3. Molecular orbital calculations using chemical graph theory

    CERN Document Server

    Dias, Jerry Ray

    1993-01-01

    Professor John D. Roberts published a highly readable book on Molecular Orbital Calculations directed toward chemists in 1962. That timely book is the model for this book. The audience this book is directed toward are senior undergraduate and beginning graduate students as well as practicing bench chemists who have a desire to develop conceptual tools for understanding chemical phenomena. Although, ab initio and more advanced semi-empirical MO methods are regarded as being more reliable than HMO in an absolute sense, there is good evidence that HMO provides reliable relative answers particularly when comparing related molecular species. Thus, HMO can be used to rationalize electronic structure in 1t-systems, aromaticity, and the shape use HMO to gain insight of simple molecular orbitals. Experimentalists still into subtle electronic interactions for interpretation of UV and photoelectron spectra. Herein, it will be shown that one can use graph theory to streamline their HMO computational efforts and to arrive...

  4. Particle induced nuclear reaction calculations of Boron target nuclei

    Directory of Open Access Journals (Sweden)

    Tel Eyyup

    2017-01-01

    Full Text Available Boron is usable element in many areas such as health, industry and energy. Especially, Boron neutron capture therapy (BNCT is one of the medical applications. Boron target is irradiated with low energy thermal neutrons and at the end of reactions alpha particles occur. After this process recoiling lithium-7 nuclei is composed. In this study, charge particle induced nuclear reactions calculations of Boron target nuclei were investigated in the incident proton and alpha energy range of 5–50 MeV. The excitation functions for 10B target nuclei reactions have been calculated by using PCROSS Programming code. The semi-empirical calculations for (p,α reactions have been done by using cross section formula with new coefficient obtained by Tel et al. The calculated results were compared with the experimental data from the literature.

  5. Particle induced nuclear reaction calculations of Boron target nuclei

    Science.gov (United States)

    Tel, Eyyup; Sahan, Muhittin; Sarpün, Ismail Hakki; Kavun, Yusuf; Gök, Ali Armagan; Poyraz, Meltem

    2017-09-01

    Boron is usable element in many areas such as health, industry and energy. Especially, Boron neutron capture therapy (BNCT) is one of the medical applications. Boron target is irradiated with low energy thermal neutrons and at the end of reactions alpha particles occur. After this process recoiling lithium-7 nuclei is composed. In this study, charge particle induced nuclear reactions calculations of Boron target nuclei were investigated in the incident proton and alpha energy range of 5-50 MeV. The excitation functions for 10B target nuclei reactions have been calculated by using PCROSS Programming code. The semi-empirical calculations for (p,α) reactions have been done by using cross section formula with new coefficient obtained by Tel et al. The calculated results were compared with the experimental data from the literature.

  6. Proton bombarded reactions of Calcium target nuclei

    Directory of Open Access Journals (Sweden)

    Tel Eyyup

    2017-01-01

    Full Text Available In this study, proton bombarded nuclear reactions calculations of Calcium target nuclei have been investigated in the incident proton energy range of 1–50 MeV. The excitation functions for 40Ca target nuclei reactions have been calculated by using PCROSS nuclear reaction calculation code. Weisskopf-Ewing and the full exciton models were used for equilibrium and for pre-equilibrium calculations, respectively. The excitation functions for 40Ca target nuclei reactions (p,α, (p,n, (p,p have been calculated using the semi-empirical formula Tel et al. [5].

  7. Mechanism of formation of the pre-equilibrium part of cross section in sup 1 sup 9 sup 7 Au(alpha, t), sup 1 sup 9 sup 7 Au(alpha, sup 3 He) reactions and a role of entrance states

    CERN Document Server

    Blekhman, A M

    2000-01-01

    Inclusive sup 1 sup 9 sup 7 Au(alpha, t) and sup 1 sup 9 sup 7 Au(alpha, sup 3 He) reaction spectra at incident alpha-particles energy E subalpha=50 MeV were measured in wide angular and energy range. The experimental results were analyzed basing in the coalescence version of the pre-equilibrium decay excitation model. In its framework, for the case of alpha-particle induced reactions, was suggested a new mechanism for formation of states, ranged by number of unbound excitons, and for emission from them of complex particles. (author)

  8. Calculations of proton chemical shifts in olefins and aromatics

    CERN Document Server

    Escrihuela, M C

    2000-01-01

    induced reagents on alpha,beta unsaturated ketones has also been investigated in order to deduce molecular structures and to obtain the assignment of the spectra of these molecules. A semi-empirical calculation of the partial atomic charges in organic compounds based on molecular dipole moments (CHARGE3) was developed into a model capable of predicting proton chemical shifts in a wide variety of organic compounds to a reasonable degree of accuracy. The model has been modified to include condensed aromatic hydrocarbons and substituted benzenes, alkenes, halo-monosubstituted benzenes and halo-alkenes. Within the aromatic compounds the influence of the pi electron densities and the ring current have been investigated, along with the alpha, beta and gamma effects. The model gives the first accurate calculation of the proton chemical shifts of condensed aromatic compounds and the proton substituent chemical shifts (SCS) in the benzene ring. For the data set of 55 proton chemical shifts spanning 3 ppm the rms error...

  9. Influence of geometric and hydro-dynamic parameters of injector on calculation of spray characteristics of diesel engines

    Directory of Open Access Journals (Sweden)

    Filipović Ivan

    2011-01-01

    Full Text Available The main role in air/fuel mixture formation at the IC diesel engines has the energy introduced by fuel into the IC engine that is the characteristics of spraying fuel into the combustion chamber. The characteristic can be defined by the spray length, the spray cone angle, the physical and the chemical structure of fuel spray by different sections. Having in mind very complex experimental setups for researching in this field, the mentioned characteristics are mostly analyzed by calculations. There are two methods in the literature, the first based on use of the semi-empirical expressions (correlations and the second, the calculations of spray characteristics by use of very complex mathematical methods. The second method is dominant in the modern literature. The main disadvantage of the calculation methods is a correct definition of real state at the end of the nozzle orifice (real boundary conditions. The majority of the researchers in this field use most frequently the coefficient of total losses inside the injector. This coefficient depends on injector design, as well as depends on the level of fuel energy and fuel energy transformation along the injector. Having in mind the importance of the real boundary conditions, the complex methods for calculation of the fuel spray characteristics should have the calculation of fuel flows inside the injector and the calculation of spray characteristics together. This approach is a very complex numerical problem and there are no existing computer programs with satisfactory calculation results. Analysis of spray characteristics by use of the semi-empirical expressions (correlations is presented in this paper. The special attention is dedicated to the analysis of the constant in the semi-empirical expressions and influence parameters on this constant. Also, the method for definition of realistic boundary condition at the end of the nozzle orifice is presented in the paper. By use of this method completely

  10. Calculation and Identification of the Aerodynamic Parameters for Small-Scaled Fixed-Wing UAVs.

    Science.gov (United States)

    Shen, Jieliang; Su, Yan; Liang, Qing; Zhu, Xinhua

    2018-01-13

    The establishment of the Aircraft Dynamic Model(ADM) constitutes the prerequisite for the design of the navigation and control system, but the aerodynamic parameters in the model could not be readily obtained especially for small-scaled fixed-wing UAVs. In this paper, the procedure of computing the aerodynamic parameters is developed. All the longitudinal and lateral aerodynamic derivatives are firstly calculated through semi-empirical method based on the aerodynamics, rather than the wind tunnel tests or fluid dynamics software analysis. Secondly, the residuals of each derivative are proposed to be identified or estimated further via Extended Kalman Filter(EKF), with the observations of the attitude and velocity from the airborne integrated navigation system. Meanwhile, the observability of the targeted parameters is analyzed and strengthened through multiple maneuvers. Based on a small-scaled fixed-wing aircraft driven by propeller, the airborne sensors are chosen and the model of the actuators are constructed. Then, real flight tests are implemented to verify the calculation and identification process. Test results tell the rationality of the semi-empirical method and show the improvement of accuracy of ADM after the compensation of the parameters.

  11. Calculation and Identification of the Aerodynamic Parameters for Small-Scaled Fixed-Wing UAVs

    Science.gov (United States)

    Shen, Jieliang; Su, Yan; Liang, Qing; Zhu, Xinhua

    2018-01-01

    The establishment of the Aircraft Dynamic Model (ADM) constitutes the prerequisite for the design of the navigation and control system, but the aerodynamic parameters in the model could not be readily obtained especially for small-scaled fixed-wing UAVs. In this paper, the procedure of computing the aerodynamic parameters is developed. All the longitudinal and lateral aerodynamic derivatives are firstly calculated through semi-empirical method based on the aerodynamics, rather than the wind tunnel tests or fluid dynamics software analysis. Secondly, the residuals of each derivative are proposed to be identified or estimated further via Extended Kalman Filter (EKF), with the observations of the attitude and velocity from the airborne integrated navigation system. Meanwhile, the observability of the targeted parameters is analyzed and strengthened through multiple maneuvers. Based on a small-scaled fixed-wing aircraft driven by propeller, the airborne sensors are chosen and the model of the actuators are constructed. Then, real flight tests are implemented to verify the calculation and identification process. Test results tell the rationality of the semi-empirical method and show the improvement of accuracy of ADM after the compensation of the parameters. PMID:29342856

  12. Semi-empirical model for estimating molar fraction of syngas ...

    African Journals Online (AJOL)

    To optimize the efficiency of the wood gasification, tar which limits the use of syngas in thermal engines must be reduced. The quantity, quality and composition of syngas produced after thermal cracking of tar were analysed, and mathematical equations formulated based on Newton's bivariate polynomial interpolation were ...

  13. Semi-Empiric Algorithm for Assessment of the Vehicle Mobility

    Directory of Open Access Journals (Sweden)

    Ticusor CIOBOTARU

    2009-12-01

    Full Text Available The mobility of military vehicles plays a key role in operation. The ability to reach the desired area in war theatre represents the most important condition for a successful accomplishment of the mission for military vehicles. The off-road vehicles face a broad spectrum of terrains to cross. These terrains differ by geometry and the soil characteristics.NATO References Mobility Model (NRMM software is based on empirical relationship between the terrain characteristics, running conditions and vehicles design. The paper presents the main results of a comparative mobility analysis for M1 and HMMWV vehicles obtained using NRMM.

  14. Semi-empirical system scaling rules for DWDM system design.

    Science.gov (United States)

    DeMuth, Brian; Frankel, Michael Y; Pelekhaty, Vladimir

    2012-01-30

    Recently, several theoretical papers have derived relationships for fiber-optic transmission system performance in terms of associated physical layer parameters. At the same time, a large number of detailed experiments have been and continue being performed that demonstrate increasing capacities and unregenerated reach. We use this wealth of experimental data to validate the aforementioned relationships, and to propose a set of simple scaling rules for performance. We find that, despite substantial differences in experimental configurations, overall performance in terms of spectral efficiency and unregenerated reach is well explained by scaling rules. These scaling rules will be useful to carriers seeking to understand what they should expect to see in terms of network performance using deployed or easily accessible technology, which may be radically different from hero experiment results. These rules will also be useful to design engineers seeking cost effective tradeoffs to achieving higher performance using realistic upgrade strategies, and what might be encountered as a fundamental limit.

  15. Semi-empirical software for the aluminothermic and carbothermic reactions

    Directory of Open Access Journals (Sweden)

    Milorad Gavrilovski

    2014-09-01

    Full Text Available Understanding the reaction thermochemistry as well as formatting the empirical data about element distribution in gas-metal-slag phases is essential for creating a good model for aluminothermic and carbothermic reaction. In this paper modeling of material and energy balance of these reactions is described with the algorithm. The software, based on this model is basically made for production of high purity ferro alloys through aluminothermic process and then extended for some carbothermic process. Model validation is demonstrated with production of FeTi, FeW, FeB and FeMo in aluminothermic and reduction of mill scale, pyrite cinders and magnetite fines in carbothermic process.

  16. A Semi-Empirical Low-Latitude Ionospheric Model

    Science.gov (United States)

    1988-10-06

    13, taken from the paper by Anderson and Klobuchar [1983], shows the large day- to-day variation in TEC at Ascension Island for the 10 a month of...September 1979. Often the premidnight maximum in TEC is greater than the daytime maxi- mum value. Anderson and Klobuchar found that the 0 strength of the... Klobuchar et al., 1977]. The con- 00 12 24 tour shapes are very similar; however, the observed LOCAL TIME (hrs) magnitudes are higher during solar

  17. Semi-empirical software for the aluminothermic and carbothermic reactions

    OpenAIRE

    Milorad Gavrilovski; Vaso Manojlović; Željko Kamberović; Marija Korać; Miroslav Sokić

    2014-01-01

    Understanding the reaction thermochemistry as well as formatting the empirical data about element distribution in gas-metal-slag phases is essential for creating a good model for aluminothermic and carbothermic reaction. In this paper modeling of material and energy balance of these reactions is described with the algorithm. The software, based on this model is basically made for production of high purity ferro alloys through aluminothermic process and then extended for some carbothermic proc...

  18. Semi-Empirical Method Interpretation of Cone Penetration Test (CPT ...

    African Journals Online (AJOL)

    Cone Penetration Test (CPT) is a reliable technique for measuring subsurface soil friction, cohesion and bearing capacity for pile foundation. In some parts of the ... The approach is suitable because of the insensitivity of the mechanical cone penetrometer in measuring skin friction, especially in clay deposits. Discovery and ...

  19. Semi-Empirical Models for Buoyancy-Driven Ventilation

    DEFF Research Database (Denmark)

    Terpager Andersen, Karl

    2015-01-01

    A literature study is presented on the theories and models dealing with buoyancy-driven ventilation in rooms. The models are categorised into four types according to how the physical process is conceived: column model, fan model, neutral plane model and pressure model. These models are analysed...

  20. High Througput pKa Prediction Using Semi Empirical Methods

    CERN Document Server

    Jensen, Jan H

    2015-01-01

    A large proportion of organic molecules relevant to medicine and biotechnology contain one or more ionizable groups, which means that fundamental physical and chemical properties (e.g. the charge of the molecule) depend on the pH of the surroundings via the corresponding pKa values of the molecules. As drug- and material design increasingly is being done through high throughput screens, fast - yet accurate - computational pKa prediction methods are becoming crucial to the design process. Current empirical pKa predictors are increasingly found to fail because they are being applied to parts of chemical space for which experimental parameterization data is lacking. We propose to develop a pKa predictor that, due its quantum mechanical foundation, is more generally applicable but still fast enough to be used in high throughput screening. The method has the potential to impact virtually any biotechnological design process involving organic molecules as we will demonstrate for metabolic engineering and organic bat...

  1. Parameters in semi-empirical theories of alloy phase formation

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, L H; Watson, R E

    1979-01-01

    Many theories of alloy solubility, structural stability of compounds, and heats of formation in alloying rely on parameters such as valence, size or electronegativity for their predictions. Nature, of course, requires only one parameter, the nuclear charge to completely specify all the electronic properties of the elements. Thus, the atomic parameters are, of necessity, initimately connected with one another. This presentation reviews the physical origins of some of the more popular parameters used. The relaionship of the different electronegativity scales to each other, and the relationship of electronegativity to other parameters such as atomic size are emphasized. Structural stability maps employing electronegativity and some other parameters are shown for intermetallic compounds formed from different classes of elements: main group-main group, transition metal-main group, and transition metal-transition metal.

  2. QSPR modeling of thermal stability of nitroaromatic compounds: DFT vs. AM1 calculated descriptors.

    Science.gov (United States)

    Fayet, Guillaume; Rotureau, Patricia; Joubert, Laurent; Adamo, Carlo

    2010-04-01

    The quantitative structure-property relationship (QSPR) methodology was applied to predict the decomposition enthalpies of 22 nitroaromatic compounds, used as indicators of thermal stability. An extended series of descriptors (constitutional, topological, geometrical charge related and quantum chemical) was calculated at two different levels of theory: density functional theory (DFT) and semi-empirical AM1 approaches. Reliable models have been developed for each level, leading to similar correlations between calculated and experimental data (R(2) > 0.98). Hence, both of them can be employed as screening tools for the prediction of thermal stability of nitroaromatic compounds. If using the AM1 model presents the advantage to be less time consuming, DFT allows the calculation of more accurate molecular quantum properties, e.g., conceptual DFT descriptors. In this study, our best QSPR model is based on such descriptors, providing more chemical comprehensive relationships with decomposition reactivity, a particularly complex property for the specific class of nitroaromatic compounds.

  3. Alpha decay calculations with a new formula

    Science.gov (United States)

    Akrawy, D. T.; Poenaru, D. N.

    2017-10-01

    A new semi-empirical formula for calculations of α decay half-lives is presented. It was derived from the Royer relationship by introducing new parameters which are fixed by fit to a set of experimental data. We are using three sets: set A with 130 e-e (even-even), 119 e-o (even-odd), 109 o-e, and 96 o-o, set B with 188 e-e, 147 e-o, 131 o-e and 114 o-o, and set C with 136 e-e, 84 e-o, 76 o-e and 48 o-o alpha emitters. A comparison of results obtained with the new formula (newF) and the following well known relationships: semiempirical relationship based on fission theory (semFIS), analytical superasymmetric fission (ASAF) model and universal formula (UNIV) made in terms of rms standard deviation. We also introduced a weighted mean value of this quantity, allowing us to compare the global properties of a given model. For set B the order of the four models is the following: semFIS, UNIV, newF and ASAF. Nevertheless for even-even alpha emitters, UNIV gives the second best result after semFIS, and for odd-even parents the second is newF. Despite its simplicity in comparison with semFIS, newF, presented in this article, behaves quite well, competing with the other well known relationships.

  4. Adaptação de métodos semi-empíricos para estimar capacidade de carga de estacas de pequeno diâmetro no solo de Londrina, Estado do Paraná = Adaptation of the semi-empiric methods to calculate small diameter piles bearing capacity in the soil of Londrina City, Paraná State

    Directory of Open Access Journals (Sweden)

    Miriam Gonçalves Miguel

    2005-07-01

    Full Text Available A cidade de Londrina, Estado do Paraná, possui um perfil geotécnicoconstituído de uma camada superficial de solo argilo-siltoso, poroso, laterítico e muitas vezes colapsível, que se estende até a profundidade máxima de 12 metros. As estacas utilizadas em obras de pequeno a médio porte se encontram totalmente embutidas nesta camada, sofrendo a influência de seu comportamento laterítico e colapsível. Os métodos clássicos brasileiros de estimativa de capacidade de carga de estacas tornam-se conservadores, frente aos resultados reais, quando aplicados em solos lateríticos e, contra a segurança, quando aplicados em solos colapsíveis, isto é, na condição crítica ao colapso. Este trabalho avalia os coeficientes de ajuste das resistências de ponta e ao atrito lateral para esses métodos, no caso de estacas apiloadas, sendo estes coeficientes obtidos pela retro-análise de resultados de provas de carga estática à compressão, realizadas no Campo Experimental de Engenharia Geotécnica da Universidade Estadual de Londrina.The city of Londrina, Paraná, has a typical geotechnical profile defined by a superficial layer of porous silty clay with maximum depth of about 12 meters, that shows lateritic characteristics, andmany times, collapsibility. Casts in place piles are often used for small buildings in the region and are fully embedded in this soil layer. Therefore, this type of foundation is subjected to the lateritic and occasionally collapsible influence of soil. Brazilian pile bearing capacity methods may yield conservative results when applied to tropical soils, as far as the lateritic origin in concerned. On the other hand, it can be unsafe if collapsibility prevails. This paper evaluates coefficients to adjust both point and lateral resistance of cast in place small diameter piles in the situation described. The work was carried out at the Londrina State University Geotechnical Experimental Site, and back analysis from static compression load tests data was done.

  5. Equilibrium and pre-equilibrium emissions in proton-induced ...

    Indian Academy of Sciences (India)

    Author Affiliations. A Kaplan1 A Aydin2 E Tel3 B Şarer3. Faculty of Arts and Sciences, Süleyman Demirel University, 32260, Isparta, Turkey; Faculty of Arts and Sciences, Kirikkale University, 71450, Kirikkale, Turkey; Faculty of Arts and Sciences, Gazi University, 06500 Ankara, Turkey ...

  6. Declination Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Declination is calculated using the current International Geomagnetic Reference Field (IGRF) model. Declination is calculated using the current World Magnetic Model...

  7. Monte Carlo based geometrical model for efficiency calculation of an n-type HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Padilla Cabal, Fatima, E-mail: fpadilla@instec.c [Instituto Superior de Tecnologias y Ciencias Aplicadas, ' Quinta de los Molinos' Ave. Salvador Allende, esq. Luaces, Plaza de la Revolucion, Ciudad de la Habana, CP 10400 (Cuba); Lopez-Pino, Neivy; Luis Bernal-Castillo, Jose; Martinez-Palenzuela, Yisel; Aguilar-Mena, Jimmy; D' Alessandro, Katia; Arbelo, Yuniesky; Corrales, Yasser; Diaz, Oscar [Instituto Superior de Tecnologias y Ciencias Aplicadas, ' Quinta de los Molinos' Ave. Salvador Allende, esq. Luaces, Plaza de la Revolucion, Ciudad de la Habana, CP 10400 (Cuba)

    2010-12-15

    A procedure to optimize the geometrical model of an n-type detector is described. Sixteen lines from seven point sources ({sup 241}Am, {sup 133}Ba, {sup 22}Na, {sup 60}Co, {sup 57}Co, {sup 137}Cs and {sup 152}Eu) placed at three different source-to-detector distances (10, 20 and 30 cm) were used to calibrate a low-background gamma spectrometer between 26 and 1408 keV. Direct Monte Carlo techniques using the MCNPX 2.6 and GEANT 4 9.2 codes, and a semi-empirical procedure were performed to obtain theoretical efficiency curves. Since discrepancies were found between experimental and calculated data using the manufacturer parameters of the detector, a detail study of the crystal dimensions and the geometrical configuration is carried out. The relative deviation with experimental data decreases from a mean value of 18-4%, after the parameters were optimized.

  8. PRECO-D2: program for calculating preequilibrium and direct reaction double differential cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Kalbach, C.

    1985-02-01

    The code PRECO-D2 uses the exciton model for preequilibrium nuclear reactions to describe the emission of particles with mass numbers of 1 to 4 from an equilibrating composite nucleus. A distinction is made between open and closed configurations in this system and between the multi-step direct (MSD) and multi-step compound (MSC) components of the preequilibrium cross section. Additional MSD components are calculated semi-empirically to account for direct nucleon transfer reactions and direct knockout processes involving cluster degrees of freedom. Evaporation from the equilibrated composite nucleus is included in the full MSC cross section. Output of energy differential and double differential cross sections is provided for the first particle emitted from the composite system. Multiple particle emission is not considered. This report describes the reaction models used in writing PRECO-D2 and explains the organization and utilization of the code. 21 refs.

  9. Calculated nuclide production yields in relativistic collisions of fissile nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Benlliure, J.; Schmidt, K.-H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Grewe, A.; Jong, M. de [Institut fuer Kernphysik, Darmstadt (Germany); Zhdanov, S. [Inst. of Nuclear Physcis, Alma Ata (Kazakstan)

    1998-01-19

    A model calculation is presented which predicts the complex nuclide distribution resulting from peripheral relativistic heavy-ion collisions involving fissile nuclei. The model is based on a modern version of the abrasion-ablation model which describes the formation of excited prefragments due to the nuclear collisions and their consecutive decay. The competition between the evaporation of different light particles and fission is computed with an evaporation code which takes dissipative effects and the emission of intermediate-mass fragments into account. The nuclide distribution resulting from fission processes is treated by a semi-empirical description which includes the excitation-energy dependent influence of nuclear shell effects and pairing correlations. The calculations of collisions between {sup 238}U and different reaction partners reveal that a huge number of isotopes of all elements up to uranium is produced. The complex nuclide distribution shows the characteristics of fragmentation, mass-asymmetric low-energy fission and mass-symmetric high-energy fission. The yields of the different components for different reaction partners are studied. Consequences for technical applications are discussed. (orig.). 78 refs.

  10. MEMS Calculator

    Science.gov (United States)

    SRD 166 MEMS Calculator (Web, free access)   This MEMS Calculator determines the following thin film properties from data taken with an optical interferometer or comparable instrument: a) residual strain from fixed-fixed beams, b) strain gradient from cantilevers, c) step heights or thicknesses from step-height test structures, and d) in-plane lengths or deflections. Then, residual stress and stress gradient calculations can be made after an optical vibrometer or comparable instrument is used to obtain Young's modulus from resonating cantilevers or fixed-fixed beams. In addition, wafer bond strength is determined from micro-chevron test structures using a material test machine.

  11. Detailed Analysis of Configuration Interaction and Calculation of Radiative Transition Rates in Seven Times Ionized Tungsten (W VIII

    Directory of Open Access Journals (Sweden)

    Jérôme Deprince

    2015-06-01

    Full Text Available A new set of oscillator strengths and transition probabilities for EUV spectral lines of seven times ionized tungsten (W VIII is reported in the present paper. These results have been obtained using the pseudo-relativistic Hartree-Fock (HFR method combined with a semi-empirical optimization of the radial parameters minimizing the discrepancies between computed energy levels and available experimental data. The final physical model considered in the calculations has been chosen further to a detailed investigation of the configuration interaction in this atomic system characterized by complex configurations of the type 4f145s25p5, 4f145s25p4nl, 4f145s5p6, 4f135s25p6, 4f135s25p5nl and 4f125s25p6nl (nl = 5d, 6s.

  12. Abinitio powder x-ray diffraction and PIXEL energy calculations on thiophene derived 1,4 dihydropyridine

    Energy Technology Data Exchange (ETDEWEB)

    Karthikeyan, N., E-mail: karthin10@gmail.com; Sivakumar, K. [Department of Physics, College of Engineering, Guindy, Anna University, Chennai-600 025, Tamilnadu (India); Pachamuthu, M. P. [Assistant Professor of Chemistry, Bannari Amman Institute of Technology Sathyamangalam - 638401, Tamilnadu (India)

    2016-05-06

    We focus on the application of powder diffraction data to get abinitio crystal structure determination of thiophene derived 1,4 DHP prepared by cyclocondensation method using solid catalyst. Crystal structure of the compound has been solved by direct-space approach on Monte Carlo search in parallel tempering mode using FOX program. Initial atomic coordinates were derived using Gaussian 09W quantum chemistry software in semi-empirical approach and Rietveld refinement was carried out using GSAS program. The crystal structure of the compound is stabilized by one N-H…O and three C-H…O hydrogen bonds. PIXEL lattice energy calculation was carried out to understand the physical nature of intermolecular interactions in the crystal packing, on which the total lattice energy is contributed into Columbic, polarization, dispersion, and repulsion energies.

  13. Calculation Software

    Science.gov (United States)

    1994-01-01

    MathSoft Plus 5.0 is a calculation software package for electrical engineers and computer scientists who need advanced math functionality. It incorporates SmartMath, an expert system that determines a strategy for solving difficult mathematical problems. SmartMath was the result of the integration into Mathcad of CLIPS, a NASA-developed shell for creating expert systems. By using CLIPS, MathSoft, Inc. was able to save the time and money involved in writing the original program.

  14. Experimental investigation on predictive models for motive flow calculation through ejectors for transcritical CO2 heat pumps

    Science.gov (United States)

    Boccardi, G.; Lillo, G.; Mastrullo, R.; Mauro, A. W.; Saraceno, L.; Pieve, M.; Trinchieri, R.

    2017-11-01

    Nowadays, air conditioning systems, especially those used in residential and office buildings, contribute largely to the energy consumptions and to the direct and indirect emissions of greenhouse gases. Carbon dioxide (CO2) is an interesting option to replace traditional HFCs in vapor compression systems, due to its environmentally friendly characteristics: zero ODP and extremely low GWP. In the case of heat pumps, the use of ejection systems for the expansion phase can contribute to recovery a fraction of the mechanical energy otherwise dissipated as friction, bringing to significant benefits in terms of performance. Currently, at the laboratory DTE-PCU-SPCT of the research center ENEA (Casaccia) in cooperation with the Industrial Engineering Department of Federico II University of Naples, a project is in progress, in order to evaluate experimentally the effect of several ejectors geometries on the global performance of a CO2 heat pump working with a transcritical cycle. As a part of this project, measurements of the motive flow mass flow rate have been carried out, in transcritical CO2 conditions. The ejector sizing is a crucial point for the balancing of components and the correct operation of the CO2 heat pump and therefore the availability of reliable calculation methods for the motive flowrate would be useful. This paper presents the results obtained by a comparison between the new experimental data and the predictions of some predictive semi-empirical correlations available in the open literature for transcritical CO2 conditions. Their predictions are analyzed as a function of the main physical parameters of the process to assess their reliability compared to the experimental data. Based on these indications and of the available experimental data, a new semi-empirical correlations and a calculation method based on the hypothesis of isentropic and choked two-phase flow are presented.

  15. Structural identification by differential mass spectrometry as a criterion for selecting the best quantum chemical calculation of formation enthalpy for tetrachlorinated biphenyls.

    Science.gov (United States)

    Dinca, Nicolae; Covaci, Adrian

    2012-09-15

    The assignment of correct structures for isomers with similar mass spectra (e.g. polyhalogenated aromatic compounds) is not always successful when spectral libraries alone are employed or, even worse, when the compounds are not present in commercial spectral libraries. We present a computational method based on differential mass spectrometry (Diff-MS) for the validation of formation enthalpy (Δ(f)H) series calculated using quantum chemistry for the fragments produced in electron ionization (EI)-MS. The method simulates the chemical structure identification (CSI) of isomers with similar mass spectra using differential mass spectra and Δ(f)H series. The best Δ(f)H values were those from which the correct structures could be derived. We have used six tetrachlorinated biphenyl isomers (TeCBs 44, 46, 52, 66, 74, 77). Their EI mass spectra were acquired at 70 eV and, for the principal ions, five series of Δ(f) H values were computed by the semi-empirical methods, AM1, MINDO3, MNDO, PM3, and RM1. The generation of differential mass spectra and the correlation with the Δ(f)H series for the calculation of probabilities from the list of structural assignments were carried out with the ordering algorithm (ORD) of the CSI-Diff-MS Data Analysis 3.1.1 program. Intelligent software, used for structural elucidation based on MS and QCC, was employed to select the best values of the formation enthalpies of TeCBs. The advantages and disadvantages of the semi-empirical methods for the calculation of Δ(f)H values for different TeCB ions are critically presented. The best semi-empirical methods were RM1, AM1 and MINDO3, which can be used to calculate the Δ(f)H database necessary to identify TeCB isomers. This approach allowed the correct assignment of structures for isomers with very similar mass spectra and demonstrated the reliability of the correlation between differential mass spectra and the formation enthalpies of the fragment ions. Copyright © 2012 John Wiley & Sons, Ltd.

  16. Calculator calculus

    CERN Document Server

    McCarty, George

    1982-01-01

    How THIS BOOK DIFFERS This book is about the calculus. What distinguishes it, however, from other books is that it uses the pocket calculator to illustrate the theory. A computation that requires hours of labor when done by hand with tables is quite inappropriate as an example or exercise in a beginning calculus course. But that same computation can become a delicate illustration of the theory when the student does it in seconds on his calculator. t Furthermore, the student's own personal involvement and easy accomplishment give hi~ reassurance and en­ couragement. The machine is like a microscope, and its magnification is a hundred millionfold. We shall be interested in limits, and no stage of numerical approximation proves anything about the limit. However, the derivative of fex) = 67.SgX, for instance, acquires real meaning when a student first appreciates its values as numbers, as limits of 10 100 1000 t A quick example is 1.1 , 1.01 , 1.001 , •••• Another example is t = 0.1, 0.01, in the functio...

  17. Reliability Calculations

    DEFF Research Database (Denmark)

    Petersen, Kurt Erling

    1986-01-01

    Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety...... and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic...... approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very...

  18. The potential, limitations, and challenges of divide and conquer quantum electronic structure calculations on energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jon R.; Magyar, Rudolph J.

    2012-02-01

    High explosives are an important class of energetic materials used in many weapons applications. Even with modern computers, the simulation of the dynamic chemical reactions and energy release is exceedingly challenging. While the scale of the detonation process may be macroscopic, the dynamic bond breaking responsible for the explosive release of energy is fundamentally quantum mechanical. Thus, any method that does not adequately describe bonding is destined to lack predictive capability on some level. Performing quantum mechanics calculations on systems with more than dozens of atoms is a gargantuan task, and severe approximation schemes must be employed in practical calculations. We have developed and tested a divide and conquer (DnC) scheme to obtain total energies, forces, and harmonic frequencies within semi-empirical quantum mechanics. The method is intended as an approximate but faster solution to the full problem and is possible due to the sparsity of the density matrix in many applications. The resulting total energy calculation scales linearly as the number of subsystems, and the method provides a path-forward to quantum mechanical simulations of millions of atoms.

  19. Transport calculation of thermal and cold neutrons using NMTC/JAERI-MCNP4A code system

    Energy Technology Data Exchange (ETDEWEB)

    Iga, Kiminori [Kyushu Univ., Fukuoka (Japan); Takada, Hiroshi; Nagao, Tadashi

    1998-01-01

    In order to investigate the applicability of the NMTC/JAERI-MCNP4A code system to the neutronics design study in the neutron science research project of JAERI, transport calculations of thermal and cold neutrons are performed with the code system on a spallation neutron source composed of light water cooled tantalum target with a moderator and a reflector system. The following neutronic characteristics are studied in the calculation : the variation of the intensity of neutrons emitted from a light water moderator or a liquid hydrogen with/without the B{sub 4}C decoupler, which are installed to produce sharp pulse, and that dependent on the position of external source neutrons in the tantalum target. The calculated neutron energy spectra are reproduced well by the semi-empirical formula with the parameter values reliable in physical meanings. It is found to be necessary to employ proper importance sampling technique in the statistics. It is confirmed from this work that the NMTC/JAERI-MCNP4A code system is applicable to the neutronics design study of spallation neutron sources proposed for the neutron science research project. (author)

  20. Rapid calculation of protein chemical shifts using bond polarization theory and its application to protein structure refinement.

    Science.gov (United States)

    Jakovkin, Igor; Klipfel, Marco; Muhle-Goll, Claudia; Ulrich, Anne S; Luy, Burkhard; Sternberg, Ulrich

    2012-09-21

    Although difficult to analyze, NMR chemical shifts provide detailed information on protein structure. We have adapted the semi-empirical bond polarization theory (BPT) to protein chemical shift calculation and chemical shift driven protein structure refinement. A new parameterization for BPT amide nitrogen chemical shift calculation has been derived from MP2 ab initio calculations and successfully evaluated using crystalline tripeptides. We computed the chemical shifts of the small globular protein ubiquitin, demonstrating that BPT calculations can match the results obtained at the DFT level of theory at very low computational cost. In addition to the calculation of chemical shift tensors, BPT allows the calculation of chemical shift gradients and consequently chemical shift driven geometry optimizations. We applied chemical shift driven protein structure refinement to the conformational analysis of a set of Trypanosoma brucei (the causative agent of African sleeping sickness) tryparedoxin peroxidase Px III structures. We found that the interaction of Px III with its reaction partner Tpx seems to be governed by conformational selection rather than by induced fit.

  1. Thermal neutron scattering law calculations using ab initio molecular dynamics

    Science.gov (United States)

    Wormald, Jonathan; Hawari, Ayman I.

    2017-09-01

    In recent years, methods for the calculation of the thermal scattering law (i.e. S(α,β), where α and β are dimensionless momentum and energy transfer variables, respectively) were developed based on ab initio lattice dynamics (AILD) and/or classical molecular dynamics (CMD). While these methods are now mature and efficient, further advancement in the application of such atomistic techniques is possible using ab initio molecular dynamics (AIMD) methods. In this case, temperature effects are inherently included in the calculation, e.g. phonon density of states (DOS), while using ab initio force fields that eliminate the need for parameterized semi-empirical force fields. In this work, AIMD simulations were performed to predict the phonon spectra as a function of temperature for beryllium and graphite, which are representative nuclear reactor moderator and reflector materials. Subsequently, the calculated phonon spectra were utilized to predict S(α,β) using the LEAPR module of the NJOY code. The AIMD models of beryllium and graphite were 5 × 5 × 5 crystal unit cells (250 atoms and 500 atoms respectively). Electronic structure calculations for the prediction of Hellman-Feynman forces were performed using density functional theory with a GGA exchange correlation functional and corresponding core electron pseudopotentials. AIMD simulations of 1000-10,000 time-steps were performed with the canonical ensemble (NVT thermostat) for several temperatures between 300 K and 900 K. The phonon DOS were calculated as the power spectrum of the AIMD predicted velocity autocorrelation functions. The resulting AIMD phonon DOS and corresponding inelastic thermal neutron scattering cross sections at 300 K, where anharmonic effects are expected to be small, were found to be in reasonable agreement with the results generated using traditional AILD. This illustrated the validity of the AIMD approach. However, since the impact of the temperature on the phonon DOS (e.g. broadening of

  2. (n,p, (n,2n, (n,d, and (n,α cross-section calculations of 16O with 0-40 MeV energy neutrons

    Directory of Open Access Journals (Sweden)

    Ozdemir Omer Faruk

    2015-01-01

    Full Text Available Oxygen is one of the elements which interacts with emitted neutrons after fission reactions. Oxygen exists abundantly both in nuclear fuel (UO2 and moderators (H2O. Nuclear reactions of oxygen with neutrons are important in terms of stability of nuclear fuel and neutron economy. In this study, equilibrium and pre-equilibrium models have been used to calculate (n,p, (n,d, (n,2n and (n,α nuclear reaction cross-sections of 16O. In these calculations, neutron incident energy has been taken up to 40 MeV. Hybrid and Standard Weisskopf-Ewing Models in ALICE-2011 program, Weisskopf-Ewing and Full Exciton Models in PCROSS program, and Cascade Exciton Model in CEM03.01 program have been utilized. The calculated results have been compared with experimental and theroretical cross-section data which are obtained from libraries of EXFOR and ENDF/B VII.1.

  3. Stability studies of double-base propellants with centralite and malonanilide stabilizers using MO calculations in comparison to thermal studies.

    Science.gov (United States)

    Zayed, M A; Mohamed, Adel A; Hassan, M A M

    2010-07-15

    Propellants containing nitrate esters need stabilizers to avoid early decomposition or even explosion during storage. Newly prepared malonanilides M1-M5 were tested in stabilizing double-base propellants (DBPs). Their stabilization was compared with the effect of classical stabilizer N,N'-diethyldiphenyl urea (C1) using both practical thermal stability tests (qualitative and quantitative tests) and theoretical molecular orbital calculations. This research shows that the new stabilizers (malonanilides) have good stabilizing effects. Some of malonanilides e.g. (M5) and (M2) have higher stability effects. Different mechanisms were suggested to explain the role of different stabilizers. Molecular orbital calculations using the semi-empirical program AM1 are performed on the new and classical stabilizers. Correlation was made between the volume (ml) of NO(x), weight loss (wt%), other thermal analyses data, calculated thermodynamic parameters like activation energy (E(a), kJ mol(-1)) of the decomposed propellant samples containing different stabilizers and some of their calculated properties such as HOMO, LUMO energies, the charge distribution and the pi-bond order. The stabilization effect decreases with the increase in HOMO energy. The correlation between the net charge and parameters measured for the stabilization effect shows good accordance. Comparison of the results obtained show that the high electron charge on N atom of the stabilizers and on its benzene ring is the most important factor, but not the only factor governing the stabilization effect of the stabilizers. 2010 Elsevier B.V. All rights reserved.

  4. Calculation of coupled bunch effects in the synchrotron light source BESSY VSR

    Energy Technology Data Exchange (ETDEWEB)

    Ruprecht, Martin

    2016-02-22

    In the scope of this thesis, the strength of coupled bunch instabilities (CBIs) driven by longitudinal monopole higher order modes (HOMs) and transverse dipole and quadrupole HOMs is evaluated for the upgrade project BESSY Variable Pulse Length Storage Ring (BESSY VSR) at Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH (HZB), based on analytic calculations and tracking simulations, and compared to the performance of an active bunch-by-bunch feedback (BBFB). Algorithms for tracking codes are derived, and a semi-empirical formula for the estimation of transverse quadrupole CBIs is presented. CBI studies are an integral part of the benchmarking of the cavity models for BESSY VSR and have been accompanying and influencing their entire design process. Based on the BESSY VSR cavity model with highly advanced HOM damping, beam stability is likely to be reached with a BBFB system, independent of the bunch fill pattern. Additionally, measurements of CBIs have been performed at BESSY II and the Metrology Light Source of the Physikalisch-Technische Bundesanstalt (MLS), where the longitudinal long range impedance was characterized. Transient beam loading is evaluated by means of analytic formulas and new experimentally verified tracking codes. For the baseline bunch fill pattern of BESSY VSR, it is shown that the particular setup of cavity frequencies amplifies the transient effect on the long bunch, limiting its elongation and potentially resulting in increased Touschek losses.

  5. Polymorphism and thermodynamic ground state of silver fulminate studied from van der Waals density functional calculations

    Science.gov (United States)

    Yedukondalu, N.; Vaitheeswaran, G.

    2014-06-01

    Silver fulminate (AgCNO) is a primary explosive, which exists in two polymorphic phases, namely, orthorhombic (Cmcm) and trigonal (Rbar{3}) forms at ambient conditions. In the present study, we have investigated the effect of pressure and temperature on relative phase stability of the polymorphs using planewave pseudopotential approaches based on Density Functional Theory (DFT). van der Waals interactions play a significant role in predicting the phase stability and they can be effectively captured by semi-empirical dispersion correction methods in contrast to standard DFT functionals. Based on our total energy calculations using DFT-D2 method, the Cmcm structure is found to be the preferred thermodynamic equilibrium phase under studied pressure and temperature range. Hitherto Cmcm and Rbar{3} phases denoted as α- and β-forms of AgCNO, respectively. Also a pressure induced polymorphic phase transition is seen using DFT functionals and the same was not observed with DFT-D2 method. The equation of state and compressibility of both polymorphic phases were investigated. Electronic structure and optical properties were calculated using full potential linearized augmented plane wave method within the Tran-Blaha modified Becke-Johnson potential. The calculated electronic structure shows that α, β phases are indirect bandgap insulators with a bandgap values of 3.51 and 4.43 eV, respectively. The nature of chemical bonding is analyzed through the charge density plots and partial density of states. Optical anisotropy, electric-dipole transitions, and photo sensitivity to light of the polymorphs are analyzed from the calculated optical spectra. Overall, the present study provides an early indication to experimentalists to avoid the formation of unstable β-form of AgCNO.

  6. Polymorphism and thermodynamic ground state of silver fulminate studied from van der Waals density functional calculations.

    Science.gov (United States)

    Yedukondalu, N; Vaitheeswaran, G

    2014-06-14

    Silver fulminate (AgCNO) is a primary explosive, which exists in two polymorphic phases, namely, orthorhombic (Cmcm) and trigonal (R3) forms at ambient conditions. In the present study, we have investigated the effect of pressure and temperature on relative phase stability of the polymorphs using planewave pseudopotential approaches based on Density Functional Theory (DFT). van der Waals interactions play a significant role in predicting the phase stability and they can be effectively captured by semi-empirical dispersion correction methods in contrast to standard DFT functionals. Based on our total energy calculations using DFT-D2 method, the Cmcm structure is found to be the preferred thermodynamic equilibrium phase under studied pressure and temperature range. Hitherto Cmcm and R3 phases denoted as α- and β-forms of AgCNO, respectively. Also a pressure induced polymorphic phase transition is seen using DFT functionals and the same was not observed with DFT-D2 method. The equation of state and compressibility of both polymorphic phases were investigated. Electronic structure and optical properties were calculated using full potential linearized augmented plane wave method within the Tran-Blaha modified Becke-Johnson potential. The calculated electronic structure shows that α, β phases are indirect bandgap insulators with a bandgap values of 3.51 and 4.43 eV, respectively. The nature of chemical bonding is analyzed through the charge density plots and partial density of states. Optical anisotropy, electric-dipole transitions, and photo sensitivity to light of the polymorphs are analyzed from the calculated optical spectra. Overall, the present study provides an early indication to experimentalists to avoid the formation of unstable β-form of AgCNO.

  7. Calculation of fluorine chemical shift tensors for the interpretation of oriented (19)F-NMR spectra of gramicidin A in membranes.

    Science.gov (United States)

    Sternberg, Ulrich; Klipfel, Marco; Grage, Stephan L; Witter, Raiker; Ulrich, Anne S

    2009-08-28

    A semi-empirical method for the prediction of chemical shifts, based on bond polarization theory, has recently been introduced for (13)C. Here, we extended this approach to calculate the (19)F chemical shift tensors of fluorine bound to aromatic rings and in aliphatic CF(3) groups. For the necessary parametrization, ab initio chemical shift calculations were performed at the MP2 level for a set of fluorinated molecules including tryptophan. The bond polarization parameters obtained were used to calculate the (19)F chemical shift tensors for several crystalline molecules, and to reference the calculated values on a chemical shift scale relative to CFCl(3). As a first biophysical application, we examined the distribution of conformations of a (19)F-labeled tryptophan side chain in the membrane-bound ion channel peptide, gramicidin A. The fluorine chemical shift tensors were calculated from snapshots of a molecular dynamics simulation employing the (19)F-parametrized bond polarization theory. In this MD simulation, published (2)H quadrupolar and (15)N-(1)H dipolar couplings of the indole ring were used as orientational constraints to determine the conformational distribution of the 5F-Trp(13) side chain. These conformations were then used to interpret the spectra of (19)F-labeled gramicidin A in fluid and gel phase lipid bilayers.

  8. A semi-empirical model to assess uncertainty of spatial patterns of erosion

    NARCIS (Netherlands)

    Sterk, G.; Vigiak, O.; Romanowicz, R.J.; Beven, K.J.

    2006-01-01

    Distributed erosion models are potentially good tools for locating soil sediment sources and guiding efficient Soil and Water Conservation (SWC) planning, but the uncertainty of model predictions may be high. In this study, the distribution of erosion within a catchment was predicted with a

  9. Semi-empirical seismic relations of A-F stars from COROT and Kepler legacy data

    Science.gov (United States)

    Moya, A.; Suárez, J. C.; García Hernández, A.; Mendoza, M. A.

    2017-10-01

    Asteroseismology is witnessing a revolution, thanks to high-precise asteroseismic space data (MOST, COROT, Kepler, BRITE) and their large ground-based follow-up programs. Those instruments have provided an unprecedented large amount of information, which allows us to scrutinize its statistical properties in the quest for hidden relations among pulsational and/or physical observables. This approach might be particularly useful for stars whose pulsation content is difficult to interpret. This is the case of intermediate-mass classical pulsating stars (I.e. γ Dor, δ Scuti, hybrids) for which current theories do not properly predict the observed oscillation spectra. Here, we establish a first step in finding such hidden relations from data mining techniques for these stars. We searched for those hidden relations in a sample of δ Scuti and hybrid stars observed by COROT and Kepler (74 and 153, respectively). No significant correlations between pairs of observables were found. However, two statistically significant correlations emerged from multivariable correlations in the observed seismic data, which describe the total number of observed frequencies and the largest one, respectively. Moreover, three different sets of stars were found to cluster according to their frequency density distribution. Such sets are in apparent agreement with the asteroseismic properties commonly accepted for A-F pulsating stars.

  10. A summary and evaluation of semi-empirical methods for the prediction of helicopter rotor noise

    Science.gov (United States)

    Pegg, R. J.

    1979-01-01

    Existing prediction techniques are compiled and described. The descriptions include input and output parameter lists, required equations and graphs, and the range of validity for each part of the prediction procedures. Examples are provided illustrating the analysis procedure and the degree of agreement with experimental results.

  11. A semi-empirical model for pressurised air-blown fluidized-bed gasification of biomass.

    Science.gov (United States)

    Hannula, Ilkka; Kurkela, Esa

    2010-06-01

    A process model for pressurised fluidized-bed gasification of biomass was developed using Aspen Plus simulation software. Eight main blocks were used to model the fluidized-bed gasifier, complemented with FORTRAN subroutines nested in the programme to simulate hydrocarbon and NH(3) formation as well as carbon conversion. The model was validated with experimental data derived from a PDU-scale test rig operated with various types of biomass. The model was shown to be suitable for simulating the gasification of pine sawdust, pine and eucalyptus chips as well as forest residues, but not for pine bark or wheat straw. (c) 2010 Elsevier Ltd. All rights reserved.

  12. Evaluation of three semi-empirical soil moisture estimation models with RADARSAT-2 imagery

    Science.gov (United States)

    Deschamps, Benjamin

    Performance of the Oh et al. (1992), Oh (2004) and Dubois et al. (1995a) soil moisture estimation models was evaluated with three RADARSAT-2 scenes over the Casselman, Ontario area. Root mean square error (RMSE), mean bias error (MBE), correlation coefficients and the number of valid pixels were used to assess the influence of boxcar speckle filter sizes and pre-extraction averaging filtering on the estimates. Highest agreement with the field data was obtained with speckle filter and pre-extraction filter sizes from 3 x 3 to 7 x 7. Bias of the estimates was found to be highly negatively correlated with incidence angle (r2= DAD, 0.15, 0.51). Correlations between the estimated and observed soil moisture contents were not significant for most dates and the correlations with soil properties data were also weak. The effects of tillage method on the relative error of estimates were significant with lower relative errors in low-roughness tillage methods.

  13. A Semi-Empirical Two Step Carbon Corrosion Reaction Model in PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Young, Alan; Colbow, Vesna; Harvey, David; Rogers, Erin; Wessel, Silvia

    2013-01-01

    The cathode CL of a polymer electrolyte membrane fuel cell (PEMFC) was exposed to high potentials, 1.0 to 1.4 V versus a reversible hydrogen electrode (RHE), that are typically encountered during start up/shut down operation. While both platinum dissolution and carbon corrosion occurred, the carbon corrosion effects were isolated and modeled. The presented model separates the carbon corrosion process into two reaction steps; (1) oxidation of the carbon surface to carbon-oxygen groups, and (2) further corrosion of the oxidized surface to carbon dioxide/monoxide. To oxidize and corrode the cathode catalyst carbon support, the CL was subjected to an accelerated stress test cycled the potential from 0.6 VRHE to an upper potential limit (UPL) ranging from 0.9 to 1.4 VRHE at varying dwell times. The reaction rate constants and specific capacitances of carbon and platinum were fitted by evaluating the double layer capacitance (Cdl) trends. Carbon surface oxidation increased the Cdl due to increased specific capacitance for carbon surfaces with carbon-oxygen groups, while the second corrosion reaction decreased the Cdl due to loss of the overall carbon surface area. The first oxidation step differed between carbon types, while both reaction rate constants were found to have a dependency on UPL, temperature, and gas relative humidity.

  14. Semi-empirical approach for calibration of CR-39 detectors in diffusion chambers for radon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pereyra A, P.; Lopez H, M. E. [Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, San Miguel Lima 32 (Peru); Palacios F, D.; Sajo B, L. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apartado 89000 Caracas (Venezuela, Bolivarian Republic of); Valdivia, P., E-mail: ppereyr@pucp.edu.pe [Universidad Nacional de Ingenieria, Av. Tupac Amaru s/n, Rimac, Lima 25 (Peru)

    2016-10-15

    Simulated and measured calibration of PADC detectors is given for cylindrical diffusion chambers employed in environmental radon measurements. The method is based on determining the minimum alpha energy (E{sub min}), average critical angle (<Θ{sub c}>), and fraction of {sup 218}Po atoms; the volume of the chamber (f{sub 1}), are compared to commercially available devices. Radon concentration for exposed detectors is obtained from induced track densities and the well-established calibration coefficient for NRPB monitor. Calibration coefficient of a PADC detector in a cylindrical diffusion chamber of any size is determined under the same chemical etching conditions and track analysis methodology. In this study the results of numerical examples and comparison between experimental calibration coefficients and simulation purpose made code. Results show that the developed method is applicable when uncertainties of 10% are acceptable. (Author)

  15. NUMERICAL SIMULATION OF CAVITY FLOW AND FLOW OVER AIRCRAFT COMPARTMENT USING SEMI-EMPIRICAL TURBULENCE MODELS

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The article is devoted to the validation and application of CFD code for turbulent flows. Two-dimensional un- steady flows in the cavities and compartments and three-dimensional flow in the compartment of complex geometry have been considered. Two turbulence parameter oriented models are used.Numerical simulation of unsteady transonic flow (Mоо=0.74 in a narrow channel with a cavity inside has been conducted. The dependence of the static pressure on time at fixed points in space has been obtained. The fast Fourier trans- form has been applied for processing data of static pressure. The difference of 6-10% between the numerical and experi-mental data has been obtained.The computations of unsteady transonic cavity flow with Mach number Mоо=0.85 have been performed. Low fre- quency oscillations of the static pressure in several fixed points in space have been obtained. Power spectrum of oscilla- tions at the center of the cavity is compared with experimental data and Rossiter modes. An acceptable agreement between experimental and computed data has been achieved. The influence of geometrical factors on the frequency characteristics of the flow has been investigated. For this purpose two round flaps have been added to the cavity. The most low-frequency oscillation modes changed by the presence of the flaps. The first mode was gone, the second mode amplitude decreased and the third mode amplitude significantly decreased. The changes in height of protruding part of the geometry to the external flow have led to changes in pressure pulsation amplitude without changing the frequency. The spectral functions obtained while using the two considered models of turbulence have been compared for this case. It is found that the frequency values are only slightly different; the main difference is present at the amplitude of pulsations.The effect of deflection of flat flap on the non-stationary subsonic flow parameters in a cylindrical body with an inner compartment has been investigated. The cases of deflection angles of the flap inside the compartment with values 26º and 41º above the horizontal plane, and also the case without flap have been considered. Low-frequency oscillations of the static pressure have been obtained. The presence of the flap did not change the frequency of static pressure pulsations. With the increase of the choke deflection angle, the oscillation amplitude increases at all considered points of the flow too.

  16. CARDIOGRAMA: a stochastic, semi-empirical methodology for power-reactor surveillance and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    March-Leuba, J.A.; deSaussure, G.; Perez, R.B.

    1981-01-01

    The utilization of stochastic methods (reactor noise) for power reactor diagnostics and surveillance applications is by now a relatively well-established technique. In this technique, the power spectral density (PSD) of the fluctuations of a specified state variable is often used to define the reactor's signature at a given configuration. The purpose of the present work is to address the problem of handling efficiently the substantial amount of information involved in the application of reactor surveillance and diagnostics methods. Specifically, a methodology is described for: (a) representing the PSDs parametrically, and (b) detecting changes from the reactor's baseline PSD (normal signature).

  17. Semi-empirical model for optimising future heavy-ion luminosity of the LHC

    CERN Document Server

    Schaumann, M

    2014-01-01

    The wide spectrum of intensities and emittances imprinted on the LHC Pb bunches during the accumulation of bunch trains in the injector chain result in a significant spread in the single bunch luminosities and lifetimes in collision. Based on the data collected in the 2011 Pb-Pb run, an empirical model is derived to predict the single-bunch peak luminosity depending on the bunch’s position within the beam. In combination with this model, simulations of representative bunches are used to estimate the luminosity evolution for the complete ensemble of bunches. Several options are being considered to improve the injector performance and to increase the number of bunches in the LHC, leading to several potential injection scenarios, resulting in different peak and integrated luminosities. The most important options for after the long shutdown (LS) 1 and 2 are evaluated and compared.

  18. A semi-empirical model for magnetic braking of solar-type stars

    Science.gov (United States)

    Sadeghi Ardestani, Leila; Guillot, Tristan; Morel, Pierre

    2017-12-01

    We develop new angular momentum evolution models for stars with masses of 0.5 to 1.6 M⊙ and from the pre-main-sequence (PMS) through the end of their main-sequence (MS) lifetime. The parametric models include magnetic braking based on numerical simulations of magnetized stellar winds, mass-loss-rate prescription, core-envelope decoupling as well as disc locking phenomena. We have also accounted for recent developments in modelling dramatically weakened magnetic braking in stars more evolved than the Sun. We fit the free parameters in our model by comparing model predictions to rotational distributions of a number of stellar clusters as well as individual field stars. Our model reasonably successfully reproduces the rotational behaviour of stars during the PMS phase to the zero-age main-sequence (ZAMS) spin-up, sudden ZAMS spin-down and convergence of the rotation rates afterwards. We find that including core-envelope decoupling improves our models, especially for low-mass stars at younger ages. In addition, by accounting for the almost complete suppression of magnetic braking at slow-spin periods, we provide better fits to observations of stellar rotations compared to previous models.

  19. A semi-empirical airfoil stall noise model based on surface pressure measurements

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Fischer, Andreas

    2017-01-01

    This work is concerned with the experimental study of airfoil stall and the modelling of stall noise. Using pressure taps and high-frequency surface pressure microphones flush-mounted on airfoils measured in wind tunnels and on an operating wind turbine blade, the characteristics of stall are ana...

  20. A semi-empirical airfoil stall noise model based on surface pressure measurements

    Science.gov (United States)

    Bertagnolio, Franck; Madsen, Helge Aa.; Fischer, Andreas; Bak, Christian

    2017-01-01

    This work is concerned with the experimental study of airfoil stall and the modelling of stall noise. Using pressure taps and high-frequency surface pressure microphones flush-mounted on airfoils measured in wind tunnels and on an operating wind turbine blade, the characteristics of stall are analyzed. This study shows that the main quantities of interest, namely convection velocity, spatial correlation and surface pressure spectra, can be scaled highlighting the universal nature of stall independently of airfoil shapes and flow conditions, although within a certain range of experimental conditions. Two main regimes for the scaling of the correlation lengths and the surface pressure spectra, depending on the Reynolds number of the flow, can be distinguished. These results are used to develop a model for the surface pressure spectra within the detached flow region valid for Reynolds numbers ranging from 1 ×106 to 6 ×106. Subsequently, this model is used to derive a model for stall noise. Modelled noise spectra are compared with experimental data measured in anechoic wind tunnels with reasonably satisfactory agreement.

  1. A Semi-Empirical Airborne Particle Erosion Model for Polyesteric Matrix Fiberglass Composites

    Directory of Open Access Journals (Sweden)

    Valeriu DRAGAN

    2013-12-01

    Full Text Available The paper deals with the mathematical modeling of the airborne solid particle erosion rate of composite materials, in particular non-oriented fiberglass reinforced polyesteric matrices. Using the mathematical tool of non-linear regression, based on experimental data available in the state of the art, an algebraic equation has been determined to estimate the relative erosion rate of such composites. The formulation is tailored so that it relates to classical erosion models such as Finnie’s, Bitter’s or Tulsa angle dependent model which can be implemented into commercial computational fluid dynamics software. Although the implementation - per se - is not described herein, the model proposed can be useful in estimating the global effect of solid particle erosion on composite materials in this class. Further theoretical developments may add to the model the capacity to evaluate the erosion rate for a wider class of matrices as well as more types of weavings.

  2. Semi-Empirical, First-Principles, and Hybrid Modeling of the Thermosphere to Enhance Data Assimilation

    Science.gov (United States)

    2015-10-27

    Mauersberger, K., D. C. Kayser, W. E. Potter , and A. O. Nier (1976), Seasonal variation of neutral thermospheric constituents in the Northern Hemisphere...J. Geophys. Res., 81, pp. 7–11, doi:10.1029/JA081i001p00007. [41] Mauersberger, K., W. E. Potter , and D. C. Kayser (1976), A direct measurement of...Geophys. Res., 79, p. 619, doi:10.1029/JA079i004p00619. [45] Mayr, H. G., I. Harris , and N. W. Spencer (1978), Some properties of upper atmosphere

  3. A Semi-Empirical Noise Modeling Method for Helicopter Maneuvering Flight Operations

    Science.gov (United States)

    Greenwood, Eric; Schmitz, Fredric; Sickenberger, Richard D.

    2012-01-01

    A new model for Blade-Vortex Interaction noise generation during maneuvering flight is developed in this paper. Acoustic and performance data from both flight and wind tunnels are used to derive a non-dimensional and analytical performance/acoustic model that describes BVI noise in steady flight. The model is extended to transient maneuvering flight (pure pitch and roll transients) by using quasisteady assumptions throughout the prescribed maneuvers. Ground noise measurements, taken during maneuvering flight of a Bell 206B helicopter, show that many of the noise radiation details are captured. The result is a computationally efficient Blade-Vortex Interaction noise model with sufficient accuracy to account for transient maneuvering flight. The code can be run in real time to predict transient maneuver noise and is suitable for use in an acoustic mission-planning tool.

  4. submitter Dose prescription in carbon ion radiotherapy: How to compare two different RBE-weighted dose calculation systems

    CERN Document Server

    Molinelli, Silvia; Mairani, Andrea; Matsufuji, Naruhiro; Kanematsu, Nobuyuki; Inaniwa, Taku; Mirandola, Alfredo; Russo, Stefania; Mastella, Edoardo; Hasegawa, Azusa; Tsuji, Hiroshi; Yamada, Shigeru; Vischioni, Barbara; Vitolo, Viviana; Ferrari, Alfredo; Ciocca, Mario; Kamada, Tadashi; Tsujii, Hirohiko; Orecchia, Roberto; Fossati, Piero

    2016-01-01

    Background and purpose: In carbon ion radiotherapy (CIRT), the use of different relative biological effectiveness (RBE) models in the RBE-weighted dose $(D_{RBE})$ calculation can lead to deviations in the physical dose $(D_{phy})$ delivered to the patient. Our aim is to reduce target $D_{phy}$ deviations by converting prescription dose values. Material and methods: Planning data of patients treated at the National Institute of Radiological Sciences (NIRS) were collected, with prescribed doses per fraction ranging from 3.6 Gy (RBE) to 4.6 Gy (RBE), according to the Japanese semi-empirical model. The $D_{phy}$ was Monte Carlo (MC) re-calculated simulating the NIRS beamline. The local effect model (LEM)_I was then applied to estimate $D_{RBE}$. Target median $D_{RBE}$ ratios between MC + LEM_I and NIRS plans determined correction factors for the conversion of prescription doses. Plans were re-optimized in a LEM_I-based commercial system, prescribing the NIRS uncorrected and corrected $D_{RBE}$. Results: The MC ...

  5. Restricted active space calculations of L-edge X-ray absorption spectra: from molecular orbitals to multiplet states.

    Science.gov (United States)

    Pinjari, Rahul V; Delcey, Mickaël G; Guo, Meiyuan; Odelius, Michael; Lundberg, Marcus

    2014-09-28

    The metal L-edge (2p → 3d) X-ray absorption spectra are affected by a number of different interactions: electron-electron repulsion, spin-orbit coupling, and charge transfer between metal and ligands, which makes the simulation of spectra challenging. The core restricted active space (RAS) method is an accurate and flexible approach that can be used to calculate X-ray spectra of a wide range of medium-sized systems without any symmetry constraints. Here, the applicability of the method is tested in detail by simulating three ferric (3d(5)) model systems with well-known electronic structure, viz., atomic Fe(3+), high-spin [FeCl6](3-) with ligand donor bonding, and low-spin [Fe(CN)6](3-) that also has metal backbonding. For these systems, the performance of the core RAS method, which does not require any system-dependent parameters, is comparable to that of the commonly used semi-empirical charge-transfer multiplet model. It handles orbitally degenerate ground states, accurately describes metal-ligand interactions, and includes both single and multiple excitations. The results are sensitive to the choice of orbitals in the active space and this sensitivity can be used to assign spectral features. A method has also been developed to analyze the calculated X-ray spectra using a chemically intuitive molecular orbital picture.

  6. A comparative study of trypsin specificity based on QM/MM molecular dynamics simulation and QM/MM GBSA calculation.

    Science.gov (United States)

    Chen, Jianzhong; Wang, Jinan; Zhang, Qinggang; Chen, Kaixian; Zhu, Weiliang

    2015-01-01

    Hydrogen bonding and polar interactions play a key role in identification of protein-inhibitor binding specificity. Quantum mechanics/molecular mechanics molecular dynamics (QM/MM MD) simulations combined with DFT and semi-empirical Hamiltonian (AM1d, RM1, PM3, and PM6) methods were performed to study the hydrogen bonding and polar interactions of two inhibitors BEN and BEN1 with trypsin. The results show that the accuracy of treating the hydrogen bonding and polar interactions using QM/MM MD simulation of PM6 can reach the one obtained by the DFT QM/MM MD simulation. Quantum mechanics/molecular mechanics generalized Born surface area (QM/MM-GBSA) method was applied to calculate binding affinities of inhibitors to trypsin and the results suggest that the accuracy of binding affinity prediction can be significantly affected by the accurate treatment of the hydrogen bonding and polar interactions. In addition, the calculated results also reveal the binding specificity of trypsin: (1) the amidinium groups of two inhibitors generate favorable salt bridge interaction with Asp189 and form hydrogen bonding interactions with Ser190 and Gly214, (2) the phenyl of inhibitors can produce favorable van der Waals interactions with the residues His58, Cys191, Gln192, Trp211, Gly212, and Cys215. This systematic and comparative study can provide guidance for the choice of QM/MM MD methods and the designs of new potent inhibitors targeting trypsin.

  7. Magnetic Field Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Calculator will calculate the total magnetic field, including components (declination, inclination, horizontal intensity, northerly intensity,...

  8. Alcohol Calorie Calculator

    Science.gov (United States)

    ... NIAAA College Materials Supporting Research Special Features CollegeAIM College Administrators Parents & Students Home > Special Features > Calculators > Alcohol Calorie Calculator Weekly Total 0 Calories Alcohol Calorie ...

  9. Accounting for detector crystal edge rounding in gamma-efficiency calculations theoretical elaboration and application in ANGLE software

    Directory of Open Access Journals (Sweden)

    Mihaljević Nikola

    2012-01-01

    Full Text Available In absolute and semi-empirical calculations of full gamma-energy peak efficiencies (ep, geometrical/compositional data characterizing the detector should be known in much detail. Among these, detector crystal edge rounding (bulletization, if neglected, may lead to large systematic errors, especially for low gamma-energies and close counting geometries. The errors show quadratic dependence on the extent of bulletization (bulletization radius. Mathematical/analytical solution to the problem - not reported so far - is elaborated in the present work. Relevant mathematical formulae are derived for a number of counting arrangements most frequently encountered in gamma-spectrometry practice (point, disc, cylinder, and Marinelli sources. These are subsequently programmed for numerical calculations and are now part of commercially available ANGLE software. Extensive calculation testing is performed for HPGe (both p- and n-type and LEPD detectors (several sizes each, with various sources (point, disc, cylinder, Marinelli and counting geometries (0-20 cm source-to-detector distance. Energy range considered was 10-3000 keV. To elucidate the significance of the issue, an error propagation study was conducted: results with bulletization taken into account are compared to those when bulletization was neglected. Corresponding errors are tabulated in an extensive Excel file. The file comprises about 152 000 error calculation results which are available for download; a few characteristic ones are selected for presenting in the paper. ANGLE proved handy (in programming and fast (in calculations when accomplishing this task. The data convincingly illustrate the impact of detector bulletization on gamma-efficiency and thus the need to account for. Even only slight bulletization (1-2 mm bulletization radius is not negligible in many realistic counting situations. Reader/analyst can (1 compare his/her counting situation with these data so as to get the first

  10. Test Your Calculator IQ.

    Science.gov (United States)

    Williams, David E.

    1981-01-01

    This short quiz for teachers is intended to help them to brush up on their calculator operating skills and to prepare for the types of questions their students will ask about calculator idiosyncracies. (SJL)

  11. Calculating correct compilers

    OpenAIRE

    Bahr, Patrick; Hutton, Graham

    2015-01-01

    In this article we present a new approach to the problem of calculating compilers. In particular, we develop a simple but general technique that allows us to derive correct compilers from high- level semantics by systematic calculation, with all details of the implementation of the compilers falling naturally out of the calculation process. Our approach is based upon the use of standard equational reasoning techniques, and has been applied to calculate compilers for a wide range of language f...

  12. Autistic Savant Calendar Calculators.

    Science.gov (United States)

    Patti, Paul J.

    This study identified 10 savants with developmental disabilities and an exceptional ability to calculate calendar dates. These "calendar calculators" were asked to demonstrate their abilities, and their strategies were analyzed. The study found that the ability to calculate dates into the past or future varied widely among these…

  13. Flexible Mental Calculation.

    Science.gov (United States)

    Threlfall, John

    2002-01-01

    Suggests that strategy choice is a misleading characterization of efficient mental calculation and that teaching mental calculation methods as a whole is not conducive to flexibility. Proposes an alternative in which calculation is thought of as an interaction between noticing and knowledge. Presents an associated teaching approach to promote…

  14. Cross Sections Calculations of ( d, t) Nuclear Reactions up to 50 MeV

    Science.gov (United States)

    Tel, E.; Yiğit, M.; Tanır, G.

    2013-04-01

    In nuclear fusion reactions two light atomic nuclei fuse together to form a heavier nucleus. Fusion power is the power generated by nuclear fusion processes. In contrast with fission power, the fusion reaction processes does not produce radioactive nuclides. The fusion will not produce CO2 or SO2. So the fusion energy will not contribute to environmental problems such as particulate pollution and excessive CO2 in the atmosphere. Fusion powered electricity generation was initially believed to be readily achievable, as fission power had been. However, the extreme requirements for continuous reactions and plasma containment led to projections being extended by several decades. In 2010, more than 60 years after the first attempts, commercial power production is still believed to be unlikely before 2050. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. In the fusion reactor, tritium self-sufficiency must be maintained for a commercial power plant. Therefore, for self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of ( d, t) nuclear reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. Since the experimental data of charged particle induced reactions are scarce, self-consistent calculation and analyses using nuclear theoretical models are very important. In this study, ( d, t) cross sections for target nuclei 19F, 50Cr, 54Fe, 58Ni, 75As, 89Y, 90Zr, 107Ag, 127I, 197Au and 238U have been investigated up to 50 MeV deuteron energy. The excitation functions for ( d, t) reactions have been calculated by pre-equilibrium reaction mechanism. Calculation results have been also compared with the available measurements in

  15. Quantum chemical calculation of electron ionization mass spectra for general organic and inorganic molecules† †Electronic supplementary information (ESI) available: GFN-xTB calculated potential energy surfaces for example coordinates. Additional calculated mass spectra. Computational timing statistics. See DOI: 10.1039/c7sc00601b Click here for additional data file.

    Science.gov (United States)

    Ásgeirsson, Vilhjálmur; Bauer, Christoph A.

    2017-01-01

    We introduce a fully stand-alone version of the Quantum Chemistry Electron Ionization Mass Spectra (QCEIMS) program [S. Grimme, Angew. Chem. Int. Ed., 2013, 52, 6306] allowing efficient simulations for molecules composed of elements with atomic numbers up to Z = 86. The recently developed extended tight-binding semi-empirical method GFN-xTB has been combined with QCEIMS, thereby eliminating dependencies on third-party electronic structure software. Furthermore, for reasonable calculations of ionization potentials, as required by the method, a second tight-binding variant, IPEA-xTB, is introduced here. This novel combination of methods allows the automatic, fast and reasonably accurate computation of electron ionization mass spectra for structurally different molecules across the periodic table. In order to validate and inspect the transferability of the method, we perform large-scale simulations for some representative organic, organometallic, and main-group inorganic systems. Theoretical spectra for 23 molecules are compared directly to experimental data taken from standard databases. For the first time, realistic quantum chemistry based EI-MS for organometallic systems like ferrocene or copper(ii)acetylacetonate are presented. Compared to previously used semiempirical methods, GFN-xTB is faster, more robust, and yields overall higher quality spectra. The partially analysed theoretical reaction and fragmentation mechanisms are chemically reasonable and reveal in unprecedented detail the extreme complexity of high energy gas phase ion chemistry including complicated rearrangement reactions prior to dissociation. PMID:28959412

  16. Core calculations of JMTR

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, Yoshiharu [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    1998-03-01

    In material testing reactors like the JMTR (Japan Material Testing Reactor) of 50 MW in Japan Atomic Energy Research Institute, the neutron flux and neutron energy spectra of irradiated samples show complex distributions. It is necessary to assess the neutron flux and neutron energy spectra of an irradiation field by carrying out the nuclear calculation of the core for every operation cycle. In order to advance core calculation, in the JMTR, the application of MCNP to the assessment of core reactivity and neutron flux and spectra has been investigated. In this study, in order to reduce the time for calculation and variance, the comparison of the results of the calculations by the use of K code and fixed source and the use of Weight Window were investigated. As to the calculation method, the modeling of the total JMTR core, the conditions for calculation and the adopted variance reduction technique are explained. The results of calculation are shown. Significant difference was not observed in the results of neutron flux calculations according to the difference of the modeling of fuel region in the calculations by K code and fixed source. The method of assessing the results of neutron flux calculation is described. (K.I.)

  17. Cation-exchanged SAPO-34 for adsorption-based hydrocarbon separations: predictions from dispersion-corrected DFT calculations.

    Science.gov (United States)

    Fischer, Michael; Bell, Robert G

    2014-10-21

    The influence of the nature of the cation on the interaction of the silicoaluminophosphate SAPO-34 with small hydrocarbons (ethane, ethylene, acetylene, propane, propylene) is investigated using periodic density-functional theory calculations including a semi-empirical dispersion correction (DFT-D). Initial calculations are used to evaluate which of the guest-accessible cation sites in the chabazite-type structure is energetically preferred for a set of ten cations, which comprises four alkali metals (Li(+), Na(+), K(+), Rb(+)), three alkaline earth metals (Mg(2+), Ca(2+), Sr(2+)), and three transition metals (Cu(+), Ag(+), Fe(2+)). All eight cations that are likely to be found at the SII site (centre of a six-ring) are then included in the following investigation, which studies the interaction with the hydrocarbon guest molecules. In addition to the interaction energies, some trends and peculiarities regarding the adsorption geometries are analysed, and electron density difference plots obtained from the calculations are used to gain insights into the dominant interaction types. In addition to dispersion interactions, electrostatic and polarisation effects dominate for the main group cations, whereas significant orbital interactions are observed for unsaturated hydrocarbons interacting with transition metal (TM) cations. The differences between the interaction energies obtained for pairs of hydrocarbons of interest (such as ethylene-ethane and propylene-propane) deliver some qualitative insights: if this energy difference is large, it can be expected that the material will exhibit a high selectivity in the adsorption-based separation of alkene-alkane mixtures, which constitutes a problem of considerable industrial relevance. While the calculations show that TM-exchanged SAPO-34 materials are likely to exhibit a very high preference for alkenes over alkanes, the strong interaction may render an application in industrial processes impractical due to the large amount

  18. Multiphase flow calculation software

    Science.gov (United States)

    Fincke, James R.

    2003-04-15

    Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.

  19. Radar Signature Calculation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: The calculation, analysis, and visualization of the spatially extended radar signatures of complex objects such as ships in a sea multipath environment and...

  20. Waste Package Lifting Calculation

    Energy Technology Data Exchange (ETDEWEB)

    H. Marr

    2000-05-11

    The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation.

  1. Electrical installation calculations advanced

    CERN Document Server

    Kitcher, Christopher

    2013-01-01

    All the essential calculations required for advanced electrical installation workThe Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike. The book provides a step-by-step guide to the successful application of electrical installation calculations required in day-to-day electrical engineering practiceA step-by-step guide to everyday calculations used on the job An essential aid to the City & Guilds certificates at Levels 2 and 3For apprentices and electrical installatio

  2. Evapotranspiration Calculator Desktop Tool

    Science.gov (United States)

    The Evapotranspiration Calculator estimates evapotranspiration time series data for hydrological and water quality models for the Hydrologic Simulation Program - Fortran (HSPF) and the Stormwater Management Model (SWMM).

  3. Electronics Environmental Benefits Calculator

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Electronics Environmental Benefits Calculator (EEBC) was developed to assist organizations in estimating the environmental benefits of greening their purchase,...

  4. Electrical installation calculations basic

    CERN Document Server

    Kitcher, Christopher

    2013-01-01

    All the essential calculations required for basic electrical installation workThe Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike. The book provides a step-by-step guide to the successful application of electrical installation calculations required in day-to-day electrical engineering practice. A step-by-step guide to everyday calculations used on the job An essential aid to the City & Guilds certificates at Levels 2 and 3Fo

  5. Chemical calculations and chemicals that might calculate

    Science.gov (United States)

    Barnett, Michael P.

    I summarize some applications of symbolic calculation to the evaluation of molecular integrals over Slater orbitals, and discuss some spin-offs of this work that have wider potential. These include the exploration of the mechanized use of analogy. I explain the methods that I use to do this, in relation to mathematical proofs and to modeling step by step processes such as organic syntheses and NMR pulse sequences. Another spin-off relates to biological information processing. Some challenges and opportunities in the information infrastructure of interdisciplinary research are discussed.

  6. [Understanding dosage calculations].

    Science.gov (United States)

    Benlahouès, Daniel

    2016-01-01

    The calculation of dosages in paediatrics is the concern of the whole medical and paramedical team. This activity must generate a minimum of risks in order to prevent care-related adverse events. In this context, the calculation of dosages is a practice which must be understood by everyone. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  7. Calculativeness and trust

    DEFF Research Database (Denmark)

    Frederiksen, Morten

    2014-01-01

    Williamson’s characterisation of calculativeness as inimical to trust contradicts most sociological trust research. However, a similar argument is found within trust phenomenology. This paper re-investigates Williamson’s argument from the perspective of Løgstrup’s phenomenological theory of trust....... Contrary to Williamson, however, Løgstrup’s contention is that trust, not calculativeness, is the default attitude and only when suspicion is awoken does trust falter. The paper argues that while Williamson’s distinction between calculativeness and trust is supported by phenomenology, the analysis needs...... to take actual subjective experience into consideration. It points out that, first, Løgstrup places trust alongside calculativeness as a different mode of engaging in social interaction, rather conceiving of trust as a state or the outcome of a decision-making process. Secondly, the analysis must take...

  8. Unit Cost Compendium Calculations

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Unit Cost Compendium (UCC) Calculations raw data set was designed to provide for greater accuracy and consistency in the use of unit costs across the USEPA...

  9. Magnetic Field Grid Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Properties Calculator will computes the estimated values of Earth's magnetic field(declination, inclination, vertical component, northerly...

  10. National Stormwater Calculator

    Science.gov (United States)

    EPA’s National Stormwater Calculator (SWC) is a desktop application that estimates the annual amount of rainwater and frequency of runoff from a specific site anywhere in the United States (including Puerto Rico).

  11. Systematics of (p,alpha) (p,nalpha), and (p,np) reaction cross-sections.

    Science.gov (United States)

    Broeders, C H M; Konobeyev, A Yu

    2007-11-01

    Semi-empirical systematics of (p,alpha) (p,nalpha), and (p,np) reaction cross-sections were obtained at various incident proton energies from 17.9 to 28.5 MeV. Systematics are based on analytical formulas derived using the pre-equilibrium exciton model, evaporation model and semi-empirical mass formula. Parameters of systematics were fitted to the data obtained from the analysis of available measured cross-sections for (p,alpha) (p,nalpha), and (p,np) reactions.

  12. Calculation Tool for Engineering

    OpenAIRE

    Lampinen, Samuli

    2016-01-01

    The Study was conducted as qualitative research for K-S Konesuunnittelu Oy. The company provides mechanical engineering for technology suppliers in the Finnish export industries. The main objective was to study if the competitiveness of the case company could be improved using a self-made Calculation Tool (Excel Tool). The mission was to clarify processes in the case company to see the possibilities of Excel Tool and to compare it with other potential calculation applications. In addition,...

  13. Current interruption transients calculation

    CERN Document Server

    Peelo, David F

    2014-01-01

    Provides an original, detailed and practical description of current interruption transients, origins, and the circuits involved, and how they can be calculated Current Interruption Transients Calculationis a comprehensive resource for the understanding, calculation and analysis of the transient recovery voltages (TRVs) and related re-ignition or re-striking transients associated with fault current interruption and the switching of inductive and capacitive load currents in circuits. This book provides an original, detailed and practical description of current interruption transients, origins,

  14. Online plasma calculator

    Science.gov (United States)

    Wisniewski, H.; Gourdain, P.-A.

    2017-10-01

    APOLLO is an online, Linux based plasma calculator. Users can input variables that correspond to their specific plasma, such as ion and electron densities, temperatures, and external magnetic fields. The system is based on a webserver where a FastCGI protocol computes key plasma parameters including frequencies, lengths, velocities, and dimensionless numbers. FastCGI was chosen to overcome security problems caused by JAVA-based plugins. The FastCGI also speeds up calculations over PHP based systems. APOLLO is built upon the WT library, which turns any web browser into a versatile, fast graphic user interface. All values with units are expressed in SI units except temperature, which is in electron-volts. SI units were chosen over cgs units because of the gradual shift to using SI units within the plasma community. APOLLO is intended to be a fast calculator that also provides the user with the proper equations used to calculate the plasma parameters. This system is intended to be used by undergraduates taking plasma courses as well as graduate students and researchers who need a quick reference calculation.

  15. LHC Bellows Impedance Calculations

    CERN Document Server

    Dyachkov, M

    1997-01-01

    To compensate for thermal expansion the LHC ring has to accommodate about 2500 bellows which, together with beam position monitors, are the main contributors to the LHC broad-band impedance budget. In order to reduce this impedance to an acceptable value the bellows have to be shielded. In this paper we compare different designs proposed for the bellows and calculate their transverse and longitudinal wakefields and impedances. Owing to the 3D geometry of the bellows, the code MAFIA was used for the wakefield calculations; when possible the MAFIA results were compared to those obtained with ABCI. The results presented in this paper indicate that the latest bellows design, in which shielding is provided by sprung fingers which can slide along the beam screen, has impedances smaller tha those previously estimated according to a rather conservative scaling of SSC calculations and LEP measurements. Several failure modes, such as missing fingers and imperfect RF contact, have also been studied.

  16. INVAP's Nuclear Calculation System

    Directory of Open Access Journals (Sweden)

    Ignacio Mochi

    2011-01-01

    Full Text Available Since its origins in 1976, INVAP has been on continuous development of the calculation system used for design and optimization of nuclear reactors. The calculation codes have been polished and enhanced with new capabilities as they were needed or useful for the new challenges that the market imposed. The actual state of the code packages enables INVAP to design nuclear installations with complex geometries using a set of easy-to-use input files that minimize user errors due to confusion or misinterpretation. A set of intuitive graphic postprocessors have also been developed providing a fast and complete visualization tool for the parameters obtained in the calculations. The capabilities and general characteristics of this deterministic software package are presented throughout the paper including several examples of its recent application.

  17. Calculating Quenching Weights

    CERN Document Server

    Salgado, C A; Salgado, Carlos A.; Wiedemann, Urs Achim

    2003-01-01

    We calculate the probability (``quenching weight'') that a hard parton radiates an additional energy fraction due to scattering in spatially extended QCD matter. This study is based on an exact treatment of finite in-medium path length, it includes the case of a dynamically expanding medium, and it extends to the angular dependence of the medium-induced gluon radiation pattern. All calculations are done in the multiple soft scattering approximation (Baier-Dokshitzer-Mueller-Peign\\'e-Schiff--Zakharov ``BDMPS-Z''-formalism) and in the single hard scattering approximation (N=1 opacity approximation). By comparison, we establish a simple relation between transport coefficient, Debye screening mass and opacity, for which both approximations lead to comparable results. Together with this paper, a CPU-inexpensive numerical subroutine for calculating quenching weights is provided electronically. To illustrate its applications, we discuss the suppression of hadronic transverse momentum spectra in nucleus-nucleus colli...

  18. Graphing Calculator Mini Course

    Science.gov (United States)

    Karnawat, Sunil R.

    1996-01-01

    The "Graphing Calculator Mini Course" project provided a mathematically-intensive technologically-based summer enrichment workshop for teachers of American Indian students on the Turtle Mountain Indian Reservation. Eleven such teachers participated in the six-day workshop in summer of 1996 and three Sunday workshops in the academic year. The project aimed to improve science and mathematics education on the reservation by showing teachers effective ways to use high-end graphing calculators as teaching and learning tools in science and mathematics courses at all levels. In particular, the workshop concentrated on applying TI-82's user-friendly features to understand the various mathematical and scientific concepts.

  19. FT-IR, FT-Raman and NMR characterization of 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate and investigation of its reactive and optoelectronic properties by molecular dynamics simulations and DFT calculations

    Science.gov (United States)

    Menon, Vidya V.; Fazal, Edakot; Mary, Y. Sheena; Panicker, C. Yohannan; Armaković, Stevan; Armaković, Sanja J.; Nagarajan, Subban; Van Alsenoy, C.

    2017-01-01

    The FT-IR and FT-Raman spectra of the synthesized compound, 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate is recorded and analyzed. Optimized molecular structure, wave numbers, corresponding assignments regarding 2-isopropyl-5-methylcyclohexyl quinoline-2-carboxylate has become screened tentatively as well as hypothetically using Gaussian09 program package. Natural bonding orbital assessment has been completed with a reason to clarify charge transfer or conjugative interaction, the intra-molecular re-hybridization and delocalization of electron density within the molecule. The NMR spectral assessment had been made choosing structure property relationship by chemical shifts along with the magnetic shielding effects regarding the title compound. The first and second hyperpolarizabilities were calculated. The calculated first order hyperpolarizability is commensurate with the documented worth of very similar derivatives and could be an interesting object for more experiments on nonlinear optics. Local reactivity properties have been investigated using average local ionization energies and Fukui functions. Investigation of optoelectronic properties encompassed calculations of reorganization energies and hopping rates of charge carriers within the framework of Marcus semi-empiric approach. The docked ligand title compound forms a stable complex with CDK inhibitors and gives a binding affinity value of -9.7 kcal/mol and molecular docking results suggest that the compound might exhibit inhibitory activity against CDK inhibitors.

  20. QSAR STUDY OF 1,10-PHENANTHROLINE DERIVATIVES AS THE ANTIMALARIAL COMPOUNDS USING ELECTRONIC DESCRIPTORS BASED ON SEMIEMPIRICAL AM1 CALCULATION

    Directory of Open Access Journals (Sweden)

    Mustofa Mustofa

    2010-06-01

    Full Text Available Quantitative Structure-Activity Relationship (QSAR analysis of 1,10-phenantroline analogs as antimalarial drug has been conducted using atomic net charges (q as predictors of their activity. Data of predictors are obtained from computational chemistry method using semi-empirical molecular orbital AM1 calculation. Antimalarial activities are taken as the activity of the drugs against plasmodium falciparum (FcM29-Cameroun strain and are presented as the value of ln(1/IC50 where IC50 is an effective concentration inhibiting 50 % of the parasite growth.  The results show that there is correlation between antiplasmodial activity and electronic structure as represented by a linear function of activity versus atomic net charges of N1, C7, C10, C14 atoms on the 1,10-phenanthroline skeleton and is expressed by : log IC50 = -3,4398 - 14,9050 qN1 - 8,5589 qC10 - 14,7565 qC7 + 5,0457 qC11 The equation is significant at 95% level with statistical parameters : n = 13; r = 0,96275; r2 = 0,92689; SE = 0,61578 and F (4,8 = 25,3556.   Keywords: antimalarial drug; 1,10-phenanthroline; QSAR; antiplasmodial activity.

  1. Gravitational constant calculation methodologies

    OpenAIRE

    Shakhparonov, V. M.; Karagioz, O. V.; Izmailov, V. P.

    2011-01-01

    We consider the gravitational constant calculation methodologies for a rectangular block of the torsion balance body presented in the papers Phys. Rev. Lett. 102, 240801 (2009) and Phys.Rev. D. 82, 022001 (2010). We have established the influence of non-equilibrium gas flows on the obtained values of G.

  2. Charge calculation studies done on a single walled carbon nanotube using MOPAC

    Science.gov (United States)

    Negi, S.; Bhartiya, Vivek Kumar; Chaturvedi, S.

    2017-11-01

    Dipole symmetry of induced charges on DWNTs are required for their application as a nanomotor. Earlier a molecular dynamics analysis was performed for a double-walled carbon-nanotube based motor driven by an externally applied sinusoidally varying electric field. One of the ways to get such a system is chemical or end functionalization, which promises to accomplish this specific and rare configuration of the induced charges on the surface of the carbon nanotube (CNT). CNTs are also a promising system for attaching biomolecules for bio-related applications. In an earlier work, ab initio calculations were done to study the electronic and structural properties of the groups -COOH, -OH, -NH2 and -CONH2 functionalized to an (8, 0) SWNT. The systems were shown to have a very stable interaction with the CNTs. The exterior surface of the SWNT is found to be reactive to NH2 (amidogen). In this work, charge calculations are done on a CNT using MOPAC, which is a semi empirical quantum chemistry software package. As a first step, we calculate the effect of NH2 functionalization to a (5,0) SWNT of infinite length. The symmetric charge distribution of the bare SWNT is observed to be disturbed on addition of a single NH2 in the close proximity of the SWNT. A net positive and opposite charge is observed to be induced on the opposite sides of the nanotube circumference, which is, in turn, imperative for the nanomotor applications. The minimum and maximum value of the charge on any atom is observed to increase from - 0.3 to 0.6 and from - 0.3 to - 1.8 electronic charge as compared to the bare SWNT. This fluctuation of the surface charge to larger values than bare CNT, can be attributed to the coulomb repulsion between NH2 and the rest of the charge on the surface which results into minimizing the total energy of the system. No such opposite polarity of charges are observed on adding NH2 to each ring of the SWNT implying addition of a single amidogen to be the most appropriate

  3. A deterministic partial differential equation model for dose calculation in electron radiotherapy.

    Science.gov (United States)

    Duclous, R; Dubroca, B; Frank, M

    2010-07-07

    High-energy ionizing radiation is a prominent modality for the treatment of many cancers. The approaches to electron dose calculation can be categorized into semi-empirical models (e.g. Fermi-Eyges, convolution-superposition) and probabilistic methods (e.g.Monte Carlo). A third approach to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. We derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on Berthon et al (2007 J. Sci. Comput. 31 347-89) that exactly preserves the key properties of the analytical solution on the discrete level. We discuss several test cases taken from the medical physics literature. A test case with an academic Henyey-Greenstein scattering kernel is considered. We compare our model to a benchmark discrete ordinate solution. A simplified model of electron interactions with tissue is employed to compute the dose of an electron beam in a water phantom, and a case of irradiation of the vertebral column. Here our model is compared to the PENELOPE Monte Carlo code. In the academic example, the fluences computed with the new model and a benchmark result differ by less than 1%. The depths at half maximum differ by less than 0.6%. In the two comparisons with Monte Carlo, our model gives qualitatively reasonable dose distributions. Due to the crude interaction model, these so far do not have the accuracy needed in clinical practice. However, the new model has a computational cost that is less than one-tenth of the cost of a Monte Carlo simulation. In addition, simulations can be set up in a similar way as a Monte Carlo simulation. If more detailed effects such as coupled electron-photon transport, bremsstrahlung

  4. Calculation of collisional mixing

    Science.gov (United States)

    Koponen, I.; Hautala, M.

    1990-06-01

    Collisional mixing of markers is calculated by splitting the calculation into two parts. Relocation cross sections have been calculated using a realistic potential in a Monte Carlo simulation. The cross sections are used in the computation of marker relocation. The cumulative effect of successive relocations is assumed to be an uncorrelated transport process and it is treated as a weighted random walk. Matrix relocation was not included in the calculations. The results from this two-step simulation model are compared with analytical models. A fit to the simulated differential relocation cross sections has been found which makes the numerical integration of the Bothe formula feasible. The influence of primaries has been treated in this way. When all the recoils are included the relocation profiles are nearly Gaussian and the Pearson IV distributions yield acceptable profiles in the studied cases. The approximations and cut-off procedures which cause the major uncertainties in calculations are pointed out. The choice of the cut-off energy is shown to be the source of the largest uncertainty whereas the mathematical approximations can be used with good accuracy. The methods are used to study the broadening of a Pt marker in Si mixed by 300 keV Xe ions, broadening of a Ti marker in Al mixed by 300 keV Xe ions and broadening of a Ti marker in Hf mixed by 750 keV Kr ions. The fluence in each case is 2 × 10 16{ions}/{cm 2}. The calculated averages of half widths at half maximum vary between 11-18, 9-12 and 10-15 nm, respectively, depending on the cut-off energy and the mixing efficiencies vary between 11-29, 6-11 and 6-14 {Å5}/{eV}, respectively. The broadenings of Pt in Si and Ti in Al are about two times smaller than the measured values and the broadening of Ti in Hf is in agreement with the measured values.

  5. Microcomputer calculations in physics

    Science.gov (United States)

    Killingbeck, J. P.

    1985-01-01

    The use of microcomputers to carry out computations in an interactive manner allows the judgement of the operator to be allied with the calculating power of the machine in a synthesis which speeds up the creation and testing of mathematical techniques for physical problems. This advantage is accompanied by a disadvantage, in that microcomputers are limited in capacity and power, and special analysis is needed to compensate for this. These two features together mean that there is a fairly recognisable body of methods which are particularly appropriate for interactive microcomputing. This article surveys a wide range of mathematical methods used in physics, indicating how they can be applied using microcomputers and giving several original calculations which illustrate the value of the microcomputer in stimulating the exploration of new methods. Particular emphasis is given to methods which use iteration, recurrence relation or extrapolation procedures which are well adapted to the capabilities of modern microcomputers.

  6. CONVEYOR FOUNDATIONS CALCULATION

    Energy Technology Data Exchange (ETDEWEB)

    S. Romanos

    1995-03-10

    The purpose of these calculations is to design foundations for all conveyor supports for the surface conveyors that transport the muck resulting from the TBM operation, from the belt storage to the muck stockpile. These conveyors consist of: (1) Conveyor W-TO3, from the belt storage, at the starter tunnel, to the transfer tower. (2) Conveyor W-SO1, from the transfer tower to the material stacker, at the muck stockpile.

  7. Calculations in furnace technology

    CERN Document Server

    Davies, Clive; Hopkins, DW; Owen, WS

    2013-01-01

    Calculations in Furnace Technology presents the theoretical and practical aspects of furnace technology. This book provides information pertinent to the development, application, and efficiency of furnace technology. Organized into eight chapters, this book begins with an overview of the exothermic reactions that occur when carbon, hydrogen, and sulfur are burned to release the energy available in the fuel. This text then evaluates the efficiencies to measure the quantity of fuel used, of flue gases leaving the plant, of air entering, and the heat lost to the surroundings. Other chapters consi

  8. The Use of Meteosat Second Generation Satellite Data Within A New Type of Solar Irradiance Calculation Scheme

    Science.gov (United States)

    Mueller, R. W.; Beyer, H. G.; Cros, S.; Dagestad, K. F.; Dumortier, D.; Ineichen, P.; Hammer, A.; Heinemann, D.; Kuhlemann, R.; Olseth, J. A.; Piernavieja, G.; Reise, C.; Schroedter, M.; Skartveit, A.; Wald, L.

    1-University of Oldenburg, 2-University of Appl. Sciences Magdeburg, 3-Ecole des Mines de Paris, 4-University of Bergen, 5-Ecole Nationale des Travaux Publics de l'Etat, 6-University of Geneva, 7-Instituto Tecnologico de Canarias, 8-Fraunhofer Institute for Solar Energy Systems, 9-German Aerospace Center Geostationary satellites such as Meteosat provide cloud information with a high spatial and temporal resolution. Such satellites are therefore not only useful for weather fore- casting, but also for the estimation of solar irradiance since the knowledge of the light reflected by clouds is the basis for the calculation of the transmitted light. Additionally an the knowledge of atmospheric parameters involved in scattering and absorption of the sunlight is necessary for an accurate calculation of the solar irradiance. An accurate estimation of the downward solar irradiance is not only of particular im- portance for the assessment of the radiative forcing of the climate system, but also necessary for an efficient planning and operation of solar energy systems. Currently, most of the operational calculation schemes for solar irradiance are semi- empirical. They use cloud information from the current Meteosat satellite and clima- tologies of atmospheric parameters e.g. turbidity (aerosols and water vapor). The Me- teosat Second Generation satellites (MSG, to be launched in 2002) will provide not only a higher spatial and temporal resolution, but also the potential for the retrieval of atmospheric parameters such as ozone, water vapor and with restrictions aerosols. With this more detailed knowledge about atmospheric parameters it is evident to set up a new calculation scheme based on radiative transfer models using the retrieved atmospheric parameters as input. Unfortunately the possibility of deriving aerosol in- formation from MSG data is limited. As a cosequence the use of data from additional satellite instruments ( e.g. GOME/ATSR-2) is neeeded. Within this

  9. Calculating Speed of Sound

    Science.gov (United States)

    Bhatnagar, Shalabh

    2017-01-01

    Sound is an emerging source of renewable energy but it has some limitations. The main limitation is, the amount of energy that can be extracted from sound is very less and that is because of the velocity of the sound. The velocity of sound changes as per medium. If we could increase the velocity of the sound in a medium we would be probably able to extract more amount of energy from sound and will be able to transfer it at a higher rate. To increase the velocity of sound we should know the speed of sound. If we go by the theory of classic mechanics speed is the distance travelled by a particle divided by time whereas velocity is the displacement of particle divided by time. The speed of sound in dry air at 20 °C (68 °F) is considered to be 343.2 meters per second and it won't be wrong in saying that 342.2 meters is the velocity of sound not the speed as it's the displacement of the sound not the total distance sound wave covered. Sound travels in the form of mechanical wave, so while calculating the speed of sound the whole path of wave should be considered not just the distance traveled by sound. In this paper I would like to focus on calculating the actual speed of sound wave which can help us to extract more energy and make sound travel with faster velocity.

  10. Multilayer optical calculations

    CERN Document Server

    Byrnes, Steven J

    2016-01-01

    When light hits a multilayer planar stack, it is reflected, refracted, and absorbed in a way that can be derived from the Fresnel equations. The analysis is treated in many textbooks, and implemented in many software programs, but certain aspects of it are difficult to find explicitly and consistently worked out in the literature. Here, we derive the formulas underlying the transfer-matrix method of calculating the optical properties of these stacks, including oblique-angle incidence, absorption-vs-position profiles, and ellipsometry parameters. We discuss and explain some strange consequences of the formulas in the situation where the incident and/or final (semi-infinite) medium are absorptive, such as calculating $T>1$ in the absence of gain. We also discuss some implementation details like complex-plane branch cuts. Finally, we derive modified formulas for including one or more "incoherent" layers, i.e. very thick layers in which interference can be neglected. This document was written in conjunction with ...

  11. Spectroscopic characterization of 1-[3-(1H-imidazol-1-yl)propyl]-3-phenylthiourea and assessment of reactive and optoelectronic properties employing DFT calculations and molecular dynamics simulations

    Science.gov (United States)

    War, Javeed Ahmad; Jalaja, K.; Mary, Y. Sheena; Panicker, C. Yohannan; Armaković, Stevan; Armaković, Sanja J.; Srivastava, Santosh Kumar; Van Alsenoy, C.

    2017-02-01

    IR and Raman spectra of 1-[3-(1H-imidazol-1-yl)propyl]-3-phenylthiourea (HIPPT) have been recorded in the solid phase and the vibrational wave numbers are calculated theoretically by B3LYP/6-31G(d,p) (6D, 7F) method. All the fundamental vibrational modes have been assigned using potential energy distribution values and the molecular structure was analyzed in terms of parameters like bond length, bond angles and dihedral angles. The ring breathing mode of the phenyl ring is observed at 1016 cm-1 in the IR spectrum, 1014 cm-1 in the Raman spectrum and at 1014 cm-1 theoretically. The values of polarizability and hyperpolarizabilities were calculated and nonlinear optical properties are discussed. The HOMO-LUMO plot reveals the charge transfer possibilities in the molecule. The NBO analysis was computed and possible transitions were correlated with the electronic transitions. In the title compound, the imidazole ring and CH2 groups are tilted from each other and the thiourea group is tilted from the phenyl ring. Using MEP plot the electrophilic and nucleophilic regions are identified. Local reactivity properties were investigated by analysis of ALIE surfaces and Fukui functions. Oxidation and degradation properties were initially assessed by calculation of bond dissociation energies of all single acyclic bonds. Determination of atoms with pronounced interactions with water molecules was performed by calculation of radial distribution functions after molecular dynamics simulations. Chargehopping rates were calculated within Marcus semi-empiric approach, employing both DFT calculations and MD simulations. The molecular docking computational predictions were complemented by the in vitro antibacterial activity evaluation.

  12. IPC - Isoelectric Point Calculator.

    Science.gov (United States)

    Kozlowski, Lukasz P

    2016-10-21

    Accurate estimation of the isoelectric point (pI) based on the amino acid sequence is useful for many analytical biochemistry and proteomics techniques such as 2-D polyacrylamide gel electrophoresis, or capillary isoelectric focusing used in combination with high-throughput mass spectrometry. Additionally, pI estimation can be helpful during protein crystallization trials. Here, I present the Isoelectric Point Calculator (IPC), a web service and a standalone program for the accurate estimation of protein and peptide pI using different sets of dissociation constant (pKa) values, including two new computationally optimized pKa sets. According to the presented benchmarks, the newly developed IPC pKa sets outperform previous algorithms by at least 14.9 % for proteins and 0.9 % for peptides (on average, 22.1 % and 59.6 %, respectively), which corresponds to an average error of the pI estimation equal to 0.87 and 0.25 pH units for proteins and peptides, respectively. Moreover, the prediction of pI using the IPC pKa's leads to fewer outliers, i.e., predictions affected by errors greater than a given threshold. The IPC service is freely available at http://isoelectric.ovh.org Peptide and protein datasets used in the study and the precalculated pI for the PDB and some of the most frequently used proteomes are available for large-scale analysis and future development. This article was reviewed by Frank Eisenhaber and Zoltán Gáspári.

  13. The rating reliability calculator

    Directory of Open Access Journals (Sweden)

    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.

  14. Newly developed semi-empirical formulas for (p, α) at 17.9 MeV and ...

    Indian Academy of Sciences (India)

    Department of Physics, Faculty of Arts and Sciences, Gazi University, TR-06500 Ankara, Turkey; Faculty of Arts and Sciences, Kırıkkale University, 71450 Kırıkkale, Turkey; Faculty of Arts and Sciences, Süleyman Demirel University, 32260 Isparta, Turkey; Department of Physics Engineering, Faculty of Engineering, Ankara ...

  15. The choice of the optimum terms for semi-empirical description of s-wave neutron resonance level densities

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarczyk, Maria; Lason, Lech [Division of Nuclear Physics, University of Lodz, ul Pomorska 149/153, 90-236 Lodz (Poland)

    2006-04-01

    This paper presents a function describing the dependence of the neutron resonance level density {rho} on the neutron number N in the target nucleus. The function describes quite well, with an accuracy of one order, the experimental data for 284 nuclides. Moreover, it adequately describes the general tendency and shell model effects for magic nuclei and for nuclei close to magic ones. The achieved agreement between the values obtained from the proposed description and the experimental data {rho}{sub exp} can be improved if the {rho}{sub exp} values are normalized energetically and reduced to a narrow range of angular momentum J.

  16. The semi-empirical tight-binding model for carbon allotropes “between diamond and graphite”

    Energy Technology Data Exchange (ETDEWEB)

    Lytovchenko, V.; Kurchak, A.; Strikha, M., E-mail: maksym-strikha@hotmail.com [Institute of Semiconductor Physics, NAS of Ukraine, Pr. Nauky 41, Kyiv 03028 (Ukraine)

    2014-06-28

    The new carbon allotropes “between diamond and graphite” have come under intensive examination during the last decade due to their numerous technical applications. The modification of energy gap in thin films of these allotropes was studied experimentally using optical methods. The proposed simple model of carbon clusters with variable lengths of chemical bonds allows us to imitate the transfer from diamond and diamond-like to graphite-like structures, as well as the corresponding modification of hybridization sp{sup 3}/sp{sup 2} for diamond-like and sp{sub z} for graphite-like phases. This enables us to estimate various allotropes parameters, like the gap E{sub g}, energies of valence E{sub v}, and conduction E{sub c} band edges, and the value of electronic affinity, i.e., optical work function X, which are all of practical importance. The obtained estimations correspond to the experimental data.

  17. Newly developed semi-empirical formulas for (p, α) at 17.9 MeV and ...

    Indian Academy of Sciences (India)

    Turkey. 2Faculty of Arts and Sciences, Kırıkkale University, 71450 Kırıkkale, Turkey. 3Faculty of Arts and Sciences, Süleyman Demirel University, 32260 ... neutron source (capable of incinerating nuclear waste and of producing energy), high-energy proton-induced fission as an alternative for the isotope production etc. [1,2].

  18. A Parameter Identification Method for Helicopter Noise Source Identification and Physics-Based Semi-Empirical Modeling

    Science.gov (United States)

    Greenwood, Eric, II; Schmitz, Fredric H.

    2010-01-01

    A new physics-based parameter identification method for rotor harmonic noise sources is developed using an acoustic inverse simulation technique. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. This new method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor Blade-Vortex Interaction (BVI) noise, allowing accurate estimates of BVI noise to be made for operating conditions based on a small number of measurements taken at different operating conditions.

  19. A Semi-empirical approach for the modelling and analysis of microvibration sources on-board spacecraft.

    OpenAIRE

    Addari, Daniele

    2017-01-01

    The term microvibrations generally refers to accelerations in the order of micro-gs and which manifest in a bandwidth from a few Hz up to say 500-1000 Hz. The need to accurately characterise this small disturbances acting on-board modern satellites, thus allowing the design of dedicated minimisation and control systems, is nowadays a major concern for the success of some space missions. The main issues related to microvibrations are the feasibility to analytically describe the microvibrat...

  20. Chlorination pattern effect on thermodynamic parameters and environmental degradability for C₁₀-SCCPs: Quantum chemical calculation based on virtual combinational library.

    Science.gov (United States)

    Sun, Yuzhen; Pan, Wenxiao; Lin, Yuan; Fu, Jianjie; Zhang, Aiqian

    2016-01-01

    Short-chain chlorinated paraffins (SCCPs) are still controversial candidates for inclusion in the Stockholm Convention. The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental behaviors. A virtual molecule library of 42,720 C10-SCCP congeners covering the full structure spectrum was constructed. We explored the structural effects on the thermodynamic parameters and environmental degradability of C10-SCCPs through semi-empirical quantum chemical calculations. The thermodynamic properties were acquired using the AM1 method, and frontier molecular orbital analysis was carried out to obtain the E(HOMO), E(LUMO) and E(LUMO)-E(HOMO) for degradability exploration at the same level. The influence of the chlorination degree (N(Cl)) on the relative stability and environmental degradation was elucidated. A novel structural descriptor, μ, was proposed to measure the dispersion of the chlorine atoms within a molecule. There were significant correlations between thermodynamic values and N(Cl), while the reported N(Cl)-dependent pollution profile of C10-SCCPs in environmental samples was basically consistent with the predicted order of formation stability of C10-SCCP congeners. In addition, isomers with large μ showed higher relative stability than those with small μ. This could be further verified by the relationship between μ and the reactivity of nucleophilic substitution and OH attack respectively. The C10-SCCP congeners with less Cl substitution and lower dispersion degree are susceptible to environmental degradation via nucleophilic substitution and hydroxyl radical attack, while direct photolysis of C10-SCCP congeners cannot readily occur due to the large E(LUMO)-E(HOMO) values. The chlorination effect and the conclusions were further checked with appropriate density functional theory (DFT) calculations. Copyright © 2015. Published by Elsevier B.V.

  1. Point Defect Calculations in Tungsten

    National Research Council Canada - National Science Library

    Danilowicz, Ronald

    1968-01-01

    .... The vacancy migration energy for tungsten was calculated. The calculated value of 1.73 electron volts, together with experimental data, suggests that vacancies migrate in stage III recovery in tungsten...

  2. Some calculated (p,α) cross-sections using the alpha particle knock-on and triton pick-up reaction mechanisms: An optimisation of the single-step Feshbach-Kerman-Koonin (FKK) theory

    Energy Technology Data Exchange (ETDEWEB)

    Olise, Felix S.; Ajala, Afis; Olamiyl, Hezekiah B. [Dept. of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife (Nigeria)

    2016-04-15

    The Feshbach-Kerman-Koonin (FKK) multi-step direct (MSD) theory of pre-equilibrium reactions has been used to compute the single-step cross-sections for some (p,α) reactions using the knock-on and pick-up reaction mechanisms at two incident proton energies. For the knock-on mechanism, the reaction was assumed to have taken place by the direct ejection of a preformed alpha cluster in a shell-model state of the target. But the reaction was assumed to have taken place by the pick-up of a preformed triton cluster (also bound in a shell-model state of the target core) by the incident proton for the pick-up mechanism. The Yukawa forms of potential were used for the proton-alpha (for the knock-on process) and proton-triton (for the pick-up process) interaction and several parameter sets for the proton and alpha-particle optical potentials. The calculated cross-sections for both mechanisms gave satisfactory fits to the experimental data. Furthermore, it has been shown that some combinations of the calculated distorted wave Born approximation cross-sections for the two reaction mechanisms in the FKK MSD theory are able to give better fits to the experimental data, especially in terms of range of agreement. In addition, the theory has been observed to be valid over a wider range of energy.

  3. Some Calculated (p,α Cross-Sections Using the Alpha Particle Knock-On and Triton Pick-Up Reaction Mechanisms: An Optimisation of the Single-Step Feshbach–Kerman–Koonin (FKK Theory

    Directory of Open Access Journals (Sweden)

    Felix S. Olise

    2016-04-01

    Full Text Available The Feshbach–Kerman–Koonin (FKK multi-step direct (MSD theory of pre-equilibrium reactions has been used to compute the single-step cross-sections for some (p,α reactions using the knock-on and pick-up reaction mechanisms at two incident proton energies. For the knock-on mechanism, the reaction was assumed to have taken place by the direct ejection of a preformed alpha cluster in a shell-model state of the target. But the reaction was assumed to have taken place by the pick-up of a preformed triton cluster (also bound in a shell-model state of the target core by the incident proton for the pick-up mechanism. The Yukawa forms of potential were used for the proton-alpha (for the knock-on process and proton-triton (for the pick-up process interaction and several parameter sets for the proton and alpha-particle optical potentials. The calculated cross-sections for both mechanisms gave satisfactory fits to the experimental data. Furthermore, it has been shown that some combinations of the calculated distorted wave Born approximation cross-sections for the two reaction mechanisms in the FKK MSD theory are able to give better fits to the experimental data, especially in terms of range of agreement. In addition, the theory has been observed to be valid over a wider range of energy.

  4. Assessment of Density-Functional Tight-Binding Ionization Potentials and Electron Affinities of Molecules of Interest for Organic Solar Cells Against First-Principles GW Calculations

    Directory of Open Access Journals (Sweden)

    Ala Aldin M. H. M. Darghouth

    2015-12-01

    Full Text Available Ionization potentials (IPs and electron affinities (EAs are important quantities input into most models for calculating the open-circuit voltage (Voc of organic solar cells. We assess the semi-empirical density-functional tight-binding (DFTB method with the third-order self-consistent charge (SCC correction and the 3ob parameter set (the third-order DFTB (DFTB3 organic and biochemistry parameter set against experiments (for smaller molecules and against first-principles GW (Green’s function, G, times the screened potential, W calculations (for larger molecules of interest in organic electronics for the calculation of IPs and EAs. Since GW calculations are relatively new for molecules of this size, we have also taken care to validate these calculations against experiments. As expected, DFTB is found to behave very much like density-functional theory (DFT, but with some loss of accuracy in predicting IPs and EAs. For small molecules, the best results were found with ΔSCF (Δ self-consistent field SCC-DFTB calculations for first IPs (good to ± 0.649 eV. When considering several IPs of the same molecule, it is convenient to use the negative of the orbital energies (which we refer to as Koopmans’ theorem (KT IPs as an indication of trends. Linear regression analysis shows that KT SCC-DFTB IPs are nearly as accurate as ΔSCF SCC-DFTB eigenvalues (± 0.852 eV for first IPs, but ± 0.706 eV for all of the IPs considered here for small molecules. For larger molecules, SCC-DFTB was also the ideal choice with IP/EA errors of ± 0.489/0.740 eV from ΔSCF calculations and of ± 0.326/0.458 eV from (KT orbital energies. Interestingly, the linear least squares fit for the KT IPs of the larger molecules also proves to have good predictive value for the lower energy KT IPs of smaller molecules, with significant deviations appearing only for IPs of 15–20 eV or larger. We believe that this quantitative analysis of errors in SCC-DFTB IPs and EAs may be of

  5. Structural, electronic and optical properties of pure and Ni{sup 2+}-doped CdI{sub 2} layered crystals as explored by ab initio and crystal field calculations

    Energy Technology Data Exchange (ETDEWEB)

    Brik, M.G., E-mail: brik@fi.tartu.e [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Kityk, I.V. [Electrical Engineering Department, Czestochowa University of Technology, Al. Armii Krajowej 17/19, 42-200 Czestochowa (Poland); Ozga, K.; Slezak, A. [Chair of Public Health, Czestochowa University of Technology, Al. Armii Krajowej 36B, 42-200 Czestochowa (Poland)

    2011-01-15

    Influence of impurity Ni{sup 2+} ions on optical absorption spectra of layered CdI{sub 2} single crystals has been considered for localized level of doping. Optical properties of CdI{sub 2}:Ni{sup 2+} crystals were modeled using two independent approaches: (i) DFT-based ab initio calculations and (ii) semi-empirical crystal field theory. The former method allowed for locating the Ni{sup 2+} 3d states with respect to the host's band structure, providing a link between the properties of impurity and host itself. The latter method allowed for calculations of crystal field splitting of the Ni{sup 2+} LS terms, giving an opportunity to assign the main bands in the absorption spectrum of the doped crystal. To increase accuracy in calculating the point charge contribution to the crystal field parameters (CFP), contributions of all crystal lattice ions located at a distance of up to 72.999 A from the Ni ion were included into the crystal lattice sums. The crystal field Hamiltonian was diagonalized in the space of 25 wave functions of the spin-triplet terms {sup 3}F, {sup 3}P and the spin-singlet terms {sup 1}S, {sup 1}D, {sup 1}G of the 3d{sup 8} electron configuration of Ni{sup 2+} ion. Additional calculations of the band structure and optical functions were performed to reveal the structure of the energy bands, their role in the formation of optical properties of this system in the overlapping impurity-ligand effects. Electron density distribution in the space between atoms before and after doping was compared; hybridization of the Ni 3d states with iodine 5p states was demonstrated. The role of the crystal anisotropy in the observed effects is discussed.

  6. Computational techniques in tribology and material science at the atomic level

    Science.gov (United States)

    Ferrante, J.; Bozzolo, G. H.

    1992-01-01

    Computations in tribology and material science at the atomic level present considerable difficulties. Computational techniques ranging from first-principles to semi-empirical and their limitations are discussed. Example calculations of metallic surface energies using semi-empirical techniques are presented. Finally, application of the methods to calculation of adhesion and friction are presented.

  7. Structure investigation of codeine drug using mass spectrometry, thermal analyses and semi-emperical molecular orbital (MO) calculations

    Science.gov (United States)

    Zayed, M. A.; Hawash, M. F.; Fahmey, M. A.

    2006-05-01

    Codeine is an analgesic with uses similar to morphine, but it has a mild sedative effect. It is preferable used as phosphate form and it is often administrated by mouth with aspirin or paracetamol. Therefore, it is important to investigate its structure to know the active groups and weak bonds responsible for its medical activity. Consequently in the present work, codeine was investigated by mass spectrometry and thermal analyses (TG, DTG and DTA) and confirming by semi-empirical MO-calculation (PM3 method) in the neutral and positively charged forms of the drug. Some results of studying the d-block element complexes of codeine were used to declare the relationship between drug structure and its chemical reactivity in vitro system. The mass spectra and thermal analyses fragmentation pathways were proposed and compared to each other to select the most suitable scheme representing the correct fragmentation of this drug. From EI mass spectra, the main primary cleavage site of the charged drug molecule is that due to β-cleavage to nitrogen atom in its skeleton. It occurs in two parallel mechanisms with the same possibility, i.e. no difference in appearance activation energy between them. In the neutral drug form the primary site cleavage is that occurs in the ether ring. Thermal analyses of the neutral form of the drug revealed the high response of the drug to the temperature variation with very fast rate. It decomposed in several sequential steps in the temperature range 200-600 °C. The initial thermal fragments are very similar to that obtained by mass spectrometric fragmentation. Therefore, comparison between mass and thermal helps in selection of the proper pathway representing the fragmentation of this drug. This comparison successfully confirmed by MOC. These calculations give the bond order, charge distribution, heat of formation and possible hybridization of some atoms in different position of the drug skeleton. This helps the successful choice of the weakest

  8. relline: Relativistic line profiles calculation

    Science.gov (United States)

    Dauser, Thomas

    2015-05-01

    relline calculates relativistic line profiles; it is compatible with the common X-ray data analysis software XSPEC (ascl:9910.005) and ISIS (ascl:1302.002). The two basic forms are an additive line model (RELLINE) and a convolution model to calculate relativistic smearing (RELCONV).

  9. Calculated neutron intensities for SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Atchison, F

    1998-03-01

    A fully detailed calculation of the performance of the SINQ neutron source, using the PSI version of the HETC code package, was made in 1996 to provide information useful for source commissioning. Relevant information about the formulation of the problem, cascade analysis and some of the results are presented. Aspects of the techniques used to verify the results are described and discussed together with a limited comparison with earlier results obtained from neutron source design calculations. A favourable comparison between the measured and calculated differential neutron flux in one of the guides gives further indirect evidence that such calculations can give answers close to reality in absolute terms. Due to the complex interaction between the many nuclear (and other) models involved, no quantitative evaluation of the accuracy of the calculational method in general terms can be given. (author) refs., 13 figs., 9 tabs.

  10. Alaska Village Electric Load Calculator

    Energy Technology Data Exchange (ETDEWEB)

    Devine, M.; Baring-Gould, E. I.

    2004-10-01

    As part of designing a village electric power system, the present and future electric loads must be defined, including both seasonal and daily usage patterns. However, in many cases, detailed electric load information is not readily available. NREL developed the Alaska Village Electric Load Calculator to help estimate the electricity requirements in a village given basic information about the types of facilities located within the community. The purpose of this report is to explain how the load calculator was developed and to provide instructions on its use so that organizations can then use this model to calculate expected electrical energy usage.

  11. Practical astronomy with your calculator

    CERN Document Server

    Duffett-Smith, Peter

    1989-01-01

    Practical Astronomy with your Calculator, first published in 1979, has enjoyed immense success. The author's clear and easy to follow routines enable you to solve a variety of practical and recreational problems in astronomy using a scientific calculator. Mathematical complexity is kept firmly in the background, leaving just the elements necessary for swiftly making calculations. The major topics are: time, coordinate systems, the Sun, the planetary system, binary stars, the Moon, and eclipses. In the third edition there are entirely new sections on generalised coordinate transformations, nutr

  12. Calculate Your Body Mass Index

    Science.gov (United States)

    ... Institutes of Health Contact Us Get Email Alerts Font Size Accessible Search Form Search the NHLBI, use ... Be Physically Active Healthy Weight Tools BMI Calculator Menu Plans Portion Distortion Key Recommendations Healthy Weight Resources ...

  13. Computer Calculation of Fire Danger

    Science.gov (United States)

    William A. Main

    1969-01-01

    This paper describes a computer program that calculates National Fire Danger Rating Indexes. fuel moisture, buildup index, and drying factor are also available. The program is written in FORTRAN and is usable on even the smallest compiler.

  14. Landfill Gas Energy Benefits Calculator

    Science.gov (United States)

    This page contains the LFG Energy Benefits Calculator to estimate direct, avoided, and total greenhouse gas reductions, as well as environmental and energy benefits, for a landfill gas energy project.

  15. Nursing students' mathematic calculation skills.

    Science.gov (United States)

    Rainboth, Lynde; DeMasi, Chris

    2006-12-01

    This mixed method study used a pre-test/post-test design to evaluate the efficacy of a teaching strategy in improving beginning nursing student learning outcomes. During a 4-week student teaching period, a convenience sample of 54 sophomore level nursing students were required to complete calculation assignments, taught one calculation method, and mandated to attend medication calculation classes. These students completed pre- and post-math tests and a major medication mathematic exam. Scores from the intervention student group were compared to those achieved by the previous sophomore class. Results demonstrated a statistically significant improvement from pre- to post-test and the students who received the intervention had statistically significantly higher scores on the major medication calculation exam than did the students in the control group. The evaluation completed by the intervention group showed that the students were satisfied with the method and outcome.

  16. Transfer Area Mechanical Handling Calculation

    Energy Technology Data Exchange (ETDEWEB)

    B. Dianda

    2004-06-23

    This calculation is intended to support the License Application (LA) submittal of December 2004, in accordance with the directive given by DOE correspondence received on the 27th of January 2004 entitled: ''Authorization for Bechtel SAX Company L.L. C. to Include a Bare Fuel Handling Facility and Increased Aging Capacity in the License Application, Contract Number DE-AC28-01R W12101'' (Arthur, W.J., I11 2004). This correspondence was appended by further Correspondence received on the 19th of February 2004 entitled: ''Technical Direction to Bechtel SAIC Company L.L. C. for Surface Facility Improvements, Contract Number DE-AC28-OIRW12101; TDL No. 04-024'' (BSC 2004a). These documents give the authorization for a Fuel Handling Facility to be included in the baseline. The purpose of this calculation is to establish preliminary bounding equipment envelopes and weights for the Fuel Handling Facility (FHF) transfer areas equipment. This calculation provides preliminary information only to support development of facility layouts and preliminary load calculations. The limitations of this preliminary calculation lie within the assumptions of section 5 , as this calculation is part of an evolutionary design process. It is intended that this calculation is superseded as the design advances to reflect information necessary to support License Application. The design choices outlined within this calculation represent a demonstration of feasibility and may or may not be included in the completed design. This calculation provides preliminary weight, dimensional envelope, and equipment position in building for the purposes of defining interface variables. This calculation identifies and sizes major equipment and assemblies that dictate overall equipment dimensions and facility interfaces. Sizing of components is based on the selection of commercially available products, where applicable. This is not a specific recommendation for the future use

  17. Calculation of Rydberg interaction potentials

    Science.gov (United States)

    Weber, Sebastian; Tresp, Christoph; Menke, Henri; Urvoy, Alban; Firstenberg, Ofer; Büchler, Hans Peter; Hofferberth, Sebastian

    2017-07-01

    The strong interaction between individual Rydberg atoms provides a powerful tool exploited in an ever-growing range of applications in quantum information science, quantum simulation and ultracold chemistry. One hallmark of the Rydberg interaction is that both its strength and angular dependence can be fine-tuned with great flexibility by choosing appropriate Rydberg states and applying external electric and magnetic fields. More and more experiments are probing this interaction at short atomic distances or with such high precision that perturbative calculations as well as restrictions to the leading dipole-dipole interaction term are no longer sufficient. In this tutorial, we review all relevant aspects of the full calculation of Rydberg interaction potentials. We discuss the derivation of the interaction Hamiltonian from the electrostatic multipole expansion, numerical and analytical methods for calculating the required electric multipole moments and the inclusion of electromagnetic fields with arbitrary direction. We focus specifically on symmetry arguments and selection rules, which greatly reduce the size of the Hamiltonian matrix, enabling the direct diagonalization of the Hamiltonian up to higher multipole orders on a desktop computer. Finally, we present example calculations showing the relevance of the full interaction calculation to current experiments. Our software for calculating Rydberg potentials including all features discussed in this tutorial is available as open source.

  18. A Romberg Integral Spreadsheet Calculator

    Directory of Open Access Journals (Sweden)

    Kim Gaik Tay

    2015-04-01

    Full Text Available Motivated by the work of Richardson’s extrapolation spreadsheet calculator up to level 4 to approximate definite differentiation, we have developed a Romberg integral spreadsheet calculator to approximate definite integral. The main feature of this version of spreadsheet calculator is a friendly graphical user interface developed to capture the needed information to solve the integral by Romberg method. Users simply need to enter the variable in the integral, function to be integrated, lower and upper limits of the integral, select the desired accuracy of computation, select the exact function if it exists and lastly click the Compute button which is associated with VBA programming written to compute Romberg integral table. The full solution of the Romberg integral table up to any level can be obtained quickly and easily using this method. The attached spreadsheet calculator together with this paper helps educators to prepare their marking scheme easily and assist students in checking their answers instead of reconstructing the answers from scratch. A summative evaluation of this Romberg Spreadsheet Calculator has been conducted by involving 36 students as sample. The data was collected using questionnaire. The findings showed that the majority of the students agreed that the Romberg Spreadsheet Calculator provides a structured learning environment that allows learners to be guided through a step-by-step solution.

  19. Recursive calculation of Hansen coefficients

    Science.gov (United States)

    Branham, Richard L., Jr.

    1990-06-01

    Hansen coefficients are used in expansions of the elliptic motion. Three methods for calculating the coefficients are studied: Tisserand's method, the Von Zeipel-Andoyer (VZA) method with explicit representation of the polynomials required to compute the Hansen coefficients, and the VZA method with the values of the polynomials calculated recursively. The VZA method with explicit polynomials is by far the most rapid, but the tabulation of the polynomials only extends to 12th order in powers of the eccentricity, and unless one has access to the polynomials in machine-readable form their entry is laborious and error-prone. The recursive calculation of the VZA polynomials, needed to compute the Hansen coefficients, while slower, is faster than the calculation of the Hansen coefficients by Tisserand's method, up to 10th order in the eccentricity and is still relatively efficient for higher orders. The main advantages of the recursive calculation are the simplicity of the program and one's being able to extend the expansions to any order of eccentricity with ease. Because FORTRAN does not implement recursive procedures, this paper used C for all of the calculations. The most important conclusion is recursion's genuine usefulness in scientific computing.

  20. Mordred: a molecular descriptor calculator.

    Science.gov (United States)

    Moriwaki, Hirotomo; Tian, Yu-Shi; Kawashita, Norihito; Takagi, Tatsuya

    2018-02-06

    Molecular descriptors are widely employed to present molecular characteristics in cheminformatics. Various molecular-descriptor-calculation software programs have been developed. However, users of those programs must contend with several issues, including software bugs, insufficient update frequencies, and software licensing constraints. To address these issues, we propose Mordred, a developed descriptor-calculation software application that can calculate more than 1800 two- and three-dimensional descriptors. It is freely available via GitHub. Mordred can be easily installed and used in the command line interface, as a web application, or as a high-flexibility Python package on all major platforms (Windows, Linux, and macOS). Performance benchmark results show that Mordred is at least twice as fast as the well-known PaDEL-Descriptor and it can calculate descriptors for large molecules, which cannot be accomplished by other software. Owing to its good performance, convenience, number of descriptors, and a lax licensing constraint, Mordred is a promising choice of molecular descriptor calculation software that can be utilized for cheminformatics studies, such as those on quantitative structure-property relationships.

  1. Precision Calculations in Supersymmetric Theories

    Directory of Open Access Journals (Sweden)

    L. Mihaila

    2013-01-01

    Full Text Available In this paper we report on the newest developments in precision calculations in supersymmetric theories. An important issue related to this topic is the construction of a regularization scheme preserving simultaneously gauge invariance and supersymmetry. In this context, we discuss in detail dimensional reduction in component field formalism as it is currently the preferred framework employed in the literature. Furthermore, we set special emphasis on the application of multi-loop calculations to the analysis of gauge coupling unification, the prediction of the lightest Higgs boson mass, and the computation of the hadronic Higgs production and decay rates in supersymmetric models. Such precise theoretical calculations up to the fourth order in perturbation theory are required in order to cope with the expected experimental accuracy on the one hand and to enable us to distinguish between the predictions of the Standard Model and those of supersymmetric theories on the other hand.

  2. Monte Carlo calculations for HTRs

    Energy Technology Data Exchange (ETDEWEB)

    Hogenbirk, A. [ECN Nuclear Research, Petten (Netherlands)

    1998-09-01

    From a neutronics point of view pebble-bed HTRs are completely different from standard LWRs. The most important differences are to be found in the reactor geometry, the properties of the moderator (graphite instead of water) and the self-shielding of the fuel regions. Therefore, computer packages normally used for core analyses should be validated with experimental data before they can be used for HTR analyses. This especially holds for deterministic computer codes, in which approximations are made which may not be valid in pebble-bed HTRs. Monte Carlo codes more based on first principles suffer much less from this problem. In order to study small- and medium-sized LEU-HTR systems in the late 1980s an IAEA Coordinated Research Programme (CRP) was started. This CRP was mainly directed to the effects of water ingress and neutron streaming. The PROTEUS facility at the Paul Scherrer Institute (PSI) in Villigen, Switzerland, played a central role in this CRP. Benchmark quality measurements were provided in clean, easy-to-interpret critical configurations, using pebble-type fuel. ECN in Petten, Netherlands, contributed to the CRP by performing reactor calculations using the WIMS code system with deterministic calculations. However, a need was felt for reference calculations, in which as few approximations as possible were made. These analyses were performed with the Monte Carlo code MCNP-4A. In this contribution the results are given of the main MCNP-calculations. In these analyses a detailed model of the PROTEUS experimental set-up was used, whereas in the calculations use was made of high-quality continuous-energy cross-section data. The attention was focused on the calculation of the value of k{sub eff} and of streaming effects in the pebble-bed core. 15 refs.

  3. Friction and wear calculation methods

    CERN Document Server

    Kragelsky, I V; Kombalov, V S

    1981-01-01

    Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a

  4. Algorithmes Efficaces en Calcul Formel

    OpenAIRE

    Bostan, Alin; Chyzak, Frédéric; Giusti, Marc; Lebreton, Romain; Lecerf, Grégoire; Salvy, Bruno; Schost, Eric

    2017-01-01

    Voir la page du livre à l’adresse \\url{https://hal.archives-ouvertes.fr/AECF/}; International audience; Le calcul formel traite des objets mathématiques exacts d’un point de vue informatique. Cet ouvrage « Algorithmes efficaces en calcul formel » explore deux directions : la calculabilité et la complexité. La calculabilité étudie les classes d’objets mathématiques sur lesquelles des réponses peuvent être obtenues algorithmiquement. La complexité donne ensuite des outils pour comparer des algo...

  5. Synthesis, spectroscopic, molecular orbital calculation, cytotoxic, molecular docking of DNA binding and DNA cleavage studies of transition metal complexes with N-benzylidene-N'-salicylidene-1,1-diaminopropane

    Science.gov (United States)

    Al-Mogren, Muneerah M.; Alaghaz, Abdel-Nasser M. A.; Elbohy, Salwa A. H.

    2013-10-01

    Eight mononuclear chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of Schiff's base ligand were synthesized and determined by different physical techniques. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMSO indicate that the complexes are non-electrolytic in nature. All the eight metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The analytical data helped to elucidate the structure of the metal complexes. The Schiff base is found to act as tridentate ligand using N2O donor set of atoms leading to an octahedral geometry for the complexes around all the metal ions. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of the ligand and its complexes. Additionally in silico, the docking studies and the calculated pharmacokinetic parameters show promising futures for application of the ligand and complexes as high potency agents for DNA binding activity. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption method, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed. The Schiff base and their complexes have been screened for their antibacterial activity against bacterial strains [Staphylococcus aureus (RCMB010027), Staphylococcus epidermidis (RCMB010024), Bacillis subtilis (RCMB010063), Proteous vulgaris (RCMB 010085), Klebsiella pneumonia (RCMB 010093) and Shigella flexneri (RCMB 0100542)] and fungi [(Aspergillus fumigates (RCMB 02564), Aspergillus clavatus (RCMB 02593) and Candida albicans (RCMB05035)] by disk diffusion method. All the metal complexes have potent biocidal activity than the free ligand.

  6. Methods for Melting Temperature Calculation

    Science.gov (United States)

    Hong, Qi-Jun

    Melting temperature calculation has important applications in the theoretical study of phase diagrams and computational materials screenings. In this thesis, we present two new methods, i.e., the improved Widom's particle insertion method and the small-cell coexistence method, which we developed in order to capture melting temperatures both accurately and quickly. We propose a scheme that drastically improves the efficiency of Widom's particle insertion method by efficiently sampling cavities while calculating the integrals providing the chemical potentials of a physical system. This idea enables us to calculate chemical potentials of liquids directly from first-principles without the help of any reference system, which is necessary in the commonly used thermodynamic integration method. As an example, we apply our scheme, combined with the density functional formalism, to the calculation of the chemical potential of liquid copper. The calculated chemical potential is further used to locate the melting temperature. The calculated results closely agree with experiments. We propose the small-cell coexistence method based on the statistical analysis of small-size coexistence MD simulations. It eliminates the risk of a metastable superheated solid in the fast-heating method, while also significantly reducing the computer cost relative to the traditional large-scale coexistence method. Using empirical potentials, we validate the method and systematically study the finite-size effect on the calculated melting points. The method converges to the exact result in the limit of a large system size. An accuracy within 100 K in melting temperature is usually achieved when the simulation contains more than 100 atoms. DFT examples of Tantalum, high-pressure Sodium, and ionic material NaCl are shown to demonstrate the accuracy and flexibility of the method in its practical applications. The method serves as a promising approach for large-scale automated material screening in which

  7. Ab initio calculations of biomolecules

    Science.gov (United States)

    Leś, Andrzej; Adamowicz, Ludwik

    1995-08-01

    Ab initio quantum mechanical calculations are valuable tools for interpretation and elucidation of elemental processes in biochemical systems. With the ab initio approach one can calculate data that sometimes are difficult to obtain by experimental techniques. The most popular computational theoretical methods include the Hartree-Fock method as well as some lower-level variational and perturbational post-Hartree Fock approaches which allow to predict molecular structures and to calculate spectral properties. We have been involved in a number of joined theoretical and experimental studies in the past and some examples of these studies are given in this presentation. The systems chosen cover a wide variety of simple biomolecules, such as precursors of nucleic acids, double-proton transferring molecules, and simple systems involved in processes related to first stages of substrate-enzyme interactions. In particular, examples of some ab initio calculations used in the assignment of IR spectra of matrix isolated pyrimidine nucleic bases are shown. Some radiation-induced transformations in model chromophores are also presented. Lastly, we demonstrate how the ab-initio approach can be used to determine the initial several steps of the molecular mechanism of thymidylate synthase inhibition by dUMP analogues.

  8. Dead reckoning calculating without instruments

    CERN Document Server

    Doerfler, Ronald W

    1993-01-01

    No author has gone as far as Doerfler in covering methods of mental calculation beyond simple arithmetic. Even if you have no interest in competing with computers you'll learn a great deal about number theory and the art of efficient computer programming. -Martin Gardner

  9. CALCULATION OF PHYSISORPTION ENERGIES OF

    African Journals Online (AJOL)

    o-Fe:Os (I) SURFACE USING A CRYSTAL FIELD CLUSTER MODEL. A. Uzairu' ... is of considerable interest in industry and theoretial calculations of ... This choice of cluster naturally assumes an oxygen vacancy at the physisorption site and the adoption of at least three top Llli planes of atomic layers as the surface region.

  10. QCD calculations for jet substructure

    CERN Document Server

    Dasgupta, Mrinal; Salam, Gavin P.

    2014-01-01

    We present results on novel analytic calculations to describe invariant mass distributions of QCD jets with three substructure algorithms: trimming, pruning and the mass-drop taggers. These results not only lead to considerable insight into the behaviour of these tools, but also show how they can be improved. As an example, we discuss the remarkable properties of the modified mass-drop tagger.

  11. Affect and Graphing Calculator Use

    Science.gov (United States)

    McCulloch, Allison W.

    2011-01-01

    This article reports on a qualitative study of six high school calculus students designed to build an understanding about the affect associated with graphing calculator use in independent situations. DeBellis and Goldin's (2006) framework for affect as a representational system was used as a lens through which to understand the ways in which…

  12. Algorithm Calculates Cumulative Poisson Distribution

    Science.gov (United States)

    Bowerman, Paul N.; Nolty, Robert C.; Scheuer, Ernest M.

    1992-01-01

    Algorithm calculates accurate values of cumulative Poisson distribution under conditions where other algorithms fail because numbers are so small (underflow) or so large (overflow) that computer cannot process them. Factors inserted temporarily to prevent underflow and overflow. Implemented in CUMPOIS computer program described in "Cumulative Poisson Distribution Program" (NPO-17714).

  13. Heat transfer, insulation calculations simplified

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, V.

    1985-08-19

    Determination of heat transfer coefficients for air, water, and steam flowing in tubes and calculation of heat loss through multilayered insulated surfaces have been simplified by two computer programs. The programs, written in BASIC, have been developed for the IBM and equivalent personal computers.

  14. Calculating the Number of Tunnels

    NARCIS (Netherlands)

    Li, Fajie; Klette, Reinhard; RuizShulcloper, J; Kropatsch, WG

    2008-01-01

    This paper considers 2-regions of grid cubes and proposes an algorithm for calculating the number of tunnels of such a. region. The graph-theoretical algorithm proceeds layer by layer; a proof of its correctness is provided, and its time complexity is also given.

  15. Monte Carlo calculations of nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, S.C. [Argonne National Lab., IL (United States). Physics Div.

    1997-10-01

    Nuclear many-body calculations have the complication of strong spin- and isospin-dependent potentials. In these lectures the author discusses the variational and Green`s function Monte Carlo techniques that have been developed to address this complication, and presents a few results.

  16. The "Intelligence" of Calendrical Calculators.

    Science.gov (United States)

    Young, R. L.; Nettelbeck, T.

    1994-01-01

    The strategies of four men with mild mental retardation when performing calendar calculations were investigated. Results suggested that subjects were aware of calendar rules and regularities, including knowledge of the 14 different calendar templates. Their strategies were rigidly applied and relied heavily on memory, with little manipulation of…

  17. Ab Initio Calculations of Oxosulfatovanadates

    DEFF Research Database (Denmark)

    Frøberg, Torben; Johansen, Helge

    1996-01-01

    Restricted Hartree-Fock and multi-configurational self-consistent-field calculations together with secondorder perturbation theory have been used to study the geometry, the electron density, and the electronicspectrum of (VO2SO4)-. A bidentate sulphate attachment to vanadium was found to be stabl...

  18. Distorted Wave Calculations and Applications

    Science.gov (United States)

    Bhatia, A. K.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    Physical properties such as temperature and electron density of solar plasma and other astrophysical objects can be inferred from EUV and X-ray emission lines observed from space. These lines are emitted when the higher states of an ion are excited by electron impact and then decay by photon emission. Excitation cross sections are required for the spectroscopic analyses of the observations and various approximations have been used to calculate the scattering functions. One of them which has been widely used is a distorted wave approximation. This approximation, along with its applications to solar observations, is discussed. The Bowen fluorescence mechanism and optical depth effects are also discussed. It is concluded that such calculations are reliable for highly charged ions and for high electron temperatures.

  19. CONTRIBUTION FOR MINING ATMOSPHERE CALCULATION

    Directory of Open Access Journals (Sweden)

    Franica Trojanović

    1989-12-01

    Full Text Available Humid air is an unavoidable feature of mining atmosphere, which plays a significant role in defining the climate conditions as well as permitted circumstances for normal mining work. Saturated humid air prevents heat conduction from the human body by means of evaporation. Consequently, it is of primary interest in the mining practice to establish the relative air humidity either by means of direct or indirect methods. Percentage of water in the surrounding air may be determined in various procedures including tables, diagrams or particular calculations, where each technique has its specific advantages and disadvantages. Classical calculation is done according to Sprung's formula, in which case partial steam pressure should also be taken from the steam table. The new method without the use of diagram or tables, established on the functional relation of pressure and temperature on saturated line, is presented here for the first time (the paper is published in Croatian.

  20. Algorithm project weight calculation aircraft

    Directory of Open Access Journals (Sweden)

    Г. В. Абрамова

    2013-07-01

    Full Text Available The paper describes the process of a complex technical object design on the example of the aircraft, using information technology such as CAD/CAM/CAE-systems, presents the basic models of aircraft which are developed in the process of designing and reflect the different aspects of its structure and function. The idea of control parametric model at complex technical object design is entered, which is a set of initial data for the development of design stations and enables the optimal complex technical object control at all stages of design using modern computer technology. The paper discloses a process of weight design, which is associated with all stages of development aircraft and its production. Usage of a scheduling algorithm that allows to organize weight calculations are carried out at various stages of planning and weighing options to optimize the use of available database of formulas and methods of calculation

  1. MARKOV MODELS IN CALCULATING CLV

    OpenAIRE

    DECEWICZ, Anna

    2015-01-01

    The  paper  presents  a  me hod  of  calculating  customer  lifetime  value and  finding optimal remarketing  strategy  basing on Markov model  with  short-term memory of  client's activity. Furthermore, sensitivity analysis of optimal strategy is conducted for two ty pes of retention rate functional form defining transitin probabilities

  2. Parallel plasma fluid turbulence calculations

    Science.gov (United States)

    Leboeuf, J. N.; Carreras, B. A.; Charlton, L. A.; Drake, J. B.; Lynch, V. E.; Newman, D. E.; Sidikman, K. L.; Spong, D. A.

    The study of plasma turbulence and transport is a complex problem of critical importance for fusion-relevant plasmas. To this day, the fluid treatment of plasma dynamics is the best approach to realistic physics at the high resolution required for certain experimentally relevant calculations. Core and edge turbulence in a magnetic fusion device have been modeled using state-of-the-art, nonlinear, three-dimensional, initial-value fluid and gyrofluid codes. Parallel implementation of these models on diverse platforms--vector parallel (National Energy Research Supercomputer Center's CRAY Y-MP C90), massively parallel (Intel Paragon XP/S 35), and serial parallel (clusters of high-performance workstations using the Parallel Virtual Machine protocol)--offers a variety of paths to high resolution and significant improvements in real-time efficiency, each with its own advantages. The largest and most efficient calculations have been performed at the 200 Mword memory limit on the C90 in dedicated mode, where an overlap of 12 to 13 out of a maximum of 16 processors has been achieved with a gyrofluid model of core fluctuations. The richness of the physics captured by these calculations is commensurate with the increased resolution and efficiency and is limited only by the ingenuity brought to the analysis of the massive amounts of data generated.

  3. Calculation of minimum miscibility pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Orr, F.M. [Department of Petroleum Engineering, Stanford University, Mitchell Bldg., Room 360, 94305-2220 Stanford, CA (United States)

    2000-09-01

    A method is described and tested for calculation of minimum miscibility pressure (MMP) that makes use of an analytical theory for one-dimensional, dispersion-free flow of multicomponent mixtures. The theory shows that in a displacement of an oil by a gas with n{sub c} components, the behavior of the displacement is controlled by a sequence of n{sub c}-1 key tie lines. Besides, the tie lines that extend through the initial oil and injection gas compositions, there are n{sub c}-3 tie lines, known as crossover tie lines, that can be found from a set of conditions that require the extensions of the appropriate tie lines to intersect each other. The MMP is calculated as the pressure at which one of the key tie lines becomes a tie line of zero length that is tangent to the critical locus. The numerical approach for solving the tie line intersection equations is described; slim tube test and compositional simulation data reported in the literature are used to show that the proposed approach can be used to calculate MMP accurately for displacements with an arbitrary number of components present.

  4. Investigation of the atmospheric boundary layer characteristics on gust factor for the calculation of wind load

    Science.gov (United States)

    Ghanadi, Farzin; Emes, Matthew; Yu, Jeremy; Arjomandi, Maziar; Kelso, Richard

    2017-06-01

    Dynamic amplification and gust effects from turbulence can increase wind loads significantly over and above the static wind loads that have been used for heliostat design. This paper presents the results of analyzing the relationship between gust factor and turbulence intensity within the atmospheric boundary layer (ABL) based on the high fidelity measurements of wind velocity at the SLTEST facility in the Utah desert. Results showed that there are distinct characteristics of a low roughness ABL that deviate from semi-empirical relationships derived for open country and urban terrains with larger surface roughness heights. The analysis also indicated that gust factor is increased by 2.4% when lowering the gust period from 3s to 1s in the low roughness field experiment ABL, compared to a 3.6% increase in a suburban terrain at a 10m height. Although 3s gust periods are recommended in AS/NZS 1170.2 [1], comparison of gust factor data with a 1s gust period is recommended particularly in high roughness ABLs such as in urban areas, to ensure that buildings are adequately designed to withstand higher frequency gusts. This research proved the strength of the correlation between gust factor and turbulence intensity is dependent on the surface roughness height of the terrain. It is recommended that the coefficient in the previous semi-empirical equation must be adjusted to be fitted to the low roughness desert terrain in the field experiment ABL.

  5. AGING FACILITY CRITICALITY SAFETY CALCULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    C.E. Sanders

    2004-09-10

    The purpose of this design calculation is to revise and update the previous criticality calculation for the Aging Facility (documented in BSC 2004a). This design calculation will also demonstrate and ensure that the storage and aging operations to be performed in the Aging Facility meet the criticality safety design criteria in the ''Project Design Criteria Document'' (Doraswamy 2004, Section 4.9.2.2), and the functional nuclear criticality safety requirement described in the ''SNF Aging System Description Document'' (BSC [Bechtel SAIC Company] 2004f, p. 3-12). The scope of this design calculation covers the systems and processes for aging commercial spent nuclear fuel (SNF) and staging Department of Energy (DOE) SNF/High-Level Waste (HLW) prior to its placement in the final waste package (WP) (BSC 2004f, p. 1-1). Aging commercial SNF is a thermal management strategy, while staging DOE SNF/HLW will make loading of WPs more efficient (note that aging DOE SNF/HLW is not needed since these wastes are not expected to exceed the thermal limits form emplacement) (BSC 2004f, p. 1-2). The description of the changes in this revised document is as follows: (1) Include DOE SNF/HLW in addition to commercial SNF per the current ''SNF Aging System Description Document'' (BSC 2004f). (2) Update the evaluation of Category 1 and 2 event sequences for the Aging Facility as identified in the ''Categorization of Event Sequences for License Application'' (BSC 2004c, Section 7). (3) Further evaluate the design and criticality controls required for a storage/aging cask, referred to as MGR Site-specific Cask (MSC), to accommodate commercial fuel outside the content specification in the Certificate of Compliance for the existing NRC-certified storage casks. In addition, evaluate the design required for the MSC that will accommodate DOE SNF/HLW. This design calculation will achieve the objective of providing the

  6. Band calculation of lonsdaleite Ge

    Science.gov (United States)

    Chen, Pin-Shiang; Fan, Sheng-Ting; Lan, Huang-Siang; Liu, Chee Wee

    2017-01-01

    The band structure of Ge in the lonsdaleite phase is calculated using first principles. Lonsdaleite Ge has a direct band gap at the Γ point. For the conduction band, the Γ valley is anisotropic with the low transverse effective mass on the hexagonal plane and the large longitudinal effective mass along the c axis. For the valence band, both heavy-hole and light-hole effective masses are anisotropic at the Γ point. The in-plane electron effective mass also becomes anisotropic under uniaxial tensile strain. The strain response of the heavy-hole mass is opposite to the light hole.

  7. Yet another partial wave calculator

    Energy Technology Data Exchange (ETDEWEB)

    Greenwald, Daniel; Rauch, Johannes [TUM, Munich (Germany)

    2016-07-01

    We will present a new C++ library for partial wave analysis: YAP - yet another partial wave calculator. YAP is intended for amplitude analyses of the decays of spin-0 heavy mesons (principally B and D) to multiple (3, 4, etc.) pseudoscalar mesons but is not hard coded for such situations and is flexible enough to handle other decay scenarios. The library allows for both model dependent and model independent analysis methods. We introduce the software, and demonstrate examples for generating Monte Carlo data efficiently, and for analyzing data (both with the aid of the Bayesian Analysis Toolkit).

  8. Entanglement entropy: a perturbative calculation

    Energy Technology Data Exchange (ETDEWEB)

    Rosenhaus, Vladimir; Smolkin, Michael [Center for Theoretical Physics and Department of Physics,University of California, Berkeley, CA 94720 (United States)

    2014-12-31

    We provide a framework for a perturbative evaluation of the reduced density matrix. The method is based on a path integral in the analytically continued spacetime. It suggests an alternative to the holographic and ‘standard’ replica trick calculations of entanglement entropy. We implement this method within solvable field theory examples to evaluate leading order corrections induced by small perturbations in the geometry of the background and entangling surface. Our findings are in accord with Solodukhin’s formula for the universal term of entanglement entropy for four dimensional CFTs.

  9. The Dental Trauma Internet Calculator

    DEFF Research Database (Denmark)

    Gerds, Thomas Alexander; Lauridsen, Eva Fejerskov; Christensen, Søren Steno Ahrensburg

    2012-01-01

    Background/Aim Prediction tools are increasingly used to inform patients about the future dental health outcome. Advanced statistical methods are required to arrive at unbiased predictions based on follow-up studies. Material and Methods The Internet risk calculator at the Dental Trauma Guide...... provides prognoses for teeth with traumatic injuries based on the Copenhagen trauma database: http://www.dentaltraumaguide.org The database includes 2191 traumatized permanent teeth from 1282 patients that were treated at the dental trauma unit at the University Hospital in Copenhagen (Denmark...

  10. Calculation of confined swirling jets

    Science.gov (United States)

    Chen, C. P.

    1986-01-01

    Computations of a confined coaxial swirling jet are carried out using a standard two-equation (k-epsilon) model and two modifications of this model based on Richardson-number corrections of the length-scale (epsilon) governing equation. To avoid any uncertainty involved in the setting up of inlet boundary conditions, actual measurements are used at the inlet plane of this calculation domain. The results of the numerical investigation indicate that the k-epsilon model is inadequate for the predictions of confined swirling flows. Although marginal improvement of the flow predictions can be achieved by these two corrections, neither can be judged satisfactory.

  11. Calculation of Rydberg interaction potentials

    DEFF Research Database (Denmark)

    Weber, Sebastian; Tresp, Christoph; Menke, Henri

    2017-01-01

    The strong interaction between individual Rydberg atoms provides a powerful tool exploited in an ever-growing range of applications in quantum information science, quantum simulation and ultracold chemistry. One hallmark of the Rydberg interaction is that both its strength and angular dependence...... for calculating the required electric multipole moments and the inclusion of electromagnetic fields with arbitrary direction. We focus specifically on symmetry arguments and selection rules, which greatly reduce the size of the Hamiltonian matrix, enabling the direct diagonalization of the Hamiltonian up...

  12. Electronics reliability calculation and design

    CERN Document Server

    Dummer, Geoffrey W A; Hiller, N

    1966-01-01

    Electronics Reliability-Calculation and Design provides an introduction to the fundamental concepts of reliability. The increasing complexity of electronic equipment has made problems in designing and manufacturing a reliable product more and more difficult. Specific techniques have been developed that enable designers to integrate reliability into their products, and reliability has become a science in its own right. The book begins with a discussion of basic mathematical and statistical concepts, including arithmetic mean, frequency distribution, median and mode, scatter or dispersion of mea

  13. Digital calculations of engine cycles

    CERN Document Server

    Starkman, E S; Taylor, C Fayette

    1964-01-01

    Digital Calculations of Engine Cycles is a collection of seven papers which were presented before technical meetings of the Society of Automotive Engineers during 1962 and 1963. The papers cover the spectrum of the subject of engine cycle events, ranging from an examination of composition and properties of the working fluid to simulation of the pressure-time events in the combustion chamber. The volume has been organized to present the material in a logical sequence. The first two chapters are concerned with the equilibrium states of the working fluid. These include the concentrations of var

  14. Calculational Tool for Skin Contamination Dose Assessment

    CERN Document Server

    Hill, R L

    2002-01-01

    Spreadsheet calculational tool was developed to automate the calculations preformed for dose assessment of skin contamination. This document reports on the design and testing of the spreadsheet calculational tool.

  15. Dissecting Reactor Antineutrino Flux Calculations

    Science.gov (United States)

    Sonzogni, A. A.; McCutchan, E. A.; Hayes, A. C.

    2017-09-01

    Current predictions for the antineutrino yield and spectra from a nuclear reactor rely on the experimental electron spectra from 235U, 239Pu, 241Pu and a numerical method to convert these aggregate electron spectra into their corresponding antineutrino ones. In the present work we investigate quantitatively some of the basic assumptions and approximations used in the conversion method, studying first the compatibility between two recent approaches for calculating electron and antineutrino spectra. We then explore different possibilities for the disagreement between the measured Daya Bay and the Huber-Mueller antineutrino spectra, including the 238U contribution as well as the effective charge and the allowed shape assumption used in the conversion method. We observe that including a shape correction of about +6 % MeV-1 in conversion calculations can better describe the Daya Bay spectrum. Because of a lack of experimental data, this correction cannot be ruled out, concluding that in order to confirm the existence of the reactor neutrino anomaly, or even quantify it, precisely measured electron spectra for about 50 relevant fission products are needed. With the advent of new rare ion facilities, the measurement of shape factors for these nuclides, for many of which precise beta intensity data from TAGS experiments already exist, would be highly desirable.

  16. Calculation of sound propagation in fibrous materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1996-01-01

    Calculations of attenuation and velocity of audible sound waves in glass wools are presented. The calculations use only the diameters of fibres and the mass density of glass wools as parameters. The calculations are compared with measurements.......Calculations of attenuation and velocity of audible sound waves in glass wools are presented. The calculations use only the diameters of fibres and the mass density of glass wools as parameters. The calculations are compared with measurements....

  17. FLAG-SGH Sedov calculations

    Energy Technology Data Exchange (ETDEWEB)

    Fung, Jimmy [Los Alamos National Laboratory; Schofield, Sam [LLNL; Shashkov, Mikhail J. [Los Alamos National Laboratory

    2012-06-25

    We did not run with a 'cylindrically painted region'. However, we did compute two general variants of the original problem. Refinement studies where a single zone at each level of refinement contains the entire internal energy at t=0 or A 'finite' energy source which has the same physical dimensions as that for the 91 x 46 mesh, but consisting of increasing numbers of zones with refinement. Nominal mesh resolution: 91 x 46. Other mesh resolutions: 181 x 92 and 361 x 184. Note, not identical to the original specification. To maintain symmetry for the 'fixed' energy source, the mesh resolution was adjusted slightly. FLAG Lagrange or full (Eulerian) ALE was used with various options for each simulation. Observation - for either Lagrange or ALE, point or 'fixed' source, calculations converge on density and pressure with mesh resolution, but not energy, (not vorticity either).

  18. Dyscalculia and the Calculating Brain.

    Science.gov (United States)

    Rapin, Isabelle

    2016-08-01

    Dyscalculia, like dyslexia, affects some 5% of school-age children but has received much less investigative attention. In two thirds of affected children, dyscalculia is associated with another developmental disorder like dyslexia, attention-deficit disorder, anxiety disorder, visual and spatial disorder, or cultural deprivation. Infants, primates, some birds, and other animals are born with the innate ability, called subitizing, to tell at a glance whether small sets of scattered dots or other items differ by one or more item. This nonverbal approximate number system extends mostly to single digit sets as visual discrimination drops logarithmically to "many" with increasing numerosity (size effect) and crowding (distance effect). Preschoolers need several years and specific teaching to learn verbal names and visual symbols for numbers and school agers to understand their cardinality and ordinality and the invariance of their sequence (arithmetic number line) that enables calculation. This arithmetic linear line differs drastically from the nonlinear approximate number system mental number line that parallels the individual number-tuned neurons in the intraparietal sulcus in monkeys and overlying scalp distribution of discrete functional magnetic resonance imaging activations by number tasks in man. Calculation is a complex skill that activates both visual and spatial and visual and verbal networks. It is less strongly left lateralized than language, with approximate number system activation somewhat more right sided and exact number and arithmetic activation more left sided. Maturation and increasing number skill decrease associated widespread non-numerical brain activations that persist in some individuals with dyscalculia, which has no single, universal neurological cause or underlying mechanism in all affected individuals. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. RTU Comparison Calculator Enhancement Plan

    Energy Technology Data Exchange (ETDEWEB)

    Miller, James D.; Wang, Weimin; Katipamula, Srinivas

    2014-03-31

    Over the past two years, Department of Energy’s Building Technologies Office (BTO) has been investigating ways to increase the operating efficiency of the packaged rooftop units (RTUs) in the field. First, by issuing a challenge to the RTU manufactures to increase the integrated energy efficiency ratio (IEER) by 60% over the existing ASHRAE 90.1-2010 standard. Second, by evaluating the performance of an advanced RTU controller that reduces the energy consumption by over 40%. BTO has previously also funded development of a RTU comparison calculator (RTUCC). RTUCC is a web-based tool that provides the user a way to compare energy and cost savings for two units with different efficiencies. However, the RTUCC currently cannot compare savings associated with either the RTU Challenge unit or the advanced RTU controls retrofit. Therefore, BTO has asked PNNL to enhance the tool so building owners can compare energy and savings associated with this new class of products. This document provides the details of the enhancements that are required to support estimating energy savings from use of RTU challenge units or advanced controls on existing RTUs.

  20. RTU Comparison Calculator Enhancement Plan

    Energy Technology Data Exchange (ETDEWEB)

    Miller, James D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Weimin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Katipamula, Srinivas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-01

    Over the past two years, Department of Energy’s Building Technologies Office (BTO) has been investigating ways to increase the operating efficiency of the packaged rooftop units (RTUs) in the field. First, by issuing a challenge to the RTU manufactures to increase the integrated energy efficiency ratio (IEER) by 60% over the existing ASHRAE 90.1-2010 standard. Second, by evaluating the performance of an advanced RTU controller that reduces the energy consumption by over 40%. BTO has previously also funded development of a RTU comparison calculator (RTUCC). RTUCC is a web-based tool that provides the user a way to compare energy and cost savings for two units with different efficiencies. However, the RTUCC currently cannot compare savings associated with either the RTU Challenge unit or the advanced RTU controls retrofit. Therefore, BTO has asked PNNL to enhance the tool so building owners can compare energy and savings associated with this new class of products. This document provides the details of the enhancements that are required to support estimating energy savings from use of RTU challenge units or advanced controls on existing RTUs.

  1. Selfconsistent calculations for hyperdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)

    1996-12-31

    Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.

  2. McEliece PKC Calculator

    Science.gov (United States)

    Marek, Repka

    2015-01-01

    The original McEliece PKC proposal is interesting thanks to its resistance against all known attacks, even using quantum cryptanalysis, in an IND-CCA2 secure conversion. Here we present a generic implementation of the original McEliece PKC proposal, which provides test vectors (for all important intermediate results), and also in which a measurement tool for side-channel analysis is employed. To our best knowledge, this is the first such an implementation. This Calculator is valuable in implementation optimization, in further McEliece/Niederreiter like PKCs properties investigations, and also in teaching. Thanks to that, one can, for example, examine side-channel vulnerability of a certain implementation, or one can find out and test particular parameters of the cryptosystem in order to make them appropriate for an efficient hardware implementation. This implementation is available [1] in executable binary format, and as a static C++ library, as well as in form of source codes, for Linux and Windows operating systems.

  3. 76 FR 71431 - Civil Penalty Calculation Methodology

    Science.gov (United States)

    2011-11-17

    ... TRANSPORTATION Federal Motor Carrier Safety Administration Civil Penalty Calculation Methodology AGENCY: Federal... its civil penalty methodology. Part of this evaluation includes a forthcoming explanation of the... methodology for calculation of certain civil penalties. To induce compliance with federal regulations, FMCSA...

  4. Dissociated brain potentials for two calculation strategies.

    Science.gov (United States)

    Luo, Wenbo; Liu, Dianzhi; He, Weiqi; Tao, Weidong; Luo, Yuejia

    2009-03-04

    Event-related brain potentials were used to investigate the shortcut calculation strategy and nonshortcut calculation strategy in performing addition using mental arithmetic. Results showed that the shortcut calculation strategy elicited a larger P220 than the nonshortcut calculation strategy in the 180-280 ms. Dipole source analysis of the difference wave (shortcut calculation minus nonshortcut calculation) indicated that a generator was localized in the posterior cingulate cortex, which reflected the evaluation effect of number in the use of the shortcut strategy. In the 320-500 ms time window, a greater N400 was found in the nonshortcut calculation as compared with the shortcut calculation. Dipole source analysis of the difference wave indicated that a generator was localized in the anterior cingulate cortex. The N400 might reflect the greater working memory load.

  5. Pressure Vessel Calculations for VVER-440 Reactors

    Science.gov (United States)

    Hordósy, G.; Hegyi, Gy.; Keresztúri, A.; Maráczy, Cs.; Temesvári, E.; Vértes, P.; Zsolnay, É.

    2003-06-01

    Monte Carlo calculations were performed for a selected cycle of the Paks NPP Unit II to test a computational model. In the model the source term was calculated by the core design code KARATE and the neutron transport calculations were performed by the MCNP. Different forms of the source specification were examined. The calculated results were compared with measurements and in most cases fairly good agreement was found.

  6. 46 CFR 154.429 - Calculations.

    Science.gov (United States)

    2010-10-01

    ... § 154.429 Calculations. The tank design load calculations for a membrane tank must include the following... submitted to meet this paragraph. (c) The combined strains from static, dynamic, and thermal loads. ... 46 Shipping 5 2010-10-01 2010-10-01 false Calculations. 154.429 Section 154.429 Shipping COAST...

  7. 47 CFR 1.1623 - Probability calculation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Probability calculation. 1.1623 Section 1.1623... Mass Media Services General Procedures § 1.1623 Probability calculation. (a) All calculations shall be computed to no less than three significant digits. Probabilities will be truncated to the number of...

  8. Mathematical Creative Activity and the Graphic Calculator

    Science.gov (United States)

    Duda, Janina

    2011-01-01

    Teaching mathematics using graphic calculators has been an issue of didactic discussions for years. Finding ways in which graphic calculators can enrich the development process of creative activity in mathematically gifted students between the ages of 16-17 is the focus of this article. Research was conducted using graphic calculators with…

  9. Recursive Delay Calculation Unit for Parametric Beamformer

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Jensen, Jørgen Arendt; Tomov, Borislav Gueorguiev

    2006-01-01

    This paper presents a recursive approach for parametric delay calculations for a beamformer. The suggested calculation procedure is capable of calculating the delays for any image line defined by an origin and arbitrary direction. It involves only add and shift operations making it suitable...

  10. A simple model for calculating air pollution within street canyons

    Science.gov (United States)

    Venegas, Laura E.; Mazzeo, Nicolás A.; Dezzutti, Mariana C.

    2014-04-01

    This paper introduces the Semi-Empirical Urban Street (SEUS) model. SEUS is a simple mathematical model based on the scaling of air pollution concentration inside street canyons employing the emission rate, the width of the canyon, the dispersive velocity scale and the background concentration. Dispersive velocity scale depends on turbulent motions related to wind and traffic. The parameterisations of these turbulent motions include two dimensionless empirical parameters. Functional forms of these parameters have been obtained from full scale data measured in street canyons at four European cities. The sensitivity of SEUS model is studied analytically. Results show that relative errors in the evaluation of the two dimensionless empirical parameters have less influence on model uncertainties than uncertainties in other input variables. The model estimates NO2 concentrations using a simple photochemistry scheme. SEUS is applied to estimate NOx and NO2 hourly concentrations in an irregular and busy street canyon in the city of Buenos Aires. The statistical evaluation of results shows that there is a good agreement between estimated and observed hourly concentrations (e.g. fractional bias are -10.3% for NOx and +7.8% for NO2). The agreement between the estimated and observed values has also been analysed in terms of its dependence on wind speed and direction. The model shows a better performance for wind speeds >2 m s-1 than for lower wind speeds and for leeward situations than for others. No significant discrepancies have been found between the results of the proposed model and that of a widely used operational dispersion model (OSPM), both using the same input information.

  11. How to calculate sample size and why.

    Science.gov (United States)

    Kim, Jeehyoung; Seo, Bong Soo

    2013-09-01

    Calculating the sample size is essential to reduce the cost of a study and to prove the hypothesis effectively. Referring to pilot studies and previous research studies, we can choose a proper hypothesis and simplify the studies by using a website or Microsoft Excel sheet that contains formulas for calculating sample size in the beginning stage of the study. There are numerous formulas for calculating the sample size for complicated statistics and studies, but most studies can use basic calculating methods for sample size calculation.

  12. Nigerian Journal of Physics

    African Journals Online (AJOL)

    The relationship between the semi-empirical and the embedded atom model usually employed in total energy calculation . EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. EE Aigbekaen, F Ighrakpata, 35-41 ...

  13. Pervaporation of Ethanol/Water Mixtures Through a High-Silica MFI Membrane: Comparison of Different Semi-Empirical Mass Transfer Models

    National Research Council Canada - National Science Library

    Tiina Leppäjärvi; Ilkka Malinen; Danil Korelskiy; Jani Kangas; Jonas Hedlund; Juha Tanskanen

    2015-01-01

      Pervaporation of binary ethanol/water solutions of 5-10 wt.% ethanol was studied experimentally through a thin supported high-silica MFI zeolite membrane of hydrophobic character in the temperature range of 30-70 °C...

  14. Force limited random vibration testing: the computation of the semi-empirical constant $C(2) $ C 2 for a real test article and unknown supporting structure

    Science.gov (United States)

    Wijker, J. J.; Ellenbroek, M. H. M.; Boer, A. de

    2015-09-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the test article (load), C^2 is a very important parameter for FLVT. A number of computational methods to estimate C^2 are described in the literature, i.e. the simple and the complex two degree of freedom system, STDFS and CTDFS, respectively. The motivation of this work is to evaluate the method for the computation of a realistic value of C^2 to perform a representative random vibration test based on force limitation, when the description of the supporting structure (source) is more or less unknown. Marchand discussed the formal description of obtaining C^2, using the maximum PSD of the acceleration and maximum PSD of the force, both at the interface between test article and supporting structure. Stevens presented the coupled systems modal approach (CSMA), where simplified asparagus patch models (parallel-oscillator representation) of load and source are connected. The asparagus patch model consists of modal effective masses and spring stiffnesses associated with the natural frequencies. When the random acceleration vibration specification is given the CSMA method is suitable to compute the value of the parameter C^2. When no mathematical model of the source can be made available, estimations of the value C^2 can be find in literature. In this paper a probabilistic mathematical representation of the unknown source is proposed, such that the asparagus patch model of the source can be approximated. The chosen probabilistic design parameters have a uniform distribution. The computation of the value C^2 can be done in conjunction with the CSMA method, knowing the apparent mass of the load and the random acceleration specification at the interface between load and source, respectively. Data of two cases available from literature has been analyzed and discussed to get more knowledge about the applicability of the probabilistic method.

  15. Force limited random vibration testing: the computation of the semi-empirical constant C2 for a real test article and unknown supporting structure

    NARCIS (Netherlands)

    Wijker, Jacob J; Ellenbroek, Marcellinus Hermannus Maria; de Boer, Andries

    2015-01-01

    To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the test article (load),

  16. A semi-empirical model of the contribution from sporadic meteoroid sources on the meteor input function in the MLT observed at Arecibo

    Science.gov (United States)

    Fentzke, Jonathan T.; Janches, Diego

    2008-03-01

    In this paper, we present a modeling and observational study of the micrometeor input function with a focus on understanding how each of the extraterrestrial sporadic meteoroid sources contributes to the observed meteoric flux in the Mesosphere and Lower Thermosphere (MLT) atmospheric region. For this purpose, we expand the model presented by Janches et al. (2006) using a Monte Carlo technique and incorporating: 1) a widely accepted global mass flux, which is divided into different proportions among the known sporadic meteoroid sources as the initial input above Earth's atmosphere; 2) contemporary knowledge on the source's velocity and radiant distributions; and 3) the full integration of the canonical meteor equations that describe the meteoroid entry and ablation physics. In addition, we constrain the initial input through a comparison of our modeled results with meteor observations obtained with the 430 MHz High Power and Large Aperture (HPLA) Arecibo radar in Puerto Rico that covers all seasons. The predicted meteor rates and velocity distributions are in excellent agreement with the observed ones without the need for any additional normalization factor. Our results indicate that although the Earth's Apex centered radiant source, which is characterized by high geocentric speeds (˜55 km/s), appears to be ˜33% of the meteoroids in the Solar System at 1 AU, it accounts for ˜60% of the meteors observed by the Arecibo HPLA radar in the atmosphere. The remaining 40% of observed meteors originate mostly from the Helion and Anti-Helion sources, with a very small, but constant during the day, contribution of the South and North Toroidal sources. These results also suggest that particles smaller than ˜10-3μg with slow velocities (more precise MIF model needed for the subsequent modeling of the atmospheric phenomena related to the meteoric flux.

  17. Multi-model radiometric slope correction of SAR images of complex terrain using a two-stage semi-empirical approach

    NARCIS (Netherlands)

    Hoekman, D.H.; Reiche, J.

    2015-01-01

    Practical approaches for the implementation of terrain type dependent radiometric slope correction for SAR data are introduced. Radiometric slope effects are modelled as the products of two models. The first is a simple physical model based on the assumption of a uniform opaque layer of isotropic

  18. Quantitative Structure-Cytotoxicity Relationship of Bioactive Heterocycles by the Semi-empirical Molecular Orbital Method with the Concept of Absolute Hardness

    Science.gov (United States)

    Ishihara, Mariko; Sakagami, Hiroshi; Kawase, Masami; Motohashi, Noboru

    The relationship between the cytotoxicity of N-heterocycles (13 4-trifluoromethylimidazole, 15 phenoxazine and 12 5-trifluoromethyloxazole derivatives), O-heterocycles (11 3-formylchromone and 20 coumarin derivatives) and seven vitamin K2 derivatives against eight tumor cell lines (HSC-2, HSC-3, HSC-4, T98G, HSG, HepG2, HL-60, MT-4) and a maximum of 15 chemical descriptors was investigated using CAChe Worksystem 4.9 project reader. After determination of the conformation of these compounds and approximation to the molecular form present in vivo (biomimetic) by CONFLEX5, the most stable structure was determined by CAChe Worksystem 4.9 MOPAC (PM3). The present study demonstrates the best relationship between the cytotoxic activity and molecular shape or molecular weight of these compounds. Their biological activities can be estimated by hardness and softness, and by using η-χ activity diagrams.

  19. Experimental investigation and nuclear model calculations on proton-induced reactions on highly enriched 114Cd at low energies.

    Science.gov (United States)

    Said, S A; Elmaghraby, E K; Asfour, F I

    2006-12-01

    The excitation functions of both Cd(p,n)(114m)In114 and Cd(p,2n)(113m)In114 reactions were evaluated experimentally by the stacked-foil technique on highly enriched (114)Cd isotope. Two stacks were irradiated by proton beam with energies 14.7 and 18MeV on the MGC-20 cyclotron at Nuclear Research Center, AEA, Egypt. The present results support the previous measurements. The theoretical interpretations of the measured excitation functions were done by EMPIRE-II (v2.18 Mondovi) code. Compatibility with predictions of hybrid Monte Carlo simulation (HMS) pre-equilibrium mechanism was obtained.

  20. The Band Structure of Polymers: Its Calculation and Interpretation. Part 2. Calculation.

    Science.gov (United States)

    Duke, B. J.; O'Leary, Brian

    1988-01-01

    Details ab initio crystal orbital calculations using all-trans-polyethylene as a model. Describes calculations based on various forms of translational symmetry. Compares these calculations with ab initio molecular orbital calculations discussed in a preceding article. Discusses three major approximations made in the crystal case. (CW)

  1. MATNORM: Calculating NORM using composition matrices

    Science.gov (United States)

    Pruseth, Kamal L.

    2009-09-01

    This paper discusses the implementation of an entirely new set of formulas to calculate the CIPW norm. MATNORM does not involve any sophisticated programming skill and has been developed using Microsoft Excel spreadsheet formulas. These formulas are easy to understand and a mere knowledge of the if-then-else construct in MS-Excel is sufficient to implement the whole calculation scheme outlined below. The sequence of calculation used here differs from that of the standard CIPW norm calculation, but the results are very similar. The use of MS-Excel macro programming and other high-level programming languages has been deliberately avoided for simplicity.

  2. The conundrum of calculating carbon footprints

    DEFF Research Database (Denmark)

    Strobel, Bjarne W.; Erichsen, Anders Christian; Gausset, Quentin

    2016-01-01

    A pre-condition for reducing global warming is to minimise the emission of greenhouse gasses (GHGs). A common approach to informing people about the link between behaviour and climate change rests on developing GHG calculators that quantify the ‘carbon footprint’ of a product, a sector or an actor....... There is, however, an abundance of GHG calculators that rely on very different premises and give very different estimates of carbon footprints. In this chapter, we compare and analyse the main principles of calculating carbon footprints, and discuss how calculators can inform (or misinform) people who wish...

  3. Methodology for embedded transport core calculation

    Science.gov (United States)

    Ivanov, Boyan D.

    The progress in the Nuclear Engineering field leads to developing new generations of Nuclear Power Plants (NPP) with complex rector core designs, such as cores loaded partially with mixed-oxide (MOX) fuel, high burn-up loadings, and cores with advanced designs of fuel assemblies and control rods. Such heterogeneous cores introduce challenges for the diffusion theory that has been used for several decades for calculations of the current Pressurized Water Rector (PWR) cores. To address the difficulties the diffusion approximation encounters new core calculation methodologies need to be developed by improving accuracy, while preserving efficiency of the current reactor core calculations. In this thesis, an advanced core calculation methodology is introduced, based on embedded transport calculations. Two different approaches are investigated. The first approach is based on embedded finite element (FEM), simplified P3 approximation (SP3), fuel assembly (FA) homogenization calculation within the framework of the diffusion core calculation with NEM code (Nodal Expansion Method). The second approach involves embedded FA lattice physics eigenvalue calculation based on collision probability method (CPM) again within the framework of the NEM diffusion core calculation. The second approach is superior to the first because most of the uncertainties introduced by the off-line cross-section generation are eliminated.

  4. Pile Load Capacity – Calculation Methods

    Directory of Open Access Journals (Sweden)

    Wrana Bogumił

    2015-12-01

    Full Text Available The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.

  5. Calculation reliability in vehicle accident reconstruction.

    Science.gov (United States)

    Wach, Wojciech

    2016-06-01

    The reconstruction of vehicle accidents is subject to assessment in terms of the reliability of a specific system of engineering and technical operations. In the article [26] a formalized concept of the reliability of vehicle accident reconstruction, defined using Bayesian networks, was proposed. The current article is focused on the calculation reliability since that is the most objective section of this model. It is shown that calculation reliability in accident reconstruction is not another form of calculation uncertainty. The calculation reliability is made dependent on modeling reliability, adequacy of the model and relative uncertainty of calculation. All the terms are defined. An example is presented concerning the analytical determination of the collision location of two vehicles on the road in the absence of evidential traces. It has been proved that the reliability of this kind of calculations generally does not exceed 0.65, despite the fact that the calculation uncertainty itself can reach only 0.05. In this example special attention is paid to the analysis of modeling reliability and calculation uncertainty using sensitivity coefficients and weighted relative uncertainty. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Calculated optical absorption of different perovskite phases

    DEFF Research Database (Denmark)

    Castelli, Ivano Eligio; Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2015-01-01

    We present calculations of the optical properties of a set of around 80 oxides, oxynitrides, and organometal halide cubic and layered perovskites (Ruddlesden-Popper and Dion-Jacobson phases) with a bandgap in the visible part of the solar spectrum. The calculations show that for different classes...

  7. Impedance Calculations of Induction Machine Rotor Conductors ...

    African Journals Online (AJOL)

    The exact calculation of the impedance of induction machine rotor conductors at several operating frequencies are necessary if the dynamic behaviour of the machine is to give a good correlation between the simulated starting torque and current and the experimental results. This paper describes a method of' calculating ...

  8. 46 CFR 154.520 - Piping calculations.

    Science.gov (United States)

    2010-10-01

    ...: (a) Pipe weight loads; (b) Acceleration loads; (c) Internal pressure loads; (d) Thermal loads; and (e... 46 Shipping 5 2010-10-01 2010-10-01 false Piping calculations. 154.520 Section 154.520 Shipping... Process Piping Systems § 154.520 Piping calculations. A piping system must be designed to meet the...

  9. Calculated Atomic Volumes of the Actinide Metals

    DEFF Research Database (Denmark)

    Skriver, H.; Andersen, O. K.; Johansson, B.

    1979-01-01

    The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium.......The equilibrium atomic volume is calculated for the actinide metals. It is possible to account for the localization of the 5f electrons taking place in americium....

  10. Numerical calculations of turbulent swirling flow

    Science.gov (United States)

    Kubo, I.; Gouldin, F. C.

    1974-01-01

    Description of a numerical technique for solving axisymmetric, incompressible, turbulent swirling flow problems. Isothermal flow calculations are presented for a coaxial flow configuration of special interest. The calculation results are discussed in regard to their implications for the design of gas turbine combustors.

  11. 47 CFR 54.609 - Calculating support.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Calculating support. 54.609 Section 54.609... SERVICE Universal Service Support for Health Care Providers § 54.609 Calculating support. (a) Except with... amount of universal service support for an eligible service provided to a public or non-profit rural...

  12. Calculation of the Poisson cumulative distribution function

    Science.gov (United States)

    Bowerman, Paul N.; Nolty, Robert G.; Scheuer, Ernest M.

    1990-01-01

    A method for calculating the Poisson cdf (cumulative distribution function) is presented. The method avoids computer underflow and overflow during the process. The computer program uses this technique to calculate the Poisson cdf for arbitrary inputs. An algorithm that determines the Poisson parameter required to yield a specified value of the cdf is presented.

  13. Data base to compare calculations and observations

    Energy Technology Data Exchange (ETDEWEB)

    Tichler, J.L.

    1985-01-01

    Meteorological and climatological data bases were compared with known tritium release points and diffusion calculations to determine if calculated concentrations could replace measure concentrations at the monitoring stations. Daily tritium concentrations were monitored at 8 stations and 16 possible receptors. Automated data retrieval strategies are listed. (PSB)

  14. Lewis Carroll's Formula for Calendar Calculating.

    Science.gov (United States)

    Spitz, Herman H.

    1993-01-01

    This paper presents Lewis Carroll's formula for mentally calculating the day of the week of a given date. The paper concludes that such formulas are too complex for individuals of low intelligence to learn by themselves, and thus "idiots savants" who perform such calendar calculations must be using other systems. (JDD)

  15. BURDEN OF DISEASE CALCULATION, COST OF ILLNESS ...

    African Journals Online (AJOL)

    CIU

    individual's relatives and the society can channel such resources and energy to other uses that would ..... European countries. Useful Steps in BoD Calculation and CoI Analysis. The first useful step in the calculation is the outcome tree. Others are perspective of evaluation ... illustrating their conditional dependency. The first ...

  16. 10 CFR 766.102 - Calculation methodology.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Calculation methodology. 766.102 Section 766.102 Energy DEPARTMENT OF ENERGY URANIUM ENRICHMENT DECONTAMINATION AND DECOMMISSIONING FUND; PROCEDURES FOR SPECIAL ASSESSMENT OF DOMESTIC UTILITIES Procedures for Special Assessment § 766.102 Calculation methodology. (a...

  17. Calculation of LDL apoB

    NARCIS (Netherlands)

    Sniderman, A.D.; Tremblay, A.J.; Graaf, J. de; Couture, P.

    2014-01-01

    OBJECTIVES: This study tests the validity of the Hattori formula to calculate LDL apoB based on plasma lipids and total apoB. METHODS: In 2178 patients in a tertiary care lipid clinic, LDL apoB calculated as suggested by Hattori et al. was compared to directly measured LDL apoB isolated by

  18. 5 CFR 1653.4 - Calculating entitlements.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Calculating entitlements. 1653.4 Section 1653.4 Administrative Personnel FEDERAL RETIREMENT THRIFT INVESTMENT BOARD COURT ORDERS AND LEGAL PROCESSES AFFECTING THRIFT SAVINGS PLAN ACCOUNTS Retirement Benefits Court Orders § 1653.4 Calculating...

  19. Calculation of Temperature Rise in Calorimetry.

    Science.gov (United States)

    Canagaratna, Sebastian G.; Witt, Jerry

    1988-01-01

    Gives a simple but fuller account of the basis for accurately calculating temperature rise in calorimetry. Points out some misconceptions regarding these calculations. Describes two basic methods, the extrapolation to zero time and the equal area method. Discusses the theoretical basis of each and their underlying assumptions. (CW)

  20. Direct calculation of wind turbine tip loss

    DEFF Research Database (Denmark)

    Wood, D.H.; Okulov, Valery; Bhattacharjee, D.

    2016-01-01

    The usual method to account for a finite number of blades in blade element calculations of wind turbine performance is through a tip loss factor. Most analyses use the tip loss approximation due to Prandtl which is easily and cheaply calculated but is known to be inaccurate at low tip speed ratio...

  1. HP-67 calculator programs for thermodynamic data and phase diagram calculations

    Energy Technology Data Exchange (ETDEWEB)

    Brewer, L.

    1978-05-25

    This report is a supplement to a tabulation of the thermodynamic and phase data for the 100 binary systems of Mo with the elements from H to Lr. The calculations of thermodynamic data and phase equilibria were carried out from 5000/sup 0/K to low temperatures. This report presents the methods of calculation used. The thermodynamics involved is rather straightforward and the reader is referred to any advanced thermodynamic text. The calculations were largely carried out using an HP-65 programmable calculator. In this report, those programs are reformulated for use with the HP-67 calculator; great reduction in the number of programs required to carry out the calculation results.

  2. Normal mode calculations of trigonal selenium

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; McMurry, H. L.

    1980-01-01

    . With such coordinates a potential energy, calculated with only a diagonal force matrix, is equivalent to one calculated with both off diagonal and diagonal elements when conventional coordinates are used. Another advantage is that often some force constants may be determined directly from frequencies at points of high....... In this way we have eliminated the ambiguity in the choice of valence coordinates, which has been a problem in previous models which used valence type interactions. Calculated sound velocities and elastic moduli are also given. The Journal of Chemical Physics is copyrighted by The American Institute...

  3. Spreadsheet Based Scaling Calculations and Membrane Performance

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, T D; Bourcier, W L; Speth, T F

    2000-12-28

    Many membrane element manufacturers provide a computer program to aid buyers in the use of their elements. However, to date there are few examples of fully integrated public domain software available for calculating reverse osmosis and nanofiltration system performance. The Total Flux and Scaling Program (TFSP), written for Excel 97 and above, provides designers and operators new tools to predict membrane system performance, including scaling and fouling parameters, for a wide variety of membrane system configurations and feedwaters. The TFSP development was funded under EPA contract 9C-R193-NTSX. It is freely downloadable at www.reverseosmosis.com/download/TFSP.zip. TFSP includes detailed calculations of reverse osmosis and nanofiltration system performance. Of special significance, the program provides scaling calculations for mineral species not normally addressed in commercial programs, including aluminum, iron, and phosphate species. In addition, ASTM calculations for common species such as calcium sulfate (CaSO{sub 4}{times}2H{sub 2}O), BaSO{sub 4}, SrSO{sub 4}, SiO{sub 2}, and LSI are also provided. Scaling calculations in commercial membrane design programs are normally limited to the common minerals and typically follow basic ASTM methods, which are for the most part graphical approaches adapted to curves. In TFSP, the scaling calculations for the less common minerals use subsets of the USGS PHREEQE and WATEQ4F databases and use the same general calculational approach as PHREEQE and WATEQ4F. The activities of ion complexes are calculated iteratively. Complexes that are unlikely to form in significant concentration were eliminated to simplify the calculations. The calculation provides the distribution of ions and ion complexes that is used to calculate an effective ion product ''Q.'' The effective ion product is then compared to temperature adjusted solubility products (Ksp's) of solids in order to calculate a Saturation Index (SI

  4. Ti-84 Plus graphing calculator for dummies

    CERN Document Server

    McCalla

    2013-01-01

    Get up-to-speed on the functionality of your TI-84 Plus calculator Completely revised to cover the latest updates to the TI-84 Plus calculators, this bestselling guide will help you become the most savvy TI-84 Plus user in the classroom! Exploring the standard device, the updated device with USB plug and upgraded memory (the TI-84 Plus Silver Edition), and the upcoming color screen device, this book provides you with clear, understandable coverage of the TI-84's updated operating system. Details the new apps that are available for download to the calculator via the USB cabl

  5. Hamming generalized corrector for reactivity calculation

    Energy Technology Data Exchange (ETDEWEB)

    Suescun-Diaz, Daniel; Ibarguen-Gonzalez, Maria C.; Figueroa-Jimenez, Jorge H. [Pontificia Universidad Javeriana Cali, Cali (Colombia). Dept. de Ciencias Naturales y Matematicas

    2014-06-15

    This work presents the Hamming method generalized corrector for numerically resolving the differential equation of delayed neutron precursor concentration from the point kinetics equations for reactivity calculation, without using the nuclear power history or the Laplace transform. A study was carried out of several correctors with their respective modifiers with different time step calculations, to offer stability and greater precision. Better results are obtained for some correctors than with other existing methods. Reactivity can be calculated with precision of the order h{sup 5}, where h is the time step. (orig.)

  6. REVIEW: Review and history of photon cross section calculations

    Science.gov (United States)

    Hubbell, J. H.

    2006-07-01

    Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, μ/ρ, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's μ/ρ compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Øverbø, these names being representative of the vast legions of other researchers whose work fed into these

  7. NASCAP/LEO calculations of current collection

    Science.gov (United States)

    Mandell, Myron J.; Katz, Ira; Davis, Victoria A.; Kuharski, Robert A.

    1990-12-01

    NASCAP/LEO is a 3-dimensional computer code for calculating the interaction of a high-voltage spacecraft with the cold dense plasma found in Low Earth Orbit. Although based on a cubic grid structure, NASCAP/LEO accepts object definition input from standard computer aided design (CAD) programs so that a model may be correctly proportioned and important features resolved. The potential around the model is calculated by solving the finite element formulation of Poisson's equation with an analytic space charge function. Five previously published NASCAP/LEO calculations for three ground test experiments and two space flight experiments are presented. The three ground test experiments are a large simulated panel, a simulated pinhole, and a 2-slit experiment with overlapping sheaths. The two space flight experiments are a solar panel biased up to 1000 volts, and a rocket-mounted sphere biased up to 46 kilovolts. In all cases, the authors find good agreement between calculation and measurement.

  8. Carbon Footprint Calculator | Climate Change | US EPA

    Science.gov (United States)

    2016-12-12

    An interactive calculator to estimate your household's carbon footprint. This tool will estimate carbon pollution emissions from your daily activities and show how to reduce your emissions and save money through simple steps.

  9. Calculated Leaf Carbon and Nitrogen, 1992 (ACCP)

    Data.gov (United States)

    National Aeronautics and Space Administration — Study plot canopy chemistry values were calculated from leaf chemistry and litterfall weight values. Average leaf concentrations of nitrogen and carbon were used to...

  10. Calculating Employee Compensation Using An Economic Principle

    National Research Council Canada - National Science Library

    Puneet Jaiprakash

    2015-01-01

    .... This paper develops an intuitive method for calculating the minimum amount by which an employee's compensation must be adjusted taking into account changes in economic conditions since the start of employment...

  11. Teaching Graphing Concepts with Graphing Calculators.

    Science.gov (United States)

    Mercer, Joseph

    1995-01-01

    Presents five lessons to demonstrate how graphing calculators can be used to teach the slope-intercept concept of linear equations and to establish more general principles about two-dimensional graphs. Contains a reproducible student quiz. (MKR)

  12. Numerical calculations in quantum field theories

    Energy Technology Data Exchange (ETDEWEB)

    Rebbi, C.

    1984-01-01

    Four lecture notes are included: (1) motivation for numerical calculations in Quantum Field Theory; (2) numerical simulation methods; (3) Monte Carlo studies of Quantum Chromo Dynamics; and (4) systems with fermions. 23 references. (WHK)

  13. 108 NUMERICAL CALCULATIONS IN THE GENERAL DYNAMICAL ...

    African Journals Online (AJOL)

    DR. AMINU

    Correspondence Author ... of Moving Bodies”, the following postulates were introduced:- .... 110. Table1: calculated values of the ratio of coordinate time to proper time for both general relativity and dynamical theory of gravitation. Body. Mass (M) Kg.

  14. Fair and Reasonable Rate Calculation Data -

    Data.gov (United States)

    Department of Transportation — This dataset provides guidelines for calculating the fair and reasonable rates for U.S. flag vessels carrying preference cargoes subject to regulations contained at...

  15. Temperature calculation in fire safety engineering

    CERN Document Server

    Wickström, Ulf

    2016-01-01

    This book provides a consistent scientific background to engineering calculation methods applicable to analyses of materials reaction-to-fire, as well as fire resistance of structures. Several new and unique formulas and diagrams which facilitate calculations are presented. It focuses on problems involving high temperature conditions and, in particular, defines boundary conditions in a suitable way for calculations. A large portion of the book is devoted to boundary conditions and measurements of thermal exposure by radiation and convection. The concepts and theories of adiabatic surface temperature and measurements of temperature with plate thermometers are thoroughly explained. Also presented is a renewed method for modeling compartment fires, with the resulting simple and accurate prediction tools for both pre- and post-flashover fires. The final chapters deal with temperature calculations in steel, concrete and timber structures exposed to standard time-temperature fire curves. Useful temperature calculat...

  16. IOL Power Calculation after Corneal Refractive Surgery

    OpenAIRE

    Maddalena De Bernardo; Luigi Capasso; Luisa Caliendo; Francesco Paolercio; Nicola Rosa

    2014-01-01

    Purpose. To describe the different formulas that try to overcome the problem of calculating the intraocular lens (IOL) power in patients that underwent corneal refractive surgery (CRS). Methods. A Pubmed literature search review of all published articles, on keyword associated with IOL power calculation and corneal refractive surgery, as well as the reference lists of retrieved articles, was performed. Results. A total of 33 peer reviewed articles dealing with methods that try to overcome the...

  17. PROSPECTS OF MANAGEMENT ACCOUNTING AND COST CALCULATION

    Directory of Open Access Journals (Sweden)

    Marian ŢAICU

    2014-11-01

    Full Text Available Progress in improving production technology requires appropriate measures to achieve an efficient management of costs. This raises the need for continuous improvement of management accounting and cost calculation. Accounting information in general, and management accounting information in particular, have gained importance in the current economic conditions, which are characterized by risk and uncertainty. The future development of management accounting and cost calculation is essential to meet the information needs of management.

  18. Flow calculation of a bulb turbine

    Energy Technology Data Exchange (ETDEWEB)

    Goede, E.; Pestalozzi, J.

    1987-01-01

    In recent years remarkable progress has been made in the field of theoretical flow calculation. Studying the relevant literature one might receive the impression that most problems have been solved. But probing more deeply into details one becomes aware that by no means all questions are answered. The report tries to point out what may be expected of the quasi-three-dimensional flow calculation method employed and - much more important - what it must not be expected to accomplish. (orig.)

  19. Providing driving rain data for hygrothermal calculations

    DEFF Research Database (Denmark)

    Kragh, Mikkel Kristian

    1996-01-01

    Due to a wish for driving rain data as input for hygrothermal calculations, this report deals with utilizing commonly applied empirical relations and standard meteorological data, in an attempt to provide realistic estimates rather than exact correlations.......Due to a wish for driving rain data as input for hygrothermal calculations, this report deals with utilizing commonly applied empirical relations and standard meteorological data, in an attempt to provide realistic estimates rather than exact correlations....

  20. DOWNSCALE APPLICATION OF BOILER THERMAL CALCULATION APPROACH

    OpenAIRE

    Zelený, Zbynĕk; Hrdlička, Jan

    2016-01-01

    Commonly used thermal calculation methods are intended primarily for large scale boilers. Hot water small scale boilers, which are commonly used for home heating have many specifics, that distinguish them from large scale boilers especially steam boilers. This paper is focused on application of thermal calculation procedure that is designed for large scale boilers, on a small scale boiler for biomass combustion of load capacity 25 kW. Special issue solved here is influence of formation of dep...

  1. Efficient Finite Element Calculation of Nγ

    DEFF Research Database (Denmark)

    Clausen, Johan; Damkilde, Lars; Krabbenhøft, K.

    2007-01-01

    This paper deals with the computational aspects of the Mohr-Coulomb material model, in particular the calculation of the bearing capacity factor Nγfor a strip and a circular footing.......This paper deals with the computational aspects of the Mohr-Coulomb material model, in particular the calculation of the bearing capacity factor Nγfor a strip and a circular footing....

  2. Internal Mechanism of a Schoonschip Calculation

    CERN Document Server

    Strubbe, H

    1973-01-01

    Schoonschip is a general purpose "Algebraic Manipulation" program. It is designed to do long - but in principle straightforward - analytic calculations. It can be used interactively. It is very fast in execution and very economical in storage (25K). This is achieved by writing the program almost entirely in (CDC 6000) machine code. Therefore, the representation of the algebraic formulae (list structure) and the calculation mechanism can be set up very efficiently. Input, Output and a few numerical tasks are done in Fortran.

  3. Environmental flow allocation and statistics calculator

    Science.gov (United States)

    Konrad, Christopher P.

    2011-01-01

    The Environmental Flow Allocation and Statistics Calculator (EFASC) is a computer program that calculates hydrologic statistics based on a time series of daily streamflow values. EFASC will calculate statistics for daily streamflow in an input file or will generate synthetic daily flow series from an input file based on rules for allocating and protecting streamflow and then calculate statistics for the synthetic time series. The program reads dates and daily streamflow values from input files. The program writes statistics out to a series of worksheets and text files. Multiple sites can be processed in series as one run. EFASC is written in MicrosoftRegistered Visual BasicCopyright for Applications and implemented as a macro in MicrosoftOffice Excel 2007Registered. EFASC is intended as a research tool for users familiar with computer programming. The code for EFASC is provided so that it can be modified for specific applications. All users should review how output statistics are calculated and recognize that the algorithms may not comply with conventions used to calculate streamflow statistics published by the U.S. Geological Survey.

  4. Automated method for determination of dissolved organic carbon-water distribution constants of structurally diverse pollutants using pre-equilibrium solid-phase microextraction.

    Science.gov (United States)

    Ripszam, Matyas; Haglund, Peter

    2015-02-01

    Dissolved organic carbon (DOC) plays a key role in determining the environmental fate of semivolatile organic environmental contaminants. The goal of the present study was to develop a method using commercially available hardware to rapidly characterize the sorption properties of DOC in water samples. The resulting method uses negligible-depletion direct immersion solid-phase microextraction (SPME) and gas chromatography-mass spectrometry. Its performance was evaluated using Nordic reference fulvic acid and 40 priority environmental contaminants that cover a wide range of physicochemical properties. Two SPME fibers had to be used to cope with the span of properties, 1 coated with polydimethylsiloxane and 1 coated with polystyrene divinylbenzene polydimethylsiloxane, for nonpolar and semipolar contaminants, respectively. The measured DOC-water distribution constants showed reasonably good reproducibility (standard deviation ≤ 0.32) and good correlation (R(2)  = 0.80) with log octanol-water partition coefficients for nonpolar persistent organic pollutants. The sample pretreatment is limited to filtration, and the method is easy to adjust to different DOC concentrations. These experiments also utilized the latest SPME automation that largely decreases total cycle time (to 20 min or shorter) and increases sample throughput, which is advantageous in cases when many samples of DOC must be characterized or when the determinations must be performed quickly, for example, to avoid precipitation, aggregation, and other changes of DOC structure and properties. The data generated by this method are valuable as a basis for transport and fate modeling studies. © 2014 SETAC.

  5. Biases for current FFTF calculational methods

    Energy Technology Data Exchange (ETDEWEB)

    Ombrellaro, P.A.; Bennett, R.A.; Daughtry, J.W.; Dobbin, K.D.; Harris, R.A.; Nelson, J.V.; Peterson, R.E.; Rothrock, R.B.

    1978-01-01

    Uncertainties in nuclear data and approximate calculational methods used in safety design, and operational support of a reactor yield biased as well as uncertain results. Experimentally based biases for use in Fast Flux Test Facility (FFTF) core calculations have been evaluated and are presented together with a description of calculational methods. Experimental data for these evaluations were obtained from an Engineering Mockup Critical (EMC) of the FFTF core built at the Argonne National Laboratory (ANL). The experiments were conceived and planned by the Hanford Engineering Development Laboratory (HEDL) in cooperation with the Westinghouse Advanced Reactors Division (WARD) and ANL personnel, and carried out by the ANL staff. All experiments were designed specifically to provide data for evaluation of current FFTF core calculational methods. These comprehensive experiments were designed to allow simultaneous evaluations of biases and uncertainties in calculated reactivities, fuel sub-assembly and material reactivity worths, small sample worths, absorber rod worths, spatial fission rate distributions, power tilting effects and spatial neutron spectra. Modified source multiplication and reactivity anomaly methods have also been evaluated. Uncertainties in the biases have been established and are sufficiently small to attain a high degree of confidence in the design, safety and operational aspects of the FFTF core.

  6. Good Practices in Free-energy Calculations

    Science.gov (United States)

    Pohorille, Andrew; Jarzynski, Christopher; Chipot, Christopher

    2013-01-01

    As access to computational resources continues to increase, free-energy calculations have emerged as a powerful tool that can play a predictive role in drug design. Yet, in a number of instances, the reliability of these calculations can be improved significantly if a number of precepts, or good practices are followed. For the most part, the theory upon which these good practices rely has been known for many years, but often overlooked, or simply ignored. In other cases, the theoretical developments are too recent for their potential to be fully grasped and merged into popular platforms for the computation of free-energy differences. The current best practices for carrying out free-energy calculations will be reviewed demonstrating that, at little to no additional cost, free-energy estimates could be markedly improved and bounded by meaningful error estimates. In energy perturbation and nonequilibrium work methods, monitoring the probability distributions that underlie the transformation between the states of interest, performing the calculation bidirectionally, stratifying the reaction pathway and choosing the most appropriate paradigms and algorithms for transforming between states offer significant gains in both accuracy and precision. In thermodynamic integration and probability distribution (histogramming) methods, properly designed adaptive techniques yield nearly uniform sampling of the relevant degrees of freedom and, by doing so, could markedly improve efficiency and accuracy of free energy calculations without incurring any additional computational expense.

  7. Paramedics’ Ability to Perform Drug Calculations

    Directory of Open Access Journals (Sweden)

    Eastwood, Kathyrn J

    2009-11-01

    Full Text Available Background: The ability to perform drug calculations accurately is imperative to patient safety. Research into paramedics’ drug calculation abilities was first published in 2000 and for nurses’ abilities the research dates back to the late 1930s. Yet, there have been no studies investigating an undergraduate paramedic student’s ability to perform drug or basic mathematical calculations. The objective of this study was to review the literature and determine the ability of undergraduate and qualified paramedics to perform drug calculations.Methods: A search of the prehospital-related electronic databases was undertaken using the Ovid and EMBASE systems available through the Monash University Library. Databases searched included the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, CINAHL, JSTOR, EMBASE and Google Scholar, from their beginning until the end of August 2009. We reviewed references from articles retrieved.Results: The electronic database search located 1,154 articles for review. Six additional articles were identified from reference lists of retrieved articles. Of these, 59 were considered relevant. After reviewing the 59 articles only three met the inclusion criteria. All articles noted some level of mathematical deficiencies amongst their subjects.Conclusions: This study identified only three articles. Results from these limited studies indicate a significant lack of mathematical proficiency amongst the paramedics sampled. A need exists to identify if undergraduate paramedic students are capable of performing the required drug calculations in a non-clinical setting.[WestJEM. 2009;10:240-243.

  8. Paramedics’ Ability to Perform Drug Calculations

    Science.gov (United States)

    Eastwood, Kathryn J; Boyle, Malcolm J; Williams, Brett

    2009-01-01

    Background: The ability to perform drug calculations accurately is imperative to patient safety. Research into paramedics’ drug calculation abilities was first published in 2000 and for nurses’ abilities the research dates back to the late 1930s. Yet, there have been no studies investigating an undergraduate paramedic student’s ability to perform drug or basic mathematical calculations. The objective of this study was to review the literature and determine the ability of undergraduate and qualified paramedics to perform drug calculations. Methods: A search of the prehospital-related electronic databases was undertaken using the Ovid and EMBASE systems available through the Monash University Library. Databases searched included the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, CINAHL, JSTOR, EMBASE and Google Scholar, from their beginning until the end of August 2009. We reviewed references from articles retrieved. Results: The electronic database search located 1,154 articles for review. Six additional articles were identified from reference lists of retrieved articles. Of these, 59 were considered relevant. After reviewing the 59 articles only three met the inclusion criteria. All articles noted some level of mathematical deficiencies amongst their subjects. Conclusions: This study identified only three articles. Results from these limited studies indicate a significant lack of mathematical proficiency amongst the paramedics sampled. A need exists to identify if undergraduate paramedic students are capable of performing the required drug calculations in a non-clinical setting. PMID:20046240

  9. Paramedics' ability to perform drug calculations.

    Science.gov (United States)

    Eastwood, Kathryn J; Boyle, Malcolm J; Williams, Brett

    2009-11-01

    The ability to perform drug calculations accurately is imperative to patient safety. Research into paramedics' drug calculation abilities was first published in 2000 and for nurses' abilities the research dates back to the late 1930s. Yet, there have been no studies investigating an undergraduate paramedic student's ability to perform drug or basic mathematical calculations. The objective of this study was to review the literature and determine the ability of undergraduate and qualified paramedics to perform drug calculations. A search of the prehospital-related electronic databases was undertaken using the Ovid and EMBASE systems available through the Monash University Library. Databases searched included the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, CINAHL, JSTOR, EMBASE and Google Scholar, from their beginning until the end of August 2009. We reviewed references from articles retrieved. The electronic database search located 1,154 articles for review. Six additional articles were identified from reference lists of retrieved articles. Of these, 59 were considered relevant. After reviewing the 59 articles only three met the inclusion criteria. All articles noted some level of mathematical deficiencies amongst their subjects. This study identified only three articles. Results from these limited studies indicate a significant lack of mathematical proficiency amongst the paramedics sampled. A need exists to identify if undergraduate paramedic students are capable of performing the required drug calculations in a non-clinical setting.

  10. Automated one-loop calculations with GOSAM

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, Gavin [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, Nicolas [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Physics; Max-Planck-Institut fuer Physik, Muenchen (Germany); Heinrich, Gudrun; Reiter, Thomas [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, Gionata [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, Pierpaolo [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, Giovanni [New York City Univ., NY (United States). New York City College of Technology; New York City Univ., NY (United States). The Graduate School and University Center; Tramontano, Francesco [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2011-11-15

    We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop. (orig.)

  11. Resolving resonances in R-matrix calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, J.M.; Bautista, Manuel A. [Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas (IVIC), Caracas (Venezuela)

    2002-10-28

    We present a technique to obtain detailed resonance structures from R-matrix calculations of atomic cross sections for both collisional and radiative processes. The resolving resonances (RR) method relies on the QB method of Quigley-Berrington (Quigley L, Berrington K A and Pelan J 1998 Comput. Phys. Commun. 114 225) to find the position and width of resonances directly from the reactance matrix. Then one determines the symmetry parameters of these features and generates an energy mesh whereby fully resolved cross sections are calculated with minimum computational cost. The RR method is illustrated with the calculation of the photoionization cross sections and the unified recombination rate coefficients of Fe XXIV, O VI, and Fe XVII. The RR method reduces numerical errors arising from unresolved R-matrix cross sections in the computation of synthetic bound-free opacities, thermally averaged collision strengths and recombination rate coefficients. (author)

  12. Green's function calculation from equipartition theorem.

    Science.gov (United States)

    Perton, Mathieu; Sánchez-Sesma, Francisco José

    2016-08-01

    A method is presented to calculate the elastodynamic Green's functions by using the equipartition principle. The imaginary parts are calculated as the average cross correlations of the displacement fields generated by the incidence of body and surface waves with amplitudes weighted by partition factors. The real part is retrieved using the Hilbert transform. The calculation of the partition factors is discussed for several geometrical configurations in two dimensional space: the full-space, a basin in a half-space and for layered media. For the last case, it results in a fast computation of the full Green's functions. Additionally, if the contribution of only selected states is desired, as for instance the surface wave part, the computation is even faster. Its use for full waveform inversion may then be advantageous.

  13. Daylight calculations using constant luminance curves

    Energy Technology Data Exchange (ETDEWEB)

    Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda

    2005-02-01

    This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)

  14. Using inverted indices for accelerating LINGO calculations.

    Science.gov (United States)

    Kristensen, Thomas G; Nielsen, Jesper; Pedersen, Christian N S

    2011-03-28

    The ever growing size of chemical databases calls for the development of novel methods for representing and comparing molecules. One such method called LINGO is based on fragmenting the SMILES string representation of molecules. Comparison of molecules can then be performed by calculating the Tanimoto coefficient, which is called LINGOsim when used on LINGO multisets. This paper introduces a verbose representation for storing LINGO multisets, which makes it possible to transform them into sparse fingerprints such that fingerprint data structures and algorithms can be used to accelerate queries. The previous best method for rapidly calculating the LINGOsim similarity matrix required specialized hardware to yield a significant speedup over existing methods. By representing LINGO multisets in the verbose representation and using inverted indices, it is possible to calculate LINGOsim similarity matrices roughly 2.6 times faster than existing methods without relying on specialized hardware.

  15. Note about socio-economic calculations

    DEFF Research Database (Denmark)

    Landex, Alex; Andersen, Jonas Lohmann Elkjær; Salling, Kim Bang

    2006-01-01

    This note gives a short introduction of how to make socio-economic evaluations in connection with the teaching at the Centre for Traffic and Transport (CTT). It is not a manual for making socio-economic calculations in transport infrastructure projects – in this context we refer to the guidelines...... for socio-economic calculations within the transportation area (Ministry of Traffic, 2003). The note also explains the theory of socio-economic calculations – reference is here made to ”Road Infrastructure Planning – a Decision-oriented approach” (Leleur, 2000). Socio-economic evaluations of infrastructure...... projects are common and can be made at different levels of detail depending on the type of project and the decision making phase. A common feature of the different levels of detail of the socio-economic analysis is that the planned project(s) is compared with a basic; the basic alternative or a null...

  16. eQuilibrator—the biochemical thermodynamics calculator

    Science.gov (United States)

    Flamholz, Avi; Noor, Elad; Bar-Even, Arren; Milo, Ron

    2012-01-01

    The laws of thermodynamics constrain the action of biochemical systems. However, thermodynamic data on biochemical compounds can be difficult to find and is cumbersome to perform calculations with manually. Even simple thermodynamic questions like ‘how much Gibbs energy is released by ATP hydrolysis at pH 5?’ are complicated excessively by the search for accurate data. To address this problem, eQuilibrator couples a comprehensive and accurate database of thermodynamic properties of biochemical compounds and reactions with a simple and powerful online search and calculation interface. The web interface to eQuilibrator (http://equilibrator.weizmann.ac.il) enables easy calculation of Gibbs energies of compounds and reactions given arbitrary pH, ionic strength and metabolite concentrations. The eQuilibrator code is open-source and all thermodynamic source data are freely downloadable in standard formats. Here we describe the database characteristics and implementation and demonstrate its use. PMID:22064852

  17. Undergraduate paramedic students cannot do drug calculations

    Science.gov (United States)

    Eastwood, Kathryn; Boyle, Malcolm J; Williams, Brett

    2012-01-01

    BACKGROUND: Previous investigation of drug calculation skills of qualified paramedics has highlighted poor mathematical ability with no published studies having been undertaken on undergraduate paramedics. There are three major error classifications. Conceptual errors involve an inability to formulate an equation from information given, arithmetical errors involve an inability to operate a given equation, and finally computation errors are simple errors of addition, subtraction, division and multiplication. The objective of this study was to determine if undergraduate paramedics at a large Australia university could accurately perform common drug calculations and basic mathematical equations normally required in the workplace. METHODS: A cross-sectional study methodology using a paper-based questionnaire was administered to undergraduate paramedic students to collect demographical data, student attitudes regarding their drug calculation performance, and answers to a series of basic mathematical and drug calculation questions. Ethics approval was granted. RESULTS: The mean score of correct answers was 39.5% with one student scoring 100%, 3.3% of students (n=3) scoring greater than 90%, and 63% (n=58) scoring 50% or less, despite 62% (n=57) of the students stating they ‘did not have any drug calculations issues’. On average those who completed a minimum of year 12 Specialist Maths achieved scores over 50%. Conceptual errors made up 48.5%, arithmetical 31.1% and computational 17.4%. CONCLUSIONS: This study suggests undergraduate paramedics have deficiencies in performing accurate calculations, with conceptual errors indicating a fundamental lack of mathematical understanding. The results suggest an unacceptable level of mathematical competence to practice safely in the unpredictable prehospital environment. PMID:25215067

  18. Calculation of water activation for the LHC

    Science.gov (United States)

    Vollaire, Joachim; Brugger, Markus; Forkel-Wirth, Doris; Roesler, Stefan; Vojtyla, Pavol

    2006-06-01

    The management of activated water in the Large Hadron Collider (LHC) at CERN is a key concern for radiation protection. For this reason, the induced radioactivity of the different water circuits is calculated using the Monte-Carlo (MC) code FLUKA. The results lead to the definition of procedures to be taken into account during the repair and maintenance of the machine, as well as to measures being necessary for a release of water into the environment. In order to assess the validity of the applied methods, a benchmark experiment was carried out at the CERN-EU High Energy Reference Field (CERF) facility, where a hadron beam (120 GeV) is impinging on a copper target. Four samples of water, as used at the LHC, and different in their chemical compositions, were irradiated near the copper target. In addition to the tritium activity measured with a liquid scintillation counter, the samples were also analyzed using gamma spectroscopy in order to determine the activity of the gamma emitting isotopes such as Be7 and Na24. While for the latter an excellent agreement between simulation and measurement was found, for the calculation of tritium a correction factor is derived to be applied for future LHC calculations in which the activity is calculated by direct scoring of produced nuclei. A simplified geometry representing the LHC Arc sections is then used to evaluate the different calculation methods with FLUKA. By comparing these methods and by taking into account the benchmark results, a strategy for the environmental calculations can be defined.

  19. First principles calculations for litiated manganese oxides

    Energy Technology Data Exchange (ETDEWEB)

    Benedek, R; Prasad, R; Thackeray, M; Wills, J M; Yang, L H

    1998-12-22

    First principles calculations using the local-spin-density-functional theory are presented of densities of electronic states for MnO, LiMnO{sub 2} in the monoclinic and orthorhombic structures, cubic LiMn{sub 2}O{sub 4} spinel, and {lambda}-MnO{sub 2} (delithiated spinel), all in antiferromagnetic spin configurations. The changes in energy spectra as the Mn oxidation state varies between 2+ and 4+ are illustrated. Preliminary calculations for Co-doped LiMnO{sub 2} are presented, and the destabilization of a monoclinic relative to a rhombohedral structure is discussed.

  20. Transmission pipeline calculations and simulations manual

    CERN Document Server

    Menon, E Shashi

    2014-01-01

    Transmission Pipeline Calculations and Simulations Manual is a valuable time- and money-saving tool to quickly pinpoint the essential formulae, equations, and calculations needed for transmission pipeline routing and construction decisions. The manual's three-part treatment starts with gas and petroleum data tables, followed by self-contained chapters concerning applications. Case studies at the end of each chapter provide practical experience for problem solving. Topics in this book include pressure and temperature profile of natural gas pipelines, how to size pipelines for specified f

  1. Calculation of a Shock Response Spectra

    Directory of Open Access Journals (Sweden)

    Jiri Tuma

    2011-11-01

    Full Text Available As it is stated in the ISO 18431-4 Standard, a Shock Response Spectrum is defined as the response to a given accelerationacting at a set of mass-damper-spring oscillators, which are adjusted to the different resonance frequencies while their resonancegains (Q-factor are equal to the same value. The maximum of the absolute value of the calculated responses as a function of theresonance frequencies compose the shock response spectrum (SRS. The paper will deal with employing Signal Analyzer, the softwarefor signal processing, for calculation of the SRS. The theory is illustrated by examples.

  2. Histidine in Continuum Electrostatics Protonation State Calculations

    Science.gov (United States)

    Couch, Vernon; Stuchebruckhov, Alexei

    2014-01-01

    A modification to the standard continuum electrostatics approach to calculate protein pKas which allows for the decoupling of histidine tautomers within a two state model is presented. Histidine with four intrinsically coupled protonation states cannot be easily incorporated into a two state formalism because the interaction between the two protonatable sites of the imidazole ring is not purely electrostatic. The presented treatment, based on a single approximation of the interrelation between histidine’s charge states, allows for a natural separation of the two protonatable sites associated with the imidazole ring as well as the inclusion of all protonation states within the calculation. PMID:22072521

  3. The new pooled cohort equations risk calculator

    DEFF Research Database (Denmark)

    Preiss, David; Kristensen, Søren L

    2015-01-01

    total cardiovascular risk score. During development of joint guidelines released in 2013 by the American College of Cardiology (ACC) and American Heart Association (AHA), the decision was taken to develop a new risk score. This resulted in the ACC/AHA Pooled Cohort Equations Risk Calculator. This risk...... disease and any measure of social deprivation. An early criticism of the Pooled Cohort Equations Risk Calculator has been its alleged overestimation of ASCVD risk which, if confirmed in the general population, is likely to result in statin therapy being prescribed to many individuals at lower risk than...

  4. Ab initio valence calculations in chemistry

    CERN Document Server

    Cook, D B

    1974-01-01

    Ab Initio Valence Calculations in Chemistry describes the theory and practice of ab initio valence calculations in chemistry and applies the ideas to a specific example, linear BeH2. Topics covered include the Schrödinger equation and the orbital approximation to atomic orbitals; molecular orbital and valence bond methods; practical molecular wave functions; and molecular integrals. Open shell systems, molecular symmetry, and localized descriptions of electronic structure are also discussed. This book is comprised of 13 chapters and begins by introducing the reader to the use of the Schrödinge

  5. BASIC program calculates flue gas energy balance

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, V. (ABCO Industries, Inc., Abilene, TX (United States))

    1993-10-01

    Engineers always seek cost-cutting, energy-efficient ways to operate boilers and waste-heat recovery systems. The starting point in the design or performance evaluation of any heat transfer equipment is an energy balance calculation. This easy-to-use BASIC program tackles this problem. Using the gas stream analysis as percent weight or volume, the program calculates inlet and exit temperatures, heat duty, the gas stream's molecular weight, etc. This program is a definite must for the plant engineering notebook.

  6. Criticality calculation of non-ordinary systems

    Energy Technology Data Exchange (ETDEWEB)

    Kalugin, A. V., E-mail: Kalugin-AV@nrcki.ru; Tebin, V. V. [National Research Centre Kurchatov Institute (Russian Federation)

    2016-12-15

    The specific features of calculation of the effective multiplication factor using the Monte Carlo method for weakly coupled and non-asymptotic multiplying systems are discussed. Particular examples are considered and practical recommendations on detection and Monte Carlo calculation of systems typical in numerical substantiation of nuclear safety for VVER fuel management problems are given. In particular, the problems of the choice of parameters for the batch mode and the method for normalization of the neutron batch, as well as finding and interpretation of the eigenvalue spectrum for the integral fission matrix, are discussed.

  7. Engineering calculations in radiative heat transfer

    CERN Document Server

    Gray, W A; Hopkins, D W

    1974-01-01

    Engineering Calculations in Radiative Heat Transfer is a six-chapter book that first explains the basic principles of thermal radiation and direct radiative transfer. Total exchange of radiation within an enclosure containing an absorbing or non-absorbing medium is then described. Subsequent chapters detail the radiative heat transfer applications and measurement of radiation and temperature.

  8. Calculators and the SAT: A Status Report.

    Science.gov (United States)

    Rigol, Gretchen W.

    1991-01-01

    The College Entrance Examination Board has not permitted calculator use on the Scholastic Aptitude Test because of unresolved concerns about equity, implications for test content, and logistical and security issues. Those issues no longer seem insurmountable, and significant changes are being introduced on many tests. (MSE)

  9. Cubic scaling GW: Towards fast quasiparticle calculations

    Czech Academy of Sciences Publication Activity Database

    Liu, P.; Kaltak, M.; Klimeš, Jiří; Kresse, G.

    2016-01-01

    Roč. 94, č. 16 (2016), s. 165109 ISSN 2469-9950 Institutional support: RVO:61388955 Keywords : MEAN-FIELD THEORY * ELECTRONIC-STRUCTURE CALCULATIONS * AUGMENTED-WAVE METHOD Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.836, year: 2016

  10. IOL Power Calculation after Corneal Refractive Surgery

    Directory of Open Access Journals (Sweden)

    Maddalena De Bernardo

    2014-01-01

    Full Text Available Purpose. To describe the different formulas that try to overcome the problem of calculating the intraocular lens (IOL power in patients that underwent corneal refractive surgery (CRS. Methods. A Pubmed literature search review of all published articles, on keyword associated with IOL power calculation and corneal refractive surgery, as well as the reference lists of retrieved articles, was performed. Results. A total of 33 peer reviewed articles dealing with methods that try to overcome the problem of calculating the IOL power in patients that underwent CRS were found. According to the information needed to try to overcome this problem, the methods were divided in two main categories: 18 methods were based on the knowledge of the patient clinical history and 15 methods that do not require such knowledge. The first group was further divided into five subgroups based on the parameters needed to make such calculation. Conclusion. In the light of our findings, to avoid postoperative nasty surprises, we suggest using only those methods that have shown good results in a large number of patients, possibly by averaging the results obtained with these methods.

  11. IOL power calculation after corneal refractive surgery.

    Science.gov (United States)

    De Bernardo, Maddalena; Capasso, Luigi; Caliendo, Luisa; Paolercio, Francesco; Rosa, Nicola

    2014-01-01

    To describe the different formulas that try to overcome the problem of calculating the intraocular lens (IOL) power in patients that underwent corneal refractive surgery (CRS). A Pubmed literature search review of all published articles, on keyword associated with IOL power calculation and corneal refractive surgery, as well as the reference lists of retrieved articles, was performed. A total of 33 peer reviewed articles dealing with methods that try to overcome the problem of calculating the IOL power in patients that underwent CRS were found. According to the information needed to try to overcome this problem, the methods were divided in two main categories: 18 methods were based on the knowledge of the patient clinical history and 15 methods that do not require such knowledge. The first group was further divided into five subgroups based on the parameters needed to make such calculation. In the light of our findings, to avoid postoperative nasty surprises, we suggest using only those methods that have shown good results in a large number of patients, possibly by averaging the results obtained with these methods.

  12. {ital Ab} {ital initio} calculations of biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Les, A. [Department of Chemistry, University of Warsaw, 02-093 Warsaw (Poland)]|[Department of Chemistry, University of Arizona, Tucson, Arizona 85721 (United States); Adamowicz, L. [Department of Theoretical Chemistry, University of Lund, Lund, S-22100 (Sweden)]|[Department of Chemistry, University of Arizona, Tucson, Arizona 85721 (United States)

    1995-08-01

    {ital Ab} {ital initio} quantum mechanical calculations are valuable tools for interpretation and elucidation of elemental processes in biochemical systems. With the {ital ab} {ital initio} approach one can calculate data that sometimes are difficult to obtain by experimental techniques. The most popular computational theoretical methods include the Hartree-Fock method as well as some lower-level variational and perturbational post-Hartree Fock approaches which allow to predict molecular structures and to calculate spectral properties. We have been involved in a number of joined theoretical and experimental studies in the past and some examples of these studies are given in this presentation. The systems chosen cover a wide variety of simple biomolecules, such as precursors of nucleic acids, double-proton transferring molecules, and simple systems involved in processes related to first stages of substrate-enzyme interactions. In particular, examples of some {ital ab} {ital initio} calculations used in the assignment of IR spectra of matrix isolated pyrimidine nucleic bases are shown. Some radiation-induced transformations in model chromophores are also presented. Lastly, we demonstrate how the {ital ab}-{ital initio} approach can be used to determine the initial several steps of the molecular mechanism of thymidylate synthase inhibition by dUMP analogues.

  13. 24 CFR 3280.811 - Calculations.

    Science.gov (United States)

    2010-04-01

    ... neutral load determined by Article 220.61 of the National Electrical Code, NFPA No. 70-2005. The loads... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Electrical Systems § 3280.811 Calculations. (a... motors and heater loads (exhaust fans, air conditioners, electric, gas, or oil heating). Omit smaller of...

  14. COMPARISON OF CALCULATED AND DIRECT LOW DENSITY ...

    African Journals Online (AJOL)

    hi-tech

    2004-03-03

    Mar 3, 2004 ... linear regression analyses using SPSS (VER 10.0). To assess the degree of agreement ... Summary of Cholesterol, TG's, HDL-C and LDL-C; and correlation between calculated and direct. LDC-C among the groups(a) .... associated with hyperlipidaemia, including diabetes mellitus, nephrotic syndrome and ...

  15. Work Function Calculation For Hafnium- Barium System

    Directory of Open Access Journals (Sweden)

    K.A. Tursunmetov

    2015-08-01

    Full Text Available The adsorption process of barium atoms on hafnium is considered. A structural model of the system is presented and on the basis of calculation of interaction between ions dipole system the dependence of the work function on the coating.

  16. molecular dynamics simulations and quantum chemical calculations ...

    African Journals Online (AJOL)

    KEYWORDS: Molecular dynamic simulation; iron surface; adsorption; imidazoline derivatives; quantum chemical calculations ..... break any bond. This means that the closer the nuclei of the bonding atoms are a greater supply of energy is needed to separate the atoms due to large force of attraction between the atoms.

  17. Simple Calculation Programs for Biology Other Methods

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Simple Calculation Programs for Biology Other Methods. Hemolytic potency of drugs. Raghava et al., (1994) Biotechniques 17: 1148. FPMAP: methods for classification and identification of microorganisms 16SrRNA. graphical display of restriction and fragment map of ...

  18. Molecular transport calculations with Wannier Functions

    DEFF Research Database (Denmark)

    Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2005-01-01

    We present a scheme for calculating coherent electron transport in atomic-scale contacts. The method combines a formally exact Green's function formalism with a mean-field description of the electronic structure based on the Kohn-Sham scheme of density functional theory. We use an accurate plane-wave...

  19. Unified approach to alpha decay calculations

    Indian Academy of Sciences (India)

    2014-05-02

    May 2, 2014 ... a small error in E can cause a much bigger error in τ. Due to this reason, in many analyses of α decay one uses experimentally measured E rather than the theoretically calculated one, even though a more satisfactory theoretical approach should generate both E and τ within a unified framework. Further ...

  20. A New Iterative Method to Calculate [pi

    Science.gov (United States)

    Dion, Peter; Ho, Anthony

    2012-01-01

    For at least 2000 years people have been trying to calculate the value of [pi], the ratio of the circumference to the diameter of a circle. People know that [pi] is an irrational number; its decimal representation goes on forever. Early methods were geometric, involving the use of inscribed and circumscribed polygons of a circle. However, real…

  1. Auger yield calculations for medical radioisotopes

    Directory of Open Access Journals (Sweden)

    Lee Boon Q.

    2015-01-01

    Full Text Available Auger yields from the decays of 71Ge, 99mTc, 111In and 123–125I have been calculated using a Monte Carlo model of the Auger cascade that has been developed at the ANU. In addition, progress to improve the input data of the model has been made with the Multiconfiguration Dirac-Hartree-Fock method.

  2. Attitudes towards Graphing Calculators in Developmental Mathematics

    Science.gov (United States)

    Rajan, Shaun Thomas

    2013-01-01

    The purpose of this exploratory study was to examine instructor and student attitudes towards the use of the graphing calculator in the developmental mathematics classroom. A focus of the study was to see if instructors or students believed there were changes in the conceptual understanding of mathematics as a result of graphing calculator…

  3. Calculation of the CIPW norm: New formulas

    Indian Academy of Sciences (India)

    A completely new set of formulas,based on matrix algebra,has been suggested for the calculation of the CIPW norm for igneous rocks to achieve highly consistent and accurate norms.The suggested sequence of derivation of the normative minerals greatly deviates from the sequence followed in the classical scheme.

  4. 7 CFR 1416.704 - Payment calculation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Payment calculation. 1416.704 Section 1416.704 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... necessary to ensure successful plant survival; (3) Chemicals and nutrients necessary for successful...

  5. Conductance calculations with a wavelet basis set

    DEFF Research Database (Denmark)

    Thygesen, Kristian Sommer; Bollinger, Mikkel; Jacobsen, Karsten Wedel

    2003-01-01

    . The linear-response conductance is calculated from the Green's function which is represented in terms of a system-independent basis set containing wavelets with compact support. This allows us to rigorously separate the central region from the contacts and to test for convergence in a systematic way...

  6. Simple Calculation Programs for Biology Immunological Methods

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Simple Calculation Programs for Biology Immunological Methods. Computation of Ab/Ag Concentration from EISA data. Graphical Method; Raghava et al., 1992, J. Immuno. Methods 153: 263. Determination of affinity of Monoclonal Antibody. Using non-competitive ...

  7. Gaseous Nitrogen Orifice Mass Flow Calculator

    Science.gov (United States)

    Ritrivi, Charles

    2013-01-01

    The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.

  8. Bullet Design of MEMS Cantilever - Hand Calculation

    Directory of Open Access Journals (Sweden)

    Abhijeet V. KSHIRSAGAR

    2008-04-01

    Full Text Available The present article describes the basic hand calculations for design of MEMS cantilever for beginners. The MATLAB software code was written to analysis the all formulae. Further the article gives insight of important parameters, its dependence and consideration for a good design.

  9. Model calculations in correlated finite nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Guardiola, R.; Ros, J. (Granada Univ. (Spain). Dept. de Fisica Nuclear); Polls, A. (Tuebingen Univ. (Germany, F.R.). Inst. fuer Theoretische Physik)

    1980-10-21

    In order to study the convergence condition of the FAHT cluster expansion several model calculations are described and numerically tested. It is concluded that this cluster expansion deals properly with the central part of the two-body distribution function, but presents some difficulties for the exchange part.

  10. Total energy calculations and bonding at interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Louie, S.G.

    1984-08-01

    Some of the concepts and theoretical techniques employed in recent ab initio studies of the electronic and structural properties of surfaces and interfaces are discussed. Results of total energy calculations for the 2 x 1 reconstructed diamond (111) surface and for stacking faults in Si are reviewed. 30 refs., 8 figs.

  11. Calculating Free Energies Using Average Force

    Science.gov (United States)

    Darve, Eric; Pohorille, Andrew; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    A new, general formula that connects the derivatives of the free energy along the selected, generalized coordinates of the system with the instantaneous force acting on these coordinates is derived. The instantaneous force is defined as the force acting on the coordinate of interest so that when it is subtracted from the equations of motion the acceleration along this coordinate is zero. The formula applies to simulations in which the selected coordinates are either unconstrained or constrained to fixed values. It is shown that in the latter case the formula reduces to the expression previously derived by den Otter and Briels. If simulations are carried out without constraining the coordinates of interest, the formula leads to a new method for calculating the free energy changes along these coordinates. This method is tested in two examples - rotation around the C-C bond of 1,2-dichloroethane immersed in water and transfer of fluoromethane across the water-hexane interface. The calculated free energies are compared with those obtained by two commonly used methods. One of them relies on determining the probability density function of finding the system at different values of the selected coordinate and the other requires calculating the average force at discrete locations along this coordinate in a series of constrained simulations. The free energies calculated by these three methods are in excellent agreement. The relative advantages of each method are discussed.

  12. Block Tridiagonal Matrices in Electronic Structure Calculations

    DEFF Research Database (Denmark)

    Petersen, Dan Erik

    This thesis focuses on some of the numerical aspects of the treatment of the electronic structure problem, in particular that of determining the ground state electronic density for the non–equilibrium Green’s function formulation of two–probe systems and the calculation of transmission...

  13. Deconstructing Calculation Methods, Part 3: Multiplication

    Science.gov (United States)

    Thompson, Ian

    2008-01-01

    In this third of a series of four articles, the author deconstructs the primary national strategy's approach to written multiplication. The approach to multiplication, as set out on pages 12 to 15 of the primary national strategy's "Guidance paper" "Calculation" (DfES, 2007), is divided into six stages: (1) mental…

  14. Calculated Bulk Properties of the Actinide Metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1978-01-01

    Self-consistent relativistic calculations of the electronic properties for seven actinides (Ac-Am) have been performed using the linear muffin-tin orbitals method within the atomic-sphere approximation. Exchange and correlation were included in the local spin-density scheme. The theory explains t...

  15. Unified approach to alpha decay calculations

    Indian Academy of Sciences (India)

    2014-05-02

    May 2, 2014 ... We describe the analytic -matrix (SM) method which gives a procedure for the calculation of decay energy and mean life in an integrated way by evaluating the resonance pole of the -matrix in the complex momentum or energy plane. We make an illustrative comparative study of WKB and -matrix ...

  16. CALCULATION OF THE PROCESS OF BURDEN HEATING

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2009-01-01

    Full Text Available The original method of calculation of duration of burden heating till predetermined temperature is stated. The results of numerical modeling of nonstationary heating of fixed bed are given. Experimental check of the received results is carried out at full-scale plants.

  17. 5 CFR 1653.14 - Calculating entitlements.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Calculating entitlements. 1653.14 Section 1653.14 Administrative Personnel FEDERAL RETIREMENT THRIFT INVESTMENT BOARD COURT ORDERS AND LEGAL PROCESSES AFFECTING THRIFT SAVINGS PLAN ACCOUNTS Legal Process for the Enforcement of a Participant's Legal...

  18. 30 CFR 5.30 - Fee calculation.

    Science.gov (United States)

    2010-07-01

    ... MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.30 Fee calculation. (a) MSHA bases fees under this subchapter on the direct and indirect costs of the services provided, except... product. (d) If the actual cost of processing the application is less than MSHA's maximum fee estimate...

  19. Calculating track thrust with track functions

    Science.gov (United States)

    Chang, Hsi-Ming; Procura, Massimiliano; Thaler, Jesse; Waalewijn, Wouter J.

    2013-08-01

    In e+e- event shapes studies at LEP, two different measurements were sometimes performed: a “calorimetric” measurement using both charged and neutral particles and a “track-based” measurement using just charged particles. Whereas calorimetric measurements are infrared and collinear safe, and therefore calculable in perturbative QCD, track-based measurements necessarily depend on nonperturbative hadronization effects. On the other hand, track-based measurements typically have smaller experimental uncertainties. In this paper, we present the first calculation of the event shape “track thrust” and compare to measurements performed at ALEPH and DELPHI. This calculation is made possible through the recently developed formalism of track functions, which are nonperturbative objects describing how energetic partons fragment into charged hadrons. By incorporating track functions into soft-collinear effective theory, we calculate the distribution for track thrust with next-to-leading logarithmic resummation. Due to a partial cancellation between nonperturbative parameters, the distributions for calorimeter thrust and track thrust are remarkably similar, a feature also seen in LEP data.

  20. Relativistic calculations of coalescing binary neutron stars

    Indian Academy of Sciences (India)

    We have designed and tested a new relativistic Lagrangian hydrodynamics code, which treats gravity in the conformally flat approximation to general relativity. We have tested the resulting code extensively, finding that it performs well for calculations of equilibrium single-star models, collapsing relativistic dust clouds, and ...

  1. Relativistic calculations of coalescing binary neutron stars

    Indian Academy of Sciences (India)

    Relativistic calculations of coalescing binary neutron stars. JOSHUA FABER, PHILIPPE GRANDCLÉMENT and FREDERIC RASIO. Department of Physics and Astronomy, Northwestern University, Evanston,. IL 60208-0834, USA. E-mail: rasio@mac.com. Abstract. We have designed and tested a new relativistic Lagrangian ...

  2. Fast calculation of best focus position

    NARCIS (Netherlands)

    Bezzubik, V.; Belashenkov, N.; Vdovin, G.V.

    2015-01-01

    New computational technique based on linear-scale differential analysis (LSDA) of digital image is proposed to find the best focus position in digital microscopy by means of defocus estimation in two near-focal positions only. The method is based on the calculation of local gradients of the image on

  3. Synthesis, characterization, ab initio calculations, thermal behaviour ...

    Indian Academy of Sciences (India)

    Administrator

    through titration of the ligands with the metal ions at constant ionic strength (0⋅1 M NaClO4) and at 25°C. According to the thermodynamic studies, as the steric character of the ligand increases, the complexation tendency to VO(IV) center decreases. Also, the ab initio calculations were carried out to determine the structural ...

  4. A Tabular Approach to Titration Calculations

    Science.gov (United States)

    Lim, Kieran F.

    2012-01-01

    Titrations are common laboratory exercises in high school and university chemistry courses, because they are easy, relatively inexpensive, and they illustrate a number of fundamental chemical principles. While students have little difficulty with calculations involving a single titration step, there is a significant leap in conceptual difficulty…

  5. Ammonia synthesis from first principles calculations

    DEFF Research Database (Denmark)

    Honkala, Johanna Karoliina; Hellman, Anders; Remediakis, Ioannis

    2005-01-01

    The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinet...

  6. Why Do Calculators Have Rubber Feet?

    Science.gov (United States)

    Heavers, Richard M.

    2007-01-01

    Our students like using the covers of their TI graphing calculators in an inquiry-based extension of a traditional exercise that challenges their preconceived ideas about friction. Biology major Fiona McGraw (Fig. 1) is obviously excited about the large coefficient of static friction ([mu][subscript s] = 1.3) for the four little rubber feet on her…

  7. Calculation of U-value for Concrete Element

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    This report is a U-value calculation of a typical concrete element used in industrial buildings.The calculations are performed using a 2-dimensional finite difference calculation programme.......This report is a U-value calculation of a typical concrete element used in industrial buildings.The calculations are performed using a 2-dimensional finite difference calculation programme....

  8. Procedures for Calculating Residential Dehumidification Loads

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Jon [National Renewable Energy Lab. (NREL), Golden, CO (United States); Booten, Chuck [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    Residential building codes and voluntary labeling programs are continually increasing the energy efficiency requirements of residential buildings. Improving a building's thermal enclosure and installing energy-efficient appliances and lighting can result in significant reductions in sensible cooling loads leading to smaller air conditioners and shorter cooling seasons. However due to fresh air ventilation requirements and internal gains, latent cooling loads are not reduced by the same proportion. Thus, it's becoming more challenging for conventional cooling equipment to control indoor humidity at part-load cooling conditions and using conventional cooling equipment in a non-conventional building poses the potential risk of high indoor humidity. The objective of this project was to investigate the impact the chosen design condition has on the calculated part-load cooling moisture load, and compare calculated moisture loads and the required dehumidification capacity to whole-building simulations. Procedures for sizing whole-house supplemental dehumidification equipment have yet to be formalized; however minor modifications to current Air-Conditioner Contractors of America (ACCA) Manual J load calculation procedures are appropriate for calculating residential part-load cooling moisture loads. Though ASHRAE 1% DP design conditions are commonly used to determine the dehumidification requirements for commercial buildings, an appropriate DP design condition for residential buildings has not been investigated. Two methods for sizing supplemental dehumidification equipment were developed and tested. The first method closely followed Manual J cooling load calculations; whereas the second method made more conservative assumptions impacting both sensible and latent loads.

  9. Radionuclide release calculations for SAR-08

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan (Enviros Consulting Ltd, Wolverhampton (United Kingdom))

    2008-04-15

    Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

  10. Coupled-cluster calculations of nucleonic matter

    Science.gov (United States)

    Hagen, G.; Papenbrock, T.; Ekström, A.; Wendt, K. A.; Baardsen, G.; Gandolfi, S.; Hjorth-Jensen, M.; Horowitz, C. J.

    2014-01-01

    Background: The equation of state (EoS) of nucleonic matter is central for the understanding of bulk nuclear properties, the physics of neutron star crusts, and the energy release in supernova explosions. Because nuclear matter exhibits a finely tuned saturation point, its EoS also constrains nuclear interactions. Purpose: This work presents coupled-cluster calculations of infinite nucleonic matter using modern interactions from chiral effective field theory (EFT). It assesses the role of correlations beyond particle-particle and hole-hole ladders, and the role of three-nucleon forces (3NFs) in nuclear matter calculations with chiral interactions. Methods: This work employs the optimized nucleon-nucleon (NN) potential NNLOopt at next-to-next-to leading order, and presents coupled-cluster computations of the EoS for symmetric nuclear matter and neutron matter. The coupled-cluster method employs up to selected triples clusters and the single-particle space consists of a momentum-space lattice. We compare our results with benchmark calculations and control finite-size effects and shell oscillations via twist-averaged boundary conditions. Results: We provide several benchmarks to validate the formalism and show that our results exhibit a good convergence toward the thermodynamic limit. Our calculations agree well with recent coupled-cluster results based on a partial wave expansion and particle-particle and hole-hole ladders. For neutron matter at low densities, and for simple potential models, our calculations agree with results from quantum Monte Carlo computations. While neutron matter with interactions from chiral EFT is perturbative, symmetric nuclear matter requires nonperturbative approaches. Correlations beyond the standard particle-particle ladder approximation yield non-negligible contributions. The saturation point of symmetric nuclear matter is sensitive to the employed 3NFs and the employed regularization scheme. 3NFs with nonlocal cutoffs exhibit a

  11. Black hole entropy calculations based on symmetries

    CERN Document Server

    Dreyer, O; Wísniewski, J A; Dreyer, Olaf; Ghosh, Amit; Wisniewski, Jacek

    2001-01-01

    Symmetry based approaches to the black hole entropy problem have a number of attractive features; in particular they are very general and do not depend on the details of the quantization method. However we point out that, of the two available approaches, one faces conceptual problems (also emphasized by others), while the second contains certain technical flaws. We correct these errors and, within the new, improved scheme, calculate the entropy of 3-dimensional black holes. We find that, while the new symmetry vector fields are well-defined on the ``stretched horizon,'' and lead to well-defined Hamiltonians satisfying the expected Lie algebra, they fail to admit a well-defined limit to the horizon. This suggests that, although the formal calculation can be carried out at the classical level, its real, conceptual origin probably lies in the quantum theory.

  12. On the Origins of Calculation Abilities

    Directory of Open Access Journals (Sweden)

    A. Ardila

    1993-01-01

    Full Text Available A historical review of calculation abilities is presented. Counting, starting with finger sequencing, has been observed in different ancient and contemporary cultures, whereas number representation and arithmetic abilities are found only during the last 5000–6000 years. The rationale for selecting a base of ten in most numerical systems and the clinical association between acalculia and finger agnosia are analyzed. Finger agnosia (as a restricted form of autotopagnosia, right–left discrimination disturbances, semantic aphasia, and acalculia are proposed to comprise a single neuropsychological syndrome associated with left angular gyrus damage. A classification of calculation disturbances resulting from brain damage is presented. It is emphasized that using historical/anthropological analysis, it becomes evident that acalculia, finger agnosia, and disorders in right–left discrimination (as in general, in the use of spatial concepts must constitute a single clinical syndrome, resulting from the disruption of some common brain activity and the impairment of common cognitive mechanisms.

  13. Labview virtual instruments for calcium buffer calculations.

    Science.gov (United States)

    Reitz, Frederick B; Pollack, Gerald H

    2003-01-01

    Labview VIs based upon the calculator programs of Fabiato and Fabiato (J. Physiol. Paris 75 (1979) 463) are presented. The VIs comprise the necessary computations for the accurate preparation of multiple-metal buffers, for the back-calculation of buffer composition given known free metal concentrations and stability constants used, for the determination of free concentrations from a given buffer composition, and for the determination of apparent stability constants from absolute constants. As implemented, the VIs can concurrently account for up to three divalent metals, two monovalent metals and four ligands thereof, and the modular design of the VIs facilitates further extension of their capacity. As Labview VIs are inherently graphical, these VIs may serve as useful templates for those wishing to adapt this software to other platforms.

  14. A priori calculations for the rotational stabilisation

    Directory of Open Access Journals (Sweden)

    Iwata Yoritaka

    2013-12-01

    Full Text Available The synthesis of chemical elements are mostly realised by low-energy heavy-ion reactions. Synthesis of exotic and heavy nuclei as well as that of superheavy nuclei is essential not only to find out the origin and the limit of the chemical elements but also to clarify the historical/chemical evolution of our universe. Despite the life time of exotic nuclei is not so long, those indispensable roles in chemical evolution has been pointed out. Here we are interested in examining the rotational stabilisation. In this paper a priori calculation (before microscopic density functional calculations is carried out for the rotational stabilisation effect in which the balance between the nuclear force, the Coulomb force and the centrifugal force is taken into account.

  15. A corrector for spacecraft calculated electron moments

    Directory of Open Access Journals (Sweden)

    J. Geach

    2005-03-01

    Full Text Available We present the application of a numerical method to correct electron moments calculated on-board spacecraft from the effects of potential broadening and energy range truncation. Assuming a shape for the natural distribution of the ambient plasma and employing the scalar approximation, the on-board moments can be represented as non-linear integral functions of the underlying distribution. We have implemented an algorithm which inverts this system successfully over a wide range of parameters for an assumed underlying drifting Maxwellian distribution. The outputs of the solver are the corrected electron plasma temperature Te, density Ne and velocity vector Ve. We also make an estimation of the temperature anisotropy A of the distribution. We present corrected moment data from Cluster's PEACE experiment for a range of plasma environments and make comparisons with electron and ion data from other Cluster instruments, as well as the equivalent ground-based calculations using full 3-D distribution PEACE telemetry.

  16. CALCULATION ALGORITHM TRUSS UNDER CRANE BEAMS

    Directory of Open Access Journals (Sweden)

    N. K. Akaev1

    2016-01-01

    Full Text Available Aim.The task of reducing the deflection and increase the rigidity of single-span beams are made. In the article the calculation algorithm for truss crane girders is determined.Methods. To identify the internal effort required for the selection of cross section elements the design uses the Green's function.Results. It was found that the simplest truss system reduces deflection and increases the strength of design. The upper crossbar is subjected not only to bending and shear and compression work due to tightening tension. Preliminary determination of the geometrical characteristics of the crane farms elements are offered to make a comparison with previous similar configuration of his farms, using a simple approximate calculation methods.Conclusion.The method of sequential movements (incrementally the two bridge cranes along the length of the upper crossbar truss beams is suggested. We give the corresponding formulas and conditions of safety.

  17. Fastlim: a fast LHC limit calculator

    CERN Document Server

    Papucci, Michele; Weiler, Andreas; Zeune, Lisa

    2014-01-01

    Fastlim is a tool to calculate conservative limits on extensions of the Standard Model from direct LHC searches without performing any Monte Carlo event generation. The program reconstructs the visible cross sections from pre-calculated efficiency tables and cross section tables for simplified event topologies. As a proof of concept of the approach, we have implemented searches relevant for supersymmetric models with R-parity conservation. Fastlim takes the spectrum and coupling information of a given model point and provides, for each signal region of the implemented analyses, the visible cross sections normalised to the corresponding upper limit, reported by the experiments, as well as the exclusion $p$-value. To demonstrate the utility of the program we study the sensitivity of the recent ATLAS missing energy searches to the parameter space of natural SUSY models. The program structure allows the straight-forward inclusion of external efficiency tables and can be generalised to R-parity violating scenarios...

  18. Calculation of coherent synchrotron radiation using mesh

    Directory of Open Access Journals (Sweden)

    T. Agoh

    2004-05-01

    Full Text Available We develop a new method to simulate coherent synchrotron radiation numerically. It is based on the mesh calculation of the electromagnetic field in the frequency domain. We make an approximation in the Maxwell equation which allows a mesh size much larger than the relevant wavelength so that the computing time is tolerable. Using the equation, we can perform a mesh calculation of coherent synchrotron radiation in transient states with shielding effects by the vacuum chamber. The simulation results obtained by this method are compared with analytic solutions. Though, for the comparison with theories, we adopt simplifications such as longitudinal Gaussian distribution, zero-width transverse distribution, horizontal uniform bend, and a vacuum chamber with rectangular cross section, the method is applicable to general cases.

  19. Comparative Study of Daylighting Calculation Methods

    Directory of Open Access Journals (Sweden)

    Mandala Ariani

    2018-01-01

    Full Text Available The aim of this study is to assess five daylighting calculation method commonly used in architectural study. The methods used include hand calculation methods (SNI/DPMB method and BRE Daylighting Protractors, scale models studied in an artificial sky simulator and computer programs using Dialux and Velux lighting software. The test room is conditioned by the uniform sky conditions, simple room geometry with variations of the room reflectance (black, grey, and white color. The analyses compared the result (including daylight factor, illumination, and coefficient of uniformity value and examines the similarity and contrast the result different. The color variations trial is used to analyses the internally reflection factor contribution to the result.

  20. Low-energy calculations for nuclear photodisintegration

    Directory of Open Access Journals (Sweden)

    Deflorian S.

    2016-01-01

    Full Text Available In the Standard Solar Model a central role in the nucleosynthesis is played by reactions of the kind XZ1A11+XZ2A22→YZ1+Z2A1+A2+γ${}_{{Z_1}}^{{A_1}}{X_1} + {}_{{Z_2}}^{{A_2}}{X_2} \\to {}_{{Z_1} + {Z_2}}^{{A_1} + {A_2}}Y + \\gamma $, which enter the proton-proton chains. These reactions can also be studied through the inverse photodisintegration reaction. One option is to use the Lorentz Integral Transform approach, which transforms the continuum problem into a bound state-like one. A way to check the reliability of such methods is a direct calculation, for example using the Kohn Variational Principle to obtain the scattering wave function and then directly calculate the response function of the reaction.

  1. Integral dependent spin couplings in CI calculations

    Science.gov (United States)

    Iberle, K.; Davidson, E. R.

    1982-01-01

    Although the number of ways to combine Slater determinants to form spin eigenfunctions increases rapidly with the number of open shells, most of these spin couplings will make only a small contribution to a given state, provided the spin coupling is chosen judiciously. The technique of limiting calculations to the interacting subspace pioneered by Bunge (1970) was employed by Munch and Davidson (1975) to the vanadium atom. The use of an interacting space looses its advantage in more complex cases. However, the problem can always be reduced to only one interacting spin coupling by making the coefficients integral dependent. The present investigation is concerned with the performance of integral dependent interacting couplings, taking into account the results of three test calculations.

  2. A Methodology for Calculating Radiation Signatures

    Energy Technology Data Exchange (ETDEWEB)

    Klasky, Marc Louis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wilcox, Trevor [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bathke, Charles G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); James, Michael R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-01

    A rigorous formalism is presented for calculating radiation signatures from both Special Nuclear Material (SNM) as well as radiological sources. The use of MCNP6 in conjunction with CINDER/ORIGEN is described to allow for the determination of both neutron and photon leakages from objects of interest. In addition, a description of the use of MCNP6 to properly model the background neutron and photon sources is also presented. Examinations of the physics issues encountered in the modeling are investigated so as to allow for guidance in the user discerning the relevant physics to incorporate into general radiation signature calculations. Furthermore, examples are provided to assist in delineating the pertinent physics that must be accounted for. Finally, examples of detector modeling utilizing MCNP are provided along with a discussion on the generation of Receiver Operating Curves, which are the suggested means by which to determine detectability radiation signatures emanating from objects.

  3. Reading and Calculating Billing Through Mobile Devices

    Directory of Open Access Journals (Sweden)

    Pilar Alexandra Moreno

    2013-06-01

    Full Text Available This article broadly describes the analysis, design and development of the system utilitarian, called “Reading and billing calculation site through mobile devices.” The application is oriented Public Services Companies, first water services, to perform part of the billing process “in place” through phones or any mobile devices compatible with Android. Will enable you to take readings of service consumption, recording new gauging, online update and control the information for users and turnover. This technology is considered as such one site billing method as through Internet is connected with the database of the company, sending and receiving date information, which makes the calculation of the billing for the reading period, bringing benefits to the client and the service generating company.

  4. Improving the calculation of interdiffusion coefficients

    Science.gov (United States)

    Kapoor, Rakesh R.; Eagar, Thomas W.

    1990-12-01

    Least-squares spline interpolation techniques are reviewed and presented as a mathematical tool for noise reduction and interpolation of diffusion profiles. Numerically simulated diffusion profiles were interpolated using a sixth-order spline. The spline fit data were successfully used in conjunction with the Boltzmann-Matano treatment to compute the interdiffusion coefficient, demonstrating the usefulness of splines as a numerical tool for such calculations. Simulations conducted on noisy data indicate that the technique can extract the correct diffusivity data given compositional data that contain only three digits of information and are contaminated with a noise level of 0.001. Splines offer a reproducible and reliable alternative to graphical evaluation of the slope of a diffusion profile, which is used in the Boltzmann-Matano treatment. Hence, use of splines reduces the numerical errors associated with calculation of interdiffusion coefficients from raw diffusion profile data.

  5. Tearing mode stability calculations with pressure flattening

    CERN Document Server

    Ham, C J; Cowley, S C; Hastie, R J; Hender, T C; Liu, Y Q

    2013-01-01

    Calculations of tearing mode stability in tokamaks split conveniently into an external region, where marginally stable ideal MHD is applicable, and a resonant layer around the rational surface where sophisticated kinetic physics is needed. These two regions are coupled by the stability parameter. Pressure and current perturbations localized around the rational surface alter the stability of tearing modes. Equations governing the changes in the external solution and - are derived for arbitrary perturbations in axisymmetric toroidal geometry. The relationship of - with and without pressure flattening is obtained analytically for four pressure flattening functions. Resistive MHD codes do not contain the appropriate layer physics and therefore cannot predict stability directly. They can, however, be used to calculate -. Existing methods (Ham et al. 2012 Plasma Phys. Control. Fusion 54 025009) for extracting - from resistive codes are unsatisfactory when there is a finite pressure gradient at the rational surface ...

  6. Continuum RPA calculation of escape widths

    Energy Technology Data Exchange (ETDEWEB)

    Vertse, T. (Inst. of Nuclear Research, Hungarian Academy of Sciences, Debrecen (Hungary)); Curutchet, P.; Liotta, R.J. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden)); Bang, J. (Niels Bohr Inst., Copenhagen (Denmark)); Giai, N. van (Inst. de Physique Nucleaire, 91 - Orsay (France))

    1991-07-25

    Particle-hole partial decay widths are calculated within the continuum RPA exactly, i.e. without any further approximation, in a square well plus Coulomb potential and using a separable residual interaction. The results are compared with the ones obtained by making pole expansions of the single-particle Green functions (Berggren and Mittag-Leffler). It is found that the Berggren and Mittag-Leffler expansions give results in good agreement with the 'exact' ones. (orig.).

  7. Temperature Calculations in the Coastal Modeling System

    Science.gov (United States)

    2017-04-01

    System by Honghai Li and Mitchell E. Brown PURPOSE: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes procedures to calculate...strong tidal signals and sufficient wind energy to provide the vertical mixing. Also, the assumption of sufficient energy to mix over the water...of the Corrotoman River is predominated by tidal process with occasional passages of meteorological events. Tide and wind provide sufficient energy

  8. Toward a nitrogen footprint calculator for Tanzania

    Science.gov (United States)

    Hutton, Mary Olivia; Leach, Allison M.; Leip, Adrian; Galloway, James N.; Bekunda, Mateete; Sullivan, Clare; Lesschen, Jan Peter

    2017-03-01

    We present the first nitrogen footprint model for a developing country: Tanzania. Nitrogen (N) is a crucial element for agriculture and human nutrition, but in excess it can cause serious environmental damage. The Sub-Saharan African nation of Tanzania faces a two-sided nitrogen problem: while there is not enough soil nitrogen to produce adequate food, excess nitrogen that escapes into the environment causes a cascade of ecological and human health problems. To identify, quantify, and contribute to solving these problems, this paper presents a nitrogen footprint tool for Tanzania. This nitrogen footprint tool is a concept originally designed for the United States of America (USA) and other developed countries. It uses personal resource consumption data to calculate a per-capita nitrogen footprint. The Tanzania N footprint tool is a version adapted to reflect the low-input, integrated agricultural system of Tanzania. This is reflected by calculating two sets of virtual N factors to describe N losses during food production: one for fertilized farms and one for unfertilized farms. Soil mining factors are also calculated for the first time to address the amount of N removed from the soil to produce food. The average per-capita nitrogen footprint of Tanzania is 10 kg N yr-1. 88% of this footprint is due to food consumption and production, while only 12% of the footprint is due to energy use. Although 91% of farms in Tanzania are unfertilized, the large contribution of fertilized farms to N losses causes unfertilized farms to make up just 83% of the food production N footprint. In a developing country like Tanzania, the main audiences for the N footprint tool are community leaders, planners, and developers who can impact decision-making and use the calculator to plan positive changes for nitrogen sustainability in the developing world.

  9. On the Origins of Calculation Abilities

    OpenAIRE

    Ardila, A.

    1993-01-01

    A historical review of calculation abilities is presented. Counting, starting with finger sequencing, has been observed in different ancient and contemporary cultures, whereas number representation and arithmetic abilities are found only during the last 5000–6000 years. The rationale for selecting a base of ten in most numerical systems and the clinical association between acalculia and finger agnosia are analyzed. Finger agnosia (as a restricted form of autotopagnosia), right–left discrimina...

  10. Thermal Load Calculations of Multilayered Walls

    OpenAIRE

    Bashir M. Suleiman

    2012-01-01

    Thermal load calculations have been performed for multi-layered walls that are composed of three different parts; a common (sand and cement) plaster, and two types of locally produced soft and hard bricks. The masonry construction of these layered walls was based on concrete-backed stone masonry made of limestone bricks joined by mortar. These multilayered walls are forming the outer walls of the building envelope of a typical Libyan house. Based on the periodic seasonal ...

  11. Flow calculation in a bulb turbine

    Energy Technology Data Exchange (ETDEWEB)

    Goede, E.; Pestalozzi, J.

    1987-02-01

    In recent years remarkable progress has been made in the field of computational fluid dynamics. Sometimes the impression may arise when reading the relevant literature that most of the problems in this field have already been solved. Upon studying the matter more deeply, however, it is apparent that some questions still remain unanswered. The use of the quasi-3D (Q3D) computational method for calculating the flow in a fuel hydraulic turbine is described.

  12. Calculation methods of the nuclear characteristics

    OpenAIRE

    Dubovichenko, S. B.

    2010-01-01

    In the book the mathematical methods of nuclear cross sections and phases of elastic scattering, energy and characteristics of bound states in two- and three-particle nuclear systems, when the potentials of interaction contain not only central, but also tensor component, are presented. Are given the descriptions of the mathematical numerical calculation methods and computer programs in the algorithmic language "BASIC" for "Turbo Basic" of firm "Borland" for the computers of the type IBM PC AT...

  13. Calculation Of Residual Volume By Spirometric Data

    Directory of Open Access Journals (Sweden)

    R. Hashemi

    2005-05-01

    Full Text Available Background: The current practice to measure RV is either by BPG or helium dilution methods which may not be available in all clinics due to their cost. Methods: This paper outlines a method for both direct and indirect calculation of RV via PFT with acceptable sensitivity (81 %, 60% , specificity (71 %, 94% and validity (76%, 78% for obstructive and restrictive lung disease respectively at a much lower cost.

  14. Calculation of Weighted Geometric Dilution of Precision

    Directory of Open Access Journals (Sweden)

    Chien-Sheng Chen

    2013-01-01

    Full Text Available To achieve high accuracy in wireless positioning systems, both accurate measurements and good geometric relationship between the mobile device and the measurement units are required. Geometric dilution of precision (GDOP is widely used as a criterion for selecting measurement units, since it represents the geometric effect on the relationship between measurement error and positioning determination error. In the calculation of GDOP value, the maximum volume method does not necessarily guarantee the selection of the optimal four measurement units with minimum GDOP. The conventional matrix inversion method for GDOP calculation demands a large amount of operation and causes high power consumption. To select the subset of the most appropriate location measurement units which give the minimum positioning error, we need to consider not only the GDOP effect but also the error statistics property. In this paper, we employ the weighted GDOP (WGDOP, instead of GDOP, to select measurement units so as to improve the accuracy of location. The handheld global positioning system (GPS devices and mobile phones with GPS chips can merely provide limited calculation ability and power capacity. Therefore, it is very imperative to obtain WGDOP accurately and efficiently. This paper proposed two formations of WGDOP with less computation when four measurements are available for location purposes. The proposed formulae can reduce the computational complexity required for computing the matrix inversion. The simpler WGDOP formulae for both the 2D and the 3D location estimation, without inverting a matrix, can be applied not only to GPS but also to wireless sensor networks (WSN and cellular communication systems. Furthermore, the proposed formulae are able to provide precise solution of WGDOP calculation without incurring any approximation error.

  15. 40 CFR 91.1307 - Credit calculation.

    Science.gov (United States)

    2010-07-01

    ...) are to be calculated according to the following equation and rounded, in accordance with ASTM E29-93a, to the nearest gram. ASTM E29-93a has been incorporated by reference. See § 91.6. Consistent units... family in grams per kilowatt hour. CL = compliance level of the in-use testing in g/kW-hr. μuse = mean...

  16. Theoretical Calculations of Atomic Data for Spectroscopy

    Science.gov (United States)

    Bautista, Manuel A.

    2000-01-01

    Several different approximations and techniques have been developed for the calculation of atomic structure, ionization, and excitation of atoms and ions. These techniques have been used to compute large amounts of spectroscopic data of various levels of accuracy. This paper presents a review of these theoretical methods to help non-experts in atomic physics to better understand the qualities and limitations of various data sources and assess how reliable are spectral models based on those data.

  17. Bias in Dynamic Monte Carlo Alpha Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Sweezy, Jeremy Ed [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nolen, Steven Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Terry R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Trahan, Travis John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-06

    A 1/N bias in the estimate of the neutron time-constant (commonly denoted as α) has been seen in dynamic neutronic calculations performed with MCATK. In this paper we show that the bias is most likely caused by taking the logarithm of a stochastic quantity. We also investigate the known bias due to the particle population control method used in MCATK. We conclude that this bias due to the particle population control method is negligible compared to other sources of bias.

  18. Characteristic features of calculations of hydrogen generators

    Science.gov (United States)

    Troshen'kin, V. B.

    2010-03-01

    Among the methods of hydrogen generation that are economically sound for autonomous customers is the silikol method. The technique of calculation of the cylinder gas generator circuit is given. The restrictions imposed on the flow velocity in a three-phase reacting system are considered. It is established that the reaction rate in the circuit as a dissipative structure is in direct correlation with the change in the Gibbs energy.

  19. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H

    2002-01-01

    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  20. Activation Product Inverse Calculations with NDI

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Mark Girard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-27

    NDI based forward calculations of activation product concentrations can be systematically used to infer structural element concentrations from measured activation product concentrations with an iterative algorithm. The algorithm converges exactly for the basic production-depletion chain with explicit activation product production and approximately, in the least-squares sense, for the full production-depletion chain with explicit activation product production and nosub production-depletion chain. The algorithm is suitable for automation.

  1. TINTE. Nuclear calculation theory description report

    Energy Technology Data Exchange (ETDEWEB)

    Gerwin, H.; Scherer, W.; Lauer, A. [Forschungszentrum Juelich GmbH (DE). Institut fuer Energieforschung (IEF), Sicherheitsforschung und Reaktortechnik (IEF-6); Clifford, I. [Pebble Bed Modular Reactor (Pty) Ltd. (South Africa)

    2010-01-15

    The Time Dependent Neutronics and Temperatures (TINTE) code system deals with the nuclear and the thermal transient behaviour of the primary circuit of the High-temperature Gas-cooled Reactor (HTGR), taking into consideration the mutual feedback effects in twodimensional axisymmetric geometry. This document contains a complete description of the theoretical basis of the TINTE nuclear calculation, including the equations solved, solution methods and the nuclear data used in the solution. (orig.)

  2. In situ magnetotail magnetic flux calculation

    Directory of Open Access Journals (Sweden)

    M. A. Shukhtina

    2015-06-01

    Full Text Available We explore two new modifications of the magnetotail magnetic flux (F calculation algorithm based on the Petrinec and Russell (1996 (PR96 approach of the tail radius determination. Unlike in the PR96 model, the tail radius value is calculated at each time step based on simultaneous magnetotail and solar wind observations. Our former algorithm, described in Shukhtina et al. (2009, required that the "tail approximation" requirement were fulfilled, i.e., it could be applied only tailward x ∼ −15 RE. The new modifications take into account the approximate uniformity of the magnetic field of external sources in the near and middle tail. Tests, based on magnetohydrodynamics (MHD simulations, show that this approach may be applied at smaller distances, up to x ∼ −3 RE. The tests also show that the algorithm fails during long periods of strong positive interplanetary magnetic field (IMF Bz. A new empirical formula has also been obtained for the tail radius at the terminator (at x = 0 which improves the calculations.

  3. Accurate Calculation of Electric Fields Inside Enzymes.

    Science.gov (United States)

    Wang, X; He, X; Zhang, J Z H

    2016-01-01

    The specific electric field generated by a protease at its active site is considered as an important source of the catalytic power. Accurate calculation of electric field at the active site of an enzyme has both fundamental and practical importance. Measuring site-specific changes of electric field at internal sites of proteins due to, eg, mutation, has been realized by using molecular probes with CO or CN groups in the context of vibrational Stark effect. However, theoretical prediction of change in electric field inside a protein based on a conventional force field, such as AMBER or OPLS, is often inadequate. For such calculation, quantum chemical approach or quantum-based polarizable or polarized force field is highly preferable. Compared with the result from conventional force field, significant improvement is found in predicting experimentally measured mutation-induced electric field change using quantum-based methods, indicating that quantum effect such as polarization plays an important role in accurate description of electric field inside proteins. In comparison, the best theoretical prediction comes from fully quantum mechanical calculation in which both polarization and inter-residue charge transfer effects are included for accurate prediction of electrostatics in proteins. © 2016 Elsevier Inc. All rights reserved.

  4. Excited state electron affinity calculations for aluminum

    Science.gov (United States)

    Hussein, Adnan Yousif

    2017-08-01

    Excited states of negative aluminum ion are reviewed, and calculations of electron affinities of the states (3s^23p^2)^1D and (3s3p^3){^5}{S}° relative to the (3s^23p)^2P° and (3s3p^2)^4P respectively of the neutral aluminum atom are reported in the framework of nonrelativistic configuration interaction (CI) method. A priori selected CI (SCI) with truncation energy error (Bunge in J Chem Phys 125:014107, 2006) and CI by parts (Bunge and Carbó-Dorca in J Chem Phys 125:014108, 2006) are used to approximate the valence nonrelativistic energy. Systematic studies of convergence of electron affinity with respect to the CI excitation level are reported. The calculated value of the electron affinity for ^1D state is 78.675(3) meV. Detailed Calculations on the ^5S°c state reveals that is 1216.8166(3) meV below the ^4P state.

  5. Agriculture-related radiation dose calculations

    Energy Technology Data Exchange (ETDEWEB)

    Furr, J.M.; Mayberry, J.J.; Waite, D.A.

    1987-10-01

    Estimates of radiation dose to the public must be made at each stage in the identification and qualification process leading to siting a high-level nuclear waste repository. Specifically considering the ingestion pathway, this paper examines questions of reliability and adequacy of dose calculations in relation to five stages of data availability (geologic province, region, area, location, and mass balance) and three methods of calculation (population, population/food production, and food production driven). Calculations were done using the model PABLM with data for the Permian and Palo Duro Basins and the Deaf Smith County area. Extra effort expended in gathering agricultural data at succeeding environmental characterization levels does not appear justified, since dose estimates do not differ greatly; that effort would be better spent determining usage of food types that contribute most to the total dose; and that consumption rate and the air dispersion factor are critical to assessment of radiation dose via the ingestion pathway. 17 refs., 9 figs., 32 tabs.

  6. Sample size calculations for skewed distributions.

    Science.gov (United States)

    Cundill, Bonnie; Alexander, Neal D E

    2015-04-02

    Sample size calculations should correspond to the intended method of analysis. Nevertheless, for non-normal distributions, they are often done on the basis of normal approximations, even when the data are to be analysed using generalized linear models (GLMs). For the case of comparison of two means, we use GLM theory to derive sample size formulae, with particular cases being the negative binomial, Poisson, binomial, and gamma families. By simulation we estimate the performance of normal approximations, which, via the identity link, are special cases of our approach, and for common link functions such as the log. The negative binomial and gamma scenarios are motivated by examples in hookworm vaccine trials and insecticide-treated materials, respectively. Calculations on the link function (log) scale work well for the negative binomial and gamma scenarios examined and are often superior to the normal approximations. However, they have little advantage for the Poisson and binomial distributions. The proposed method is suitable for sample size calculations for comparisons of means of highly skewed outcome variables.

  7. TEA: A CODE CALCULATING THERMOCHEMICAL EQUILIBRIUM ABUNDANCES

    Energy Technology Data Exchange (ETDEWEB)

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver, E-mail: jasmina@physics.ucf.edu [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States)

    2016-07-01

    We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature–pressure pairs. We tested the code against the method of Burrows and Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows and Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.

  8. SEECAL: Program to calculate age-dependent

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, M.; Eckerman, K.F.

    1993-12-01

    This report describes the computer program SEECAL, which calculates specific effective energies (SEE) to specified target regions for ages newborn, 1 y, 5 y, 10 y, 15 y, a 70-kg adult male, and a 58-kg adult female. The dosimetric methodology is that of the International Commission on Radiological Protection (ICRP) and is generally consistent with the schema of the Medical Internal Radiation Dose committee of the US Society of Nuclear Medicine. Computation of SEEs is necessary in the computation of equivalent dose rate in a target region, for occupational or public exposure to radionuclides taken into the body. Program SEECAL replaces the program SEE that was previously used by the Dosimetry Research Group at Oak Ridge National Laboratory. The program SEE was used in the dosimetric calculations for occupational exposures for ICRP Publication 30 and is limited to adults. SEECAL was used to generate age-dependent SEEs for ICRP Publication 56, Part 1. SEECAL is also incorporated into DCAL, a radiation dose and risk calculational system being developed for the Environmental Protection Agency. Electronic copies of the program and data files and this report are available from the Radiation Shielding Information Center at Oak Ridge National Laboratory.

  9. Cost Calculation Model for Logistics Service Providers

    Directory of Open Access Journals (Sweden)

    Zoltán Bokor

    2012-11-01

    Full Text Available The exact calculation of logistics costs has become a real challenge in logistics and supply chain management. It is essential to gain reliable and accurate costing information to attain efficient resource allocation within the logistics service provider companies. Traditional costing approaches, however, may not be sufficient to reach this aim in case of complex and heterogeneous logistics service structures. So this paper intends to explore the ways of improving the cost calculation regimes of logistics service providers and show how to adopt the multi-level full cost allocation technique in logistics practice. After determining the methodological framework, a sample cost calculation scheme is developed and tested by using estimated input data. Based on the theoretical findings and the experiences of the pilot project it can be concluded that the improved costing model contributes to making logistics costing more accurate and transparent. Moreover, the relations between costs and performances also become more visible, which enhances the effectiveness of logistics planning and controlling significantly

  10. Neural correlates of arithmetic calculation strategies.

    Science.gov (United States)

    Rosenberg-Lee, Miriam; Lovett, Marsha C; Anderson, John R

    2009-09-01

    Recent research into math cognition has identified areas of the brain that are involved in number processing (Dehaene, Piazza, Pinel, & Cohen, 2003) and complex problem solving (Anderson, 2007). Much of this research assumes that participants use a single strategy; yet, behavioral research finds that people use a variety of strategies (LeFevre et al., 1996; Siegler, 1987; Siegler & Lemaire, 1997). In the present study, we examined cortical activation as a function of two different calculation strategies for mentally solving multidigit multiplication problems. The school strategy, equivalent to long multiplication, involves working from right to left. The expert strategy, used by "lightning" mental calculators (Staszewski, 1988), proceeds from left to right. The two strategies require essentially the same calculations, but have different working memory demands (the school strategy incurs greater demands). The school strategy produced significantly greater early activity in areas involved in attentional aspects of number processing (posterior superior parietal lobule, PSPL) and mental representation (posterior parietal cortex, PPC), but not in a numerical magnitude area (horizontal intraparietal sulcus, HIPS) or a semantic memory retrieval area (lateral inferior prefrontal cortex, LIPFC). An ACT-R model of the task successfully predicted BOLD responses in PPC and LIPFC, as well as in PSPL and HIPS.

  11. Lattice QCD Calculation of Nucleon Structure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Keh-Fei [University of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy; Draper, Terrence [University of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy

    2016-08-30

    It is emphasized in the 2015 NSAC Long Range Plan that "understanding the structure of hadrons in terms of QCD's quarks and gluons is one of the central goals of modern nuclear physics." Over the last three decades, lattice QCD has developed into a powerful tool for ab initio calculations of strong-interaction physics. Up until now, it is the only theoretical approach to solving QCD with controlled statistical and systematic errors. Since 1985, we have proposed and carried out first-principles calculations of nucleon structure and hadron spectroscopy using lattice QCD which entails both algorithmic development and large-scale computer simulation. We started out by calculating the nucleon form factors -- electromagnetic, axial-vector, πNN, and scalar form factors, the quark spin contribution to the proton spin, the strangeness magnetic moment, the quark orbital angular momentum, the quark momentum fraction, and the quark and glue decomposition of the proton momentum and angular momentum. The first round of calculations were done with Wilson fermions in the `quenched' approximation where the dynamical effects of the quarks in the sea are not taken into account in the Monte Carlo simulation to generate the background gauge configurations. Beginning in 2000, we have started implementing the overlap fermion formulation into the spectroscopy and structure calculations. This is mainly because the overlap fermion honors chiral symmetry as in the continuum. It is going to be more and more important to take the symmetry into account as the simulations move closer to the physical point where the u and d quark masses are as light as a few MeV only. We began with lattices which have quark masses in the sea corresponding to a pion mass at ~ 300 MeV and obtained the strange form factors, charm and strange quark masses, the charmonium spectrum and the Ds meson decay constant fDs, the strangeness and charmness, the meson mass

  12. Numerical precision calculations for LHC physics

    Energy Technology Data Exchange (ETDEWEB)

    Reuschle, Christian Andreas

    2013-02-05

    In this thesis I present aspects of QCD calculations, which are related to the fully numerical evaluation of next-to-leading order (NLO) QCD amplitudes, especially of the one-loop contributions, and the efficient computation of associated collider observables. Two interrelated topics have thereby been of concern to the thesis at hand, which give rise to two major parts. One large part is focused on the general group-theoretical behavior of one-loop QCD amplitudes, with respect to the underlying SU(N{sub c}) theory, in order to correctly and efficiently handle the color degrees of freedom in QCD one-loop amplitudes. To this end a new method is introduced that can be used in order to express color-ordered partial one-loop amplitudes with multiple quark-antiquark pairs as shuffle sums over cyclically ordered primitive one-loop amplitudes. The other large part is focused on the local subtraction of divergences off the one-loop integrands of primitive one-loop amplitudes. A method for local UV renormalization has thereby been developed, which uses local UV counterterms and efficient recursive routines. Together with suitable virtual soft and collinear subtraction terms, the subtraction method is extended to the virtual contributions in the calculations of NLO observables, which enables the fully numerical evaluation of the one-loop integrals in the virtual contributions. The method has been successfully applied to the calculation of jet rates in electron-positron annihilation to NLO accuracy in the large-N{sub c} limit.

  13. Rooftop Unit Comparison Calculator User Manual

    Energy Technology Data Exchange (ETDEWEB)

    Miller, James D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-30

    This document serves as a user manual for the Packaged rooftop air conditioners and heat pump units comparison calculator (RTUCC) and is an aggregation of the calculator’s website documentation. Content ranges from new-user guide material like the “Quick Start” to the more technical/algorithmic descriptions of the “Methods Pages.” There is also a section listing all the context-help topics that support the features on the “Controls” page. The appendix has a discussion of the EnergyPlus runs that supported the development of the building-response models.

  14. Calculating the cost of a healthcare project.

    Science.gov (United States)

    Stichler, Jaynelle F

    2008-02-01

    Nearly $200 billion of healthcare construction is expected by the year 2015, and nurse leaders must expand their knowledge and capabilities in healthcare design. This bimonthly department prepares nurse leaders to use the evidence-based design process to ensure that new, expanded, and renovated hospitals facilitate optimal patient outcomes, enhance the work environment for healthcare providers, and improve organizational performance. In this article, the author introduces important project budget terms and a method of calculating an estimation of probable cost for a building project.

  15. Calculations in bridge aeroelasticity via CFD

    Energy Technology Data Exchange (ETDEWEB)

    Brar, P.S.; Raul, R.; Scanlan, R.H. [Johns Hopkins Univ., Baltimore, MD (United States)

    1996-12-31

    The central focus of the present study is the numerical calculation of flutter derivatives. These aeroelastic coefficients play an important role in determining the stability or instability of long, flexible structures under ambient wind loading. A class of Civil Engineering structures most susceptible to such an instability are long-span bridges of the cable-stayed or suspended-span variety. The disastrous collapse of the Tacoma Narrows suspension bridge in the recent past, due to a flutter instability, has been a big impetus in motivating studies in flutter of bridge decks.

  16. Exact and approximate calculation of giant resonances

    Energy Technology Data Exchange (ETDEWEB)

    Vertse, T. [Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete; Liotta, R.J. [Royal Inst. of Tech., Stockholm (Sweden); Maglione, E. [Padua Univ. (Italy). Ist. di Fisica

    1995-02-13

    Energies, sum rules and partial decay widths of giant resonances in {sup 208}Pb are calculated solving exactly the continuum RPA equations corresponding to a central Woods-Saxon potential. For comparison an approximate treatment of those quantities in terms of pole expansions of the Green function (Berggren and Mittag-Leffler) is also performed. It is found that the approximated results agree well with the exact ones. Comparison with experimental data is made and a search for physically meaningful resonances is carried out. ((orig.))

  17. Calculation of persistent currents in superconducting magnets

    Directory of Open Access Journals (Sweden)

    C. Völlinger

    2000-12-01

    Full Text Available This paper describes a semianalytical hysteresis model for hard superconductors. The model is based on the critical state model considering the dependency of the critical current density on the varying local field in the superconducting filaments. By combining this hysteresis model with numerical field computation methods, it is possible to calculate the persistent current multipole errors in the magnet taking local saturation effects in the magnetic iron parts into consideration. As an application of the method, the use of soft magnetic iron sheets (coil protection sheets mounted between the coils and the collars for partial compensation of the multipole errors during the ramping of the magnets is investigated.

  18. Electrical Conductivity Calculations from the Purgatorio Code

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S B; Isaacs, W A; Sterne, P A; Wilson, B G; Sonnad, V; Young, D A

    2006-01-09

    The Purgatorio code [Wilson et al., JQSRT 99, 658-679 (2006)] is a new implementation of the Inferno model describing a spherically symmetric average atom embedded in a uniform plasma. Bound and continuum electrons are treated using a fully relativistic quantum mechanical description, giving the electron-thermal contribution to the equation of state (EOS). The free-electron density of states can also be used to calculate scattering cross sections for electron transport. Using the extended Ziman formulation, electrical conductivities are then obtained by convolving these transport cross sections with externally-imposed ion-ion structure factors.

  19. ICBM vulnerability: Calculations, predictions, and error bars

    Science.gov (United States)

    Hobson, Art

    1988-09-01

    The theory of intercontinental ballistic missile (ICBM) silo vulnerability is reviewed, and the present and probable future (mid-1990s) vulnerability of US silos is analyzed. The analysis emphasizes methodology, sources of information, and uncertainties. US ICBMs might still be survivable today but they will certainly be vulnerable to ICBM attack, and perhaps even to submarine-launched ballistic missile attack, by the mid-1990s. These calculations are presented not only for their immediate importance but also to introduce other physicists to some of the quantitative methods that can be used to analyze international security topics.

  20. Drift Mode Calculations in Nonaxisymmetric Geometry

    Energy Technology Data Exchange (ETDEWEB)

    G. Rewoldt; L.-P. Ku; W.A. Cooper; W.M. Tang

    1999-07-01

    A fully kinetic assessment of the stability properties of toroidal drift modes has been obtained for nonaxisymmetric (stellarator) geometry, in the electrostatic limit. This calculation is a comprehensive solution of the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities, with a model collision operator. Results for toroidal drift waves destabilized by temperature gradients and/or trapped particle dynamics are presented, using three-dimensional magnetohydrodynamic equilibria generated as part of a design effort for a quasiaxisymmetric stellarator. Comparisons of these results with those obtained for typical tokamak cases indicate that the basic trends are similar.