WorldWideScience

Sample records for bunsatsu bimolecular mechanism

  1. Report on result 1998. Research and development on fusion area. Part 3 (biomolecular mechanism and design); 1998 nendo seika hokokusho. Yugo ryoiki kenkyu kaihatsu daisan bunsatsu (bimolecular mechanism and design)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    An organism is a molecular mechanical system consisting of nucleic acid, peptide and protein having a self-forming and a self-repairing function. For the purpose of creating cells, tissues and molecular mechanism alternating these biological functions, their basic technology was developed. Concretely, studies were made on three-dimensional cellular structural module engineering and biomolecular mechanism and design. Studies on biological soft tissue resulted in success by giving atmospheric glow discharge treatment to the inner surface of a tubular PVC. An artificial vitreous body was created using PVA hydrogels. In addition, liver cells were successfully cultured for the first time in the world. Studies on biological hard tissue revealed that osteopontin plays a role of a trigger for the initial differentiation of the osteoblast cell. Further, a basic experiment was carried out on the initial response of the cartilage cell. In the research on the molecular mechanism, examination was made on the mechanism of a double-head molecular motor. Examination was also made on the adjustment of the hydrogenase LB film as an electricity/hydrogen energy conversion element and on the biomolecular mechanism and design. (NEDO)

  2. Differences in the Abilities to Mechanically Eliminate Activation Energies for Unimolecular and Bimolecular Reactions

    Science.gov (United States)

    Kochhar, Gurpaul S.; Mosey, Nicholas J.

    2016-03-01

    Mechanochemistry, i.e. the application of forces, F, at the molecular level, has attracted significant interest as a means of controlling chemical reactions. The present study uses quantum chemical calculations to explore the abilities to mechanically eliminate activation energies, ΔE‡, for unimolecular and bimolecular reactions. The results demonstrate that ΔE‡ can be eliminated for unimolecular reactions by applying sufficiently large F along directions that move the reactant and/or transition state (TS) structures parallel to the zero-F reaction coordinate, S0. In contrast, eliminating ΔE‡ for bimolecular reactions requires the reactant to undergo a force-induced shift parallel to S0 irrespective of changes in the TS. Meeting this requirement depends upon the coupling between F and S0 in the reactant. The insights regarding the differences in eliminating ΔE‡ for unimolecular and bimolecular reactions, and the requirements for eliminating ΔE‡, may be useful in practical efforts to control reactions mechanochemically.

  3. Kinetics and mechanism of bimolecular electron transfer reaction in quinone-amine systems in micellar solution

    International Nuclear Information System (INIS)

    Photoinduced electron transfer (ET) reactions between anthraquinone derivatives and aromatic amines have been investigated in sodium dodecyl sulphate (SDS) micellar solutions. Significant static quenching of the quinone fluorescence due to high amine concentration in the micellar phase has been observed in steady-state measurements. The bimolecular rate constants for the dynamic quenching in the present systems kqTR, as estimated from the time-resolved measurements, have been correlated with the free energy changes ΔG0 for the ET reactions. Interestingly it is seen that the kqTR vs ΔG0 plot displays an inversion behavior with maximum kqTR at around 0.7 eV, a trend similar to that predicted in Marcus ET theory. Like the present results, Marcus inversion in the kqTR values was also observed earlier in coumarin-amine systems in SDS and TX-100 micellar solutions, with maximum kqTR at around the same exergonicity. These results thus suggest that Marcus inversion in bimolecular ET reaction is a general phenomenon in micellar media. Present observations have been rationalized on the basis of the two-dimensional ET (2DET) theory, which seems to be more suitable for micellar ET reactions than the conventional ET theory. For the quinone-amine systems, it is interestingly seen that kqTR vs ΔG0 plot is somewhat wider in comparison to that of the coumarin-amine systems, even though the maxima in the kqTR vs ΔG0 plots appear at almost similar exergonicity for both the acceptor-donor systems. These observations have been rationalized on the basis of the differences in the reaction windows along the solvation axis, as envisaged within the framework of the 2DET theory, and arise due to the differences in the locations of the quinones and coumarin dyes in the micellar phase

  4. The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

    International Nuclear Information System (INIS)

    Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants

  5. The influence of the "cage" effect on the mechanism of reversible bimolecular multistage chemical reactions proceeding from different sites in solutions.

    Science.gov (United States)

    Doktorov, Alexander B

    2016-08-28

    Manifestations of the "cage" effect at the encounters of reactants have been theoretically treated on the example of multistage reactions (including bimolecular exchange reactions as elementary stages) proceeding from different active sites in liquid solutions. It is shown that for reactions occurring near the contact of reactants, consistent consideration of quasi-stationary kinetics of such multistage reactions (possible in the framework of the encounter theory only) can be made on the basis of chemical concepts of the "cage complex," just as in the case of one-site model described in the literature. Exactly as in the one-site model, the presence of the "cage" effect gives rise to new channels of reactant transformation that cannot result from elementary event of chemical conversion for the given reaction mechanism. Besides, the multisite model demonstrates new (as compared to one-site model) features of multistage reaction course. PMID:27586911

  6. Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo

    DEFF Research Database (Denmark)

    Jovanovic, Goran; Sheng, Xia; Ale, Angelique;

    2015-01-01

    functional relevance of the dimerization of a non-orthodox or hybrid histidine kinase along which the phosphorelay takes place has been a subject of debate. We use a combination of molecular and genetic approaches, coupled to mathematical and statistical modelling, to demonstrate that the different possible...... intra- and inter-molecular mechanisms of phosphotransfer are formally non-identifiable in Escherichia coli expressing the ArcB non-orthodox histidine kinase used in anoxic redox control. In order to resolve this issue we further analyse the mathematical model in order to identify discriminatory...... histidine kinase. This is the first detailed mechanistic analysis of the molecular processes involved in non-orthodox two-component signalling and our results suggest strongly that dimerization facilitates more discriminatory proof-reading of external signals, via these allosteric reactions, prior to them...

  7. Efficient Bimolecular Mechanism of Photochemical Hydrogen Production Using Halogenated Boron-Dipyrromethene (Bodipy) Dyes and a Bis(dimethylglyoxime) Cobalt(III) Complex.

    Science.gov (United States)

    Sabatini, Randy P; Lindley, Brian; McCormick, Theresa M; Lazarides, Theodore; Brennessel, William W; McCamant, David W; Eisenberg, Richard

    2016-01-28

    A series of Boron-dipyrromethene (Bodipy) dyes were used as photosensitizers for photochemical hydrogen production in conjunction with [Co(III)(dmgH)2pyCl] (where dmgH = dimethylglyoximate, py = pyridine) as the catalyst and triethanolamine (TEOA) as the sacrificial electron donor. The Bodipy dyes are fully characterized by electrochemistry, X-ray crystallography, quantum chemistry calculations, femtosecond transient absorption, and time-resolved fluorescence, as well as in long-term hydrogen production assays. Consistent with other recent reports, only systems containing halogenated chromophores were active for hydrogen production, as the long-lived triplet state is necessary for efficient bimolecular electron transfer. Here, it is shown that the photostability of the system improves with Bodipy dyes containing a mesityl group versus a phenyl group, which is attributed to increased electron donating character of the mesityl substituent. Unlike previous reports, the optimal ratio of chromophore to catalyst is established and shown to be 20:1, at which point this bimolecular dye/catalyst system performs 3-4 times better than similar chemically linked systems. We also show that the hydrogen production drops dramatically with excess catalyst concentration. The maximum turnover number of ∼ 700 (with respect to chromophore) is obtained under the following conditions: 1.0 × 10(-4) M [Co(dmgH)2pyCl], 5.0 × 10(-6) M Bodipy dye with iodine and mesityl substituents, 1:1 v:v (10% aqueous TEOA):MeCN (adjusted to pH 7), and irradiation by light with λ > 410 nm for 30 h. This system, containing discrete chromophore and catalyst, is more active than similar linked Bodipy-Co(dmg)2 dyads recently published, which, in conjunction with our other measurements, suggests that the nominal dyads actually function bimolecularly. PMID:26730460

  8. Luminescence Spectroscopy and Bimolecular Quenching

    Science.gov (United States)

    Demas, J. N.

    1975-01-01

    Describes an undergraduate physical chemistry experiment in which a low cost spectrofluorimeter is used to carry out elementary emission measurements on a transition metal complex. The students measure uncorrected emission and excitation spectra, and determine the rate constant for an exceedingly fast bimolecular reaction, the deactivation of an…

  9. Generation of radicals by bimolecular reactions

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, Evgenii T; Denisova, Taisa G [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2002-05-31

    The published data on bimolecular processes of radical generation in chain degradation, polymerisation, oxidation and halogenation reactions of organic compounds are systematised and analysed within the framework of the parabolic model of homolytic bimolecular reactions. The specific features of these highly endothermic reactions are discussed with a special emphasis on their striking similarity to radical abstraction processes with identical reaction centres in the transition state. The feasibility of theoretical evaluation of the activation energies and the rate constants of bimolecular reactions in radical generation is demonstrated. The bibliography includes 86 references.

  10. Recent Advances in Quantum Dynamics of Bimolecular Reactions.

    Science.gov (United States)

    Zhang, Dong H; Guo, Hua

    2016-05-27

    In this review, we survey the latest advances in theoretical understanding of bimolecular reaction dynamics in the past decade. The remarkable recent progress in this field has been driven by more accurate and efficient ab initio electronic structure theory, effective potential-energy surface fitting techniques, and novel quantum scattering algorithms. Quantum mechanical characterization of bimolecular reactions continues to uncover interesting dynamical phenomena in atom-diatom reactions and beyond, reaching an unprecedented level of sophistication. In tandem with experimental explorations, these theoretical developments have greatly advanced our understanding of key issues in reaction dynamics, such as microscopic reaction mechanisms, mode specificity, product energy disposal, influence of reactive resonances, and nonadiabatic effects. PMID:26980305

  11. RPMDrate: Bimolecular chemical reaction rates from ring polymer molecular dynamics

    OpenAIRE

    Allen, Joshua W.; Green, William H; Suleimanov, Yu. V.

    2013-01-01

    We present RPMDrate, a computer program for the calculation of gas phase bimolecular reaction rate coefficients using the ring polymer molecular dynamics (RPMD) method. The RPMD rate coefficient is calculated using the Bennett–Chandler method as a product of a static (centroid density quantum transition state theory (QTST) rate) and a dynamic (ring polymer transmission coefficient) factor. The computational procedure is general and can be used to treat bimolecular polyatomic reactions of any ...

  12. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    Energy Technology Data Exchange (ETDEWEB)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound {yields} bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN{sup {minus}}, NCO{sup {minus}} and NCS{sup {minus}}. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH{sub 3}0H,F + C{sub 2}H{sub 5}OH,F + OH and F + H{sub 2}. A time dependent framework for the simulation and interpretation of the bound {yields} free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH {yields} O({sup 3}P, {sup 1}D) + HF and F + H{sub 2}. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by the time autocorrelation function. For the benchmark F + H{sub 2} system, comparisons with three-dimensional quantum calculations are made.

  13. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    International Nuclear Information System (INIS)

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound → bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN-, NCO- and NCS-. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH30H,F + C2H5OH,F + OH and F + H2. A time dependent framework for the simulation and interpretation of the bound → free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH → O(3P, 1D) + HF and F + H2. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by the time autocorrelation function. For the benchmark F + H2 system, comparisons with three-dimensional quantum calculations are made

  14. Analysis of Brownian Dynamics Simulations of Reversible Bimolecular Reactions

    KAUST Repository

    Lipková, Jana

    2011-01-01

    A class of Brownian dynamics algorithms for stochastic reaction-diffusion models which include reversible bimolecular reactions is presented and analyzed. The method is a generalization of the λ-bcȳ model for irreversible bimolecular reactions which was introduced in [R. Erban and S. J. Chapman, Phys. Biol., 6(2009), 046001]. The formulae relating the experimentally measurable quantities (reaction rate constants and diffusion constants) with the algorithm parameters are derived. The probability of geminate recombination is also investigated. © 2011 Society for Industrial and Applied Mathematics.

  15. RPMDrate: Bimolecular chemical reaction rates from ring polymer molecular dynamics

    KAUST Repository

    Suleimanov, Yu.V.

    2013-03-01

    We present RPMDrate, a computer program for the calculation of gas phase bimolecular reaction rate coefficients using the ring polymer molecular dynamics (RPMD) method. The RPMD rate coefficient is calculated using the Bennett-Chandler method as a product of a static (centroid density quantum transition state theory (QTST) rate) and a dynamic (ring polymer transmission coefficient) factor. The computational procedure is general and can be used to treat bimolecular polyatomic reactions of any complexity in their full dimensionality. The program has been tested for the H+H2, H+CH 4, OH+CH4 and H+C2H6 reactions. © 2012 Elsevier B.V. All rights reserved.

  16. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    OpenAIRE

    Kolb, Jakob J.; Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is viola...

  17. Bimolecular recombination reactions: K-adiabatic and K-active forms of the bimolecular master equations and analytic solutions

    Science.gov (United States)

    Ghaderi, Nima

    2016-03-01

    Expressions for a K-adiabatic master equation for a bimolecular recombination rate constant krec are derived for a bimolecular reaction forming a complex with a single well or complexes with multiple well, where K is the component of the total angular momentum along the axis of least moment of inertia of the recombination product. The K-active master equation is also considered. The exact analytic solutions, i.e., the K-adiabatic and K-active steady-state population distribution function of reactive complexes, g(EJK) and g(EJ), respectively, are derived for the K-adiabatic and K-active master equation cases using properties of inhomogeneous integral equations (Fredholm type). The solutions accommodate arbitrary intermolecular energy transfer models, e.g., the single exponential, double exponential, Gaussian, step-ladder, and near-singularity models. At the high pressure limit, the krec for both the K-adiabatic and K-active master equations reduce, respectively, to the K-adiabatic and K-active bimolecular Rice-Ramsperger-Kassel-Marcus theory (high pressure limit expressions). Ozone and its formation from O + O2 are known to exhibit an adiabatic K. The ratio of the K-adiabatic to the K-active recombination rate constants for ozone formation at the high pressure limit is calculated to be ˜0.9 at 300 K. Results on the temperature and pressure dependence of the recombination rate constants and populations of O3 will be presented elsewhere.

  18. Understanding bimolecular machines: Theoretical and experimental approaches

    Science.gov (United States)

    Goler, Adam Scott

    This dissertation concerns the study of two classes of molecular machines from a physical perspective: enzymes and membrane proteins. Though the functions of these classes of proteins are different, they each represent important test-beds from which new understanding can be developed by the application of different techniques. HIV1 Reverse Transcriptase is an enzyme that performs multiple functions, including reverse transcription of RNA into an RNA/DNA duplex, RNA degradation by the RNaseH domain, and synthesis of dsDNA. These functions allow for the incorporation of the retroviral genes into the host genome. Its catalytic cycle requires repeated large-scale conformational changes fundamental to its mechanism. Motivated by experimental work, these motions were studied theoretically by the application of normal mode analysis. It was observed that the lowest order modes correlate with largest amplitude (low-frequency) motion, which are most likely to be catalytically relevant. Comparisons between normal modes obtained via an elastic network model to those calculated from the essential dynamics of a series of all-atom molecular dynamics simulations show the self-consistency between these calculations. That similar conformational motions are seen between independent theoretical methods reinforces the importance of large-scale subdomain motion for the biochemical action of DNA polymerases in general. Moreover, it was observed that the major subunits of HIV1 Reverse Transcriptase interact quasi-harmonically. The 5HT3A Serotonin receptor and P2X1 receptor, by contrast, are trans-membrane proteins that function as ligand gated ion channels. Such proteins feature a central pore, which allows for the transit of ions necessary for cellular function across a membrane. The pore is opened by the ligation of binding sites on the extracellular portion of different protein subunits. In an attempt to resolve the individual subunits of these membrane proteins beyond the diffraction

  19. Theory of Crowding Effects on Bimolecular Reaction Rates.

    Science.gov (United States)

    Berezhkovskii, Alexander M; Szabo, Attila

    2016-07-01

    An analytical expression for the rate constant of a diffusion-influenced bimolecular reaction in a crowded environment is derived in the framework of a microscopic model that accounts for: (1) the slowdown of diffusion due to crowding and the dependence of the diffusivity on the distance between the reactants, (2) a crowding-induced attractive short-range potential of mean force, and (3) nonspecific reversible binding to the crowders. This expression spans the range from reaction to diffusion control. Crowding can increase the reaction-controlled rate by inducing an effective attraction between reactants but decrease the diffusion-controlled rate by reducing their relative diffusivity. PMID:27096470

  20. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    CERN Document Server

    Kolb, Jakob J; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  1. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    Energy Technology Data Exchange (ETDEWEB)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  2. Communication: Resonance reaction in diffusion-influenced bimolecular reactions

    Science.gov (United States)

    Kolb, Jakob J.; Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2016-02-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new "resonant reaction" behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance, the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  3. Use of bimolecular fluorescence complementation in yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Skarp, Kari-Pekka; Zhao, Xueqiang; Weber, Marion; Jantti, Jussi

    2008-01-01

    Visualization of protein-protein interactions in vivo offers a powerful tool to resolve spatial and temporal aspects of cellular functions. Bimolecular fluorescence complementation (BiFC) makes use of nonfluorescent fragments of green fluorescent protein or its variants that are added as "tags" to target proteins under study. Only upon target protein interaction is a fluorescent protein complex assembled and the site of interaction can be monitored by microscopy. In this chapter, we describe the method and tools for use of BiFC in the yeast Saccharomyces cerevisiae. PMID:19066026

  4. Morse bifurcations of transition states in bimolecular reactions

    Science.gov (United States)

    MacKay, R. S.; Strub, D. C.

    2015-12-01

    The transition states and dividing surfaces used to find rate constants for bimolecular reactions are shown to undergo Morse bifurcations, in which they change diffeomorphism class, and to exist for a large range of energies, not just immediately above the critical energy for first connection between reactants and products. Specifically, we consider capture between two molecules and the associated transition states for the case of non-zero angular momentum and general attitudes. The capture between an atom and a diatom, and then a general molecule are presented, providing concrete examples of Morse bifurcations of transition states and dividing surfaces.

  5. Morse bifurcations of transition states in bimolecular reactions

    CERN Document Server

    MacKay, Robert S

    2015-01-01

    The transition states and dividing surfaces used to find rate constants for bimolecular reactions are shown to undergo qualitative changes, known as Morse bifurcations, and to exist for a large range of energies, not just immediately above the critical energy for first connection between reactants and products. Specifically, we consider capture between two molecules and the associated transition states for the case of non-zero angular momentum and general attitudes. The capture between an atom and a diatom, and then a general molecule are presented, providing concrete examples of Morse bifurcations of transition states and dividing surfaces. The reduction of the $n$-body systems representing the reactions is discussed and reviewed with comments on the difficulties associated with choosing appropriate charts and the global geometry of the reduced spaces.

  6. Bimolecular recombination and complete photocurrent decay in metallophthalocyanine thin films

    Science.gov (United States)

    Noah, Ramsey S.

    Metallophthalocyanines (MPc) are a class of planar small molecule semiconductors that are of great interest due to their applications in organic solar cells. However, a thorough understanding of many of their charge transport properties, especially those related to trap states, is lacking. In previous works the increase of grain size in MPc thin films with higher substrate temperature during the thermal evaporation process was quantified. Here, we investigate the charge transport properties of phthalocyanine with varying grain sizes in five ways: 1) intensity-varied photocurrent measurements are used to study the order of recombination in zinc phthalocyanine (ZnPc) thin films; 2) the conduction dependence on oxygen doping in copper phthalocyanine (CuPc) and ZnPc is investigated through oxygen deprivation in a closed-cycle refrigerator; 3) the complete photocurrent decay in CuPc and ZnPc is explored; 4) the bandgap of CuPc and ZnPc is derived from wide temperature range (˜ 80K - 351K) resistance measurements; 5) thermally stimulated currents (TSC) in CuPc and ZnPc are induced using a modified Reber methodology. An explanation for oxygen doping in these type of thin films is presented and in addition to bimolecular recombination a second model is also applied to measurements of intensity-varied photocurrent. Our data suggest several interesting aspects of the charge transport properties in these organic semiconductors. Recombination may not be dominated by monomolecular processes but instead bimolecular. More amorphous (low deposition temperature) samples show a greater change in conductivity due to oxygen doping. The photocurrent of more crystalline samples decays more rapidly compared to amorphous samples, suggesting that deeper trap states are present in lower deposition temperature samples. The bandgap derived from temperature-varied resistance measurements is systematically low due to slow detrapping. Unlike TSC measurements in micrometer-thick organic films

  7. Simulation study of the losses and influences of geminate and bimolecular recombination on the performances of bulk heterojunction organic solar cells

    Institute of Scientific and Technical Information of China (English)

    朱键卓; 祁令辉; 杜会静; 柴莺春

    2015-01-01

    We use the method of device simulation to study the losses and influences of geminate and bimolecular recombinations on the performances and properties of the bulk heterojunction organic solar cells. We find that a fraction of electrons (holes) in the device are collected by anode (cathode). The direction of the corresponding current is opposite to the direction of photocurrent. And the current density increases with the bias increasing but decreases as bimolecular recombination (BR) or geminate recombination (GR) intensity increases. The maximum power, short circuit current, and fill factor display a stronger dependence on GR than on BR. While the influences of GR and BR on open circuit voltage are about the same. Our studies shed a new light on the loss mechanism and may provide a new way of improving the efficiency of bulk heterojunction organic solar cells.

  8. Uncertainty for calculating transport on Titan: a probabilistic description of bimolecular diffusion parameters

    CERN Document Server

    Plessis, Sylvain; Mandt, Kathy; Greathouse, Thomas; Luspay-Kuti, Adrienn

    2015-01-01

    Bimolecular diffusion coefficients are important parameters used by atmospheric models to calculate altitude profiles of minor constituents in an atmosphere. Unfortunately, laboratory measurements of these coefficients were never conducted at temperature conditions relevant to the atmosphere of Titan. Here we conduct a detailed uncertainty analysis of the bimolecular diffusion coefficient parameters as applied to Titan's upper atmosphere to provide a better understanding of the impact of uncertainty for this parameter on models. Because temperature and pressure conditions are much lower than the laboratory conditions in which bimolecular diffusion parameters were measured, we apply a Bayesian framework, a problem-agnostic framework, to determine parameter estimates and associated uncertainties. We solve the Bayesian calibration problem using the open-source QUESO library which also performs a propagation of uncertainties in the calibrated parameters to temperature and pressure conditions observed in Titan's u...

  9. Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

    KAUST Repository

    Miller, Nichole Cates

    2012-09-05

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Nichole Cates; Gysel, Roman; Sweetnam, Sean; McGehee, Michael D. [Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Cho, Eunkyung [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Junk, Matthias J.N.; Chmelka, Bradley F. [Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA (United States); Risko, Chad; Kim, Dongwook; Bredas, Jean-Luc [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (United States); Miller, Chad E. [Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Richter, Lee J.; Kline, R. Joseph [National Institute of Standards and Technology, Gaithersburg, MD (United States); Heeney, Martin; McCulloch, Iain [Department of Chemistry, Imperial College London (United Kingdom); Amassian, Aram [King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal (Saudi Arabia); Acevedo-Feliz, Daniel; Knox, Christopher [King Abdullah University of Science and Technology (KAUST), Visualization Core Laboratory, Thuwal (Saudi Arabia); Hansen, Michael Ryan; Dudenko, Dmytro [Max Planck Institute for Polymer Research, Mainz (Germany); Toney, Michael F. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States)

    2012-11-27

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. The power-law reaction rate coefficient for an elementary bimolecular reaction

    OpenAIRE

    Yin, Cangtao; Du, Jiulin

    2013-01-01

    The power-law TST reaction rate coefficient for an elementary bimolecular reaction is studied when the reaction takes place in a nonequilibrium system with power-law distributions. We derive a generalized TST rate coefficient, which not only depends on a power-law parameter but also on the reaction coordinate frequency of transition state. The numerical analyses show a very strong dependence of TST rate coefficient on the power-law parameter, and clearly indicate that a tiny deviation from un...

  12. Uncertainty for calculating transport on Titan: A probabilistic description of bimolecular diffusion parameters

    Science.gov (United States)

    Plessis, S.; McDougall, D.; Mandt, K.; Greathouse, T.; Luspay-Kuti, A.

    2015-11-01

    Bimolecular diffusion coefficients are important parameters used by atmospheric models to calculate altitude profiles of minor constituents in an atmosphere. Unfortunately, laboratory measurements of these coefficients were never conducted at temperature conditions relevant to the atmosphere of Titan. Here we conduct a detailed uncertainty analysis of the bimolecular diffusion coefficient parameters as applied to Titan's upper atmosphere to provide a better understanding of the impact of uncertainty for this parameter on models. Because temperature and pressure conditions are much lower than the laboratory conditions in which bimolecular diffusion parameters were measured, we apply a Bayesian framework, a problem-agnostic framework, to determine parameter estimates and associated uncertainties. We solve the Bayesian calibration problem using the open-source QUESO library which also performs a propagation of uncertainties in the calibrated parameters to temperature and pressure conditions observed in Titan's upper atmosphere. Our results show that, after propagating uncertainty through the Massman model, the uncertainty in molecular diffusion is highly correlated to temperature and we observe no noticeable correlation with pressure. We propagate the calibrated molecular diffusion estimate and associated uncertainty to obtain an estimate with uncertainty due to bimolecular diffusion for the methane molar fraction as a function of altitude. Results show that the uncertainty in methane abundance due to molecular diffusion is in general small compared to eddy diffusion and the chemical kinetics description. However, methane abundance is most sensitive to uncertainty in molecular diffusion above 1200 km where the errors are nontrivial and could have important implications for scientific research based on diffusion models in this altitude range.

  13. Detonation wave solutions and linear stability in a four component gas with bimolecular chemical reaction

    OpenAIRE

    Carvalho, Filipe; De Silva, A.W.; Soares, A. J.

    2015-01-01

    We consider a four component gas undergoing a bimolecular chemical reaction of type A1 + A2 = A3 + A4, described by the Boltzmann equation (BE) for chemically reactive mixtures. We adopt hard-spheres elastic cross sections and modified line-of-centers reactive cross sections depending on both the activation energy and geometry of the reactive collisions. Then we consider the hydrodynamic limit specified by the reactive Euler equations, in an earlier stage of the chemical reaction, when the ga...

  14. Simulation study of the losses and influences of geminate and bimolecular recombination on the performances of bulk heterojunction organic solar cells

    Science.gov (United States)

    Zhu, Jian-Zhuo; Qi, Ling-Hui; Du, Hui-Jing; Chai, Ying-Chun

    2015-10-01

    We use the method of device simulation to study the losses and influences of geminate and bimolecular recombinations on the performances and properties of the bulk heterojunction organic solar cells. We find that a fraction of electrons (holes) in the device are collected by anode (cathode). The direction of the corresponding current is opposite to the direction of photocurrent. And the current density increases with the bias increasing but decreases as bimolecular recombination (BR) or geminate recombination (GR) intensity increases. The maximum power, short circuit current, and fill factor display a stronger dependence on GR than on BR. While the influences of GR and BR on open circuit voltage are about the same. Our studies shed a new light on the loss mechanism and may provide a new way of improving the efficiency of bulk heterojunction organic solar cells. Project supported by the Natural Science Foundation of Hebei Province, China (Grant No. A2012203016), the Science Fund from the Education Department of Hebei Province, China (Grant Nos. QN20131103 and Z2009114), the Doctor Foundation of Yanshan University, China (Grant No. B580), and the Young Teachers' Research Project of Yanshan University, China (Grant No. 13LGB028).

  15. Bimolecular Complementation to Visualize Filovirus VP40-Host Complexes in Live Mammalian Cells: Toward the Identification of Budding Inhibitors

    Directory of Open Access Journals (Sweden)

    Yuliang Liu

    2011-01-01

    Full Text Available Virus-host interactions play key roles in promoting efficient egress of many RNA viruses, including Ebola virus (EBOV or “e” and Marburg virus (MARV or “m”. Late- (L- domains conserved in viral matrix proteins recruit specific host proteins, such as Tsg101 and Nedd4, to facilitate the budding process. These interactions serve as attractive targets for the development of broad-spectrum budding inhibitors. A major gap still exists in our understanding of the mechanism of filovirus budding due to the difficulty in detecting virus-host complexes and mapping their trafficking patterns in the natural environment of the cell. To address this gap, we used a bimolecular complementation (BiMC approach to detect, localize, and follow the trafficking patterns of eVP40-Tsg101 complexes in live mammalian cells. In addition, we used the BiMC approach along with a VLP budding assay to test small molecule inhibitors identified by in silico screening for their ability to block eVP40 PTAP-mediated interactions with Tsg101 and subsequent budding of eVP40 VLPs. We demonstrated the potential broad spectrum activity of a lead candidate inhibitor by demonstrating its ability to block PTAP-dependent binding of HIV-1 Gag to Tsg101 and subsequent egress of HIV-1 Gag VLPs.

  16. Bimolecular Fluorescence Complementation to Assay the Interactions of Ubiquitylation Enzymes in Living Yeast Cells.

    Science.gov (United States)

    Blaszczak, Ewa; Prigent, Claude; Rabut, Gwenaël

    2016-01-01

    Ubiquitylation is a versatile posttranslational protein modification catalyzed through the concerted action of ubiquitin-conjugating enzymes (E2s) and ubiquitin ligases (E3s). These enzymes form transient complexes with each other and their modification substrates and determine the nature of the ubiquitin signals attached to their substrates. One challenge in the field of protein ubiquitylation is thus to identify the E2-E3 pairs that function in the cell. In this chapter, we describe the use of bimolecular fluorescence complementation to assay E2-E3 interactions in living cells, using budding yeast as a model organism. PMID:27613039

  17. Activation energies of photoinduced unimolecular, bimolecular and termolecular processes on silica gel surfaces.

    Science.gov (United States)

    Williams, Siân L; Worrall, David R; Kirkpatrick, Iain; Vancea, Anisoara; Pan, Jiawei

    2011-01-01

    Activation energies for energy and electron transfer have been measured in various systems on silica gel. In the case of ion-electron recombination, a facile technique involving fluorescence recovery is described which complements diffuse reflectance spectroscopy in the study of these systems. In bimolecular anthracene/azulene systems, activation energies have been shown to be independent of pre-treatment temperature in the range 25-210 °C, demonstrating that physisorbed water plays little role in determining diffusion rates on silica gel. In a ternary anthracene/azulene/perylene system, we have for the first time presented comparative activation energies for the diffusion of azulene and its radical cation, and have shown a greater activation energy for diffusion of the latter species. PMID:20978659

  18. Data preprocessing for parameter estimation. An application to a reactive bimolecular transport model

    CERN Document Server

    Cuch, Daniel A; Hasi, Claudio D El

    2015-01-01

    In this work we are concerned with the inverse problem of the estimation of modeling parameters for a reactive bimolecular transport based on experimental data that is non-uniformly distributed along the interval where the process takes place. We proposed a methodology that can help to determine the intervals where most of the data should be taken in order to obtain a good estimation of the parameters. For the purpose of reducing the cost of laboratory experiments, we propose to simulate data where is needed and it is not available, a PreProcesing Data Fitting (PPDF).We applied this strategy on the estimation of parameters for an advection-diffusion-reaction problem in a porous media. Each step is explained in detail and simulation results are shown and compared with previous ones.

  19. Sequence and solvent effects on telomeric DNA bimolecular G-quadruplex folding kinetics.

    Science.gov (United States)

    Marchand, Adrien; Ferreira, Rubén; Tateishi-Karimata, Hisae; Miyoshi, Daisuke; Sugimoto, Naoki; Gabelica, Valérie

    2013-10-17

    Telomeric DNA sequences are particularly polymorphic: the adopted structure is exquisitely sensitive to the sequence and to the chemical environment, for example, solvation. Dehydrating conditions are known to stabilize G-quadruplex structures, but information on how solvation influences the individual rates of folding and unfolding of G-quadruplexes remains scarce. Here, we used electrospray mass spectrometry for the first time to monitor bimolecular G-quadruplex formation from 12-mer telomeric strands, in the presence of common organic cosolvents (methanol, ethanol, isopropanol, and acetonitrile). Based on the ammonium ion distribution, the total dimer signal was decomposed into contributions from the parallel and antiparallel structures to obtain individual reaction rates, and the antiparallel G-quadruplex structure was found to form faster than the parallel one. A dimeric reaction intermediate, in rapid equilibrium with the single strands, was also identified. Organic cosolvents increase the stability of the final structures mainly by increasing the folding rates. Our quantitative analysis of reaction rate dependence on cosolvent percentage shows that organic cosolvent molecules can be captured or released upon G-quadruplex formation, highlighting that they are not inert with DNA. In contrast to the folding rates, the G-quadruplex unfolding rates are almost insensitive to solvation effects, but are instead governed by the sequence and by the final structure: parallel dimers dissociate slower than antiparallel dimers only when thymine bases are present at the 5'-end. These results contribute unraveling the folding pathways of telomeric G-quadruplexes. The solvent effects revealed here enlighten that G-quadruplex structure in dehydrated, and molecularly crowded environments are modulated by the nature of cosolvent (e.g., methanol favors antiparallel structures) due to direct interactions, and by the time scale of the reaction, with >200-fold acceleration of

  20. On the Temperature Dependence of the Rate Constant of the Bimolecular Reaction of two Hydrated Electrons

    Directory of Open Access Journals (Sweden)

    S.L. Butarbutar

    2013-08-01

    Full Text Available It has been a longstanding issue in the radiation chemistry of water that, even though H2 is a molecular product, its “escape” yield g(H2 increases with increasing temperature. A main source of H2 is the bimolecular reaction of two hydrated electrons (eaq. The temperature dependence of the rate constant of this reaction (k1, measured under alkaline conditions, reveals that the rate constant drops abruptly above ~150°C. Recently, it has been suggested that this temperature dependence should be regarded as being independent of pH and used in high-temperature modeling of near-neutral water radiolysis. However, when this drop in the eaq self-reaction rate constant is included in low (isolated spurs and high (cylindrical tracks linear energy transfer (LET modeling calculations, g(H2 shows a marked downward discontinuity at ~150°C which is not observed experimentally. The consequences of the presence of this discontinuity in g(H2 for both low and high LET radiation are briefly discussed in this communication. It is concluded that the applicability of the sudden drop in k1 observed at ~150°C in alkaline water to near-neutral water is questionable and that further measurements of the rate constant in pure water are highly desirable.

  1. Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

    KAUST Repository

    Alsam, Amani A.

    2015-09-02

    We explored the excited-state interactions of bimolecular, non-covalent systems consisting of cationic poly[(9,9-di(3,3’-N,N’-trimethyl-ammonium) propyl fluorenyl-2,7-diyl)-alt-co-(9,9-dioctyl-fluorenyl-2,7-diyl)] diiodide salt (PFN) and 1,4-dicyanobenzene (DCB) using steady-state and time-resolved techniques, including femto- and nanosecond transient absorption and femtosecond infrared spectroscopies with broadband capabilities. The experimental results demonstrated that photo-induced electron transfer from PFN to DCB occurs on the picosecond time scale, leading to the formation of PFN+• and DCB-• radical ions. Interestingly, real-time observations of the vibrational marker modes on the acceptor side provided direct evidence and insight into the electron transfer process indirectly inferred from UV-Vis experiments. The band narrowing on the picosecond time scale observed on the antisymmetric C-N stretching vibration of the DCB radical anion provides clear experimental evidence that a substantial part of the excess energy is channeled into vibrational modes of the electron transfer product and that the geminate ion pairs dissociate. More importantly, our nanosecond time-resolved data indicate that the charge-separated state is very long lived ( 30 ns) due to the dissociation of the contact radical ion pair into free ions. Finally, the fast electron transfer and slow charge recombination anticipate the current donor−acceptor system with potential applications in organic solar cells.

  2. A transition in the spatially integrated reaction rate of bimolecular reaction-diffusion systems

    Science.gov (United States)

    Arshadi, Masoud; Rajaram, Harihar

    2015-09-01

    Numerical simulations of diffusion with bimolecular reaction demonstrate a transition in the spatially integrated reaction rate—increasing with time initially, and transitioning to a decrease with time. In previous work, this reaction-diffusion problem has been analyzed as a Stefan problem involving a distinct moving boundary (reaction front), leading to predictions that front motion scales as √t, and correspondingly the spatially integrated reaction rate decreases as the square root of time 1/√t. We present a general nondimensionalization of the problem and a perturbation analysis to show that there is an early time regime where the spatially integrated reaction rate scales as √t rather than 1/√t. The duration of this early time regime (where the spatially integrated reaction rate is kinetically rather than diffusion controlled) is shown to depend on the kinetic rate parameters, diffusion coefficients, and initial concentrations of the two species. Numerical simulation results confirm the theoretical estimates of the transition time. We present illustrative calculations in the context of in situ chemical oxidation for remediation of fractured rock systems where contaminants are largely dissolved in the rock matrix. We consider different contaminants of concern (COCs), including TCE, PCE, MTBE, and RDX. While the early time regime is very short lived for TCE, it can persist over months to years for MTBE and RDX, due to slow oxidation kinetics.

  3. An improved bimolecular fluorescence complementation tool based on superfolder green fluorescent protein

    Institute of Scientific and Technical Information of China (English)

    Jun Zhou; Jian Lin; Cuihong Zhou; Xiaoyan Deng; Bin Xia

    2011-01-01

    Bimolecular fluorescence complementation (BiFC) has been widely used in the analysis of protein-protein interactions (PPIs) in recent years. There are many notable advantages of BiFC such as convenience and direct visualization of PPI in cells. However, BiFC has one common limitation: the separated non-fluorescent fragments can be spontaneously self-assembled into an intact protein,which leads to false-positive results. In this study, a pair of complementary fragments (sfGFPN and sfGFPC) was constructed by splitting superfolder GFP (sfGFP) between the 214 and 215 amino acid residue, and sfGFPC was mutated by site-directed gene mutagenesis to decrease the signal of negative control. Our results showed that mutations in sfGFPC (sfGFPC(m12)) can effectively decrease the signal of negative control. Thus, we provide an improved BiFC tool for the analysis of PPI. Further,since the self-assembly problem is a common shortcoming for application of BiFC, our research provides a feasible strategy for other BiFC candidate proteins with the same problem.

  4. Analysis of the papillomavirus E2 and bromodomain protein Brd4 interaction using bimolecular fluorescence complementation.

    Directory of Open Access Journals (Sweden)

    Christine M Helfer

    Full Text Available The human papillomavirus (HPV vaccines effectively protect against new infections of up to four HPV subtypes. However, these vaccines are not protective against many other clinically relevant HPV subtypes and are ineffective at treating established HPV infections. There is therefore a significant need for antiviral treatments for persistent HPV infections. A promising anti-HPV drug target is the interaction between the HPV E2 protein and cellular bromodomain-containing protein 4 (Brd4 since this protein complex mediates several processes important for the viral life cycle including viral genome maintenance, replication, and transcription. Using bimolecular fluorescence complementation (BiFC technology, we demonstrate the E2 and Brd4 interaction on both interphase chromatin and mitotic chromosomes throughout mitosis. The E2-Brd4 BiFC was significantly diminished by mutating the Brd4 binding sites in E2 or by a dominant negative inhibitor of the E2-Brd4 interaction, demonstrating the potential of BiFC for identifying inhibitors of this important virus-host interaction. Importantly, when Brd4 was released from chromatin using the bromodomain inhibitor JQ1(+, the E2-Brd4 interacting complex relocated into foci that no longer associate with mitotic chromosomes, pointing to JQ1(+ as a promising antiviral inhibitor of HPV genome maintenance during HPV persistent infection.

  5. Visualization of protein interactions in living Drosophila embryos by the bimolecular fluorescence complementation assay

    Directory of Open Access Journals (Sweden)

    Merabet Samir

    2011-01-01

    Full Text Available Abstract Background Protein interactions control the regulatory networks underlying developmental processes. The understanding of developmental complexity will, therefore, require the characterization of protein interactions within their proper environment. The bimolecular fluorescence complementation (BiFC technology offers this possibility as it enables the direct visualization of protein interactions in living cells. However, its potential has rarely been applied in embryos of animal model organisms and was only performed under transient protein expression levels. Results Using a Hox protein partnership as a test case, we investigated the suitability of BiFC for the study of protein interactions in the living Drosophila embryo. Importantly, all BiFC parameters were established with constructs that were stably expressed under the control of endogenous promoters. Under these physiological conditions, we showed that BiFC is specific and sensitive enough to analyse dynamic protein interactions. We next used BiFC in a candidate interaction screen, which led to the identification of several Hox protein partners. Conclusion Our results establish the general suitability of BiFC for revealing and studying protein interactions in their physiological context during the rapid course of Drosophila embryonic development.

  6. Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Dong Ding; David Benson; Amir Paster; Diogo Bolster

    2012-01-01

    We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle

  7. Viral bimolecular fluorescence complementation: a novel tool to study intracellular vesicular trafficking pathways.

    Directory of Open Access Journals (Sweden)

    Brennan S Dirk

    Full Text Available The Human Immunodeficiency Virus type 1 (HIV-1 accessory protein Nef interacts with a multitude of cellular proteins, manipulating the host membrane trafficking machinery to evade immune surveillance. Nef interactions have been analyzed using various in vitro assays, co-immunoprecipitation studies, and more recently mass spectrometry. However, these methods do not evaluate Nef interactions in the context of viral infection nor do they define the sub-cellular location of these interactions. In this report, we describe a novel bimolecular fluorescence complementation (BiFC lentiviral expression tool, termed viral BiFC, to study Nef interactions with host cellular proteins in the context of viral infection. Using the F2A cleavage site from the foot and mouth disease virus we generated a viral BiFC expression vector capable of concurrent expression of Nef and host cellular proteins; PACS-1, MHC-I and SNX18. Our studies confirmed the interaction between Nef and PACS-1, a host membrane trafficking protein involved in Nef-mediated immune evasion, and demonstrated co-localization of this complex with LAMP-1 positive endolysosomal vesicles. Furthermore, we utilized viral BiFC to localize the Nef/MHC-I interaction to an AP-1 positive endosomal compartment. Finally, viral BiFC was observed between Nef and the membrane trafficking regulator SNX18. This novel demonstration of an association between Nef and SNX18 was localized to AP-1 positive vesicles. In summary, viral BiFC is a unique tool designed to analyze the interaction between Nef and host cellular proteins by mapping the sub-cellular locations of their interactions during viral infection.

  8. Charge carrier concentration dependence of encounter-limited bimolecular recombination in phase-separated organic semiconductor blends

    Science.gov (United States)

    Heiber, Michael C.; Nguyen, Thuc-Quyen; Deibel, Carsten

    2016-05-01

    Understanding how the complex intermolecular configurations and nanostructure present in organic semiconductor donor-acceptor blends impacts charge carrier motion, interactions, and recombination behavior is a critical fundamental issue with a particularly major impact on organic photovoltaic applications. In this study, kinetic Monte Carlo (KMC) simulations are used to numerically quantify the complex bimolecular charge carrier recombination behavior in idealized phase-separated blends. Recent KMC simulations have identified how the encounter-limited bimolecular recombination rate in these blends deviates from the often used Langevin model and have been used to construct the new power mean mobility model. Here, we make a challenging but crucial expansion to this work by determining the charge carrier concentration dependence of the encounter-limited bimolecular recombination coefficient. In doing so, we find that an accurate treatment of the long-range electrostatic interactions between charge carriers is critical, and we further argue that many previous KMC simulation studies have used a Coulomb cutoff radius that is too small, which causes a significant overestimation of the recombination rate. To shed more light on this issue, we determine the minimum cutoff radius required to reach an accuracy of less than ±10 % as a function of the domain size and the charge carrier concentration and then use this knowledge to accurately quantify the charge carrier concentration dependence of the recombination rate. Using these rigorous methods, we finally show that the parameters of the power mean mobility model are determined by a newly identified dimensionless ratio of the domain size to the average charge carrier separation distance.

  9. Irreversible bimolecular reactions with inertia: from the trapping to the target setting at finite densities.

    Science.gov (United States)

    Piazza, Francesco; Foffi, Giuseppe; De Michele, Cristiano

    2013-06-19

    We investigate numerically pseudo-first-order irreversible bimolecular reactions of the type A + B → B between hard spheres undergoing event-driven Brownian dynamics. We study the encounter rate and the survival probability of A particles as functions of the packing fraction ϕ in the trapping (a single particle diffusing among static non-overlapping traps) and target (many traps diffusing in the presence of a single static target particle) settings, as well as in the case of diffusing traps and particles (full mobility). We show that, since inertial effects are accounted for in our simulation protocol, the standard Smoluchowski theory of coagulation of non-interacting colloids is recovered only at times greater than a characteristic time Δt, marking the transition from the under-damped to the over-damped regime. We show that the survival probability S(t) decays exponentially during this first stage, with a rate 1/τ0 is proportional to φ. Furthermore, we work out a simple analytical expression that is able to capture to an excellent extent the numerical results for t < Δt at low and intermediate densities. Moreover, we demonstrate that the time constant of the asymptotic exponential decay of S(t) for diffusing traps and particles is k(S)(-1), where kS = 4π(DA + DB)Rρ is the Smoluchowski rate. Detailed analyses of the effective decay exponent β = d [log(-logS(t))]/d (logt) and of the steady-state encounter rate reveal that the full mobility and trapping problem are characterized by very similar kinetics, rather different from the target problem. Our results do not allow one to ascertain whether the prediction S(t) is proportional to exp(-at(3/2)) (a = const.) as t → ∞ for the trapping problem in 3D is indeed recovered. In fact, at high density, S(t) is dominated by short encounter times, which makes it exceedingly hard to record the events corresponding to the exploration of large, trap-free regions. As a consequence, at high densities the steady

  10. Infrared laser induced organic reactions. 2. Laser vs. thermal inducment of unimolecular and hydrogen bromide catalyzed bimolecular dehydration of alcohols

    International Nuclear Information System (INIS)

    It has been demonstrated that a mixture of reactant molecules can be induced by pulsed infrared laser radiation to react via a route which is totally different from the pathway resulting from heating the mixture at 3000C. The high-energy unimolecular elimination of H2O from ethanol in the presence of 2-propanol and HBr can be selectively induced with a pulsed CO2 laser in preference to either a lower energy bimolecular HBr-catalyzed dehydration or the more facile dehydration of 2-propanol. Heating the mixture resulted in the almost exclusive reaction of 2-propanol to produce propylene. It was demonstrated that the bimolecular ethanol + HBr reaction cannot be effectively induced by the infrared laser radiation as evidenced by the detrimental effect on the yield of ethylene as the HBr pressure was increased. The selective, nonthermal inducement of H2O elimination from vibrationally excited ethanol in the presence of 2-propanol required relatively low reactant pressures. At higher pressures intermolecular V--V energy transfer allowed the thermally more facile dehydration from 2-propanol to become the predominant reaction channel

  11. Bimolecular Fluorescence Complementation (BiFC) Analysis of Protein-Protein Interactions and Assessment of Subcellular Localization in Live Cells.

    Science.gov (United States)

    Pratt, Evan P S; Owens, Jake L; Hockerman, Gregory H; Hu, Chang-Deng

    2016-01-01

    Bimolecular fluorescence complementation (BiFC) is a fluorescence imaging technique used to visualize protein-protein interactions (PPIs) in live cells and animals. One unique application of BiFC is to reveal subcellular localization of PPIs. The superior signal-to-noise ratio of BiFC in comparison with fluorescence resonance energy transfer or bioluminescence resonance energy transfer enables its wide applications. Here, we describe how confocal microscopy can be used to detect and quantify PPIs and their subcellular localization. We use basic leucine zipper transcription factor proteins as an example to provide a step-by-step BiFC protocol using a Nikon A1 confocal microscope and NIS-Elements imaging software. The protocol given below can be readily adapted for use with other confocal microscopes or imaging software. PMID:27515079

  12. Unusual charge transport and reduced bimolecular recombination in PDTSiTzTz:PC71BM bulk heterojunction blend

    International Nuclear Information System (INIS)

    Solar cells with bulk heterojunction active layers containing donor-acceptor copolymer PDTSiTzTz exhibit persistent high fill factors with thicknesses up to 400 nm. Transport and recombination in a blend of PDTSiTzTz and fullerene derivative PC71BM is studied using lateral organic photovoltaic structures. This material system is characterized by carrier-concentration-dependent charge carrier mobilities, a strongly reduced bimolecular recombination factor, and a negative Poole–Frenkel coefficient. The analysis provides an explanation for the relatively thickness-independent fill factor behaviour seen in solar cells using the copolymer PDTSiTzTz. Cumulative insights from this copolymer can be employed for future organic photovoltaic material development, study of existing high performance bulk heterojunciton blends, and improved solar cell design. (paper)

  13. Lighting the Way to Protein-Protein Interactions: Recommendations on Best Practices for Bimolecular Fluorescence Complementation Analyses[OPEN

    Science.gov (United States)

    Kudla, Jörg

    2016-01-01

    Techniques to detect and verify interactions between proteins in vivo have become invaluable tools in functional genomic research. While many of the initially developed interaction assays (e.g., yeast two-hybrid system and split-ubiquitin assay) usually are conducted in heterologous systems, assays relying on bimolecular fluorescence complementation (BiFC; also referred to as split-YFP assays) are applicable to the analysis of protein-protein interactions in most native systems, including plant cells. Like all protein-protein interaction assays, BiFC can produce false positive and false negative results. The purpose of this commentary is to (1) highlight shortcomings of and potential pitfalls in BiFC assays, (2) provide guidelines for avoiding artifactual interactions, and (3) suggest suitable approaches to scrutinize potential interactions and validate them by independent methods. PMID:27099259

  14. Characterization of the latent membrane protein 1 signaling complex of Epstein-Barr virus in the membrane of mammalian cells with bimolecular fluorescence complementation

    OpenAIRE

    Everly David N; Emery Amanda; Talaty Pooja

    2011-01-01

    Abstract Background Bimolecular fluorescence complementation (BiFC) is a novel technique to examine protein-protein interaction through the assembly of fluorescent proteins. In the present study, BiFC was used to study the assembly of the Epstein-Barr virus latent membrane protein 1 (LMP1) signaling complex within the membrane of mammalian cells. LMP1 signaling requires oligomerization, localization to lipid rafts, and association of the cytoplasmic domain to adaptor proteins, such as the tum...

  15. Origin of the high open circuit voltage in planar heterojunction perovskite solar cells: Role of the reduced bimolecular recombination

    Science.gov (United States)

    Yang, Wenchao; Yao, Yao; Wu, Chang-Qin

    2015-03-01

    The high open circuit voltage is an attractive feature for the currently popular organic-inorganic hybrid perovskite solar cells. In this paper, by employing the macroscopic device model simulation, we investigate its origin for the planar heterojunction perovskite solar cells. Based on the calculated current density-voltage characteristics, it is revealed that compared to the excitonic solar cells, the fast thermal-activated exciton dissociation in the bulk due to the small exciton binding energy may improve the short circuit current and the fill factor, but its beneficial role on the open circuit voltage is marginal. The most significant contribution for the open circuit voltage comes from the reduced bimolecular recombination. In the perovskites, with the recombination prefactor many orders of magnitude smaller than that based on the Langevin's theory, the internal charge density level is significantly enhanced and the density gradient is removed, leading to the high quasi-Fermi level splitting and thus the small open circuit voltage loss. For the nonradiative recombination pathway due to the deep trap states, it may induce significant loss of open circuit voltage as the trap density is high, while for the moderately low density its effect on the open circuit voltage is small and negligible.

  16. Molecular beam studies of unimolecular and bimolecular chemical reaction dynamics using VUV synchrotron radiation as a product probe

    Energy Technology Data Exchange (ETDEWEB)

    Blank, D.A.

    1997-08-01

    This dissertation describes the use of a new molecular beam apparatus designed to use tunable VUV synchrotron radiation for photoionization of the products from scattering experiments. The apparatus was built at the recently constructed Advanced Light Source at Lawrence Berkeley National Laboratory, a third generation 1-2 GeV synchrotron radiation source. The new apparatus is applied to investigations of the dynamics of unimolecular reactions, photodissociation experiments, and bimolecular reactions, crossed molecular beam experiments. The first chapter describes the new apparatus and the VUV radiation used for photoionization. This is followed by a number of examples of the many advantages provided by using VUV photoionization in comparison with the traditional technique of electron bombardment ionization. At the end of the chapter there is a discussion of the data analysis employed in these scattering experiments. The remaining four chapters are complete investigations of the dynamics of four chemical systems using the new apparatus and provide numerous additional examples of the advantages provided by VUV photoionizaiton of the products. Chapters 2-4 are photofragment translational spectroscopy studies of the photodissociation dynamics of dimethyl sulfoxide, acrylonitrile, and vinyl chloride following absorption at 193 mn. All of these systems have multiple dissociation channels and provide good examples of the ability of the new apparatus to unravel the complex UV photodissociation dynamics that can arise in small polyatomic molecules.

  17. Probing Single-Molecule Dissociations from a Bimolecular Complex NO-Co-Porphyrin.

    Science.gov (United States)

    Kim, Howon; Chang, Yun Hee; Jang, Won-Jun; Lee, Eui-Sup; Kim, Yong-Hyun; Kahng, Se-Jong

    2015-07-28

    Axial coordinations of diatomic NO molecules to metalloporphyrins play key roles in dynamic processes of biological functions such as blood pressure control and immune response. Probing such reactions at the single molecule level is essential to understand their physical mechanisms but has been rarely performed. Here we report on our single molecule dissociation experiments of diatomic NO from NO-Co-porphyrin complexes describing its dissociation mechanisms. Under tunneling junctions of scanning tunneling microscope, both positive and negative energy pulses gave rise to dissociations of NO with threshold voltages, +0.68 and -0.74 V at 0.1 nA tunneling current on Au(111). From the observed power law relations between dissociation rate and tunneling current, we argue that the dissociations were inelastically induced with molecular orbital resonances by stochastically tunneling electrons, which is supported with our density functional theory calculations. Our study shows that single molecule dissociation experiments can be used to probe reaction mechanisms in a variety of axial coordinations between small molecules and metalloporphyrins. PMID:26172541

  18. Vectors for multi-color bimolecular fluorescence complementation to investigate protein-protein interactions in living plant cells

    Directory of Open Access Journals (Sweden)

    Kuang Lin-Yun

    2008-10-01

    Full Text Available Abstract Background The investigation of protein-protein interactions is important for characterizing protein function. Bimolecular fluorescence complementation (BiFC has recently gained interest as a relatively easy and inexpensive method to visualize protein-protein interactions in living cells. BiFC uses "split YFP" tags on proteins to detect interactions: If the tagged proteins interact, they may bring the two split fluorophore components together such that they can fold and reconstitute fluorescence. The sites of interaction can be monitored using epifluorescence or confocal microscopy. However, "conventional" BiFC can investigate interactions only between two proteins at a time. There are instances when one may wish to offer a particular "bait" protein to several "prey" proteins simultaneously. Preferential interaction of the bait protein with one of the prey proteins, or different sites of interaction between the bait protein and multiple prey proteins, may thus be observed. Results We have constructed a series of gene expression vectors, based upon the pSAT series of vectors, to facilitate the practice of multi-color BiFC. The bait protein is tagged with the C-terminal portion of CFP (cCFP, and prey proteins are tagged with the N-terminal portions of either Venus (nVenus or Cerulean (nCerulean. Interaction of cCFP-tagged proteins with nVenus-tagged proteins generates yellow fluorescence, whereas interaction of cCFP-tagged proteins with nCerulean-tagged proteins generates blue fluorescence. Additional expression of mCherry indicates transfected cells and sub-cellular structures. Using this system, we have determined in both tobacco BY-2 protoplasts and in onion epidermal cells that Agrobacterium VirE2 protein interacts with the Arabidopsis nuclear transport adapter protein importin α-1 in the cytoplasm, whereas interaction of VirE2 with a different importin α isoform, importin α-4, occurs predominantly in the nucleus. Conclusion Multi

  19. Bimolecular Fluorescence Complementation (BiFC) Assay for Direct Visualization of Protein-Protein Interaction in vivo

    Science.gov (United States)

    Lai, Hsien-Tsung; Chiang, Cheng-Ming

    2016-01-01

    Bimolecular Fluorescence Complementation (BiFC) assay is a method used to directly visualize protein-protein interaction in vivo using live-cell imaging or fixed cells. This protocol described here is based on our recent paper describing the functional association of human chromatin adaptor and transcription cofactor Brd4 with p53 tumor suppressor protein (Wu et al., 2013). BiFC was first described by Hu et al. (2002) using two non-fluorescent protein fragments of enhanced yellow fluorescent protein (EYFP), which is an Aequorea victoria GFP variant protein, fused respectively to a Rel family protein and a bZIP family transcription factor to investigate interactions between these two family members in living cells. The YFP was later improved by introducing mutations to reduce its sensitivity to pH and chloride ions, thus generating a super-enhanced YFP, named Venus fluorescent protein, without showing diminished fluorescence at 37 °C as typically observed with EYFP (Nagai et al., 2006). The fluorescence signal is regenerated by complementation of two non-fluorescent fragments (e.g., the Venus N-terminal 1–158 amino acid residues, called Venus-N, and its C-terminal 159–239 amino acid residues, named Venus-C; see Figure 1A and Gully et al., 2012; Ding et al., 2006; Kerppola, 2006) that are brought together by interaction between their respective fusion partners (e.g., Venus-N to p53, and Venus-C to the PDID domain of human Brd4; see Figure 1B and 1C). The intensity and cellular location of the regenerated fluorescence signals can be detected by fluorescence microscope. The advantages of the proximity-based BiFC assay are: first, it allows a direct visualization of spatial and temporal interaction between two partner proteins in vivo; second, the fluorescence signal provides a sensitive readout for detecting protein-protein interaction even at a low expression level comparable to that of the endogenous proteins; third, the intensity of the fluorescence signal is

  20. Measurement of the rate of bimolecular electron spin relaxation between pairs of reactive radicals using time-resolved electron spin-echo spectroscopy

    International Nuclear Information System (INIS)

    The time-resolved electron spin echo (ESE) method has been employed to measure the bimolecular contribution to electron spin relaxation in the acetate radical xCH2CO-2, formed by pulse radiolysis. Time-resolved ESE signals from solutions containing up to 4 x 10-4 M initial radical concentrations were analyzed using Bloch equations modified to include the effects of strong Heisenberg exchange, chemical reaction, and CIDEP. It is found that the electron exchange rate is approx.3 times faster than the chemical reaction rate, contrary to a simple model involving only statistical factors which predicts equal rates for the two processes. It is also found that the CIDEP enhancement factor is independent of initial radical concentration over the ten fold range of concentrations studied

  1. Ultrafast photogeneration mechanisms of triplet states in para-hexaphenyl

    OpenAIRE

    Zenz, C.; Cerullo, G.; G. Lanzani; Graupner, W.; Meghdadi, F.; Leising, G.; Silvestri, S

    1999-01-01

    We present femtosecond pump-probe measurements, both conventional and electric field-assisted, on organic light-emitting devices based on para-hexaphenyl. The dominant triplet excition generation mechanism is assigned to nongeminate bimolecular recombination of photogenerated, spin-1/2 polarons. This process is active within a few hundred femtoseconds after photoexcitation and involves about 20% of the initially excited states. At higher photoexcitation densities, we observe an additional tri...

  2. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  3. Identification of transmembrane protein 134 as a novel LMP1-binding protein by using bimolecular fluorescence complementation and an enhanced retroviral mutagen.

    Science.gov (United States)

    Talaty, Pooja; Emery, Amanda; Holthusen, Kirsten; Everly, David N

    2012-10-01

    Latent membrane protein 1 (LMP1) of Epstein-Barr virus induces constitutive signaling in infected cells. LMP1 signaling requires oligomerization of LMP1 via its transmembrane domain, localization to lipid rafts in the membrane, and association of the LMP1 cytoplasmic domain to adaptor proteins, such as the tumor necrosis factor receptor-associated factors (TRAFs). Protein complementation is a novel technique to examine protein-protein interaction through the assembly of functional fluorescent proteins or enzymes from inactive fragments. A previous study in our lab demonstrated the use of bimolecular fluorescence complementation (BiFC) to study the assembly of the LMP1 signaling complexes within the plasma membrane of mammalian cells. In the present study, LMP1 was used as bait in a genome-wide BiFC screen with an enhanced retroviral mutagen to identify new LMP1-binding proteins. Our screen identified a novel LMP1-binding protein, transmembrane protein 134 (Tmem134). Tmem134 is a candidate oncogene that is amplified in breast cancer cell lines. Binding, colocalization, and cofractionation between LMP1 and Tmem134 were confirmed. Finally, Tmem134 affected LMP1-induced NF-κB induction. Together, these data suggest that BiFC is a unique and novel platform to identify proteins recruited to the LMP1-signaling complex. PMID:22855487

  4. Characterization of the latent membrane protein 1 signaling complex of Epstein-Barr virus in the membrane of mammalian cells with bimolecular fluorescence complementation

    Directory of Open Access Journals (Sweden)

    Everly David N

    2011-08-01

    Full Text Available Abstract Background Bimolecular fluorescence complementation (BiFC is a novel technique to examine protein-protein interaction through the assembly of fluorescent proteins. In the present study, BiFC was used to study the assembly of the Epstein-Barr virus latent membrane protein 1 (LMP1 signaling complex within the membrane of mammalian cells. LMP1 signaling requires oligomerization, localization to lipid rafts, and association of the cytoplasmic domain to adaptor proteins, such as the tumor necrosis factor receptor associated factors (TRAFs. Methods LMP1-TRAF and LMP1-LMP1 interactions were assayed by BiFC using fluorescence microscopy and flow cytometry. Function of LMP1 BiFC contructs were confirmed by transformation assays and nuclear factor- κB (NF-κB reporter assays. Results BiFC was observed between LMP1 and TRAF2 or TRAF3 and mutation of the LMP1 signaling domains reduced complementation. Fluorescence was observed in previously described LMP1 signaling locations. Oligomerization of LMP1 with itself induced complementation and BiFC. LMP1-BiFC constructs were fully functional in rodent fibroblast transformation assays and activation of NF-κB reporter activity. The BiFC domain partially suppressed some LMP1 mutant phenotypes. Conclusions Together these data suggest that BiFC is a unique and novel platform to identify and characterize proteins recruited to the LMP1-signaling complex.

  5. In planta Protein Interactions of Three Alphacryptoviruses and Three Betacryptoviruses from White Clover, Red Clover and Dill by Bimolecular Fluorescence Complementation Analysis

    Directory of Open Access Journals (Sweden)

    Till Lesker

    2013-10-01

    Full Text Available Plant-infecting viruses of the genera Alpha- and Betacryptovirus within the family Partitiviridae cause no visible effects on their hosts and are only transmitted by cell division and through gametes. The bipartite dsRNA genome is encoding a RNA-dependent RNA polymerase (RdRp and a coat protein (CP. Aside from sequence and structural analysis, the investigation of protein interactions is another step towards virus characterization. Therefore, ORFs of two type members White Clover Cryptic Virus 1 and 2 (WCCV-1 and WCCV-2, as well as the related viruses from Red Clover and Dill were introduced into a bimolecular fluorescence complementation assay. We showed CP-CP dimerization for all tested viruses with localization for alphacryptoviruses at the nuclear membrane and for betacryptoviruses close to cell walls within the cytoplasm. For CPs of WCCV-1 and WCCV-2, deletion mutants were created to determine internal interaction sites. Moreover, RdRp self-interaction was found for all viruses, whereas CP-RdRp interactions were only detectable for the alphacryptoviruses. An intra-genus test of CPs was successful in various virus combinations, whereas an inter-genus interaction of WCCV-1CP and WCCV-2CP was absent. This is the first report of in vivo protein interactions of members in the family Partitiviridae, indicating distinct features of the alpha- and betacryptoviruses.

  6. Live cell imaging of interactions between replicase and capsid protein of Brome mosaic virus using Bimolecular Fluorescence Complementation: Implications for replication and genome packaging

    International Nuclear Information System (INIS)

    In Brome mosaic virus, it was hypothesized that a physical interaction between viral replicase and capsid protein (CP) is obligatory to confer genome packaging specificity. Here we tested this hypothesis by employing Bimolecular Fluorescent Complementation (BiFC) as a tool for evaluating protein–protein interactions in living cells. The efficacy of BiFC was validated by a known interaction between replicase protein 1a (p1a) and protein 2a (p2a) at the endoplasmic reticulum (ER) site of viral replication. Additionally, co-expression in planta of a bona fide pair of interacting protein partners of p1a and p2a had resulted in the assembly of a functional replicase. Subsequent BiFC assays in conjunction with mCherry labeled ER as a fluorescent cellular marker revealed that CP physically interacts with p2a, but not p1a, and this CP:p2a interaction occurs at the cytoplasmic phase of the ER. The significance of the CP:p2a interaction in BMV replication and genome packaging is discussed. - Highlights: • YFP fusion proteins of BMV p1a and p2a are biologically active. • Self-interaction was observed for p1a, p2a and CP. • CP interacts with p2a but not p1a. • Majority of reconstituted YFP resulting from bona fide fusion protein partners localized on ER

  7. Non-innocent electrolyte effects on bimolecular pseudo-self-exchange reactions of ruthenium ammine complexes: Evidence for electron-transfer catalysis in H-bonded ternary assemblies

    International Nuclear Information System (INIS)

    The kinetics of bimolecular pseudo-self-exchange reactions such as that between pentaammine(pyridine)ruthenium(II) and pentaammine(3-fluoropyridine)ruthenium(III) shown below,(NH3)5RuII(py)2++(NH3)5RuIII(3-Fpy)3+-bar kex(NH3)5RuIII(py)3++(NH3)5RuII(3-Fpy)2+reveal a novel form of non-covalently mediated electron transfer over distance when salts of non-innocent electrolytes such as the conjugated dicarboxylic acid anions trans,trans-muconate2- or terephthalate2- are added to the solution. The kinetic accelerations are distinct from those seen with simple electrolytes such as KCl or CaCl2, and are thus outside the realm of classical electrolyte effects described by the Debye-Huckel theory of ion atmospheres. Kinetic simulations are presented, and the rate acceleration is interpreted in the context of possible superexchange-type interactions taking place in hydrogen-bonded ternary (or higher) association complexes which create new kinetic pathways for electron transfer over distance in aqueous solution

  8. Live cell imaging of interactions between replicase and capsid protein of Brome mosaic virus using Bimolecular Fluorescence Complementation: Implications for replication and genome packaging

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, Sonali; Rao, A.L.N., E-mail: arao@ucr.edu

    2014-09-15

    In Brome mosaic virus, it was hypothesized that a physical interaction between viral replicase and capsid protein (CP) is obligatory to confer genome packaging specificity. Here we tested this hypothesis by employing Bimolecular Fluorescent Complementation (BiFC) as a tool for evaluating protein–protein interactions in living cells. The efficacy of BiFC was validated by a known interaction between replicase protein 1a (p1a) and protein 2a (p2a) at the endoplasmic reticulum (ER) site of viral replication. Additionally, co-expression in planta of a bona fide pair of interacting protein partners of p1a and p2a had resulted in the assembly of a functional replicase. Subsequent BiFC assays in conjunction with mCherry labeled ER as a fluorescent cellular marker revealed that CP physically interacts with p2a, but not p1a, and this CP:p2a interaction occurs at the cytoplasmic phase of the ER. The significance of the CP:p2a interaction in BMV replication and genome packaging is discussed. - Highlights: • YFP fusion proteins of BMV p1a and p2a are biologically active. • Self-interaction was observed for p1a, p2a and CP. • CP interacts with p2a but not p1a. • Majority of reconstituted YFP resulting from bona fide fusion protein partners localized on ER.

  9. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  10. Study on synthesis, application and mechanism of benzophenone/amine initiator

    International Nuclear Information System (INIS)

    Through Michael addition reaction of trimethylolpropane triacrylate (TMPTA) with diethylamine (DEA), a new kind of tertiary amine derivative was synthesized and its structure was identified by 'H-NMR. When used in combination with benzophenone, this amine presented excellent curing speed and could be a substitute for initiator Darocur R 1173, which is effective but expensive. If so, the cost of UV-curable coatings can descend apparently. The functioning mechanism of benzophenone/amine bimolecular initiator was studied

  11. Title: Elucidation of Environmental Fate of Artificial Sweeteners (Aspartame, Acesulfame K and Saccharin) by Determining Bimolecular Rate Constants with Hydroxyl Radical at Various pH and Temperature Conditions and Possible Reaction By-Products

    Science.gov (United States)

    Teraji, T.; Arakaki, T.; Suzuka, T.

    2012-12-01

    Use of artificial sweeteners in beverages and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame, acefulfame K and saccharin and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far for aspartame was (2.6±1.2)×109 M-1 s-1 at pH = 3.0 and (4.9±2.3)×109 M-1 s-1 at pH = 5.5. Little effect was seen by changing the temperatures between 15 and 40 oC. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, +8.5 kJ mol-1 at pH = 5.5, which could be regarded as zero. We will report bimolecular rate constants at different pHs and temperatures for acesulfame K and saccharin, as well. Possible reaction by-products for aspartame will be also reported. We will further discuss the fate of aspartame in the coastal environment.

  12. Kinetics of the unimolecular reaction of CH2OO and the bimolecular reactions with the water monomer, acetaldehyde and acetone under atmospheric conditions.

    Science.gov (United States)

    Berndt, Torsten; Kaethner, Ralf; Voigtländer, Jens; Stratmann, Frank; Pfeifle, Mark; Reichle, Patrick; Sipilä, Mikko; Kulmala, Markku; Olzmann, Matthias

    2015-08-14

    Stabilized Criegee Intermediates (sCIs) have been identified as oxidants of atmospheric trace gases such as SO2, NO2, carboxylic acids or carbonyls. The atmospheric sCI concentrations, and accordingly their importance for trace gas oxidation, are controlled by the rate of the most important loss processes, very likely the unimolecular reactions and the reaction with water vapour (monomer and dimer) ubiquitously present at high concentrations in the troposphere. In this study, the rate coefficients of the unimolecular reaction of the simplest sCI, formaldehyde oxide, CH2OO, and its bimolecular reaction with the water monomer have been experimentally determined at T = (297 ± 1) K and at atmospheric pressure by using a free-jet flow system. CH2OO was produced by the reaction of ozone with C2H4, and CH2OO concentrations were probed indirectly by detecting H2SO4 after titration with SO2. Time-resolved experiments yield a rate coefficient of the unimolecular reaction of k(uni) = (0.19 ± 0.07) s(-1), a value that is supported by quantum-chemical and statistical rate theory calculations as well as by additional measurements performed under CH2OO steady-state conditions. A rate coefficient of k(CH2OO+H2O) = (3.2 ± 1.2) × 10(-16) cm(3) molecule(-1) s(-1) has been determined for sufficiently low H2O concentrations (<10(15) molecule cm(-3)) that allow separation from the CH2OO reaction with the water dimer. In order to evaluate the accuracy of the experimental approach, the rate coefficients of the reactions with acetaldehyde and acetone were reinvestigated. The obtained rate coefficients k(CH2OO+acetald) = (1.7 ± 0.5) × 10(-12) and k(CH2OO+acetone) = (3.4 ± 0.9) × 10(-13) cm(3) molecule(-1) s(-1) are in good agreement with literature data. PMID:26159709

  13. Computational study of hydrogen shifts and ring-opening mechanisms in α-pinene ozonolysis products

    DEFF Research Database (Denmark)

    Kurtén, Theo; Rissanen, Matti P.; Mackeprang, Kasper; Thornton, Joel A.; Hyttinen, Noora; Jørgensen, Solvejg; Ehn, Mikael; Kjærgaard, Henrik Grum

    2015-01-01

    Autoxidation by sequential peroxy radical hydrogen shifts (H-shifts) and O2 additions has recently emerged as a promising mechanism for the rapid formation of highly oxidized, low-volatility organic compounds in the atmosphere. A key prerequisite for autoxidation is that the H-shifts of the initial...... products in the α-pinene ozonolysis system, additional ring-opening reaction mechanisms breaking the cyclobutyl ring are therefore needed. We further investigate possible uni- and bimolecular pathways for opening the cyclobutyl ring in the α-pinene ozonolysis system....

  14. Thermal stabilities and decomposition mechanism of amino- and hydroxyl-functionalized ionic liquids

    International Nuclear Information System (INIS)

    Highlights: • The long term thermal stabilities of [C2NH2MIM][Br] and [C3OHMIM][Cl] are overestimated. • The thermal decomposition mechanisms of [C2NH2MIM][Br] and [C3OHMIM][Cl] are complicated. • Bimolecular nucleophilic substitution (SN2) is the main reaction mechanism. - Abstract: Thermal stabilities and thermal decomposition mechanisms of amino-functionalized ionic liquid (IL) 1-aminoethyl-3-methylimidazolium bromide ([C2NH2MIM][Br]) and hydroxyl-functionalized IL 1-hydropropyl-3-methylimidazolium chloride ([C3OHMIM][Cl]) were investigated by thermogravimetric analysis (TGA), TG–mass spectroscopy (TG–MS), density functional theory (DFT), and nuclear magnetic resonance (NMR) spectrum. Results show that the [C2NH2MIM][Br] and [C3OHMIM][Cl] are stable up to 200 °C and 220 °C, respectively. Also, DFT calculation indicates that the thermal decomposition mechanisms of [C2NH2MIM][Br] and [C3OHMIM][Cl] are complicated, while bimolecular nucleophilic substitution (SN2) is the main reaction mechanism. TG–MS and NMR spectra further prove the mechanisms

  15. Theoretical Study on the Reaction Mechanism of F2+2HBr=2HF+Br2

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The gas phase reaction mechanism of F2 + 2HBr = 2HF + Br2 has been investigated by (U)MP2 at 6-311G** level, and a series of four-center and three-center transition states have been obtained. The reaction mechanism was achieved by comparing the activation energy of seven reaction paths, i.e. the dissociation energy of F2 is less than the activation energy of the bimolecular elementary reaction F2 + HBr → HF + BrF. Thus it is theoretically proved that the title reaction occurs more easily inthe free radical reaction with three medium steps.

  16. Density functional theory (B3LYP/6-311+G** study of some semicarbazones formation mechanism

    Directory of Open Access Journals (Sweden)

    Uzairu Adamu

    2015-12-01

    Full Text Available Mechanism of formations of (E-2-(1-phenylethylidenehydrazinecarboxamide, 2-cyclohexyldenehydrazinecarboxamide, (Z-2-(1-phenylpropan-2-ylidenehydrazinecarboxamide, (Z-2-(hexan-2-ylidenehydrazinecarboxamide and (E-2-((Ephenylallylidenehydrazinecarboxamide has been investigated using density functional theory (B3LYP/6-311+G**. The mechanism was found to involve four elementary steps comprising one intermediate and two transition states. The study indicates a two-step reaction pathway, comprising an intermediate and two activated complexes for all the compounds. The mechanism involves two transition (bimolecular and unimolecular and consecutive (bimolecular and unimolecular schemes. The formation was found to occur sequentially; a fast pre-equilibrium between the reactants and the prereactive complex is established, followed by an internal rearrangement leading to elimination of a water molecule. The thermodynamic data were obtained for the stationary points and the kinetic study shows the unimolecular consecutive step to be the rate determining step in all the formation mechanisms. A general rate law was also established for the formation pathways.

  17. Understanding of the Effects of Ionic Strength on the Bimolecular Rate Constant between Structurally Identified Redox Enzymes and Charged Substrates Using Numerical Simulations on the Basis of the Poisson-Boltzmann Equation.

    Science.gov (United States)

    Sugimoto, Yu; Kitazumi, Yuki; Shirai, Osamu; Yamamoto, Masahiro; Kano, Kenji

    2016-03-31

    To understand electrostatic interactions in biomolecules, the bimolecular rate constants (k) between redox enzymes and charged substrates (in this study, redox mediators in the electrode reaction) were evaluated at various ionic strengths (I) for the mediated bioelectrocatalytic reaction. The k value between bilirubin oxidase (BOD) and positively charged mediators increased with I, while that between BOD and negatively charged mediators decreased with I. The opposite trend was observed for the reaction of glucose oxidase (GOD). In the case of noncharged mediators, the k value was independent of I for both BOD and GOD. These results reflect the electrostatic interactions between the enzymes and the mediators. Furthermore, we estimated k/k° (k° being the thermodynamic rate constant) by numerical simulation (finite element method) based on the Poisson-Boltzmann (PB) equation. By considering the charges of individual atoms involved in the amino acids around the substrate binding sites in the enzymes, the simulated k/k° values well reproduced the experimental data. In conclusion, k/k° can be predicted by PB-based simulation as long as the crystal structure of the enzyme and the substrate binding site are known. PMID:26956542

  18. Development of Bimolecular Fluorescence Complementation reagents for the detection of Arabidopsis thaliana KAT1 protein-protein interactions using the Golden Braid cloning system

    OpenAIRE

    MOSSI ALBIACH, ALEJANDRO

    2016-01-01

    [EN] KAT1 is an Arabidopsis thaliana potassium voltage-gated channel of the Shaker family. This ion channel is fundamental for the control of membrane conductance in guard cells, leading to stomatal opening or closing in response to environmental changes. The stomatal movement controls the gas exchange, as well as the amount of water lost due to transpiration. Therefore, the underlying mechanisms of these stomatal movements will likely be influenced by proteins that regulate KAT1 ...

  19. Mechanisms of lactone hydrolysis in acidic conditions.

    Science.gov (United States)

    Gómez-Bombarelli, Rafael; Calle, Emilio; Casado, Julio

    2013-07-19

    The acid-catalyzed hydrolysis of linear esters and lactones was studied using a hybrid supermolecule-polarizable continuum model (PCM) approach including up to six water molecules. The compounds studied included two linear esters, four β-lactones, two γ-lactones, and one δ-lactone: ethyl acetate, methyl formate, β-propiolactone, β-butyrolactone, β-isovalerolactone, diketene (4-methyleneoxetan-2-one), γ-butyrolactone, 2(5H)-furanone, and δ-valerolactone. The theoretical results are in good quantitative agreement with the experimental measurements reported in the literature and also in excellent qualitative agreement with long-held views regarding the nature of the hydrolysis mechanisms at molecular level. The present results help to understand the balance between the unimolecular (A(AC)1) and bimolecular (A(AC)2) reaction pathways. In contrast to the experimental setting, where one of the two branches is often occluded by the requirement of rather extreme experimental conditions, we have been able to estimate both contributions for all the compounds studied and found that a transition from A(AC)2 to A(AC)1 hydrolysis takes place as acidity increases. A parallel work addresses the neutral and base-catalyzed hydrolysis of lactones. PMID:23731203

  20. Quantum mechanics of chemical reactions: Recent developments in reactive scattering and in reaction path Hamiltonians

    International Nuclear Information System (INIS)

    Two recent developments in the theory of chemical reaction dynamics are reviewed. First, it has recently been discovered that the S- matrix version of the Kohn variational principle is free of the ''Kohn anomalies'' that have plagued other versions and prevented its general use. This has considerably simplified quantum mechanical reactive scattering calculations, which provide the rigorous characterizations of bimolecular reactions. Second, a new kind of reaction path Hamiltonian has been developed, one based on the ''least motion'' path that interpolates linearly between the reactant and product geometry of the molecule (rather than the previously used minimum energy, or ''intrinsic'' reaction path). The form of Hamiltonian which results is much simpler than the original reaction path Hamiltonian, but more important is the fact that it provides a more physically correct description of hydrogen atom transfer reactions. 44 refs., 4 figs

  1. Kinetics and mechanisms studies on dimethyl phthalate degradation in aqueous solutions by pulse radiolysis and electron beam radiolysis

    Energy Technology Data Exchange (ETDEWEB)

    Wu Minghong; Liu, Ning [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Xu Gang, E-mail: xugang@shu.edu.c [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Ma Jing; Tang Liang; Wang Liang [School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Fu Haiying [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2011-03-15

    The kinetics and mechanisms of hydroxyl radical/hydrated electron reactions with dimethyl phthalate (DMP) were investigated using pulse radiolysis and electron beam radiolysis techniques. The bimolecular rate constants for the reaction of hydroxyl radical and hydrated electron with DMP were measured to be 3.4x10{sup 9} M{sup -1} s{sup -1} and 1.6x10{sup 10} M{sup -1} s{sup -1} under pulse radiolysis experiments, respectively. The major products after radiation were elucidated by LC/MS/MS and ion chromatography analysis. It was found that DMP degradation had different mechanisms in oxidative and reductive conditions: hydroxyl radical attacked aromatic ring of DMP leading to the fracture of benzene ring, formed a series of byproducts which were completely mineralized while hydrated electron attacked the ester group of DMP, formed the product of phthalic acid in reductive conditions.

  2. New methods for quantum mechanical reaction dynamics

    International Nuclear Information System (INIS)

    Quantum mechanical methods are developed to describe the dynamics of bimolecular chemical reactions. We focus on developing approaches for directly calculating the desired quantity of interest. Methods for the calculation of single matrix elements of the scattering matrix (S-matrix) and initial state-selected reaction probabilities are presented. This is accomplished by the use of absorbing boundary conditions (ABC) to obtain a localized (L2) representation of the outgoing wave scattering Green's function. This approach enables the efficient calculation of only a single column of the S-matrix with a proportionate savings in effort over the calculation of the entire S-matrix. Applying this method to the calculation of the initial (or final) state-selected reaction probability, a more averaged quantity, requires even less effort than the state-to-state S-matrix elements. It is shown how the same representation of the Green's function can be effectively applied to the calculation of negative ion photodetachment intensities. Photodetachment spectroscopy of the anion ABC- can be a very useful method for obtaining detailed information about the neutral ABC potential energy surface, particularly if the ABC- geometry is similar to the transition state of the neutral ABC. Total and arrangement-selected photodetachment spectra are calculated for the H3O- system, providing information about the potential energy surface for the OH + H2 reaction when compared with experimental results. Finally, we present methods for the direct calculation of the thermal rate constant from the flux-position and flux-flux correlation functions. The spirit of transition state theory is invoked by concentrating on the short time dynamics in the area around the transition state that determine reactivity. These methods are made efficient by evaluating the required quantum mechanical trace in the basis of eigenstates of the Boltzmannized flux operator

  3. Puzzling Mechanisms

    Science.gov (United States)

    van Deventer, M. Oskar

    2009-01-01

    The basis of a good mechanical puzzle is often a puzzling mechanism. This article will introduce some new puzzling mechanisms, like two knots that engage like gears, a chain whose links can be interchanged, and flat gears that do not come apart. It illustrates how puzzling mechanisms can be transformed into real mechanical puzzles, e.g., by…

  4. Bohmian Mechanics

    OpenAIRE

    Duerr, Detlef; Goldstein, Sheldon; Tumulka, Roderich; Zanghi, Nino

    2009-01-01

    Bohmian mechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmian mechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmian mechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.

  5. Mechanical impedance

    OpenAIRE

    Couroussé, Damien

    2007-01-01

    Mechanical impedance is a transposition to mechanics of the term impedance that is used and defined in circuit theory. The theory of circuit (theory of Kirchhoff networks) is basically applicable to electric networks but can be considered more generally as a unifying simplified theory of physics available in several domains like mechanics, electromagnetism, aero-acoustics and fluids mechanics.

  6. Continuum mechanics

    CERN Document Server

    Spencer, A J M

    2004-01-01

    The mechanics of fluids and the mechanics of solids represent the two major areas of physics and applied mathematics that meet in continuum mechanics, a field that forms the foundation of civil and mechanical engineering. This unified approach to the teaching of fluid and solid mechanics focuses on the general mechanical principles that apply to all materials. Students who have familiarized themselves with the basic principles can go on to specialize in any of the different branches of continuum mechanics. This text opens with introductory chapters on matrix algebra, vectors and Cartesian ten

  7. Creep mechanics

    CERN Document Server

    Betten, Josef

    2008-01-01

    This book explores recent advances in the mathematical modeling of the mechanical behavior of anisotropic solids under creep conditions. It also offers an overview of other experimental investigations in creep mechanics.

  8. Mechanical design

    CERN Document Server

    Risitano, Antonino

    2011-01-01

    METHODOLOGICAL STATEMENT OF ENGINEERING DESIGNApproaches to product design and developmentMechanical design and environmental requirementsPROPERTIES OF ENGINEERING MATERIALSMaterials for mechanical designCharacterization of metalsStress conditionsFatigue of materialsOptimum material selection in mechanical designDESIGN OF MECHANICAL COMPONENTS AND SYSTEMSFailure theoriesHertz theoryLubrificationShafts and bearingsSplines and keysSpringsFlexible machine elementsSpur gearsPress and shrink fitsPressure tubesCouplingsClutchesBrakes

  9. A four-step mechanism for the formation of supported-nanoparticle heterogenous catalysts in contact with solution: the conversion of Ir(1,5-COD)Cl/γ-Al2O3 to Ir(0)(∼170)/γ-Al2O3.

    Science.gov (United States)

    Kent, Patrick D; Mondloch, Joseph E; Finke, Richard G

    2014-02-01

    Product stoichiometry, particle-size defocusing, and kinetic evidence are reported consistent with and supportive of a four-step mechanism of supported transition-metal nanoparticle formation in contact with solution: slow continuous nucleation, A → B (rate constant k1), autocatalytic surface growth, A + B → 2B (rate constant k2), bimolecular agglomeration, B + B → C (rate constant k3), and secondary autocatalytic surface growth, A + C → 1.5C (rate constant k4), where A is nominally the Ir(1,5-COD)Cl/γ-Al2O3 precursor, B the growing Ir(0) particles, and C the larger, catalytically active nanoparticles. The significance of this work is at least 4-fold: first, this is the first documentation of a four-step mechanism for supported-nanoparticle formation in contact with solution. Second, the proposed four-step mechanism, which was obtained following the disproof of 18 alternative mechanisms, is a new four-step mechanism in which the new fourth step is A + C → 1.5C in the presence of the solid, γ-Al2O3 support. Third, the four-step mechanism provides rare, precise chemical and kinetic precedent for metal particle nucleation, growth, and now agglomeration (B + B → C) and secondary surface autocatalytic growth (A + C → 1.5C) involved in supported-nanoparticle heterogeneous catalyst formation in contact with solution. Fourth, one now has firm, disproof-based chemical-mechanism precedent for two specific, balanced pseudoelementary kinetic steps and their precise chemical descriptors of bimolecular particle agglomeration, B + B → C, and autocatalytic agglomeration, B + C → 1.5C, involved in, for example, nanoparticle catalyst sintering. PMID:24444431

  10. Discrete mechanics

    International Nuclear Information System (INIS)

    This paper reviews the role of time throughout all phases of mechanics: classical mechanics, non-relativistic quantum mechanics, and relativistic quantum theory. As an example of the relativistic quantum field theory, the case of a massless scalar field interacting with an arbitrary external current is discussed. The comparison between the new discrete theory and the usual continuum formalism is presented. An example is given of a two-dimensional random lattice and its duel. The author notes that there is no evidence that the discrete mechanics is more appropriate than the usual continuum mechanics

  11. Discrete mechanics

    CERN Document Server

    Caltagirone, Jean-Paul

    2014-01-01

    This book presents the fundamental principles of mechanics to re-establish the equations of Discrete Mechanics. It introduces physics and thermodynamics associated to the physical modeling.  The development and the complementarity of sciences lead to review today the old concepts that were the basis for the development of continuum mechanics. The differential geometry is used to review the conservation laws of mechanics. For instance, this formalism requires a different location of vector and scalar quantities in space. The equations of Discrete Mechanics form a system of equations where the H

  12. Elucidation of Environmental Fate of Artificial Sweetener, Aspartame by Determining Bimolecular Rate Constants with Hydroxyl Radical at Various pH and Temperature Conditions and Reaction By-Products Presentation type:Poster Section:Ocean Sciences Session:General Contribution Authors:Takashi Teraji (1) Takemitsu Arakaki (2) AGU# 10173629 (1) Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0123, Japan (a4269bj@yahoo.co.jp), (2) Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa, 903-0123, Japan (arakakit@sci.u-ryukyu.ac.jp)

    Science.gov (United States)

    Teraji, T.; Arakaki, T.

    2011-12-01

    Use of artificial sweeteners in drinks and food has been rapidly increasing because of their non-calorie nature. In Japan, aspartame, acesulfame K and sucralose are among the most widely used artificial sweeteners. Because the artificial sweeteners are not metabolized in human bodies, they are directly excreted into the environment without chemical transformations. We initiated a study to better understand the fate of artificial sweeteners in the marine environment. In particular, we focused on the fate of aspartame by determining its bimolecular rate constants with hydroxyl radicals at various pH and temperature conditions and reaction by-products. The hydroxyl radical (OH), the most potent reactive oxygen species, reacts with various compounds and determines the environmental oxidation capacity and the life-time of many compounds. The steady-state OH concentration and the reaction rate constants between the compound and OH are used to estimate the life-time of the compound. In this study, we determine the bimolecular rate constants between aspartame and OH at various pH and temperature conditions using a competition kinetics technique. We use hydrogen peroxide as a photochemical source of OH. Bimolecular rate constant we obtained so far was (2.6±1.2)×109 M-1 s-1 at pH = 3.0. Little effect was seen by changing the temperatures between 15 and 40 °C. Activation energy (Ea) was calculated to be -1.0 kJ mol-1 at pH = 3.0, which could be regarded as zero. We will report reaction rate constants at different pHs and reaction by-products which will be analyzed by GC-MS. We will further discuss the fate of aspartame in the coastal environment.

  13. Mechanisms Design

    DEFF Research Database (Denmark)

    Restrepo-Giraldo, John Dairo

    2006-01-01

    Most products and machines involve some kind of controlled movement. From window casements to DVD players, from harbor cranes to the shears to prune your garden, all these machines require mechanisms to move. This course intends to provide the analytical and conceptual tools to design such mechan......Most products and machines involve some kind of controlled movement. From window casements to DVD players, from harbor cranes to the shears to prune your garden, all these machines require mechanisms to move. This course intends to provide the analytical and conceptual tools to design...... using criteria such as size, performance parameters, operation environment, etc. Content: Understanding Mechanisms Design (2 weeks) Definitions, mechanisms representations, kinematic diagrams, the four bar linkage, mobility, applications of mechanisms, types of mechanisms, special mechanisms, the design...... and acceleration determination (2 weeks) Graphical position analysis, analytical position analysis, graphical velocity analysis, analytical velocity analysis, instant centers, velocity analysis using instant centers, transfer functions, conservation of energy and power, virtual work, quality of mechanisms, summary...

  14. Geometric mechanics

    CERN Document Server

    Muniz Oliva, Waldyr

    2002-01-01

    Geometric Mechanics here means mechanics on a pseudo-riemannian manifold and the main goal is the study of some mechanical models and concepts, with emphasis on the intrinsic and geometric aspects arising in classical problems. The first seven chapters are written in the spirit of Newtonian Mechanics while the last two ones as well as two of the four appendices describe the foundations and some aspects of Special and General Relativity. All the material has a coordinate free presentation but, for the sake of motivation, many examples and exercises are included in order to exhibit the desirable flavor of physical applications.

  15. The thrombin binding aptamer GGTTGGTGTGGTTGG forms a bimolecular guanine tetraplex

    Czech Academy of Sciences Publication Activity Database

    Fialová, Markéta; Kypr, Jaroslav; Vorlíčková, Michaela

    2006-01-01

    Roč. 344, 1 (2006), s. 50-54. ISSN 0006-291X R&D Projects: GA AV ČR(CZ) IAA4004201 Institutional research plan: CEZ:AV0Z50040507 Keywords : DNA tetraplex * thrombin binding aptamer * CD spectroscopy Subject RIV: BO - Biophysics Impact factor: 2.855, year: 2006

  16. Bimolecular fluorescence complementation analysis of eukaryotic fusion products

    OpenAIRE

    Lin, Ho-Pi; Vincenz, Claudius; Eliceiri, Kevin W.; Kerppola, Tom K.; Ogle, Brenda M.

    2010-01-01

    Background information. Cell fusion is known to underlie key developmental processes in humans and is postulated to contribute to tissue maintenance and even carcinogenesis. The mechanistic details of cell fusion, especially between different cell types, have been difficult to characterize because of the dynamic nature of the process and inadequate means to track fusion products over time. Here we introduce an inducible system for detecting and tracking live cell fusion products in vitro and ...

  17. A general expression for bimolecular association rates with orientational constraints

    CERN Document Server

    Schlosshauer, M; Schlosshauer, Maximilian; Baker, David

    2002-01-01

    We present a general expression for the association rate for partially diffusion-controlled reactions between spherical molecules with an asymmetric reactive patch on each surface. Reaction can occur only if the two patches are in contact and properly aligned to within specified angular tolerances. This extends and generalizes previous approaches that considered only axially symmetric patches; the earlier solutions are shown to be limiting cases of our general expression. Previous numerical results on the rate of protein-protein association with high steric specificity are in very good agreement with the value computed from our analytic expression. Using the new expression, we investigate the influence of orientational constraints on the rate constant. We find that for angular constraints of ~5-15 degrees, a typical range for example in the case of protein-protein interactions, the reaction rate is about 2 to 3 orders of magnitude higher than expected from a simple geometric model.

  18. College mechanics

    CERN Document Server

    Şengül, Caner

    2016-01-01

    College Mechanics QueBank has been designed to be different, enthusiastic, interesting and helpful to you. Therefore, it is not just a test bank about mechanics but also it is like a compass in order to find your way in mechanics Each chapter in this book is put in an order to follow a hierarchy of the mechanics topics; from vectors to simple harmonic motion. Throughout the book there are many multiple choice and long answer questions for you to solve. They have been created for YGS, LYS, SAT, IB or other standardized exams in the world because mechanics has no boundaries and so Physics has no country. Learn the main principle of each chapter and explore the daily life applications. Then you can start to solve the questions by planning a problem solving method carefully. Finally, enjoy solving the questions and discover the meachanics of the universe once more.

  19. Quantum mechanics

    CERN Document Server

    Rae, Alastair I M

    2016-01-01

    A Thorough Update of One of the Most Highly Regarded Textbooks on Quantum Mechanics Continuing to offer an exceptionally clear, up-to-date treatment of the subject, Quantum Mechanics, Sixth Edition explains the concepts of quantum mechanics for undergraduate students in physics and related disciplines and provides the foundation necessary for other specialized courses. This sixth edition builds on its highly praised predecessors to make the text even more accessible to a wider audience. It is now divided into five parts that separately cover broad topics suitable for any general course on quantum mechanics. New to the Sixth Edition * Three chapters that review prerequisite physics and mathematics, laying out the notation, formalism, and physical basis necessary for the rest of the book * Short descriptions of numerous applications relevant to the physics discussed, giving students a brief look at what quantum mechanics has made possible industrially and scientifically * Additional end-of-chapter problems with...

  20. Cytoskeletal Mechanics

    Science.gov (United States)

    Mofrad, Mohammad R. K.; Kamm, Roger D.

    2011-08-01

    1. Introduction and the biological basis for cell mechanics Mohammad R. K. Mofrad and Roger Kamm; 2. Experimental measurements of intracellular mechanics Paul Janmey and Christoph Schmidt; 3. The cytoskeleton as a soft glassy material Jeffrey Fredberg and Ben Fabry; 4. Continuum elastic or viscoelastic models for the cell Mohammad R. K. Mofrad, Helene Karcher and Roger Kamm; 5. Multiphasic models of cell mechanics Farshid Guuilak, Mansoor A. Haider, Lori A. Setton, Tod A. Laursen and Frank P. T. Baaijens; 6. Models of cytoskeletal mechanics based on tensegrity Dimitrije Stamenovic; 7. Cells, gels and mechanics Gerald H. Pollack; 8. Polymer-based models of cytoskeletal networks F. C. MacKintosh; 9. Cell dynamics and the actin cytoskeleton James L. McGrath and C. Forbes Dewey, Jr; 10. Active cellular motion: continuum theories and models Marc Herant and Micah Dembo; 11. Summary Mohammad R. K. Mofrad and Roger Kamm.

  1. Fracture Mechanics

    CERN Document Server

    Zehnder, Alan T

    2012-01-01

    Fracture mechanics is a vast and growing field. This book develops the basic elements needed for both fracture research and engineering practice. The emphasis is on continuum mechanics models for energy flows and crack-tip stress- and deformation fields in elastic and elastic-plastic materials. In addition to a brief discussion of computational fracture methods, the text includes practical sections on fracture criteria, fracture toughness testing, and methods for measuring stress intensity factors and energy release rates. Class-tested at Cornell, this book is designed for students, researchers and practitioners interested in understanding and contributing to a diverse and vital field of knowledge. Alan Zehnder joined the faculty at Cornell University in 1988. Since then he has served in a number of leadership roles including Chair of the Department of Theoretical and Applied Mechanics, and Director of the Sibley School of Mechanical and Aerospace Engineering.  He teaches applied mechanics and his research t...

  2. Respiratory mechanics

    CERN Document Server

    Wilson, Theodore A

    2016-01-01

    This book thoroughly covers each subfield of respiratory mechanics: pulmonary mechanics, the respiratory pump, and flow. It presents the current understanding of the field and serves as a guide to the scientific literature from the golden age of respiratory mechanics, 1960 - 2010. Specific topics covered include the contributions of surface tension and tissue forces to lung recoil, the gravitational deformation of the lung, and the interdependence forces that act on pulmonary airways and blood vessels. The geometry and kinematics of the ribs is also covered in detail, as well as the respiratory action of the external and internal intercostal muscles, the mechanics of the diaphragm, and the quantitative compartmental models of the chest wall is also described. Additionally, flow in the airways is covered thoroughly, including the wave-speed and viscous expiratory flow-limiting mechanisms; convection, diffusion and the stationary front; and the distribution of ventilation. This is an ideal book for respiratory ...

  3. Bohmian mechanics contradicts quantum mechanics

    OpenAIRE

    Neumaier, Arnold

    2000-01-01

    It is shown that, for a harmonic oscillator in the ground state, Bohmian mechanics and quantum mechanics predict values of opposite sign for certain time correlations. The discrepancy can be explained by the fact that Bohmian mechanics has no natural way to accomodate the Heisenberg picture, since the local expectation values that define the beables of the theory depend on the Heisenberg time being used to define the operators. Relations to measurement are discussed, too, and shown to leave n...

  4. Fluid mechanics

    CERN Document Server

    Kundu, Pijush K; Dowling, David R

    2011-01-01

    Fluid mechanics, the study of how fluids behave and interact under various forces and in various applied situations-whether in the liquid or gaseous state or both-is introduced and comprehensively covered in this widely adopted text. Revised and updated by Dr. David Dowling, Fluid Mechanics, 5e is suitable for both a first or second course in fluid mechanics at the graduate or advanced undergraduate level. Along with more than 100 new figures, the text has been reorganized and consolidated to provide a better flow and more cohesion of topics.Changes made to the

  5. Quantum mechanics

    CERN Document Server

    Powell, John L

    2015-01-01

    Suitable for advanced undergraduates, this thorough text focuses on the role of symmetry operations and the essentially algebraic structure of quantum-mechanical theory. Based on courses in quantum mechanics taught by the authors, the treatment provides numerous problems that require applications of theory and serve to supplement the textual material.Starting with a historical introduction to the origins of quantum theory, the book advances to discussions of the foundations of wave mechanics, wave packets and the uncertainty principle, and an examination of the Schrödinger equation that includ

  6. Robot Mechanisms

    CERN Document Server

    Lenarcic, Jadran; Stanišić, Michael M

    2013-01-01

    This book provides a comprehensive introduction to the area of robot mechanisms, primarily considering industrial manipulators and humanoid arms. The book is intended for both teaching and self-study. Emphasis is given to the fundamentals of kinematic analysis and the design of robot mechanisms. The coverage of topics is untypical. The focus is on robot kinematics. The book creates a balance between theoretical and practical aspects in the development and application of robot mechanisms, and includes the latest achievements and trends in robot science and technology.

  7. Quantum mechanics

    International Nuclear Information System (INIS)

    This book, based on a thirty lecture course given to students at the beginning of their second year, covers the quantum mechanics required by physics undergraduates. Early chapters deal with wave mechanics, including a discussion of the energy states of the hydrogen atom. These are followed by a more formal development of the theory, leading to a discussion of some advanced applications and an introduction to the conceptual problems associated with quantum measurement theory. Emphasis is placed on the fundamentals of quantum mechanics. Problems are included at the end of each chapter. (U.K.)

  8. Mechanical memory

    Science.gov (United States)

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-08-15

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  9. Classical mechanics

    CERN Document Server

    Matzner, Richard A

    1991-01-01

    An advanced physics textbook that explains the mathematical and physical concepts of mechanics and their relationship to other branches of physics. Topics covered include tensor analysis, variational principles and Lagrangians, canonical transformations and estimation techniques.

  10. Engineering mechanics

    CERN Document Server

    Gross, Dietmar; Schröder, Jörg; Wall, Wolfgang A; Rajapakse, Nimal

    Statics is the first volume of a three-volume textbook on Engineering Mechanics. The authors, using a time-honoured straightforward and flexible approach, present the basic concepts and principles of mechanics in the clearest and simplest form possible to advanced undergraduate engineering students of various disciplines and different educational backgrounds. An important objective of this book is to develop problem solving skills in a systematic manner. Another aim of this volume is to provide engineering students as well as practising engineers with a solid foundation to help them bridge the gap between undergraduate studies on the one hand and advanced courses on mechanics and/or practical engineering problems on the other. The book contains numerous examples, along with their complete solutions. Emphasis is placed upon student participation in problem solving. The contents of the book correspond to the topics normally covered in courses on basic engineering mechanics at universities and colleges. Now in i...

  11. Computational mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Goudreau, G.L.

    1993-03-01

    The Computational Mechanics thrust area sponsors research into the underlying solid, structural and fluid mechanics and heat transfer necessary for the development of state-of-the-art general purpose computational software. The scale of computational capability spans office workstations, departmental computer servers, and Cray-class supercomputers. The DYNA, NIKE, and TOPAZ codes have achieved world fame through our broad collaborators program, in addition to their strong support of on-going Lawrence Livermore National Laboratory (LLNL) programs. Several technology transfer initiatives have been based on these established codes, teaming LLNL analysts and researchers with counterparts in industry, extending code capability to specific industrial interests of casting, metalforming, and automobile crash dynamics. The next-generation solid/structural mechanics code, ParaDyn, is targeted toward massively parallel computers, which will extend performance from gigaflop to teraflop power. Our work for FY-92 is described in the following eight articles: (1) Solution Strategies: New Approaches for Strongly Nonlinear Quasistatic Problems Using DYNA3D; (2) Enhanced Enforcement of Mechanical Contact: The Method of Augmented Lagrangians; (3) ParaDyn: New Generation Solid/Structural Mechanics Codes for Massively Parallel Processors; (4) Composite Damage Modeling; (5) HYDRA: A Parallel/Vector Flow Solver for Three-Dimensional, Transient, Incompressible Viscous How; (6) Development and Testing of the TRIM3D Radiation Heat Transfer Code; (7) A Methodology for Calculating the Seismic Response of Critical Structures; and (8) Reinforced Concrete Damage Modeling.

  12. Wave Mechanics or Wave Statistical Mechanics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    By comparison between equations of motion of geometrical optics and that of classical statistical mechanics, this paper finds that there should be an analogy between geometrical optics and classical statistical mechanics instead of geometrical mechanics and classical mechanics. Furthermore, by comparison between the classical limit of quantum mechanics and classical statistical mechanics, it finds that classical limit of quantum mechanics is classical statistical mechanics not classical mechanics, hence it demonstrates that quantum mechanics is a natural generalization of classical statistical mechanics instead of classical mechanics. Thence quantum mechanics in its true appearance is a wave statistical mechanics instead of a wave mechanics.

  13. Theoretical study on the reaction mechanism of CN radical with ketene

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The bimolecular single collision reaction potential energy surface of CN radical with ketene (CH2CO) was investigated by means of B3LYP and QCISD(T) methods. The calculated results indicate that there are three possible channels in the reaction. The first is an attack reaction by the carbon atom of CN at the carbon atom of the methylene of CH2CO to form the intermediate NCCH2CO followed by a rupture reaction of the C-C bond combined with -CO group to the products CH2CN+CO. The second is a direct addition reaction between CN and CH2CO to form the intermediate CH2C(O)CN followed by its isomerization into NCCH2CO via a CN-shift reaction, and subsequently, NCCH2CO dissociates into CH2CN+CO through a CO-loss reaction. The last is a direct hydrogen abstraction reaction of CH2CO by CN radical. Because of the existence of a 15.44 kJ/mol reaction barrier and higher energy of reaction products, the path can be ruled out as an important channel in the reaction kinetics. The present theoretical computation results, which give an available suggestion on the reaction mechanism, are in good agreement with previous experimental studies.

  14. The mechanism and kinetic model on the OH-initiated degradation of acetofenate in the atmosphere

    Science.gov (United States)

    Kang, Lingyan; Sun, Xiaomin; Zhang, Chenxi; Zhang, Xue; Chen, Jianmin

    2015-02-01

    As an analog of DDT, acetofenate (AF), one of the organochlorine pesticides, is widely used in agricultural and mosquito sprayings. In this paper, the main reaction mechanism of AF with the OH radical and ensuing reactions are researched, including the OH-initiated reaction, oxidation reaction in the presence of O2, bimolecular reaction of AF-OH-O2 with NO/H2O, bond cleavage of aromatic ring and C7-O bond, and dehydrogenation. Among all the reaction pathways, the main products are obtained via C2-C7/C7-O bond cleavage, C3-C4/C4-C5 bond cleavage of aromatic ring, and the generation of ketene and aldehyde. The kinetic model is constructed based on the rate constants of element reactions over a temperature range of 200-600 K, which are calculated with the transition state theory method and fitted with the Arrhenius formulas. According to the kinetic model, the atmospheric lifetime of AF, is 37 days, compared to OH radical.

  15. Computational mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Raboin, P J

    1998-01-01

    The Computational Mechanics thrust area is a vital and growing facet of the Mechanical Engineering Department at Lawrence Livermore National Laboratory (LLNL). This work supports the development of computational analysis tools in the areas of structural mechanics and heat transfer. Over 75 analysts depend on thrust area-supported software running on a variety of computing platforms to meet the demands of LLNL programs. Interactions with the Department of Defense (DOD) High Performance Computing and Modernization Program and the Defense Special Weapons Agency are of special importance as they support our ParaDyn project in its development of new parallel capabilities for DYNA3D. Working with DOD customers has been invaluable to driving this technology in directions mutually beneficial to the Department of Energy. Other projects associated with the Computational Mechanics thrust area include work with the Partnership for a New Generation Vehicle (PNGV) for ''Springback Predictability'' and with the Federal Aviation Administration (FAA) for the ''Development of Methodologies for Evaluating Containment and Mitigation of Uncontained Engine Debris.'' In this report for FY-97, there are five articles detailing three code development activities and two projects that synthesized new code capabilities with new analytic research in damage/failure and biomechanics. The article this year are: (1) Energy- and Momentum-Conserving Rigid-Body Contact for NIKE3D and DYNA3D; (2) Computational Modeling of Prosthetics: A New Approach to Implant Design; (3) Characterization of Laser-Induced Mechanical Failure Damage of Optical Components; (4) Parallel Algorithm Research for Solid Mechanics Applications Using Finite Element Analysis; and (5) An Accurate One-Step Elasto-Plasticity Algorithm for Shell Elements in DYNA3D.

  16. Quantum mechanics

    CERN Document Server

    Prabhakaran, Shivam

    2009-01-01

    Mechanics is the branch of Physics dealing with the effects of Forces on the motions of bodies. The world is composed of distinct elements, each possessing a definite position and velocity. These elements or particles interact with one another via forces which, in principle at least, can be completely known and whose effects can be allowed for exactly in predicating the motions of the various interacting bodies. To meet the challenge of these classically inexplicable observations, a completely new system of dynamics, quantum mechanics, was developed.The text includes advanced concepts in quant

  17. Mechanical seals

    CERN Document Server

    Mayer, E

    1977-01-01

    Mechanical Seals, Third Edition is a source of practical information on the design and use of mechanical seals. Topics range from design fundamentals and test rigs to leakage, wear, friction and power, reliability, and special designs. This text is comprised of nine chapters; the first of which gives a general overview of seals, including various types of seals and their applications. Attention then turns to the fundamentals of seal design, with emphasis on six requirements that must be considered: sealing effectiveness, length of life, reliability, power consumption, space requirements, and c

  18. Soil mechanics

    Science.gov (United States)

    Mitchell, J. K.; Carrier, W. D., III; Houston, W. N.; Scott, R. F.; Bromwell, L. G.; Durgunoglu, H. T.; Hovland, H. J.; Treadwell, D. D.; Costes, N. C.

    1972-01-01

    Preliminary results are presented of an investigation of the physical and mechanical properties of lunar soil on the Descartes slopes, and the Cayley Plains in the vicinity of the LM for Apollo 16. The soil mechanics data were derived form (1) crew commentary and debriefings, (2) television, (3) lunar surface photography, (4) performance data and observations of interactions between soil and lunar roving vehicle, (5) drive-tube and deep drill samples, (6) sample characteristics, and (7) measurements using the SRP. The general characteristics, stratigraphy and variability are described along with the core samples, penetrometer test results, density, porosity and strength.

  19. Creep mechanics

    CERN Document Server

    Betten, Josef

    2005-01-01

    Provides a short survey of recent advances in the mathematical modelling of the mechanical behavior of anisotropic solids under creep conditions, including principles, methods, and applications of tensor functions. Some examples for practical use are discussed, as well as experiments by the author to test the validity of the modelling. The monograph offers an overview of other experimental investigations in creep mechanics. Rules for specifying irreducible sets of tensor invariants, scalar coefficients in constitutive and evolutional equations, and tensorial interpolation methods are also exp

  20. Statistical mechanics

    CERN Document Server

    Davidson, Norman

    2003-01-01

    Clear and readable, this fine text assists students in achieving a grasp of the techniques and limitations of statistical mechanics. The treatment follows a logical progression from elementary to advanced theories, with careful attention to detail and mathematical development, and is sufficiently rigorous for introductory or intermediate graduate courses.Beginning with a study of the statistical mechanics of ideal gases and other systems of non-interacting particles, the text develops the theory in detail and applies it to the study of chemical equilibrium and the calculation of the thermody

  1. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  2. Soil Mechanics

    DEFF Research Database (Denmark)

    Gottlieb, Sara Wisbech Jacobsen; Hededal, Ole; Foged, Niels Nielsen;

    It is widely accepted that there is a connection between the undrained shear strength and the strain rate. Thixotropy and creep behaviour are connected to the mechanical properties of clay. Thixotropy is the ability of clay to recover its shear strength over time when the shear stress is released...

  3. Classical Mechanics

    OpenAIRE

    Gallavotti, Giovanni

    1999-01-01

    This is the English version of a friendly graduate course on Classical Mechanics, containing about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. For the Spanish version, see physics/9906066

  4. Statistical mechanics

    CERN Document Server

    Jana, Madhusudan

    2015-01-01

    Statistical mechanics is self sufficient, written in a lucid manner, keeping in mind the exam system of the universities. Need of study this subject and its relation to Thermodynamics is discussed in detail. Starting from Liouville theorem gradually, the Statistical Mechanics is developed thoroughly. All three types of Statistical distribution functions are derived separately with their periphery of applications and limitations. Non-interacting ideal Bose gas and Fermi gas are discussed thoroughly. Properties of Liquid He-II and the corresponding models have been depicted. White dwarfs and condensed matter physics, transport phenomenon - thermal and electrical conductivity, Hall effect, Magneto resistance, viscosity, diffusion, etc. are discussed. Basic understanding of Ising model is given to explain the phase transition. The book ends with a detailed coverage to the method of ensembles (namely Microcanonical, canonical and grand canonical) and their applications. Various numerical and conceptual problems ar...

  5. Fracture mechanics

    International Nuclear Information System (INIS)

    This book entitle ''Fracture Mechanics'', the first one of the monograph ''Materiologie'' is geared to design engineers, material engineers, non destructive inspectors and safety experts. This book covers fracture mechanics in isotropic homogeneous continuum. Only the monotonic static loading is considered. This book intended to be a reference with the current state of the art gives the fundamental of the issues under concern and avoids the developments too complicated or not yet mastered for not making reading cumbersome. The subject matter is organized as going from an easy to a more complicated level and thus follows the chronological evolution in the field. Similarly the microscopic scale is considered before the macroscopic scale, the physical understanding of phenomena linked to the experimental observation of the material preceded the understanding of the macroscopic behaviour of structures. In this latter field the relatively recent contribution of finite element computations with some analogy with the experimental observation is determining. However more sensitive analysis is not skipped

  6. Competing mechanisms

    OpenAIRE

    Peters, Michael

    2014-01-01

    The recent literature on competing mechanisms has devoted a lot of effort at understanding a very complex and abstract issue. In particular, an agent's type in a competitive environment is hard to conceptualize because it depends on information the agent has about what is going on in the rest of the market. This paper explains why this is such an important practical problem and illustrates how the literature has solved it.

  7. Molecular Mechanics

    OpenAIRE

    Vanommeslaeghe, Kenno; Guvench, Olgun; Alexander D MacKerell

    2014-01-01

    Molecular Mechanics (MM) force fields are the methods of choice for protein simulations, which are essential in the study of conformational flexibility. Given the importance of protein flexibility in drug binding, MM is involved in most if not all Computational Structure-Based Drug Discovery (CSBDD) projects. This section introduces the reader to the fundamentals of MM, with a special emphasis on how the target data used in the parametrization of force fields determine their strengths and wea...

  8. Aging mechanisms

    OpenAIRE

    Takahashi, Yoshiko; Kuro-o, Makoto; Ishikawa, Fuyuki

    2000-01-01

    Aging (senescence) has long been a difficult issue to be experimentally analyzed because of stochastic processes, which contrast with the programmed events during early development. However, we have recently started to learn the molecular mechanisms that control aging. Studies of the mutant mouse, klotho, showing premature aging, raise a possibility that mammals have an “anti-aging hormone.” A decrease of cell proliferation ability caused by the telomeres is also t...

  9. Mechanical engineering

    CERN Document Server

    Darbyshire, Alan

    2010-01-01

    Alan Darbyshire's best-selling text book provides five-star high quality content to a potential audience of 13,000 engineering students. It explains the most popular specialist units of the Mechanical Engineering, Manufacturing Engineering and Operations & Maintenance Engineering pathways of the new 2010 BTEC National Engineering syllabus. This challenging textbook also features contributions from specialist lecturers, ensuring that no stone is left unturned.

  10. Fiscal 1997 report of the development of high efficiency waste power generation technology. No.2 volume. Pilot plant verification test; Kokoritsu haikibutsu hatsuden gijutsu kaihatsu (pilot plant jissho shiken). 1997 nendo hokokusho (daini bunsatsu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    As to a high efficiency waste power generation system using general waste as fuel, the details of the following were described: design/construction management and operational study of pilot plant, design/manufacture/construction of pilot plant, and study of an optimal total system. Concerning the construction management and operational study, the paper described the application for governmental/official inspection procedures and taking inspection, process management of pilot plant, site patrol, safety management, management of trial run of pilot plant, drawing-up of a verification test plan and test run, etc. Relating to the design/manufacture/construction of pilot plant, an outline of the pilot plant was described. The paper also stated points to be considered in design of furnace structure and boiler structure, points to be considered of the verification test, etc. As to the study of an optimal total system, the following were described: survey of waste gasification/slagging power generation technology, basic study on RDF production process, survey of trends of waste power generation technology in the U.S., etc. 52 refs., 149 figs., 121 tabs.

  11. Quantum mechanics

    CERN Document Server

    Rae, Alastair I M

    2007-01-01

    PREFACESINTRODUCTION The Photoelectric Effect The Compton Effect Line Spectra and Atomic Structure De Broglie Waves Wave-Particle Duality The Rest of This Book THE ONE-DIMENSIONAL SCHRÖDINGER EQUATIONS The Time-Dependent Schrödinger Equation The Time-Independent Schrödinger Equation Boundary ConditionsThe Infinite Square Well The Finite Square Well Quantum Mechanical Tunneling The Harmonic Oscillator THE THREE-DIMENSIONAL SCHRÖDINGER EQUATIONS The Wave Equations Separation in Cartesian Coordinates Separation in Spherical Polar Coordinates The Hydrogenic Atom THE BASIC POSTULATES OF QUANTUM MEC

  12. Reaction mechanisms

    International Nuclear Information System (INIS)

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported

  13. Quantum mechanics

    CERN Document Server

    Zagoskin, Alexandre

    2015-01-01

    Written by Dr Alexandre Zagoskin, who is a Reader at Loughborough University, Quantum Mechanics: A Complete Introduction is designed to give you everything you need to succeed, all in one place. It covers the key areas that students are expected to be confident in, outlining the basics in clear jargon-free English, and then providing added-value features like summaries of key ideas, and even lists of questions you might be asked in your exam. The book uses a structure that is designed to make quantum physics as accessible as possible - by starting with its similarities to Newtonian physics, ra

  14. Mechanized timbering

    Energy Technology Data Exchange (ETDEWEB)

    Burchakov, A.S.; Agafonov, A.V.; Komissarov, S.N.; Sidorov, G.V.

    1982-01-01

    A section of mechanized timbering is proposed. It includes a cover, a base, a hydrostand of first and second rows, stand blocks, an advance winch with rod and piston cavities, a hydrodistributor, a hydroblock with a hydrolock and reverse valve connecting the piston cavities of the first row of the hydrostands to the rod cavities of the second row, channels, and pressure and overflow lines. It is characterized by the fact that in order to improve the safety of cleaning operations by improving the initial spacing, the timbering section is equipped with an additional hydroblock with hydroclamp and reverse valve. The rod cavity of the advance winch is connected by one channel to the hydrolock of the additional hydroblock, and by the other channel through the reverse valve of the initial hydroblock to the piston cavities of the hydrostands of the second row.

  15. Ribosome Mechanics Informs about Mechanism.

    Science.gov (United States)

    Zimmermann, Michael T; Jia, Kejue; Jernigan, Robert L

    2016-02-27

    The essential aspects of the ribosome's mechanism can be extracted from coarse-grained simulations, including the ratchet motion, the movement together of critical bases at the decoding center, and movements of the peptide tunnel lining that assist in the expulsion of the synthesized peptide. Because of its large size, coarse graining helps to simplify and to aid in the understanding of its mechanism. Results presented here utilize coarse-grained elastic network modeling to extract the dynamics, and both RNAs and proteins are coarse grained. We review our previous results, showing the well-known ratchet motions and the motions in the peptide tunnel and in the mRNA tunnel. The motions of the lining of the peptide tunnel appear to assist in the expulsion of the growing peptide chain, and clamps at the ends of the mRNA tunnel with three proteins ensure that the mRNA is held tightly during decoding and essential for the helicase activity at the entrance. The entry clamp may also assist in base recognition to ensure proper selection of the incoming tRNA. The overall precision of the ribosome machine-like motions is remarkable. PMID:26687034

  16. Gelation Mechanisms

    Science.gov (United States)

    Pekcan, Önder; Kara, Selim

    2012-10-01

    In this paper, we survey the gelation mechanisms for various polymeric systems which are classified by the type and the strength of the cross-linkages. These are the "irreversible" gels that are cross-linked chemically by covalent bonds and the "reversible" gels that are cross-linked physically by hydrogen or ionic bonds and by the physical entanglement of polymer chains. Some of the natural polymer gels fall into the class of physical gels, among which the red algae that has attracted attention for various applications is discussed in detail. Various composite gels, formed from mixture of physical and chemical gels are also discussed in the last section of the article. Theoretical models describe the gelation as a process of random linking of subunits to larger and larger molecules by formation of an infinite network, where no matter what type of objects are linked, there is always a critical "gel point" at which the system behaves neither as a liquid nor as a solid on any length scale. The Flory-Stockmayer theory and percolation theory provide bases for modeling this sol-gel phase transition. The experimental techniques for measuring the critical exponents for sol-gel phase transitions in different polymeric systems are introduced and the validation of various theoretical predictions are surveyed.

  17. Superoxide reductase from Desulfoarculus baarsii: reaction mechanism and role of glutamate 47 and lysine 48 in catalysis

    CERN Document Server

    Lombard, M; Touati, D; Fontecave, M; Nivière, V

    2015-01-01

    Superoxide reductase (SOR) is a small metalloenzyme that catalyzes reduction of O(2)(*)(-) to H(2)O(2) and thus provides an antioxidant mechanism against superoxide radicals. Its active site contains an unusual mononuclear ferrous center, which is very efficient during electron transfer to O(2)(*)(-) [Lombard, M., Fontecave, M., Touati, D., and Nivi{\\`e}re, V. (2000) J. Biol. Chem. 275, 115-121]. The reaction of the enzyme from Desulfoarculus baarsii with superoxide was studied by pulse radiolysis methods. The first step is an extremely fast bimolecular reaction of superoxide reductase with superoxide, with a rate constant of (1.1 +/- 0.3) x 10(9) M(-1) s(-1). A first intermediate is formed which is converted to a second one at a much slower rate constant of 500 +/- 50 s(-1). Decay of the second intermediate occurs with a rate constant of 25 +/- 5 s(-1). These intermediates are suggested to be iron-superoxide and iron-peroxide species. Furthermore, the role of glutamate 47 and lysine 48, which are the closest...

  18. Mechanical Design

    International Nuclear Information System (INIS)

    The particle beam of the SXR (soft x-ray) beam line in the LCLS (Linac Coherent Light Source) has a high intensity in order to penetrate through samples at the atomic level. However, the intensity is so high that many experiments fail because of severe damage. To correct this issue, attenuators are put into the beam line to reduce this intensity to a level suitable for experimentation. Attenuation is defined as 'the gradual loss in intensity of any flux through a medium' by (1). It is found that Beryllium and Boron Carbide can survive the intensity of the beam. At very thin films, both of these materials work very well as filters for reducing the beam intensity. Using a total of 12 filters, the first 9 being made of Beryllium and the rest made of Boron Carbide, the beam's energy range of photons can be attenuated between 800 eV and 9000 eV. The design of the filters allows attenuation for different beam intensities so that experiments can obtain different intensities from the beam if desired. The step of attenuation varies, but is relative to the thickness of the filter as a power function of 2. A relationship for this is f(n) = x02n where n is the step of attenuation desired and x0 is the initial thickness of the material. To allow for this desired variation, a mechanism must be designed within the test chamber. This is visualized using a 3D computer aided design modeling tool known as Solid Edge.

  19. Mechanism of mechanical activation for sulfide ores

    Institute of Scientific and Technical Information of China (English)

    HU Hui-ping; CHEN Qi-yuan; YIN Zhou-lan; HE Yue-hui; HUANG Bai-yun

    2007-01-01

    Structural changes for mechanically activated pyrite, sphalerite, galena and molybdenite with or without the exposure to ambient air, were systematically investigated using X-ray diffraction analysis(XRD), particle size analysis, gravimetrical method, X-ray photo-electron spectroscopy(XPS) and scanning electron microscopy(SEM), respectively. Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers, several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained. For brittle sulfide ores with thermal instability, and incomplete cleavage plane or extremely incomplete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with thermal instability, and complete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed, and lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with excellent thermal stability, and complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For sulfide ores with high toughness, good thermal stability and very excellent complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation, but the lattice deformation ratio is very small. The effects of mechanical activation are worst.

  20. Radiation-induced destruction of organic compounds in aqueous solutions by dual oxidation/reduction mechanism

    International Nuclear Information System (INIS)

    This research presents the feasibility and mechanisms of using high energy electrons for the dechlorination of polychlorinated biphenyls (PCBs) in marine sediment, and hazardous organic compounds in waste water. The remediation of the organic contaminants by ionizing radiation is achieved by means of both reduction and oxidation processes. PCBs in marine sediment can be effectively dechlorinated by reduction, while toxic organic compounds in water are removed mainly by oxidation. Radiolytic degradation of aqueous suspensions of PCBs in marine sediments in the presence of isopropanol was also studied. Addition of isopropanol was necessary to enhance the radiolytic yield and the dechlorination of PCBs. Also presented are results from an examination of the oxidative and reductive effects of electron-beam irradiation on the concentrations of six organic solvents in water. The organic solvents in water were prepared to mimic a pharmaceutical waste stream. Radiation-induced destruction of benzene was also investigated using pulse radiolysis technique. Pulse radiolysis with spectrophotometric and conductometric detection was utilized to study the formation and reactions of radicals from benzene and dienes in aqueous solutions. The benzene OH adduct, ●C6H6OH, reacts with O2 (k = 3x108 L mol-1 s-1) in a reversible reaction. The peroxyl radical, HOC6H6O2●, undergoes O2●- elimination, bimolecular decay, and reaction with benzene to initiate a chain reaction, depending on the dose rate, benzene concentration, and pH. The occurrence of the chain reaction is demonstrated in low-dose-rate gamma radiolysis experiments where the consumption of O2 was monitored. (author)

  1. The Mechanics of Mechanical Watches and Clocks

    CERN Document Server

    Du, Ruxu

    2013-01-01

    "The Mechanics of Mechanical Watches and Clocks" presents historical views and mathematical models of mechanical watches and clocks. Although now over six hundred years old, mechanical watches and clocks are still popular luxury items that fascinate many people around the world. However few have examined the theory of how they work as presented in this book. The illustrations and computer animations are unique and have never been published before. It will be of significant interest to researchers in mechanical engineering, watchmakers and clockmakers, as well as people who have an engineering background and are interested in mechanical watches and clocks. It will also inspire people in other fields of science and technology, such as mechanical engineering and electronics engineering, to advance their designs. Professor Ruxu Du works at the Chinese University of Hong Kong, China. Assistant Professor Longhan Xie works at the South China University of Technology, China.

  2. Mechanism of charge recombination in meso-structured organic-inorganic hybrid perovskite solar cells: A macroscopic perspective

    Science.gov (United States)

    Yang, Wenchao; Yao, Yao; Wu, Chang-Qin

    2015-04-01

    In the currently popular organic-inorganic hybrid perovskite solar cells, the slowness of the charge recombination processes is found to be a key factor for contributing to their high efficiencies and high open circuit voltages, but the underlying recombination mechanism remains unclear. In this work, we investigate the bimolecular recombination (BR) and the trap-assisted monomolecular recombination (MR) in meso-structured perovskite solar cells under steady state working condition, and try to reveal their roles on determining the device performance. Some interfacial effects such as the injection barriers at the selective contacts are examined as well. Based on the macroscopic device modeling, the recombination resistance-voltage (Rrec-V) and the current density-voltage (J-V) curves are calculated to characterize the recombination mechanism and describe the device performance, respectively. Through comparison with the impedance spectroscopy extracted Rrec data, it is found that under the typical BR reduction factor and deep trap densities observed in experiments, the MR dominates the charge recombination in the low voltage regime, while the BR dominates in the high voltage regime. The short circuit current and the fill factor could be reduced by the significant MR but the open circuit voltage is generally determined by the BR. The different electron injection barriers at the contact can change the BR rate and induce different patterns for the Rrec-V characteristics. For the perovskites of increased band gaps, the Rrec's are significantly enhanced, corresponding to the high open circuit voltages. Finally, it is revealed that the reduced effective charge mobility due to the transport in electron and hole transporting material makes the Rrec decrease slowly with the increasing voltage, which leads to increased open circuit voltage.

  3. Mechanism of charge recombination in meso-structured organic-inorganic hybrid perovskite solar cells: A macroscopic perspective

    International Nuclear Information System (INIS)

    In the currently popular organic-inorganic hybrid perovskite solar cells, the slowness of the charge recombination processes is found to be a key factor for contributing to their high efficiencies and high open circuit voltages, but the underlying recombination mechanism remains unclear. In this work, we investigate the bimolecular recombination (BR) and the trap-assisted monomolecular recombination (MR) in meso-structured perovskite solar cells under steady state working condition, and try to reveal their roles on determining the device performance. Some interfacial effects such as the injection barriers at the selective contacts are examined as well. Based on the macroscopic device modeling, the recombination resistance-voltage (Rrec−V) and the current density-voltage (J–V) curves are calculated to characterize the recombination mechanism and describe the device performance, respectively. Through comparison with the impedance spectroscopy extracted Rrec data, it is found that under the typical BR reduction factor and deep trap densities observed in experiments, the MR dominates the charge recombination in the low voltage regime, while the BR dominates in the high voltage regime. The short circuit current and the fill factor could be reduced by the significant MR but the open circuit voltage is generally determined by the BR. The different electron injection barriers at the contact can change the BR rate and induce different patterns for the Rrec–V characteristics. For the perovskites of increased band gaps, the Rrec's are significantly enhanced, corresponding to the high open circuit voltages. Finally, it is revealed that the reduced effective charge mobility due to the transport in electron and hole transporting material makes the Rrec decrease slowly with the increasing voltage, which leads to increased open circuit voltage

  4. Mechanical engineering education

    CERN Document Server

    Davim, J Paulo

    2012-01-01

    Mechanical Engineering is defined nowadays as a discipline "which involves the application of principles of physics, design, manufacturing and maintenance of mechanical systems". Recently, mechanical engineering has also focused on some cutting-edge subjects such as nanomechanics and nanotechnology, mechatronics and robotics, computational mechanics, biomechanics, alternative energies, as well as aspects related to sustainable mechanical engineering.This book covers mechanical engineering higher education with a particular emphasis on quality assurance and the improvement of academic

  5. Advances in Applied Mechanics

    OpenAIRE

    2014-01-01

    Advances in Applied Mechanics draws together recent significant advances in various topics in applied mechanics. Published since 1948, Advances in Applied Mechanics aims to provide authoritative review articles on topics in the mechanical sciences, primarily of interest to scientists and engineers working in the various branches of mechanics, but also of interest to the many who use the results of investigations in mechanics in various application areas, such as aerospace, chemical, civil, en...

  6. Mechanical engineer's handbook

    CERN Document Server

    Marghitu, Dan B

    2001-01-01

    The Mechanical Engineer's Handbook was developed and written specifically to fill a need for mechanical engineers and mechanical engineering students throughout the world. With over 1000 pages, 550 illustrations, and 26 tables the Mechanical Engineer's Handbook is very comprehensive, yet affordable, compact, and durable. The Handbook covers all major areas of mechanical engineering with succinct coverage of the definitions, formulas, examples, theory, proofs, and explanations of all principle subject areas. The Handbook is an essential, practical companion for all mechanic

  7. Tokamak engineering mechanics

    CERN Document Server

    Song, Yuntao; Du, Shijun

    2013-01-01

    Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study

  8. Analytical mechanics for relativity and quantum mechanics

    CERN Document Server

    Johns, Oliver Davis

    2011-01-01

    Analytical Mechanics for Relativity and Quantum Mechanics is an innovative and mathematically sound treatment of the foundations of analytical mechanics and the relation of classical mechanics to relativity and quantum theory. It is intended for use at the introductory graduate level. A distinguishing feature of the book is its integration of special relativity into teaching of classical mechanics. After a thorough review of the traditional theory, Part II of the book introduces extended Lagrangian and Hamiltonian methods that treat time as a transformable coordinate rather than the fixed parameter of Newtonian physics. Advanced topics such as covariant Langrangians and Hamiltonians, canonical transformations, and Hamilton-Jacobi methods are simplified by the use of this extended theory. And the definition of canonical transformation no longer excludes the Lorenz transformation of special relativity. This is also a book for those who study analytical mechanics to prepare for a critical exploration of quantum...

  9. Robust Design of Sounds in Mechanical Mechanisms

    DEFF Research Database (Denmark)

    Boegedal Jensen, Annemette; Munch, Natasja; Howard, Thomas J.;

    2015-01-01

    Current practices for creating a desired sound by a mechanical mechanism are irrelative design-build-test processes. It seems that very little guidance is available relating design to the sound output. The focus of this study was to identify, which parameters that affect the sound output of a click...... mechanism consisting of a toothed rack and a click arm. First several geometries of the teeth and the click arm’s head were investigated to identify the most robust and repeatable design. It was found that a flat surface in the valleys between the teeth is very beneficial in relation to repeatability...... mechanisms....

  10. About quantum mechanics interpretation

    OpenAIRE

    Kyriakos, Alexander G.

    2002-01-01

    There is a certainty that the modern (Copenhagen's) interpretation of quantum mechanics is correct. However, the some physicist had the opinion that the modern quantum mechanics is a phenomenological theory. The suggested theory is the new quantum mechanics interpretation that is entirely according to the modern interpretation and gives a number of results, which naturally explain the postulates of the modern quantum mechanics.

  11. What is Bohmian Mechanics

    OpenAIRE

    Allori, Valia; Zanghì, Nino

    2001-01-01

    Bohmian mechanics is a quantum theory with a clear ontology. To make clear what we mean by this, we shall proceed by recalling first what are the problems of quantum mechanics. We shall then briefly sketch the basics of Bohmian mechanics and indicate how Bohmian mechanics solves these problems and clarifies the status and the role of of the quantum formalism.

  12. Defense Mechanisms: A Bibliography.

    Science.gov (United States)

    Pedrini, D. T.; Pedrini, Bonnie C.

    This bibliography includes studies of defense mechanisms, in general, and studies of multiple mechanisms. Defense mechanisms, briefly and simply defined, are the unconscious ego defendants against unpleasure, threat, or anxiety. Sigmund Freud deserves the clinical credit for studying many mechanisms and introducing them in professional literature.…

  13. Handbook of compliant mechanisms

    CERN Document Server

    Howell, Larry L; Olsen, Brian M

    2013-01-01

    A fully illustrated reference book giving an easy-to-understand introduction to compliant mechanisms A broad compilation of compliant mechanisms to give inspiration and guidance to those interested in using compliant mechanisms in their designs, the Handbook of Compliant Mechanisms includes graphics and descriptions of many compliant mechanisms. It comprises an extensive categorization of devices that can be used to help readers identify compliant mechanisms related to their application. It also provides chapters on the basic background in compliant mechanisms, the categories o

  14. Tokamak engineering mechanics

    International Nuclear Information System (INIS)

    Provides a systematic introduction to tokamaks in engineering mechanics. Includes design guides based on full mechanical analysis, which makes it possible to accurately predict load capacity and temperature increases. Presents comprehensive information on important design factors involving materials. Covers the latest advances in and up-to-date references on tokamak devices. Numerous examples reinforce the understanding of concepts and provide procedures for design. Tokamak Engineering Mechanics offers concise and thorough coverage of engineering mechanics theory and application for tokamaks, and the material is reinforced by numerous examples. Chapter topics include general principles, static mechanics, dynamic mechanics, thermal fluid mechanics and multiphysics structural mechanics of tokamak structure analysis. The theoretical principle of the design and the methods of the analysis for various components and load conditions are presented, while the latest engineering technologies are also introduced. The book will provide readers involved in the study of mechanical/fusion engineering with a general understanding of tokamak engineering mechanics.

  15. Molecular View of Protein Crystal Growth: Molecular Interactions, Surface Reconstruction and Growth Mechanism

    Science.gov (United States)

    Nadarajah, Arunan; Li, Huayu; Konnert, John H.; Pusey, Marc L.

    2000-01-01

    Studies of the growth and molecular packing of tetragonal lysozyme crystals suggest that there is an underlying molecular growth mechanism, in addition to the classical one involving screw dislocation/2D) nucleation growth. These crystals are constructed by strongly bonded molecular chains forming helices about the 43 axes. The helices are connected to each other by weaker bonds. Crystal growth proceeds by the formation of these 4(sub 3) helices, which would explain some unexpected observations by earlier investigators, such as bimolecular growth steps on the (110) face. Another consequence of these molecular considerations is that only one of two possible packing arrangements could occur on the crystal faces and that their growth unit was at least a tetramer corresponding to the 4(sub 3) helix. Two new high resolution atomic force microscopy (AFM) techniques were developed to directly confirm these predictions on tetragonal lysozyme crystals. Most earlier investigations of protein crystal growth with AFM were in the low resolution mode which is adequate to investigate the classical growth mechanisms, but cannot resolve molecular features and mechanisms. Employing the first of the newly developed techniques, high resolution AFM images of the (110) face were compared with the theoretically constructed images for the two possible packing arrangements on this face. The prediction that the molecular packing arrangement of these faces corresponded to that for complete 4(sub 3) helices was confirmed in this manner. This investigation also showed the occurrence of surface reconstruction on protein crystals. The molecules on the surface of the (110) face were found to pack closer along the 4(sub 3) axes than those in the interior. The second new AFM technique was used to follow the growth process by measuring the dimensions of individual growth units on the (110) face. Linescans across a growth step, performed near the saturation limit of the crystals, allowed the growth

  16. 507 mechanical movements mechanisms and devices

    CERN Document Server

    Brown, Henry T

    2005-01-01

    Epicyclic trains, oblique rollers, trip hammers, and lazy-tongs are among the ingenious mechanisms defined and illustrated in this intriguing collection. Spanning the first century of the Industrial Revolution, this 1868 compilation features simplified, concise illustrations of the mechanisms used in hydraulics, steam engines, pneumatics, presses, horologes, and scores of other machines.The movements of each of the 507 mechanisms are depicted in drawings on the left-hand page, and the facing page presents a brief description of the item's use and operation. Ranging from simple to intricately c

  17. Mechanical engineers' handbook, materials and engineering mechanics

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of materials and mechanical design inengineering Mechanical Engineers' Handbook, Fourth Edition provides aquick guide to specialized areas you may encounter in your work,giving you access to the basics of each and pointing you towardtrusted resources for further reading, if needed. The accessibleinformation inside offers discussions, examples, and analyses ofthe topics covered. This first volume covers materials and mechanical design, givingyou accessible and in-depth access to the most common topics you'llencounter in the discipline: carbon and alloy steels, stainlesssteels, a

  18. Chain propagation and termination mechanisms for polymerization of conjugated polar alkenes by [Al]-based frustrated Lewis pairs

    KAUST Repository

    He, Jianghua

    2014-11-25

    A combined experimental and theoretical study on mechanistic aspects of polymerization of conjugated polar alkenes by frustrated Lewis pairs (FLPs) based on N-heterocyclic carbene (NHC) and Al(C6F5)3 pairs is reported. This study consists of three key parts: structural characterization of active propagating intermediates, propagation kinetics, and chain-termination pathways. Zwitterionic intermediates that simulate the active propagating species in such polymerization have been generated or isolated from the FLP activation of monomers such as 2-vinylpyridine and 2-isopropenyl-2-oxazoline-one of which, IMes+-CH2C(Me)=(C3H2NO)Al(C6F5)3 - (2), has been structurally characterized. Kinetics performed on the polymerization of 2-vinylpyridine by ItBu/Al(C6F5)3 revealed that the polymerization follows a zero-order dependence on monomer concentration and a first-order dependence on initiator (ItBu) and activator [Al(C6F5)3] concentrations, indicating a bimolecular, activated monomer propagation mechanism. The Lewis pair polymerization of conjugate polar alkenes such as methacrylates is accompanied by competing chain-termination side reactions; between the two possible chain-termination pathways, the one that proceeds via intramolecular backbiting cyclization involving nucleophilic attack of the activated ester group of the growing polymer chain by the O-ester enolate active chain end to generate a six-membered lactone (δ-valerolactone)-terminated polymer chain is kinetically favored, but thermodynamically disfavored, over the pathway leading to the -ketoester-terminated chain, as revealed by computational studies.

  19. Verifiably Truthful Mechanisms

    DEFF Research Database (Denmark)

    Branzei, Simina; Procaccia, Ariel D.

    2015-01-01

    It is typically expected that if a mechanism is truthful, then the agents would, indeed, truthfully report their private information. But why would an agent believe that the mechanism is truthful? We wish to design truthful mechanisms, whose truthfulness can be verified efficiently (in the...... computational sense). Our approach involves three steps: (i) specifying the structure of mechanisms, (ii) constructing a verification algorithm, and (iii) measuring the quality of verifiably truthful mechanisms. We demonstrate this approach using a case study: approximate mechanism design without money for...

  20. Mechanics of Failure Mechanisms in Structures

    CERN Document Server

    Carlson, R L; Craig, J I

    2012-01-01

    This book focuses on the mechanisms and underlying mechanics of failure in various classes of materials such as metallic, ceramic, polymeric, composite and bio-material.  Topics include tensile and compressive fracture, crack initiation and growth, fatigue and creep rupture in metallic materials, matrix cracking and delamination and environmental degradation in polymeric composites, failure of bio-materials such as prosthetic heart valves and prosthetic hip joints, failure of ceramics and ceramic matrix composites, failure of metallic matrix composites, static and dynamic buckling failure, dynamic excitations and creep buckling failure in structural systems. Chapters are devoted to failure mechanisms that are characteristic of each of the materials.  The work also provides the basic elements of fracture mechanics and studies in detail several niche topics such as the effects of toughness gradients, variable amplitude loading effects in fatigue, small fatigue cracks, and creep induced brittleness. Furthe...

  1. Vibrating Wingstroke Mechanism Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed work will develop a new method and mechanism for generating wing stroke motion of any shape and orientation. The mechanism will provide power, lift...

  2. Computational space flight mechanics

    CERN Document Server

    Weiland, Claus

    2010-01-01

    Computational Space Flight Mechanics presents numerical solutions for topics and problems within space flight mechanics. Topics include orbit determination, Lagrange's perturbation equations for disturbed Earth's orbits, the flight of a mass point in flight path coordinates, and more.

  3. Welfare Undominated Groves Mechanisms

    CERN Document Server

    Apt, Krzysztof R; Guo, Mingyu; Markakis, Evangelos

    2008-01-01

    A common objective in mechanism design is to choose the outcome (for example, allocation of resources) that maximizes the sum of the agents' valuations, without introducing incentives for agents to misreport their preferences. The class of Groves mechanisms achieves this; however, these mechanisms require the agents to make payments, thereby reducing the agents' total welfare. In this paper we introduce a measure for comparing two mechanisms with respect to the final welfare they generate. This measure induces a partial order on mechanisms and we study the question of finding minimal elements with respect to this partial order. In particular, we say a non-deficit Groves mechanism is welfare undominated if there exists no other non-deficit Groves mechanism that always has a smaller or equal sum of payments. We focus on two domains: (i) auctions with multiple identical units and unit-demand bidders, and (ii) mechanisms for public project problems. In the first domain we analytically characterize all welfare und...

  4. Project mechanisms challenges

    International Nuclear Information System (INIS)

    The project mechanism complete the quotas systems concerning the carbon dioxide emissions market. The author explains and discusses these mechanisms and provides a panorama of the existing and developing projects. More specially she brings information on the mechanism of clean developments and renewable energies, the coordinated mechanisms, the agricultural projects, the financing of the projects and the exchange systeme of the New south Wales. (A.L.B.)

  5. Methods of celestial mechanics

    CERN Document Server

    Brouwer, Dirk

    2013-01-01

    Methods of Celestial Mechanics provides a comprehensive background of celestial mechanics for practical applications. Celestial mechanics is the branch of astronomy that is devoted to the motions of celestial bodies. This book is composed of 17 chapters, and begins with the concept of elliptic motion and its expansion. The subsequent chapters are devoted to other aspects of celestial mechanics, including gravity, numerical integration of orbit, stellar aberration, lunar theory, and celestial coordinates. Considerable chapters explore the principles and application of various mathematical metho

  6. Regional social protection mechanisms

    OpenAIRE

    Elena Alekseevna Morozova; Arina Yur'evna Dobrynina

    2012-01-01

    This paper focuses on the importance and essence of social protection mechanisms, describes their legal, economical and organizational components. Social protection mechanisms are important elements of the social protection system. Social protection mechanisms are understood as a complex of economical, organizational and legal measures aiming at smoothing social inequality of population.The legal foundations of the social protection mechanism consist in the fact that the protective a...

  7. Recurrence in Quantum Mechanics

    OpenAIRE

    Duvenhage, Rocco

    2002-01-01

    We first compare the mathematical structure of quantum and classical mechanics when both are formulated in a C*-algebraic framework. By using finite von Neumann algebras, a quantum mechanical analogue of Liouville's theorem is then proposed. We proceed to study Poincare recurrence in C*-algebras by mimicking the measure theoretic setting. The results are interpreted as recurrence in quantum mechanics, similar to Poincare recurrence in classical mechanics.

  8. Defining Game Mechanics

    DEFF Research Database (Denmark)

    Sicart (Vila), Miguel Angel

    2008-01-01

    This article defins game mechanics in relation to rules and challenges. Game mechanics are methods invoked by agents for interacting with the game world. I apply this definition to a comparative analysis of the games Rez, Every Extend Extra and Shadow of the Colossus that will show the relevance...... of a formal definition of game mechanics. Udgivelsesdato: Dec 2008...

  9. Introduction to quantum mechanics

    OpenAIRE

    Villaseñor, Eduardo J. S.

    2008-01-01

    The purpose of this contribution is to give a very brief introduction to Quantum Mechanics for an audience of mathematicians. I will follow Segal's approach to Quantum Mechanics paying special attention to algebraic issues. The usual representation of Quantum Mechanics on Hilbert spaces is also discussed.

  10. Quantum Mechanics in Pseudotime

    OpenAIRE

    Kapoor, A. K

    2016-01-01

    Based on some results on reparmetrisation of time in Hamiltonian path integral formalism, a pseudo time formulation of operator formalism of quantum mechanics is presented. Relation of reparametrisation of time in quantum with super symmetric quantum mechanics is established. We show how some important concepts such as shape invariance and tools like isospectral deformation appear in pseudo time quantum mechanics.

  11. Mechanical restraint in psychiatry

    DEFF Research Database (Denmark)

    Bak, Jesper; Zoffmann, Vibeke; Sestoft, Dorte Maria;

    2014-01-01

    PURPOSE: To examine how potential mechanical restraint preventive factors in hospitals are associated with the frequency of mechanical restraint episodes. DESIGN AND METHODS: This study employed a retrospective association design, and linear regression was used to assess the associations. FINDINGS......: Three mechanical restraint preventive factors were significantly associated with low rates of mechanical restraint use: mandatory review (exp[B] = .36, p < .01), patient involvement (exp[B] = .42, p < .01), and no crowding (exp[B] = .54, p < .01). PRACTICE IMPLICATIONS: None of the three mechanical...

  12. HYDRAULIC SERVO CONTROL MECHANISM

    Science.gov (United States)

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  13. Sectoral Market Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This paper first reviews proposals for the design of sectoral and related market mechanisms currently debated, both in the UNFCCC negotiations, and in different domestic legislative contexts. Secondly, it addresses the possible principles and technical requirements that Parties may wish to consider as the foundations for further elaboration of the mechanisms. The third issue explored herein is domestic implementation of sectoral market mechanisms by host countries, incentives to move to new market mechanisms, as well as how the transition between current and future mechanisms could be managed.

  14. Introduction into fracture mechanics

    International Nuclear Information System (INIS)

    The present report gives an introduction to the basic principles of fracture mechanics. First the behaviour of a linear elastic body containing a crack is described. This is followed by a survey of experimental methods for the determination of fracture mechanics properties, like R-curve and fatigue crack growth. Two chapters deal with the most important parameters affecting stable crack growth and fracture toughness. The knowledge of the limits of applicability of linear eleastic fracture mechanics and of the concepts of elastic-plastic fracture mechanics is of particular importance. The last chapter deals with some basic procedures for the practical application of fracture mechanics. (orig.)

  15. Mechanical Systems, Classical Models

    CERN Document Server

    Teodorescu, Petre P

    2009-01-01

    This third volume completes the Work Mechanical Systems, Classical Models. The first two volumes dealt with particle dynamics and with discrete and continuous mechanical systems. The present volume studies analytical mechanics. Topics like Lagrangian and Hamiltonian mechanics, the Hamilton-Jacobi method, and a study of systems with separate variables are thoroughly discussed. Also included are variational principles and canonical transformations, integral invariants and exterior differential calculus, and particular attention is given to non-holonomic mechanical systems. The author explains in detail all important aspects of the science of mechanics, regarded as a natural science, and shows how they are useful in understanding important natural phenomena and solving problems of interest in applied and engineering sciences. Professor Teodorescu has spent more than fifty years as a Professor of Mechanics at the University of Bucharest and this book relies on the extensive literature on the subject as well as th...

  16. Mechanical Systems, Classical Models

    CERN Document Server

    Teodorescu, Petre P

    2007-01-01

    All phenomena in nature are characterized by motion; this is an essential property of matter, having infinitely many aspects. Motion can be mechanical, physical, chemical or biological, leading to various sciences of nature, mechanics being one of them. Mechanics deals with the objective laws of mechanical motion of bodies, the simplest form of motion. In the study of a science of nature mathematics plays an important role. Mechanics is the first science of nature which was expressed in terms of mathematics by considering various mathematical models, associated to phenomena of the surrounding nature. Thus, its development was influenced by the use of a strong mathematical tool; on the other hand, we must observe that mechanics also influenced the introduction and the development of many mathematical notions. In this respect, the guideline of the present book is precisely the mathematical model of mechanics. A special accent is put on the solving methodology as well as on the mathematical tools used; vectors, ...

  17. Mechanisms, Transmissions and Applications

    CERN Document Server

    Corves, Burkhard

    2012-01-01

    The first Workshop on Mechanisms, Transmissions and Applications -- MeTrApp-2011 was organized by the Mechatronics Department at the Mechanical Engineering Faculty, “Politehnica” University of Timisoara, Romania, under the patronage of the IFToMM Technical Committees Linkages and Mechanical Controls and Micromachines. The workshop brought together researchers and students who work in disciplines associated with mechanisms science and offered a great opportunity for scientists from all over the world to present their achievements, exchange innovative ideas and create solid international links, setting the trend for future developments in this important and creative field. The topics treated in this volume are mechanisms and machine design, mechanical transmissions, mechatronic and biomechanic applications, computational and experimental methods, history of mechanism and machine science and teaching methods.

  18. Complications of mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Drašković Biljana

    2011-01-01

    Full Text Available Mechanical ventilation of the lungs, as an important therapeutic measure, cannot be avoided in critically ill patients. However, when machines take over some of vital functions there is always a risk of complications and accidents. Complications associated with mechanical ventilation can be divided into: 1 airway-associated complications; 2 complications in the response of patients to mechanical ventilation; and 3 complications related to the patient’s response to the device for mechanical ventilation. Complications of artificial airway may be related to intubation and extubation or the endotracheal tube. Complications of mechanical ventilation, which arise because of the patient’s response to mechanical ventilation, may primarily cause significant side effects to the lungs. During the last two decades it was concluded that mechanical ventilation can worsen or cause acute lung injury. Mechanical ventilation may increase the alveolar/capillary permeability by overdistension of the lungs (volutrauma, it can exacerbate lung damage due to the recruitment/derecruitment of collapsed alveoli (atelectrauma and may cause subtle damages due to the activation of inflammatory processes (biotrauma. Complications caused by mechanical ventilation, beside those involving the lungs, can also have significant effects on other organs and organic systems, and can be a significant factor contributing to the increase of morbidity and mortality in critically ill of mechanically ventilated patients. Complications are fortunately rare and do not occur in every patient, but due to their seriousness and severity they require extensive knowledge, experience and responsibility by health-care workers.

  19. Nonholonomic mechanics and control

    CERN Document Server

    Murray, RM

    2015-01-01

    This book explores some of the connections between control theory and geometric mechanics; that is, control theory is linked with a geometric view of classical mechanics in both its Lagrangian and Hamiltonian formulations and in particular with the theory of mechanical systems subject to motion constraints. The synthesis of the topic is appropriate as there is a particularly rich connection between mechanics and nonlinear control theory. The book provides a unified treatment of nonlinear control theory and constrained mechanical systems and illustrates the elegant mathematics behind many simple, interesting, and useful mechanical examples. It is intended for graduate students who wish to learn this subject and researchers in the area who want to enhance their techniques. The book contains sections focusing on physical examples and elementary terms, as well as theoretical sections that use sophisticated analysis and geometry. The first four chapters offer preliminaries and background information, while the...

  20. Equilibrium statistical mechanics

    CERN Document Server

    Mayer, J E

    1968-01-01

    The International Encyclopedia of Physical Chemistry and Chemical Physics, Volume 1: Equilibrium Statistical Mechanics covers the fundamental principles and the development of theoretical aspects of equilibrium statistical mechanics. Statistical mechanical is the study of the connection between the macroscopic behavior of bulk matter and the microscopic properties of its constituent atoms and molecules. This book contains eight chapters, and begins with a presentation of the master equation used for the calculation of the fundamental thermodynamic functions. The succeeding chapters highlight t

  1. The new bosonic mechanism

    OpenAIRE

    Taratuta, Rostislav

    2015-01-01

    The main purpose of this paper is to introduce the new bosonic mechanism and newtreatment of dark energy. The bosonic mechanism focuses on obtaining masses by gauge bosonswithout assuming the existence of Higgs boson. The hypothesis on dark energy as the energy ofa postulated dark field was made and a combined gravitational-dark field was introduced. This fieldis the key to a specified approach and allows addressing the fundamental starting points of the mechanism.i. Complex scalar field is i...

  2. On Quantum Mechanics

    OpenAIRE

    Rovelli, Carlo

    1994-01-01

    We reformulate the problem of the "interpretation of quantum mechanics" as the problem of DERIVING the quantum mechanical formalism from a set of simple physical postulates. We suggest that the common unease with taking quantum mechanics as a fundamental description of nature could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer independent time. Following an an analysis of the measurement process a...

  3. Lectures on statistical mechanics

    CERN Document Server

    Bowler, M G

    1982-01-01

    Anyone dissatisfied with the almost ritual dullness of many 'standard' texts in statistical mechanics will be grateful for the lucid explanation and generally reassuring tone. Aimed at securing firm foundations for equilibrium statistical mechanics, topics of great subtlety are presented transparently and enthusiastically. Very little mathematical preparation is required beyond elementary calculus and prerequisites in physics are limited to some elementary classical thermodynamics. Suitable as a basis for a first course in statistical mechanics, the book is an ideal supplement to more convent

  4. Quantum mechanics in chemistry

    CERN Document Server

    Schatz, George C

    2002-01-01

    Intended for graduate and advanced undergraduate students, this text explores quantum mechanical techniques from the viewpoint of chemistry and materials science. Dynamics, symmetry, and formalism are emphasized. An initial review of basic concepts from introductory quantum mechanics is followed by chapters examining symmetry, rotations, and angular momentum addition. Chapter 4 introduces the basic formalism of time-dependent quantum mechanics, emphasizing time-dependent perturbation theory and Fermi's golden rule. Chapter 5 sees this formalism applied to the interaction of radiation and matt

  5. Transformable topological mechanical metamaterials

    OpenAIRE

    Rocklin, D. Zeb; Zhou, Shangnan; Sun, Kai; Mao, Xiaoming

    2015-01-01

    Mechanical metamaterials are engineered materials that gain their remarkable mechanical properties, such as negative Poisson's ratios, negative compressibility, phononic bandgaps, and topological phonon modes, from their structure rather than composition. Here we propose a new design principle, based on a uniform soft deformation of the whole structure, to allow metamaterials to be immediately and reversibly transformed between states with contrasting mechanical and acoustic properties. These...

  6. Equilibrium statistical mechanics

    CERN Document Server

    Jackson, E Atlee

    2000-01-01

    Ideal as an elementary introduction to equilibrium statistical mechanics, this volume covers both classical and quantum methodology for open and closed systems. Introductory chapters familiarize readers with probability and microscopic models of systems, while additional chapters describe the general derivation of the fundamental statistical mechanics relationships. The final chapter contains 16 sections, each dealing with a different application, ordered according to complexity, from classical through degenerate quantum statistical mechanics. Key features include an elementary introduction t

  7. Fuzzy clustering of mechanisms

    Indian Academy of Sciences (India)

    Amitabha Ghosh; Dilip Kumar Pratihar; M V V Amarnath; Guenter Dittrich; Jorg Mueller

    2012-10-01

    During the course of development of Mechanical Engineering, a large number of mechanisms (that is, linkages to perform various types of tasks) have been conceived and developed. Quite a few atlases and catalogues were prepared by the designers of machines and mechanical systems. However, often it is felt that a clustering technique for handling the list of large number of mechanisms can be very useful,if it is developed based on a scientific principle. In this paper, it has been shown that the concept of fuzzy sets can be conveniently used for this purpose, if an adequate number of properly chosen attributes (also called characteristics) are identified. Using two clustering techniques, the mechanisms have been classified in the present work and in future, it may be extended to develop an expert system, which can automate type synthesis phase of mechanical design. To the best of the authors’ knowledge, this type of clustering of mechanisms has not been attempted before. Thus, this is the first attempt to cluster the mechanisms based on some quantitative measures. It may help the engineers to carry out type synthesis of the mechanisms.

  8. Heterologous aggregates promote de novo prion appearance via more than one mechanism.

    Directory of Open Access Journals (Sweden)

    Fatih Arslan

    2015-01-01

    Full Text Available Prions are self-perpetuating conformational variants of particular proteins. In yeast, prions cause heritable phenotypic traits. Most known yeast prions contain a glutamine (Q/asparagine (N-rich region in their prion domains. [PSI+], the prion form of Sup35, appears de novo at dramatically enhanced rates following transient overproduction of Sup35 in the presence of [PIN+], the prion form of Rnq1. Here, we establish the temporal de novo appearance of Sup35 aggregates during such overexpression in relation to other cellular proteins. Fluorescently-labeled Sup35 initially forms one or a few dots when overexpressed in [PIN+] cells. One of the dots is perivacuolar, colocalizes with the aggregated Rnq1 dot and grows into peripheral rings/lines, some of which also colocalize with Rnq1. Sup35 dots that are not near the vacuole do not always colocalize with Rnq1 and disappear by the time rings start to grow. Bimolecular fluorescence complementation failed to detect any interaction between Sup35-VN and Rnq1-VC in [PSI+][PIN+] cells. In contrast, all Sup35 aggregates, whether newly induced or in established [PSI+], completely colocalize with the molecular chaperones Hsp104, Sis1, Ssa1 and eukaryotic release factor Sup45. In the absence of [PIN+], overexpressed aggregating proteins such as the Q/N-rich Pin4C or the non-Q/N-rich Mod5 can also promote the de novo appearance of [PSI+]. Similar to Rnq1, overexpressed Pin4C transiently colocalizes with newly appearing Sup35 aggregates. However, no interaction was detected between Mod5 and Sup35 during [PSI+] induction in the absence of [PIN+]. While the colocalization of Sup35 and aggregates of Rnq1 or Pin4C are consistent with the model that the heterologous aggregates cross-seed the de novo appearance of [PSI+], the lack of interaction between Mod5 and Sup35 leaves open the possibility of other mechanisms. We also show that Hsp104 is required in the de novo appearance of [PSI+] aggregates in a [PIN

  9. Contact Hamiltonian Mechanics

    CERN Document Server

    Bravetti, Alessandro; Tapias, Diego

    2016-01-01

    In this work we introduce contact Hamiltonian mechanics, an extension of symplectic Hamiltonian mechanics, and show that it is a natural candidate for a geometric description of non-dissipative and dissipative systems. For this purpose we review in detail the major features of standard symplectic Hamiltonian dynamics and show that all of them can be generalized to the contact case.

  10. Quantum mechanics. 5. ed.

    International Nuclear Information System (INIS)

    The aim of the textbook now present in fifth edition is the representation of the fundamental physical concepts of the theory of quantum mechanics. It is confined to the nonrelativistic quantum mechanics; however also themes are treated which are in an extended form important just for quantum field theory up to the modern development. (orig.) With 22 figs

  11. Quantum mechanics. 4. ed.

    International Nuclear Information System (INIS)

    The aim of the textbook now present in fourth edition is the representation of the fundamental physical concepts of the theory of quantum mechanics. It is confined to the nonrelativistic quantum mechanics; however also themes are treated which are in an extended form important just for quantum field theory up to the modern development. (orig./HSI)

  12. SOFC Cathode Mechanisms

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Zachau-Christiansen, Birgit; Bay, Lasse;

    1996-01-01

    litterature. It is argued that this kind of mechanism can only partly explain the experimental observations. The capacitive part of the low frequency response at anodic potentials is shown to be due to gas enclosures at the lectrode-electrolyte interface. As to the inductive activation mechanism of the...

  13. Mecanica Clasica (Classical Mechanics)

    OpenAIRE

    Rosu, H. C.

    1999-01-01

    First Internet graduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  14. Pulse emission mechanisms

    OpenAIRE

    Melrose, Don

    2003-01-01

    High-energy and radio emission mechanisms for pulsars are reviewed. The source region for high energy emission remains uncertain. Two preferred radio emission mechanism are identified. Some difficulties may be resolved by appealing to nonstationary pair creation distributed widely in height.

  15. Goryachkin's agricultural mechanics

    Science.gov (United States)

    Chinenova, Vera

    2016-03-01

    The paper contributes to the development of applied mechanics by establishing a new discipline, namely, agricultural mechanics by academician Vasilii Prohorovich Goryachkin (1868-1935) who was an apprentice of Nikolay Yegorovich Zhukovsky and a graduate of the Moscow University (current known as Moscow State University) and the Imperial Higher Technical School.

  16. The Clementine mechanisms

    Science.gov (United States)

    Purdy, William; Hurley, Michael

    1995-05-01

    The Clementine spacecraft was developed under the 'faster, better, cheaper' theme. The constraints of a low budget coupled with an unusually tight schedule forced many departures from the normal spacecraft development methods. This paper discusses technical lessons learned about several of the mechanisms on the Clementine spacecraft as well as managerial lessons learned for the entire mechanisms subsystem. A quick overview of the Clementine mission is included; the mission schedule and environment during the mechanisms releases and deployment are highlighted. This paper then describes the entire mechanisms subsystem. The design and test approach and key philosophies for a fast-track program are discussed during the description of the mechanisms subsystem. The mechanism subsystem included a marman clamp separation system, a separation nut separation system, a solar panel deployment and pointing system, a high gain antenna feed deployment system, and two separate sensor cover systems. Each mechanism is briefly discussed. Additional technical discussion is given on the marman clamp design, the sensor cover designs, and the design and testing practices for systems driven by heated actuators (specifically paraffin actuators and frangibolts). All of the other mechanisms were of conventional designs and will receive less emphasis. Lessons learned are discussed throughout the paper as they applied to the systems being discussed. Since there is information on many different systems, this paper is organized so that information on a particular topic can be quickly referenced.

  17. Working group inciting mechanisms

    International Nuclear Information System (INIS)

    This document deals with the inciting mechanisms under consideration in the framework of the greenhouse effect fight. The advantages and disadvantages, the coherence of these mechanisms and their articulation with the taxation, have been specified. A whole evaluation of the various scenario, taking into account the implementing problems and the evolution in an international context, is proposed. (A.L.B.)

  18. Introduction to quantum mechanics

    International Nuclear Information System (INIS)

    An introduction is presented to quantum mechanics dealing with fundamental problems, the physics of the atom (central potential, hydrogen atom, angular momentum, spin, and statistics), nuclear physics (theory of scattering, alpha decay, nucleon-nucleon interaction), and the general quantum mechanics theory using the Dirac notation. The mathematical apparatus is deliberately suppressed. Problems are appended to each chapter. (Z.J.)

  19. Discussion of corrosion mechanisms

    International Nuclear Information System (INIS)

    This appendix summarizes discussions directed toward developing an understanding of the mechanisms of cracking and factors which may contribute to both crack initiation and propagation. Discussions considered five mechanisms originally postulated and ranked in order of likelihood of occurrence; primary side initiated pure water cracking; secondary side initiated cracking; hydrogen embrittlement; pitting - OD/ID initiated; and intergranular attack - secondary side initiation

  20. Mecanica Clasica (Classical Mechanics)

    CERN Document Server

    Rosu, H C

    1999-01-01

    First Internet undergraduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  1. SOFC Cathode Mechanisms

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Zachau-Christiansen, Birgit; Bay, Lasse; Skaarup, Steen

    litterature. It is argued that this kind of mechanism can only partly explain the experimental observations. The capacitive part of the low frequency response at anodic potentials is shown to be due to gas enclosures at the lectrode-electrolyte interface. As to the inductive activation mechanism of the...

  2. Engineering quantum mechanics

    CERN Document Server

    Ahn, Doyeol

    2011-01-01

    A clear introduction to quantum mechanics concepts Quantum mechanics has become an essential tool for modern engineering, particularly due to the recent developments in quantum computing as well as the rapid progress in optoelectronic devices. Engineering Quantum Mechanics explains the fundamentals of this exciting field, providing broad coverage of both traditional areas such as semiconductor and laser physics as well as relatively new yet fast-growing areas such as quantum computation and quantum information technology. The book begins with basic quantum mechanics, reviewing measurements and probability, Dirac formulation, the uncertainty principle, harmonic oscillator, angular momentum eigenstates, and perturbation theory. Then, quantum statistical mechanics is explored, from second quantization and density operators to coherent and squeezed states, coherent interactions between atoms and fields, and the Jaynes-Cummings model. From there, the book moves into elementary and modern applications, discussing s...

  3. Introduction to quantum mechanics

    International Nuclear Information System (INIS)

    Quantum mechanics, that is now the source of numerous applications, belongs to the fundamental knowledge that any future engineer has to know. This book aims at: first giving a consistent view on elementary quantum mechanics phenomena and secondly providing a fundamental knowledge that could be developed by further reading on related subjects like statistical physics or quantum optics... The book begins with a synthesis of classical physics concepts (mechanics and electromagnetism unified in the framework of the restricted relativity) then the most meaningful experimental facts that have challenged all this knowledge are analysed. The mathematical tools of quantum mechanics (operators, wave functions...) are defined and their physical content is highlighted, a particular attention is given to concepts that are completely new in the view of classical physics, spin or quantum correlations for instance. In the last part of the book, quantum mechanics is applied to atoms and molecules in order to account their elementary properties. (A.C.)

  4. Membrane quantum mechanics

    Directory of Open Access Journals (Sweden)

    Tadashi Okazaki

    2015-01-01

    Full Text Available We consider the multiple M2-branes wrapped on a compact Riemann surface and study the arising quantum mechanics by taking the limit where the size of the Riemann surface goes to zero. The IR quantum mechanical models resulting from the BLG-model and the ABJM-model compactified on a torus are N=16 and N=12 superconformal gauged quantum mechanics. After integrating out the auxiliary gauge fields we find OSp(16|2 and SU(1,1|6 quantum mechanics from the reduced systems. The curved Riemann surface is taken as a holomorphic curve in a Calabi–Yau space to preserve supersymmetry and we present a prescription of the topological twisting. We find the N=8 superconformal gauged quantum mechanics that may describe the motion of two wrapped M2-branes in a K3 surface.

  5. Mechanics an intensive course

    CERN Document Server

    Chaichian, Masud; Tureanu, Anca

    2012-01-01

    Mechanics is one of the oldest and at the same time newest disciplines, in the sense that there are methods and principles developed first in mechanics but now widely used in almost all branches of physics: electrodynamics, quantum mechanics, classical and quantum field theory, special and general theory of relativity, etc. More than that, there are some formalisms like Lagrangian and Hamiltonian approaches, which represent the key stone for the development of the above-mentioned disciplines. During the last 20-25 years, classical mechanics has undergone an important revival associated with the progress in non-linear dynamics, applications of Noether’s theorem and the extension of variational principles in various interdisciplinary sciences (for instance, magnetofluid dynamics). Thus, there ought to exist a book concerned with the applied analytical formalism, first developed in the frame of theoretical mechanics, which has proved to be one of the most efficient tools of investigation in the entire arena of...

  6. Quantum mechanics for pedestrians

    CERN Document Server

    Pade, Jochen

    2014-01-01

    This book provides an introduction into the fundamentals of non-relativistic quantum mechanics. In Part 1, the essential principles are developed. Applications and extensions of the formalism can be found in Part 2. The book includes not only material that is presented in traditional textbooks on quantum mechanics, but also discusses in detail current issues such as interaction-free quantum measurements, neutrino oscillations, various topics in the field of quantum information as well as fundamental problems and epistemological questions, such as the measurement problem, entanglement, Bell's inequality, decoherence, and the realism debate. A chapter on current interpretations of quantum mechanics concludes the book. To develop quickly and clearly the main principles of quantum mechanics and its mathematical formulation, there is a systematic change between wave mechanics and algebraic representation in the first chapters. The required mathematical tools are introduced step by step. Moreover, the appendix coll...

  7. Advanced Visual Quantum Mechanics

    CERN Document Server

    Thaller, Bernd

    2005-01-01

    Advanced Visual Quantum Mechanics is a systematic effort to investigate and to teach quantum mechanics with the aid of computer-generated animations. It is a self-contained textbook that combines selected topics from atomic physics (spherical symmetry, the hydrogen atom, and particles with spin) with an introduction to quantum information theory (qubits, EPR paradox, teleportation, quantum computers). It explores relativistic quantum mechanics and the strange behavior of Dirac equation solutions. A series of appendices covers important topics from perturbation and scattering theory. The book places an emphasis on ideas and concepts, with a fair to moderate amount of mathematical rigor. Though this book stands alone, it can also be paired with Thaller Visual Quantum Mechanics to form a comprehensive course in quantum mechanics. The software for the first book earned the European Academic Software Award 2000 for outstanding innovation in its field.

  8. Mechanisms in environmental control

    International Nuclear Information System (INIS)

    The theory of implementation provides methods for decentralization of decisions in societies. By using mechanisms (game forms) it is possible (in theory) to implement attractive states in different economic environments. As an example the market mechanisms can implement Pareto-efficient and individual rational allocations in an Arrow-Debreu economic environment without market failures. And even when there exists externalities the market mechanism sometime can be used if it is possible to make a market for the goods not allocated on a market already - examples are marketable emission permits, and deposit refund systems. But environmental problems can often be explained by the existence of other market failures (e.g. asymmetric information), and then the market mechanism do not work properly. And instead of using regulation or traditional economic instruments (subsidies, charges, fees, liability insurance, marketable emission permits, or deposit refund systems) to correct the problems caused by market failures, some other methods can be used to deal with these problems. This paper contains a survey of mechanisms that can be used in environmental control when the problems are caused by the existence of public goods, externalities, asymmetric information, and indivisible goods in the economy. By examples it will be demonstrated how the Clarke-Groves mechanism, the Cournot-Lindahl mechanism, and other mechanisms can be used to solve specific environmental problems. This is only theory and examples, but a recent field study have used the Cournot-Lindahl mechanism to solve the problem of lake liming in Sweden. So this subject may be of some interests for environmental policy in the future. (au) 23 refs

  9. Mechanics of mixtures

    CERN Document Server

    Rajagopal, KR

    1995-01-01

    This book presents a unified treatment of the mechanics of mixtures of several constituents within the context of continuum mechanics. After an introduction to the basic theory in the first few chapters, the book deals with a detailed exposition of the mechanics of a mixture of a fluid and an elastic solid, which is either isotropic or anisotropic and is capable of undergoing large deformations. Issues regarding the specification of boundary conditions for mixtures are discussed in detail and several boundary value and initial-boundary value problems are solved. The status of some special theo

  10. Mechanics classical and quantum

    CERN Document Server

    Taylor, T T

    2015-01-01

    Mechanics: Classical and Quantum explains the principles of quantum mechanics via the medium of analytical mechanics. The book describes Schrodinger's formulation, the Hamilton-Jacobi equation, and the Lagrangian formulation. The author discusses the Harmonic Oscillator, the generalized coordinates, velocities, as well as the application of the Lagrangian formulation to systems that are partially or entirely electromagnetic in character under certain conditions. The book examines waves on a string under tension, the isothermal cavity radiation, and the Rayleigh-Jeans result pertaining to the e

  11. Lectures on quantum mechanics

    CERN Document Server

    Dirac, Paul A M

    2001-01-01

    The author of this concise, brilliant series of lectures on mathematical methods in quantum mechanics was one of the shining intellects in the field, winning a Nobel prize in 1933 for his pioneering work in the quantum mechanics of the atom. Beyond that, he developed the transformation theory of quantum mechanics (which made it possible to calculate the statistical distribution of certain variables), was one of the major authors of the quantum theory of radiation, codiscovered the Fermi-Dirac statistics, and predicted the existence of the positron.The four lectures in this book were delivered

  12. Mechanics: Ideas, problems, applications

    Science.gov (United States)

    Ishlinskii, A. Iu.

    The book contains the published articles and reports by academician Ishlinskii which deal with the concepts and ideas of modern mechanics, its role in providing a general understanding of the natural phenomena, and its applications to various problems in science and engineering. Attention is given to the methodological aspects of mechanics, to the history of the theories of plasticity, friction, gyroscopic and inertial systems, and inertial navigation, and to mathematical methods in mechanics. The book also contains essays on some famous scientists and engineers.

  13. Notes on continuum mechanics

    CERN Document Server

    Chaves, Eduardo W V

    2013-01-01

    This publication is aimed at students, teachers, and researchers of Continuum Mechanics and focused extensively on stating and developing Initial Boundary Value equations used to solve physical problems. With respect to notation, the tensorial, indicial and Voigt notations have been used indiscriminately.   The book is divided into twelve chapters with the following topics: Tensors, Continuum Kinematics, Stress, The Objectivity of Tensors, The Fundamental Equations of Continuum Mechanics, An Introduction to Constitutive Equations, Linear Elasticity, Hyperelasticity, Plasticity (small and large deformations), Thermoelasticity (small and large deformations), Damage Mechanics (small and large deformations), and An Introduction to Fluids. Moreover, the text is supplemented with over 280 figures, over 100 solved problems, and 130 references.

  14. Quantum Statistical Mechanics

    Science.gov (United States)

    Schieve, William C.; Horwitz, Lawrence P.

    2009-04-01

    1. Foundations of quantum statistical mechanics; 2. Elementary examples; 3. Quantum statistical master equation; 4. Quantum kinetic equations; 5. Quantum irreversibility; 6. Entropy and dissipation: the microscopic theory; 7. Global equilibrium: thermostatics and the microcanonical ensemble; 8. Bose-Einstein ideal gas condensation; 9. Scaling, renormalization and the Ising model; 10. Relativistic covariant statistical mechanics of many particles; 11. Quantum optics and damping; 12. Entanglements; 13. Quantum measurement and irreversibility; 14. Quantum Langevin equation: quantum Brownian motion; 15. Linear response: fluctuation and dissipation theorems; 16. Time dependent quantum Green's functions; 17. Decay scattering; 18. Quantum statistical mechanics, extended; 19. Quantum transport with tunneling and reservoir ballistic transport; 20. Black hole thermodynamics; Appendix; Index.

  15. Fluid and particle mechanics

    CERN Document Server

    Michell, S J

    2013-01-01

    Fluid and Particle Mechanics provides information pertinent to hydraulics or fluid mechanics. This book discusses the properties and behavior of liquids and gases in motion and at rest. Organized into nine chapters, this book begins with an overview of the science of fluid mechanics that is subdivided accordingly into two main branches, namely, fluid statics and fluid dynamics. This text then examines the flowmeter devices used for the measurement of flow of liquids and gases. Other chapters consider the principle of resistance in open channel flow, which is based on improper application of th

  16. Supersymmetry in quantum mechanics

    CERN Document Server

    Cooper, Fred; Sukhatme, Uday

    2001-01-01

    This invaluable book provides an elementary description of supersymmetric quantum mechanics which complements the traditional coverage found in the existing quantum mechanics textbooks. It gives physicists a fresh outlook and new ways of handling quantum-mechanical problems, and also leads to improved approximation techniques for dealing with potentials of interest in all branches of physics. The algebraic approach to obtaining eigenstates is elegant and important, and all physicists should become familiar with this. The book has been written in such a way that it can be easily appreciated by

  17. Mechanical engineers data handbook

    CERN Document Server

    Carvill, James

    1994-01-01

    This text provides the student and professional mechanical engineer with a reference text of an essentially practical nature. It is uncluttered by text, and extensive use of illustrations and tables provide quick and clear access to information. It alsoincludes examples of detailed calculations on many of the applications of technology used by mechanical and production engineers, draughtsmen and engineering designers.Although mainly intended for those studying and practising mechanical engineering, a glance at the contents will show that it is also useful to those in related br

  18. Mechanism of Gravity Impulse

    Institute of Scientific and Technical Information of China (English)

    WU Ning

    2006-01-01

    It is well known that energy-momentum is the source of gravitational field. For a long time, it is generally believed that only stars with huge masses can generate strong gravitational field. Based on the unified theory of gravitational interactions and electromagnetic interactions, a new mechanism of the generation of gravitational field is studied. According to this mechanism, in some special conditions, electromagnetic energy can be directly converted into gravitational energy, and strong gravitational field can be generated without massive stars. Gravity impulse found in experiments is generated by this mechanism.

  19. Rotary mechanical latch

    Science.gov (United States)

    Spletzer, Barry L.; Martinez, Michael A.; Marron, Lisa C.

    2012-11-13

    A rotary mechanical latch for positive latching and unlatching of a rotary device with a latchable rotating assembly having a latching gear that can be driven to latched and unlatched states by a drive mechanism such as an electric motor. A cam arm affixed to the latching gear interfaces with leading and trailing latch cams affixed to a flange within the drive mechanism. The interaction of the cam arm with leading and trailing latch cams prevents rotation of the rotating assembly by external forces such as those due to vibration or tampering.

  20. Mechanics of Generalized Continua

    CERN Document Server

    Maugin, Gerard A

    2010-01-01

    In their 1909 publication "Theorie des corps deformables", Eugene and Francois Cosserat made a historic contribution to materials science by establishing the fundamental principles of the mechanics of generalized continua. The chapters collected in this volume showcase the many areas of continuum mechanics that grew out of the foundational work of the Cosserat brothers. The included contributions provide a detailed survey of the most recent theoretical developments in the field of generalized continuum mechanics. The diverse topics covered include: the properties of Cosserat media, m

  1. Mechanical design engineering handbook

    CERN Document Server

    Childs, Peter R N

    2013-01-01

    Mechanical Design Engineering Handbook is a straight-talking and forward-thinking reference covering the design, specification, selection, use and integration of machine elements fundamental to a wide range of engineering applications. Develop or refresh your mechanical design skills in the areas of bearings, shafts, gears, seals, belts and chains, clutches and brakes, springs, fasteners, pneumatics and hydraulics, amongst other core mechanical elements, and dip in for principles, data and calculations as needed to inform and evaluate your on-the-job decisions. Covering the full spectrum

  2. Applications in solid mechanics

    DEFF Research Database (Denmark)

    Ølgaard, Kristian Breum; Wells, Garth N.

    2012-01-01

    Problems in solid mechanics constitute perhaps the largest field of application of finite element methods. The vast majority of solid mechanics problems involve the standard momentum balance equation, posed in a Lagrangian setting, with different models distinguished by the choice of nonlinear...... or linearized kinematics, and the constitutive model for determining the stress. For some common models, the constitutive relationships are rather complex. This chapter addresses a number of canonical solid mechanics models in the context of automated modeling, and focuses on some pertinent issues that arise...

  3. Analytical elements of mechanics

    CERN Document Server

    Kane, Thomas R

    2013-01-01

    Analytical Elements of Mechanics, Volume 1, is the first of two volumes intended for use in courses in classical mechanics. The books aim to provide students and teachers with a text consistent in content and format with the author's ideas regarding the subject matter and teaching of mechanics, and to disseminate these ideas. The book opens with a detailed exposition of vector algebra, and no prior knowledge of this subject is required. This is followed by a chapter on the topic of mass centers, which is presented as a logical extension of concepts introduced in connection with centroids. A

  4. Testing the Palma-Clary Reduced Dimensionality Model Using Classical Mechanics on the CH4 + H → CH3 + H2 Reaction.

    Science.gov (United States)

    Vikár, Anna; Nagy, Tibor; Lendvay, György

    2016-07-14

    Application of exact quantum scattering methods in theoretical reaction dynamics of bimolecular reactions is limited by the complexity of the equations of nuclear motion to be solved. Simplification is often achieved by reducing the number of degrees of freedom to be explicitly handled by freezing the less important spectator modes. The reaction cross sections obtained in reduced-dimensionality (RD) quantum scattering methods can be used in the calculation of rate coefficients, but their physical meaning is limited. The accurate test of the performance of a reduced-dimensionality method would be a comparison of the RD cross sections with those obtained in accurate full-dimensional (FD) calculations, which is not feasible because of the lack of complete full-dimensional results. However, classical mechanics allows one to perform reaction dynamics calculations using both the RD and the FD model. In this paper, an RD versus FD comparison is made for the 8-dimensional Palma-Clary model on the example of four isotopologs of the CH4 + H → CH3 + H2 reaction, which has 12 internal dimensions. In the Palma-Clary model, the only restriction is that the methyl group is confined to maintain C3v symmetry. Both RD and FD opacity and excitation functions as well as differential cross sections were calculated using the quasiclassical trajectory method. The initial reactant separation has been handled according to our one-period averaging method [ Nagy et al. J. Chem. Phys. 2016, 144, 014104 ]. The RD and FD excitation functions were found to be close to each other for some isotopologs, but in general, the RD reactivity parameters are lower than the FD reactivity parameters beyond statistical error, and for one of the isotopologs, the deviation is significant. This indicates that the goodness of RD cross sections cannot be taken for granted. PMID:26918703

  5. Mechanisms based on piezoactuators

    Science.gov (United States)

    Claeyssen, Frank; Le Letty, Ronan; Barillot, Francois; Lhermet, Nicolas; Fabbro, H.; Guay, Philippe; Yorck, Mickael; Bouchilloux, Philippe

    2001-06-01

    In several fields (optics, space, aircraft, fluid control, biomedical, and manufacturing) there is a strong need for compact, robust and efficient positioning mechanisms that also offer high precision, short response times, low power consumption, low electromagnetic interference and multiple degrees of freedom. Piezoelectric actuators are generally good candidates for building such mechanisms. The products manufactured by Cedrat Recherche SA are piezoelectric actuators offering compact size, high deformation (up to 1%) and high stiffness. These actuators have successfully passed different qualification tests (air and space qualification, lifetime tests). They can easily be integrated in applications, as shown by examples of mechanisms taken from various fields: a super amplified actuator for a MRI biomedical device, a tip-tilt for mirrors, a chopper for X-ray diffraction, a helicopter flap mechanism and an XYZ stage for the AFM microscope of the MIDAS instrument of the ESA ROSETTA space mission.

  6. Quantum mechanics. 4. ed.

    International Nuclear Information System (INIS)

    This represents the introductory course which would precede and so complements the author's book on Advanced Quantum Mechanics. The new edition has been up-dated and thoroughly revised throughout and now includes many new or newly drawn figures which will facilitate an easier understanding of subtle topics. The book meets students' needs in providing detailed mathematical steps along the way, with worked examples and applications throughout the text, and many problems for the reader at the end of each chapter. It contains nonrelativistic quantum mechanics and a short treatment of the quantization of the radiation field. In addition to the essentials, topics such as the theory of measurement, the Bell inequality, decoherence, entanglement and supersymmetric quantum mechanics are discussed. ''Any student wishing to develop mathematical skills and deepen their understanding of the technical side of quantum theory will find Schwabl's Quantum Mechanics very helpful''. Contemporary Physics (orig.)

  7. Mechanism of Seizure Termination

    OpenAIRE

    J Gordon Millichap

    2008-01-01

    Physiological mechanisms contributing to seizure termination and organized according to membranes, synapses, networks, and circuits are reviewed by researchers from Albert Einstein College of Medicine, and Montefiore Medical Center, Bronx, New York.

  8. Molecular Mechanisms of Preeclampsia

    OpenAIRE

    Vitoratos, N.; Hassiakos, D.; C. Iavazzo

    2012-01-01

    Preeclampsia is one of the leading causes of maternal morbidity/mortality. The pathogenesis of preeclampsia is still under investigation. The aim of this paper is to present the molecular mechanisms implicating in the pathway leading to preeclampsia.

  9. Beyond conventional quantum mechanics

    International Nuclear Information System (INIS)

    The author reviews some recent attempts to overcome the conceptual difficulties encountered by trying to interpret quantum mechanics as giving a complete, objective and unified description of natural phenomena. 38 refs

  10. Playing at Statistical Mechanics

    Science.gov (United States)

    Clark, Paul M.; And Others

    1974-01-01

    Discussed are the applications of counting techniques of a sorting game to distributions and concepts in statistical mechanics. Included are the following distributions: Fermi-Dirac, Bose-Einstein, and most probable. (RH)

  11. Statistical mechanics of superconductivity

    CERN Document Server

    Kita, Takafumi

    2015-01-01

    This book provides a theoretical, step-by-step comprehensive explanation of superconductivity for undergraduate and graduate students who have completed elementary courses on thermodynamics and quantum mechanics. To this end, it adopts the unique approach of starting with the statistical mechanics of quantum ideal gases and successively adding and clarifying elements and techniques indispensible for understanding it. They include the spin-statistics theorem, second quantization, density matrices, the Bloch–De Dominicis theorem, the variational principle in statistical mechanics, attractive interaction, and bound states. Ample examples of their usage are also provided in terms of topics from advanced statistical mechanics such as two-particle correlations of quantum ideal gases, derivation of the Hartree–Fock equations, and Landau’s Fermi-liquid theory, among others. With these preliminaries, the fundamental mean-field equations of superconductivity are derived with maximum mathematical clarity based on ...

  12. Applied mechanics of solids

    CERN Document Server

    Bower, Allan F

    2009-01-01

    Modern computer simulations make stress analysis easy. As they continue to replace classical mathematical methods of analysis, these software programs require users to have a solid understanding of the fundamental principles on which they are based. Develop Intuitive Ability to Identify and Avoid Physically Meaningless Predictions Applied Mechanics of Solids is a powerful tool for understanding how to take advantage of these revolutionary computer advances in the field of solid mechanics. Beginning with a description of the physical and mathematical laws that govern deformation in solids, the text presents modern constitutive equations, as well as analytical and computational methods of stress analysis and fracture mechanics. It also addresses the nonlinear theory of deformable rods, membranes, plates, and shells, and solutions to important boundary and initial value problems in solid mechanics. The author uses the step-by-step manner of a blackboard lecture to explain problem solving methods, often providing...

  13. Boosted Statistical Mechanics

    OpenAIRE

    Testa, Massimo

    2015-01-01

    Based on the fundamental principles of Relativistic Quantum Mechanics, we give a rigorous, but completely elementary, proof of the relation between fundamental observables of a statistical system when measured relatively to two inertial reference frames, connected by a Lorentz transformation.

  14. Miniature Release Mechanism Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective is to design, build and functionally test a miniature release mechanism for CubeSats and other small satellites. The WFF 6U satellite structure will...

  15. Computational Continuum Mechanics

    CERN Document Server

    Shabana, Ahmed A

    2011-01-01

    This text presents the theory of continuum mechanics using computational methods. Ideal for students and researchers, the second edition features a new chapter on computational geometry and finite element analysis.

  16. Mechanical Enterogenesis - A Review

    Directory of Open Access Journals (Sweden)

    Rebecca Stark

    2012-01-01

    Full Text Available Mechanical enterogenesis is a novel method of lengthening pre-existing intestine with distractive force. The application of mechanical force on small intestine aims to induce cellular proliferation and ultimately increase bowel length. This has been investigated primarily for the treatment of short bowel syndrome (SBS. Research has been ongoing for well over a decade in this arena and a multitude of advances have been made, both in the understanding of the biology behind force induced cellular proliferation and in the basic mechanics of force delivery systems. Important experimental models have been developed for studying this phenomenon and the collaboration of engineers and medical researchers has lead to the design of several devices that successfully lengthen small intestine. This has catapulted the field forward and there may soon be a device suitable for medical use in humans. This review analyses the past, present and future of mechanical enterogenesis.

  17. Mechanical Testing Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — NETL’s Mechanical Testing Laboratory in Albany, OR, helps researchers investigate materials that can withstand the heat and pressure commonly found in fossil energy...

  18. Purchase Price Mechanisms

    OpenAIRE

    Gajdošech, Martin

    2012-01-01

    My diploma thesis focuses on the M&A transaction closing mechanisms. Their function is to reflect the value changes of the target company into the purchase price. Value change occurs during the time lag between the date of the financial statements and the date of the transaction closing. Throughout history, there have been two major approaches developed. The "Completion Accounts Mechanism" uses post-completion price adjustments to reflect the change of the net working capital and net debt dur...

  19. Interfacial mechanics of graphene

    OpenAIRE

    Zhu, Yong

    2014-01-01

    Interfacial mechanics between graphene and substrate such as friction and adhesion plays a critical role in the morphology and functionality of graphene-based devices. Here I will present the interface sliding and buckling of monolayer graphene on a stretchable substrate. The nonlinear mechanical response of monolayer graphene on polyethylene terephthalate (PET) is characterized using in-situ Raman spectroscopy and atomic force microscopy. Although interfacial stress transfer leads to tension...

  20. Physics. Module 1. Mechanics

    OpenAIRE

    Бовтрук, Алла Георгіївна; Мєняйлов, Сергій Миколайович; Максимов, Сергій Леонідович; Поліщук, Аркадій Петрович

    2009-01-01

    Ukraine’s joining Bologna process requires creating new books in physics (in English in particular). The book is developed for all forms of studying physics on the Credit-based Modular System basis in higher school. «Physics. Module 1. Mechanics» presents Newtonian mechanics and Special theory of relativity. It contains eight Study Units which include theoretical information, test questions, sample problems, laboratory works and individual home tasks. It is designed for students of engi...

  1. Mechanical CPR devices

    OpenAIRE

    Halperin, Henry; Carver, David J.

    2010-01-01

    It is recognized that the quality of cardiopulmonary resuscitation (CPR) is an important predictor of outcome from cardiac arrest. Mechanical chest-compression devices provide an alternative to manual CPR. Physiological and animal data suggest that mechanical chest-compression devices are more effective than manual CPR. Consequently, there has been much interest in the development of new techniques and devices to improve the efficacy of CPR. This review will consider the evidence ...

  2. Mechanisms of Defibrillation

    OpenAIRE

    Dosdall, Derek J.; Fast, Vladimir G.; Ideker, Raymond E.

    2010-01-01

    Electrical shock has been the one effective treatment for ventricular fibrillation for several decades. With the advancement of electrical and optical mapping techniques, histology, and computer modeling, the mechanisms responsible for defibrillation are now coming to light. In this review, we discuss recent work that demonstrates the various mechanisms responsible for defibrillation. On the cellular level, membrane depolarization and electroporation affect defibrillation outcome. Cell bundle...

  3. Experimental unsaturated soil mechanics

    OpenAIRE

    Delage, Pierre

    2002-01-01

    In this general report, experimental systems and procedures of investigating the hydro-mechanical behaviour of unsaturated soils are presented. The water retention properties of unsaturated soils are commented and linked to various physical parameters and properties of the soils. Techniques of controlling suction are described together with their adaptation in various laboratory testing devices. Some typical features of the mechanical behaviour of unsaturated soils are presented within an ela...

  4. Phase Field Fracture Mechanics.

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Brett Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.

  5. The monetary transmission mechanism

    OpenAIRE

    Ireland, Peter N.

    2006-01-01

    The monetary transmission mechanism describes how policy-induced changes in the nominal money stock or the short-term nominal interest rate impact on real variables such as aggregate output and employment. Specific channels of monetary transmission operate through the effects that monetary policy has on interest rates, exchange rates, equity and real estate prices, bank lending, and firm balance sheets. Recent research on the transmission mechanism seeks to understand how these channels work ...

  6. Immune mechanisms in vasculopathies

    OpenAIRE

    Nityanand, Soniya

    1996-01-01

    Soniya Nityanand AB STRACT Most of the inflammatory vasculopathies, termed as vasculitides are considered to be mediated at least in part by immunopathogenic mechanisms. With the recent demonstration of immune cells in atherosclerotic plaques, immune mechanisms are considered to play an important role in atherosclerotic vasculopathies too. The main components involved in the immune-mediated vascular injury are immune complexes, antibodies to vascular wall antigens...

  7. On admissible canonical mechanics

    International Nuclear Information System (INIS)

    General solution has been derived for the functional c-number equation which determines all admissible realisations of various mechanics with associative (but not necessary realizable by operators) law of multiplication of the observables. The general solution includes the algebras of observables for the classical and for the quantum mechanics. In addition, the solution includes one new algebra which corresponds formally to purely imaginary value to the Planck constant. The mathematical difficulties of treating the new algebra are discussed

  8. Mechanisms of doping graphene

    OpenAIRE

    Pinto, H; Jones, R; Goss, J. P.; Briddon, P. R.

    2010-01-01

    We distinguish three mechanisms of doping graphene. Density functional theory is used to show that electronegative molecule like F4-TCNQ and electropositive metals like K dope graphene p- and n-type respectively. These dopants are expected to lead to a decrease in carrier mobility arising from Coulomb scattering but without any hysteresis effects. Secondly, a novel doping mechanism is exhibited by Au which dopes bilayer graphene but not single layer. Thirdly, electrochemical doping is effecte...

  9. Mechanics of underwater noise

    CERN Document Server

    Ross, Donald

    1976-01-01

    Mechanics of Underwater Noise elucidates the basic mechanisms by which noise is generated, transmitted by structures and radiated into the sea. Organized into 10 chapters, this book begins with a description of noise, decibels and levels, significance of spectra, and passive sonar equation. Subsequent chapters discuss sound waves in liquids; acoustic radiation fundamentals; wind-generated ocean ambient noise; vibration isolation and structural damping; and radiation by plate flexural vibrations. Other chapters address cavitation, propeller cavitation noise, radiation by fluctuating-force (dipo

  10. Mechanical Circulatory Assist Devices

    OpenAIRE

    Park, Sang B.; Magovern, George J.; Christlieb, Ignacio Y.; Kao, Race L.

    1987-01-01

    Cardiogenic shock occurs in about 10% of the 1.5 million patients who suffer myocardial infarction and in approximately 1% of the 200,000 patients who undergo open-heart surgery each year. The ventricular assist device decreases the workload of the failing ventricles and increases the blood flow through the coronary system. Recovery of failing myocardium after mechanical circulatory assistance has been well documented; however, the mechanisms that contribute to the recovery of a failing heart...

  11. Lung parenchymal mechanics.

    Science.gov (United States)

    Suki, Béla; Stamenović, Dimitrije; Hubmayr, Rolf

    2011-07-01

    The lung parenchyma comprises a large number of thin-walled alveoli, forming an enormous surface area, which serves to maintain proper gas exchange. The alveoli are held open by the transpulmonary pressure, or prestress, which is balanced by tissues forces and alveolar surface film forces. Gas exchange efficiency is thus inextricably linked to three fundamental features of the lung: parenchymal architecture, prestress, and the mechanical properties of the parenchyma. The prestress is a key determinant of lung deformability that influences many phenomena including local ventilation, regional blood flow, tissue stiffness, smooth muscle contractility, and alveolar stability. The main pathway for stress transmission is through the extracellular matrix. Thus, the mechanical properties of the matrix play a key role both in lung function and biology. These mechanical properties in turn are determined by the constituents of the tissue, including elastin, collagen, and proteoglycans. In addition, the macroscopic mechanical properties are also influenced by the surface tension and, to some extent, the contractile state of the adherent cells. This chapter focuses on the biomechanical properties of the main constituents of the parenchyma in the presence of prestress and how these properties define normal function or change in disease. An integrated view of lung mechanics is presented and the utility of parenchymal mechanics at the bedside as well as its possible future role in lung physiology and medicine are discussed. PMID:23733644

  12. The pseudohydrogen bond structures between 2-F-epoxy-butane and three kinds of bimolecular

    International Nuclear Information System (INIS)

    The weak intermolecular interactions between 2-F-epoxy-butane and Iminazole, Thiazole and Oxazole were theoretically discussed by using density functional B3LYP (Becke, three-parameter, Lee- Yang-Parr)/6-311++G** and HF (Hartree Fock)/6-311++G** methods. The results showed that both the N…H conventional hydrogen bond and C-F…H-C pseudohydrogen bond (PHB) structures are coexisting in the three complexes. The weak intermolecular interactions energies indicate the relative stabilities of the three complexes are proportionable. The calculated results showed that the stretch vibrational frequency of C-H bond (electronic acceptor) presents blue shift, but that of C-F bond, which is intensely related to F group (electronic donor), presents red shift. Electron density topological properties demonstrates that the covalent and ionic characteristics of the C-F…H-C pseudohydrogen bond are proportional to that of convention hydrogen bond. (authors)

  13. An exact solution to Brownian dynamics of a reversible bimolecular reaction in one dimension

    OpenAIRE

    Smith, Stephen; Grima, Ramon

    2016-01-01

    Brownian dynamics is a popular fine-grained method for simulating systems of interacting particles, such as chemical reactions. Though the method is simple to simulate, it is generally assumed that the dynamics is impossible to solve exactly and analytically, aside from some trivial systems. We here give the first exact analytical solution to a non-trivial Brownian dynamics system: the reaction $A+B\\xrightleftharpoons[]{}C$ in equilibrium in one-dimensional periodic space. The solution is a f...

  14. Strategies for assessing proton linkage to bimolecular interactions by global analysis of isothermal titration calorimetry data

    International Nuclear Information System (INIS)

    Highlights: ► We demonstrate the usefulness of global analysis of ITC data for proton-linked binding study. ► Various experimental strategies are evaluated for their information content. ► Data at multiple temperatures might improve the precision of binding parameters. ► Methods for detailed error analysis of parameter uncertainties are discussed. ► By global modeling, an uncertainty in molecular concentrations can be accounted for. - Abstract: Isothermal titration calorimetry (ITC) is a traditional and powerful method for studying the linkage of ligand binding to proton uptake or release. The theoretical framework has been developed for more than two decades and numerous applications have appeared. In the current work, we explored strategic aspects of experimental design. To this end, we simulated families of ITC data sets that embed different strategies with regard to the number of experiments, range of experimental pH, buffer ionization enthalpy, and temperature. We then re-analyzed the families of data sets in the context of global analysis, employing a proton linkage binding model implemented in the global data analysis platform SEDPHAT, and examined the information content of all data sets by a detailed statistical error analysis of the parameter estimates. In particular, we studied the impact of different assumptions about the knowledge of the exact concentrations of the components, which in practice presents an experimental limitation for many systems. For example, the uncertainty in concentration may reflect imperfectly known extinction coefficients and stock concentrations or may account for different extents of partial inactivation when working with proteins at different pH values. Our results show that the global analysis can yield reliable estimates of the thermodynamic parameters for intrinsic binding and protonation, and that in the context of the global analysis the exact molecular component concentrations may not be required. Additionally, a comparison of data from different experimental strategies illustrates the benefit of conducting experiments at a range of temperatures.

  15. Effects of Bimolecular Recombination on Impedance Spectra in Organic Semiconductors: Analytical Approach.

    Science.gov (United States)

    Takata, Masashi; Takagi, Kenichiro; Nagase, Takashi; Kobayashi, Takashi; Naito, Hiroyoshi

    2016-04-01

    An analytical expression for impedance spectra in the case of double injection (both electrons and holes are injected into an organic semiconductor thin film) has been derived from the basic transport equations (the current density equation, the continuity equation and the Possion's equation). Capacitance-frequency characteristics calculated from the analytical expression have been examined at different recombination constants and different values of mobility balance defined by a ratio of electron mobility to hole mobility. Negative capacitance appears when the recombination constant is lower than the Langevin recombination constant and when the value of the mobility balance approaches unity. These results are consistent with the numerical results obtained by a device simulator (Atlas, Silvaco). PMID:27451625

  16. Innovative Bimolecular-Based Advanced Logic Operations: A Prime Discriminator and An Odd Parity Checker.

    Science.gov (United States)

    Zhou, Chunyang; Liu, Dali; Dong, Shaojun

    2016-08-17

    Herein, a novel logic operation of prime discriminator is first performed for the function of identifying the prime numbers from natural numbers less than 10. The prime discriminator logic operation is developed by DNA hybridizations and the conjugation of graphene oxide and single-stranded DNA as a reacting platform. On the basis of the similar reaction principle, an odd parity checker is also developed. The odd parity checker logic operation can identify the even numbers and odd numbers from natural numbers less than 10. Such advanced logic operations with digital recognition ability can provide a new field of vision toward prototypical DNA-based logic operations and promote the development of advanced logic circuits. PMID:27459592

  17. Sequence Effect on the Topology of 3 + 1 Interlocked Bimolecular DNA G-Quadruplexes.

    Science.gov (United States)

    Gao, Shang; Cao, Yanwei; Yan, Yuting; Guo, Xinhua

    2016-05-17

    Electrospray ionization mass spectrometry (ESI-MS) combined with fluorescence, circular dichroism, UV spectrophotometer, and native polyacrylamide gel electrophoresis techniques are used to study structural features of interlocked dimers formed by DNA sequence 93del (GGGGTGGGAGGAGGGT) and its derivatives. Herein, we demonstrate that the interlocked dimers can be distinguished from stacked dimers formed by sequences T30923 (GGGTGGGTGGGTGGGT) and T30177 (GTGGTGGGTGGGTGGGT). In addition, loop length, the base at 5'-end, and the isolation of T and TT to the first 4G tract do significantly influence the formation and topologies of interlocked dimers. Furthermore, our results suggest that the 4G tract and the 2G tract in various locations in the 93del derivative sequence can form interlocked structure. This work not only provides new insight into the assembly of 3 + 1 interlocked DNA conformations but also demonstrates that ESI-MS combined with other analytical methods is rapid and useful for DNA structural studies. PMID:27027538

  18. Effect of micellar environment on Marcus correlation curves for photoinduced bimolecular electron transfer reactions

    International Nuclear Information System (INIS)

    Photoinduced electron transfer (ET) between coumarin dyes and aromatic amine has been investigated in two cationic micelles, namely, cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), and the results have been compared with those observed earlier in sodium dodecyl sulphate (SDS) and triton-X-100 (TX-100) micelles for similar donor-acceptor pairs. Due to a reasonably high effective concentration of the amines in the micellar Stern layer, the steady-state fluorescence results show significant static quenching. In the time-resolved (TR) measurements with subnanosecond time resolution, contribution from static quenching is avoided. Correlations of the dynamic quenching constants (kqTR), as estimated from the TR measurements, show the typical bell-shaped curves with the free-energy changes (ΔG0) of the ET reactions, as predicted by the Marcus outersphere ET theory. Comparing present results with those obtained earlier for similar coumarin-amine systems in SDS and TX-100 micelles, it is seen that the inversion in the present micelles occurs at an exergonicity (-ΔG0>∼1.2-1.3 eV) much higher than that observed in SDS and TX-100 micelles (-ΔG0>∼0.7 eV), which has been rationalized based on the relative propensities of the ET and solvation rates in different micelles. In CTAB and DTAB micelles, the kqTR values are lower than the solvation rates, which result in the full contribution of the solvent reorganization energy (λs) towards the activation barrier for the ET reaction. Contrary to this, in SDS and TX-100 micelles, kqTR values are either higher or comparable with the solvation rates, causing only a partial contribution of λs in these cases. Thus, Marcus inversion in present cationic micelles is inferred to be the true inversion, whereas that in the anionic SDS and neutral TX-100 micelles are understood to be the apparent inversion, as envisaged from two-dimensional ET theory

  19. A biomimetic pathway for vanadium-catalyzed aerobic oxidation of alcohols: evidence for a base-assisted dehydrogenation mechanism.

    Science.gov (United States)

    Wigington, Bethany N; Drummond, Michael L; Cundari, Thomas R; Thorn, David L; Hanson, Susan K; Scott, Susannah L

    2012-11-19

    The first step in the catalytic oxidation of alcohols by molecular O(2), mediated by homogeneous vanadium(V) complexes [LV(V)(O)(OR)], is ligand exchange. The unusual mechanism of the subsequent intramolecular oxidation of benzyl alcoholate ligands in the 8-hydroxyquinolinato (HQ) complexes [(HQ)(2)V(V)(O)(OCH(2)C(6)H(4)-p-X)] involves intermolecular deprotonation. In the presence of triethylamine, complex 3 (X = H) reacts within an hour at room temperature to generate, quantitatively, [(HQ)(2)V(IV)(O)], benzaldehyde (0.5 equivalents), and benzyl alcohol (0.5 equivalents). The base plays a key role in the reaction: in its absence, less than 12% conversion was observed after 72 hours. The reaction is first order in both 3 and NEt(3), with activation parameters ΔH(≠)=(28±4) kJ mol(-1) and ΔS(≠)=(-169±4) J K(-1)  mol(-1). A large kinetic isotope effect, 10.2±0.6, was observed when the benzylic hydrogen atoms were replaced by deuterium atoms. The effect of the para substituent of the benzyl alcoholate ligand on the reaction rate was investigated using a Hammett plot, which was constructed using σ(p). From the slope of the Hammett plot, ρ=+(1.34±0.18), a significant buildup of negative charge on the benzylic carbon atom in the transition state is inferred. These experimental findings, in combination with computational studies, support an unusual bimolecular pathway for the intramolecular redox reaction, in which the rate-limiting step is deprotonation at the benzylic position. This mechanism, that is, base-assisted dehydrogenation (BAD), represents a biomimetic pathway for transition-metal-mediated alcohol oxidations, differing from the previously identified hydride-transfer and radical pathways. It suggests a new way to enhance the activity and selectivity of vanadium catalysts in a wide range of redox reactions, through control of the outer coordination sphere. PMID:23080554

  20. Fresh look at electron-transfer mechanisms via the donor/acceptor bindings in the critical encounter complex.

    Science.gov (United States)

    Rosokha, Sergiy V; Kochi, Jay K

    2008-05-01

    Seminal insights provided by the iconic R. S. Mulliken and his "charge-transfer" theory, H. Taube and his "outer/inner-sphere" mechanisms, R. A. Marcus and his "two-state non-adiabatic" theory, and N. S. Hush and his "intervalence" theory are each separately woven into the rich panoramic tapestry constituting chemical research into electron-transfer dynamics, and its mechanistic dominance for the past half century and more. In this Account, we illustrate how the simultaneous melding of all four key concepts allows sharp focus on the charge-transfer character of the critical encounter complex to evoke the latent facet of traditional electron-transfer mechanisms. To this end, we exploit the intervalence (electronic) transition that invariably accompanies the diffusive encounter of electron-rich organic donors (D) with electron-poor acceptors (A) as the experimental harbinger of the collision complex, which is then actually isolated and X-ray crystallographically established as loosely bound pi-stacked pairs of various aromatic and olefinic donor/acceptor dyads with uniform interplanar separations of r(DA) = 3.1 +/- 0.2 A. These X-ray structures, together with the spectral measurements of their intervalence transitions, lead to the pair of important electron-transfer parameters, H(DA) (electronic coupling element) versus lambdaT (reorganization energy), the ratio of which generally defines the odd-electron mobility within such an encounter complex in terms of the resonance stabilization of the donor/acceptor assembly [D, A] as opposed to the reorganization-energy penalty required for its interconversion to the electron-transfer state [D(+*), A(-*)]. We recognize the resonance-stabilization energy relative to the intrinsic activation barrier as the mechanistic binding factor, Q = 2H(DA)/lambdaT, to represent the quantitative measure of the highly variable continuum of inner-sphere/outer-sphere interactions that are possible within various types of precursor complexes

  1. Advanced mechanics of solids

    CERN Document Server

    Bruhns, Otto T

    2003-01-01

    Mechanics, and in particular, the mechanics of solids, forms the basis of all engi­ neering sciences. It provides the essential foundations for understanding the action of forces on bodies, and the effects of these forces on the straining of the body on the one hand, and on the deformation and motion of the body on the other. Thus, it provides the solutions of many problems with which the would-be engineer is going to be confronted with on a daily basis. In addition, in engineering studies, mechanics has a more vital importance, which many students appreciate only much later. Because of its clear, and analyt­ ical setup, it aids the student to a great extent in acquiring the necessary degree of abstraction ability, and logical thinking, skills without which no engineer in the practice today would succeed. Many graduates have confirmed to me that learning mechanics is generally per­ ceived as difficult. On the other hand, they always also declared that the preoccu­ pation with mechanics made an essential c...

  2. Theory of Parallel Mechanisms

    CERN Document Server

    Huang, Zhen; Ding, Huafeng

    2013-01-01

    This book contains mechanism analysis and synthesis. In mechanism analysis, a mobility methodology is first systematically presented. This methodology, based on the author's screw theory, proposed in 1997, of which the generality and validity was only proved recently,  is a very complex issue, researched by various scientists over the last 150 years. The principle of kinematic influence coefficient and its latest developments are described. This principle is suitable for kinematic analysis of various 6-DOF and lower-mobility parallel manipulators. The singularities are classified by a new point of view, and progress in position-singularity and orientation-singularity is stated. In addition, the concept of over-determinate input is proposed and a new method of force analysis based on screw theory is presented. In mechanism synthesis, the synthesis for spatial parallel mechanisms is discussed, and the synthesis method of difficult 4-DOF and 5-DOF symmetric mechanisms, which was first put forward by the a...

  3. Mechanism of charity activity

    Directory of Open Access Journals (Sweden)

    Roman B. Golovkin

    2015-12-01

    Full Text Available Objective to establish the essential properties of the mechanism of charitable activities and to formulate the concept of quotmechanism of charitable activityquot. Methods the objective of the study is achieved using the complex of methods which are based on the interaction of dialectical and metaphysical analysis the epistemological properties of which allowed to reveal various aspects of the charitable activities mechanism functioning taking into account the principles of comprehensiveness complexity specificity and objectivity of the research. Results the rules are stated of using the term quotmechanismquot to characterize actions of state and law the essence of the charity mechanism is defined the definition of quotthe mechanism of charitable activity quot is formulated. Scientific novelty for the first time at theoretical level in legal science the definition of quotthe mechanism of charitable activityquot is formulated and its essential properties are set. Practical significance the research will contribute to improving the legal regulation in the field of philanthropy as well as to improving the efficiency and quality of charitable activity in the Russian Federation. nbsp

  4. Fundamentals of Quantum Mechanics

    Science.gov (United States)

    Tang, C. L.

    2005-06-01

    Quantum mechanics has evolved from a subject of study in pure physics to one with a wide range of applications in many diverse fields. The basic concepts of quantum mechanics are explained in this book in a concise and easy-to-read manner emphasising applications in solid state electronics and modern optics. Following a logical sequence, the book is focused on the key ideas and is conceptually and mathematically self-contained. The fundamental principles of quantum mechanics are illustrated by showing their application to systems such as the hydrogen atom, multi-electron ions and atoms, the formation of simple organic molecules and crystalline solids of practical importance. It leads on from these basic concepts to discuss some of the most important applications in modern semiconductor electronics and optics. Containing many homework problems and worked examples, the book is suitable for senior-level undergraduate and graduate level students in electrical engineering, materials science and applied physics. Clear exposition of quantum mechanics written in a concise and accessible style Precise physical interpretation of the mathematical foundations of quantum mechanics Illustrates the important concepts and results by reference to real-world examples in electronics and optoelectronics Contains homeworks and worked examples, with solutions available for instructors

  5. Conventional mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Tobias Joseph

    2010-01-01

    Full Text Available The provision of mechanical ventilation for the support of infants and children with respiratory failure or insufficiency is one of the most common techniques that are performed in the Pediatric Intensive Care Unit (PICU. Despite its widespread application in the PICUs of the 21st century, before the 1930s, respiratory failure was uniformly fatal due to the lack of equipment and techniques for airway management and ventilatory support. The operating rooms of the 1950s and 1960s provided the arena for the development of the manual skills and the refinement of the equipment needed for airway management, which subsequently led to the more widespread use of endotracheal intubation thereby ushering in the era of positive pressure ventilation. Although there seems to be an ever increasing complexity in the techniques of mechanical ventilation, its successful use in the PICU should be guided by the basic principles of gas exchange and the physiology of respiratory function. With an understanding of these key concepts and the use of basic concepts of mechanical ventilation, this technique can be successfully applied in both the PICU and the operating room. This article reviews the basic physiology of gas exchange, principles of pulmonary physiology, and the concepts of mechanical ventilation to provide an overview of the knowledge required for the provision of conventional mechanical ventilation in various clinical arenas.

  6. Mechanical Biological Treatment

    DEFF Research Database (Denmark)

    Bilitewski, B-; Oros, Christiane; Christensen, Thomas Højlund

    The basic processes and technologies of composting and anaerobic digestion, as described in the previous chapters, are usually used for specific or source-separated organic waste flows. However, in the 1990s mechanical biological waste treatment technologies (MBT) were developed for unsorted or...... residual waste (after some recyclables removed at the source). The concept was originally to reduce the amount of waste going to landfill, but MBT technologies are today also seen as plants recovering fuel as well as material fractions. As the name suggests the technology combines mechanical treatment...... technologies (screens, sieves, magnets, etc.) with biological technologies (composting, anaerobic digestion). Two main technologies are available: Mechanical biological pretreatment (MBP), which first removes an RDF fraction and then biologically treats the remaining waste before most of it is landfilled, and...

  7. Molecular mechanisms in gliomagenesis

    DEFF Research Database (Denmark)

    Hulleman, Esther; Helin, Kristian

    2005-01-01

    , in order to design novel therapies and treatments for GBM, research has recently intensified to identify the cellular and molecular mechanisms leading to GBM formation. Modeling of astrocytomas by genetic manipulation of mice suggests that deregulation of the pathways that control gliogenesis during...... pathways. The expression of several of the components of these signaling cascades has been found altered in GBM, and recent data indicate that combinations of mutations in these pathways may contribute to GBM formation, although the exact mechanisms are still to be uncovered. Use of novel techniques...... including large-scale genomics and proteomics in combination with relevant mouse models will most likely provide novel insights into the molecular mechanisms underlying glioma formation and will hopefully lead to development of treatment modalities for GBM....

  8. Foundations of quantum mechanics

    International Nuclear Information System (INIS)

    Starting from a set of assumptions mainly of an operational or experimentally based nature, a derivation of quantum mechanics is presented, with the aim of clarifying the essential features of the theory and their interpretation. Various properties of quantum mechanics such as the addition of amplitudes, the calculation of probabilities, de Broglie's equations, and energy-momentum conservation are derived from first principles. It is investigated whether quantum amplitudes may be constructed from quantities of higher order than complex numbers. Measurable physical quantitics, as traditionally understood, are seen to play a role distinct from and supplementary to the behavior of the quantum amplitudes themselves. This is related to two distinct aspects of the nature of time in the context of quantum mechanics

  9. The graviton Higgs mechanism

    CERN Document Server

    Arraut, Ivan

    2015-01-01

    The Higgs mechanism at the graviton level formulated as a Vainshtein mechanism in time domains implies that the extra-degrees of freedom become relevant depending on the direction of time (frame of reference) with respect to the preferred time direction (preferred frame) defined by the St\\"uckelberg function $T_0(r,t)$ which contains the information of the extra-degrees of freedom of the theory. In this manuscript, I make the general definition of the Higgs mechanism by analyzing the gauge symmetries of the action and the general form of the vacuum solutions for the graviton field. In general, the symmetry generators depending explicitly on the St\\"uckelberg fields are broken at the vacuum level. These broken generators, define the number of Nambu-Goldstone bosons which will be eating up by the dynamical metric in order to become massive.

  10. Understanding Defense Mechanisms.

    Science.gov (United States)

    Cramer, Phebe

    2015-12-01

    Understanding defense mechanisms is an important part of psychotherapy. In this article, we trace the history of the concept of defense, from its origin with Freud to current views. The issue of defense as an unconscious mechanism is examined. The question of whether defenses are pathological, as well as their relation to pathology, is discussed. The effect of psychotherapy on the use of defenses, and their relation to a therapeutic alliance is explored. A series of empirical research studies that demonstrate the functioning of defense mechanisms and that support the theory is presented. Research also shows that as part of normal development, different defenses emerge at different developmental periods, and that gender differences in defense use occur. PMID:26583439

  11. Epigenetics: Biology's Quantum Mechanics.

    Science.gov (United States)

    Jorgensen, Richard A

    2011-01-01

    The perspective presented here is that modern genetics is at a similar stage of development as were early formulations of quantum mechanics theory in the 1920s and that in 2010 we are at the dawn of a new revolution in genetics that promises to enrich and deepen our understanding of the gene and the genome. The interrelationships and interdependence of two views of the gene - the molecular biological view and the epigenetic view - are explored, and it is argued that the classical molecular biological view is incomplete without incorporation of the epigenetic perspective and that in a sense the molecular biological view has been evolving to include the epigenetic view. Intriguingly, this evolution of the molecular view toward the broader and more inclusive epigenetic view of the gene has an intriguing, if not precise, parallel in the evolution of concepts of atomic physics from Newtonian mechanics to quantum mechanics that are interesting to consider. PMID:22639577

  12. Epigenetics: Biology's Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Richard A Jorgensen

    2011-04-01

    Full Text Available The perspective presented here is that modern genetics is at a similar stage of development as were early formulations of quantum mechanics theory in the 1920's and that in 2010 we are at the dawn of a new revolution in genetics that promises to enrich and deepen our understanding of the gene and the genome. The interrelationships and interdependence of two views of the gene - the molecular biological view and the epigenetic view - are explored, and it is argued that the classical molecular biological view is incomplete without incorporation of the epigenetic perspective and that in a sense the molecular biological view has been evolving to include the epigenetic view. Intriguingly, this evolution of the molecular view toward the broader and more inclusive epigenetic view of the gene has an intriguing, if not precise, parallel in the evolution of concepts of atomic physics from Newtonian mechanics to quantum mechanics that are interesting to consider.

  13. Mechanical Biological Treatment

    DEFF Research Database (Denmark)

    Bilitewski, B-; Oros, Christiane; Christensen, Thomas Højlund

    2011-01-01

    The basic processes and technologies of composting and anaerobic digestion, as described in the previous chapters, are usually used for specific or source-separated organic waste flows. However, in the 1990s mechanical biological waste treatment technologies (MBT) were developed for unsorted or...... residual waste (after some recyclables removed at the source). The concept was originally to reduce the amount of waste going to landfill, but MBT technologies are today also seen as plants recovering fuel as well as material fractions. As the name suggests the technology combines mechanical treatment...... technologies (screens, sieves, magnets, etc.) with biological technologies (composting, anaerobic digestion). Two main technologies are available: Mechanical biological pretreatment (MBP), which first removes an RDF fraction and then biologically treats the remaining waste before most of it is landfilled, and...

  14. Geometrisation of Statistical Mechanics

    CERN Document Server

    Brody, D C; Brody, Dorje C.; Hughston, Lane P.

    1997-01-01

    Classical and quantum statistical mechanics are cast here in the language of projective geometry to provide a unified geometrical framework for statistical physics. After reviewing the Hilbert space formulation of classical statistical thermodynamics, we introduce projective geometry as a basis for analysing probabilistic aspects of statistical physics. In particular, the specification of a canonical polarity on $RP^{n}$ induces a Riemannian metric on the state space of statistical mechanics. In the case of the canonical ensemble, we show that equilibrium thermal states are determined by the Hamiltonian gradient flow with respect to this metric. This flow is concisely characterised by the fact that it induces a projective automorphism on the state manifold. The measurement problem for thermal systems is studied by the introduction of the concept of a random state. The general methodology is then extended to include the quantum mechanical dynamics of equilibrium thermal states. In this case the relevant state ...

  15. Fracture Mechanics of Concrete

    DEFF Research Database (Denmark)

    Ulfkjær, Jens Peder

    Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high-strength......Chapter 1 Chapter l contains the introduction to this thesis. The scope of the thesis is partly to investigate different numerical and analytical models based on fracture mechanical ideas, which are able to predict size effects, and partly to perform an experimental investigation on high......-strength concrete. Chapter 2 A description of the factors which influence the strength and cracking of concrete and high strength concrete is made. Then basic linear fracture mechanics is outlined followed by a description and evaluation of the models used to describe concrete fracture in tension. The chapter ends...

  16. Polar continuum mechanics

    CERN Document Server

    Hadjesfandiari, Ali R

    2010-01-01

    The existing polar continuum theory contains unresolved indeterminacies in the spherical part of the couple-stress tensor. This severely restricts its applicability in the study of micro and nano-scale solid and fluid mechanics and, perhaps more importantly, in the investigation of fluid turbulence phenomena, which involve a broad range of scales. In this paper, we rely on the energy equation, along with some kinematical considerations, to establish a consistent couple-stress theory for polar continua that resolves all indeterminacies. After presenting the general formulation and obtaining conservation laws, we concentrate exclusively on couple stress theory for polar fluid mechanics. We specialize the theory for linear viscous flow and consider several boundary value problems in couple-stress fluid mechanics. More generally, the resulting theory presented here may provide a basis for fundamental continuum-level studies at the finest scales.

  17. Problems in quantum mechanics

    CERN Document Server

    Kogan, VI; Gersch, Harold

    2011-01-01

    Written by a pair of distinguished Soviet mathematicians, this compilation presents 160 lucidly expressed problems in nonrelativistic quantum mechanics plus completely worked-out solutions. Some were drawn from the authors' courses at the Moscow Institute of Engineering, but most were prepared especially for this book. A high-level supplement rather than a primary text, it constitutes a masterful complement to advanced undergraduate and graduate texts and courses in quantum mechanics.The mathematics employed in the proofs of the problems-asymptotic expansions of functions, Green's functions, u

  18. Probabilistic approach to mechanisms

    CERN Document Server

    Sandler, BZ

    1984-01-01

    This book discusses the application of probabilistics to the investigation of mechanical systems. The book shows, for example, how random function theory can be applied directly to the investigation of random processes in the deflection of cam profiles, pitch or gear teeth, pressure in pipes, etc. The author also deals with some other technical applications of probabilistic theory, including, amongst others, those relating to pneumatic and hydraulic mechanisms and roller bearings. Many of the aspects are illustrated by examples of applications of the techniques under discussion.

  19. Adventures in Celestial Mechanics

    CERN Document Server

    Szebehely, Victor G

    1998-01-01

    A fascinating introduction to the basic principles of orbital mechanics. It has been three hundred years since Isaac Newton first formulated laws to explain the orbits of the Moon and the planets of our solar system. In so doing he laid the groundwork for modern science's understanding of the workings of the cosmos and helped pave the way to the age of space exploration. Adventures in Celestial Mechanics offers students an enjoyable way to become acquainted with the basic principles involved in the motions of natural and human-made bodies in space. Packed with examples in which these principle

  20. Tubular closure mechanism

    International Nuclear Information System (INIS)

    This invention relates to a closure mechanism for tubular irradiation surveillance specimen assembly holder used in nuclear reactors. The closure mechanism is composed of a latching member which includes a generally circular chamber with a plurality of elongated latches depending therefrom. The latching member circumscribes part of an actuator member which is disposed within the latching member so as to be axially movable. The axial movement of the actuator actuates positioning of the latches between positions in which the latches are locked and secured within the actuator member. Means, capable of being remotely manipulated, are provided to move the actuator in order to position the latches and load the articles within the tube

  1. Physics: quantum mechanics

    International Nuclear Information System (INIS)

    From important experiment descriptions (sometimes, intentionally simplified), the essential concepts in Quantum Mechanics are first introduced. Wave function notion is described, Schroedinger equation is established, and, after applications rich in physical signification, quantum state and Hilbert space formalism are introduced, which will help to understand many essential phenomena. Then the quantum mechanic general formulation is written and some important consequences are deduced. This formalism is applied to a simple physical problem series (angular momentum, hydrogen atom, etc.) aiming at assimilating the theory operation and its application

  2. Vortex mechanism in hydrocyclones

    Institute of Scientific and Technical Information of China (English)

    徐继润; 刘正宁; 邢军; 李新跃; 黄慧; 徐海燕; 罗茜

    2001-01-01

    On the basis of analyzing the vortex characteristics, a new mechanism of the vortex formation in hydrocyclones is developed. The main concept of the mechanism is that the vortex flow in a hydrocyclone is resulted from the overlapping of container rotation and hole leakage. The model is then used to explain the compound distribution of free vortex and forced vortex, predict the similarity of tangential velocity at different input pressures, and make count of the principle of small hydrocyclone with lower cut-size than large one. Meanwhile a new possible approach to a large hydro-cyclone with lower cut-size by minimizing or eliminating the air core is discussed briefly.

  3. Elementary quantum mechanics

    CERN Document Server

    Saxon, David S

    2012-01-01

    Based on lectures for an undergraduate UCLA course in quantum mechanics, this volume focuses on the formulas of quantum mechanics rather than applications. Widely used in both upper-level undergraduate and graduate courses, it offers a broad self-contained survey rather than in-depth treatments.Topics include the dual nature of matter and radiation, state functions and their interpretation, linear momentum, the motion of a free particle, Schrödinger's equation, approximation methods, angular momentum, and many other subjects. In the interests of keeping the mathematics as simple as possible, m

  4. Introduction to continuum mechanics

    CERN Document Server

    Lai, W Michael; Rubin, David

    1996-01-01

    Introduction to Continuum Mechanics is a recently updated and revised text which is perfect for either introductory courses in an undergraduate engineering curriculum or for a beginning graduate course.Continuum Mechanics studies the response of materials to different loading conditions. The concept of tensors is introduced through the idea of linear transformation in a self-contained chapter, and the interrelation of direct notation, indicial notation, and matrix operations is clearly presented. A wide range of idealized materials are considered through simple static and dynamic problems, a

  5. Soil mechanics experiment

    Science.gov (United States)

    Mitchell, J. K.; Bromwell, L. G.; Carrier, W. D., III; Costes, N. C.; Houston, W. N.; Scott, R. F.

    1972-01-01

    The Apollo 15 soil-mechanics experiment has offered greater opportunity for study of the mechanical properties of the lunar soil than previous missions, not only because of the extended lunar-surface stay time and enhanced mobility provided by the lunar roving vehicle (rover), but also because four new data sources were available for the first time. These sources were: (1) the self-recording penetrometer (SRP), (2) new, larger diameter, thin-walled core tubes, (3) the rover, and (4) the Apollo lunar-surface drill (ALSD). These data sources have provided the best bases for quantitative analyses thus far available in the Apollo Program.

  6. Classical mechanics with Maxima

    CERN Document Server

    Timberlake, Todd Keene

    2016-01-01

    This book guides undergraduate students in the use of Maxima—a computer algebra system—in solving problems in classical mechanics. It functions well as a supplement to a typical classical mechanics textbook. When it comes to problems that are too difficult to solve by hand, computer algebra systems that can perform symbolic mathematical manipulations are a valuable tool. Maxima is particularly attractive in that it is open-source, multiple-platform software that students can download and install free of charge. Lessons learned and capabilities developed using Maxima are easily transferred to other, proprietary software.

  7. Effective mechanic training

    International Nuclear Information System (INIS)

    The need for the training of mechanics is discussed, and the increased interest within the utility industry of placing a similar importance on this training as it has traditionally placed on operator training, is expressed. Effective approaches and techniques are described. Fundamental mechanical maintenance concepts and their practical application are discussed, including the use of supporting video programs. The importance of follow-up practical shop exercise which reinforces classroom instruction is stressed, drawing from practical utility experience. Utilizing success in training as a measure of eligibility for advancement is discussed as well as the interface between training and the company bargaining unit

  8. Computational contact mechanics

    CERN Document Server

    Wriggers, Peter

    2006-01-01

    Contact mechanics has its application in many engineering problems. No one can walk without frictional contact, and no car would move for the same r- son. Hence contact mechanics has, from an engineering point of view, a long history, beginning in ancient Egypt with the movement of large stone blocks, over ?rst experimental contributions from leading scientists like Leonardo da Vinci andCoulomb, to today's computational methods. In the past c- tact conditions were often modelled in engineering analysis by more simple boundary conditions since analytical solutions were not present for real worl

  9. Mechanism of artificial heart

    CERN Document Server

    Yamane, Takashi

    2016-01-01

    This book first describes medical devices in relation to regenerative medicine before turning to a more specific topic: artificial heart technologies. Not only the pump mechanisms but also the bearing, motor mechanisms, and materials are described, including expert information. Design methods are described to enhance hemocompatibility: main concerns are reduction of blood cell damage and protein break, as well as prevention of blood clotting. Regulatory science from R&D to clinical trials is also discussed to verify the safety and efficacy of the devices.

  10. Mechanical engineer's reference book

    CERN Document Server

    Parrish, A

    1973-01-01

    Mechanical Engineer's Reference Book: 11th Edition presents a comprehensive examination of the use of Systéme International d' Unités (SI) metrication. It discusses the effectiveness of such a system when used in the field of engineering. It addresses the basic concepts involved in thermodynamics and heat transfer. Some of the topics covered in the book are the metallurgy of iron and steel; screw threads and fasteners; hole basis and shaft basis fits; an introduction to geometrical tolerancing; mechanical working of steel; high strength alloy steels; advantages of making components as castings

  11. Fundamentals of continuum mechanics

    CERN Document Server

    Rudnicki, John W

    2014-01-01

    A concise introductory course text on continuum mechanics Fundamentals of Continuum Mechanics focuses on the fundamentals of the subject and provides the background for formulation of numerical methods for large deformations and a wide range of material behaviours. It aims to provide the foundations for further study, not just of these subjects, but also the formulations for much more complex material behaviour and their implementation computationally.  This book is divided into 5 parts, covering mathematical preliminaries, stress, motion and deformation, balance of mass, momentum and energ

  12. Computational statistical mechanics

    CERN Document Server

    Hoover, WG

    1991-01-01

    Computational Statistical Mechanics describes the use of fast computers to simulate the equilibrium and nonequilibrium properties of gases, liquids, and solids at, and away from equilibrium. The underlying theory is developed from basic principles and illustrated by applying it to the simplest possible examples. Thermodynamics, based on the ideal gas thermometer, is related to Gibb's statistical mechanics through the use of Nosé-Hoover heat reservoirs. These reservoirs use integral feedback to control temperature. The same approach is carried through to the simulation and anal

  13. Mechanics of soft materials

    CERN Document Server

    Volokh, Konstantin

    2016-01-01

    This book provides a concise introduction to soft matter modelling. It offers an up-to-date review of continuum mechanical description of soft and biological materials from the basics to the latest scientific materials. It includes multi-physics descriptions, such as chemo-, thermo-, electro- mechanical coupling. It derives from a graduate course at Technion that has been established in recent years. It presents original explanations for some standard materials and features elaborated examples on all topics throughout the text. PowerPoint lecture notes can be provided to instructors. .

  14. Mechanics of fluid flow

    CERN Document Server

    Basniev, Kaplan S; Chilingar, George V 0

    2012-01-01

    The mechanics of fluid flow is a fundamental engineering discipline explaining both natural phenomena and human-induced processes, and a thorough understanding of it is central to the operations of the oil and gas industry.  This book, written by some of the world's best-known and respected petroleum engineers, covers the concepts, theories, and applications of the mechanics of fluid flow for the veteran engineer working in the field and the student, alike.  It is a must-have for any engineer working in the oil and gas industry.

  15. Mechanically Invisible Polymer Coatings

    DEFF Research Database (Denmark)

    2014-01-01

    phase comprises particles, said particles comprising a filler material and an encapsulating coating of a second polymeric material, wherein the backbones of the first and second polymeric materials are the same. The composition may be used in electroactive polymers (EAPs) in order to obtain mechanically...... invisible polymer coatings....

  16. Turboprop Propulsion Mechanic.

    Science.gov (United States)

    Chanute AFB Technical Training Center, IL.

    This instructional package consists of a plan of instruction, glossary, and student handouts and exercises for use in training Air Force personnel to become turboprop propulsion mechanics. Addressed in the individual lessons of the course are the following: common hand tools, hardware, measuring devices, and safety wiring; aircraft and engine…

  17. Principles of Mechanical Excavation

    International Nuclear Information System (INIS)

    Mechanical excavation of rock today includes several methods such as tunnel boring, raiseboring, roadheading and various continuous mining systems. Of these raiseboring is one potential technique for excavating shafts in the repository for spent nuclear fuel and dry blind boring is promising technique for excavation of deposition holes, as demonstrated in the Research Tunnel at Olkiluoto. In addition, there is potential for use of other mechanical excavation techniques in different parts of the repository. One of the main objectives of this study was to analyze the factors which affect the feasibility of mechanical rock excavation in hard rock conditions and to enhance the understanding of factors which affect rock cutting so as to provide an improved basis for excavator performance prediction modeling. The study included the following four main topics: (a) phenomenological model based on similarity analysis for roller disk cutting, (b) rock mass properties which affect rock cuttability and tool life, (c) principles for linear and field cutting tests and performance prediction modeling and (d) cutter head lacing design procedures and principles. As a conclusion of this study, a test rig was constructed, field tests were planned and started up. The results of the study can be used to improve the performance prediction models used to assess the feasibility of different mechanical excavation techniques at various repository investigation sites. (orig.)

  18. Alternative conformal quantum mechanics

    OpenAIRE

    Ho, Shih-Hao

    2011-01-01

    We investigate a one dimensional quantum mechanical model, which is invariant under translations and dilations but does not respect the conventional conformal invariance. We describe the possibility of modifying the conventional conformal transformation such that a scale invariant theory is also invariant under this new conformal transformation.

  19. Electro-Mechanical Curriculum.

    Science.gov (United States)

    EASTCONN Regional Educational Services Center, North Windham, CT.

    This electromechanical technician curriculum covers the following general areas: (1) basic soldering; (2) reading diagrams and following schematics; and (3) repairing circuitry and mechanics common to major appliances, vending machines, amusement equipment, and small office machines. The manual includes the following sections: (1) course…

  20. Making "The Mechanical Universe"

    OpenAIRE

    Goodstein, David L.; Olenick, Richard P.

    1988-01-01

    ‘‘The Mechanical Universe and Beyond’’ is an introductory college‐level physics telecourse, including calculus, made for broadcast television and classroom use. This article describes the inception and history of the project and the techniques and strategies that were used in producing it. A project to adapt the series for use in high schools is also discussed.

  1. Mechanical integrity of canisters

    International Nuclear Information System (INIS)

    This document constitutes the final report from 'SKBs reference group for mechanical integrity of canisters for spent nuclear fuel'. A complete list of all reports initiated by the reference group can be found in the summary report in this document. The main task of the reference group has been to advice SKB regarding the choice (ranking of alternatives) of canister type for different types of storage. The choice should be based on requirements of impermeability for a given time period and identification of possible limiting mechanisms. The main conclusions from the work were: From mechanical point of view, low phosphorous oxygen free copper (Cu-OFP) is a preferred canisters material. It exhibits satisfactory ductility both during tensile and creep testing. The residual stresses in the canisters are of such a magnitude that the estimated time to creep rupture with the data obtained for the Cu-OFP material is essentially infinite. Based on the present knowledge of stress corrosion cracking of copper there appears to be a small risk for such to occur in the projected environment. This risk need some further study. Rock shear movements of the size of 10 cm should pose no direct threat to the integrity of the canisters. Considering mechanical integrity, the composite copper/steel canister is an advantageous alternative. The recommendations for further research included continued studies of the creep properties of copper and of stress corrosion cracking. However, the studies should focus more directly on the design and fabrication aspect of the canister

  2. Statistical mechanics of solitons

    International Nuclear Information System (INIS)

    The status of statistical mechanics theory (classical and quantum, statics and dynamics) is reviewed for 1-D soliton or solitary-wave-bearing systems. Primary attention is given to (i) perspective for existing results with evaluation and representative literature guide; (ii) motivation and status report for remaining problems; (iii) discussion of connections with other 1-D topics

  3. Mechanical model for gravity

    OpenAIRE

    Heiss, Jonny

    2000-01-01

    Assuming the existence of a Multidirectional Homogeneous and Constant Shower of Elementary Particles (MHCSEP) traveling at light speed in space, several basic laws of physics are derived mainly by geometrical considerations. When placing two bodies in space, obstruction of the MHCSEP creates an attractive force among them that coincides, for two bodies, with Newton's law of gravity, generating a mechanical explanation for gravity.

  4. Mechanism of clean development

    International Nuclear Information System (INIS)

    The mechanism of clean development represents an opportunity to attract significant foreign investment for the realization of projects in a country like Colombia, characterized by its forest vocation and with enormous potential to reduce emissions in sectors of energy generation, industry, transport and agro-industry

  5. Basic Retention Mechanisms

    DEFF Research Database (Denmark)

    Jensen, Bror Skytte; Jensen, H.

    1986-01-01

    . The data for kaolinite were similarly interpreted as adsorption of hydroxylated complexes of the polyvalent cations, a mechanism which has previously been suggested for the adsorption of heavy metals onto muds, sludges and organic debris. In the case of kaolinite, indications of additional reactions...

  6. Motorcycle Mechanic. Teacher Edition.

    Science.gov (United States)

    Baugus, Mickey; Fulkerson, Dan, Ed.

    These teacher's materials are for a 19-unit competency-based course on entry-level motorcycle mechanics at the secondary and postsecondary levels. The 19 units are: (1) introduction to motorcycle repair; (2) general safety; (3) tools and equipment; (4) metric measurements; (5) fasteners; (6) service department operations; (7) motorcycle engines;…

  7. Synthesis of Mechanisms

    DEFF Research Database (Denmark)

    Hansen, John Michael

    1999-01-01

    These notes describe an automated procedure for analysis and synthesis of mechanisms. The analysis method is based on the body coordinate formulation, and the synthesis is based on applying optimization methods, used to minimize the difference between an actual and a desired behaviour...

  8. Transformable topological mechanical metamaterials

    Science.gov (United States)

    Rocklin, D. Zeb; Zhou, Shangnan; Sun, Kai; Mao, Xiaoming

    We present a class of mechanical metamaterials characterized by a uniform soft deformation--a large, zero-energy homogeneous elastic deformation mode of the structure--that may be used to induce topological transitions and dramatically change mechanical and acoustic properties of the structure. We show that the existence of such a mode determines certain exotic mechanical and acoustic properties of the structure and its activation can reversibly alter and tune these properties. This serves as the basis for a design principle for mechanical metamaterials with tunable properties. When the structure's uniform mode is primarily dilational (shearing) its surface (bulk) possesses phonon modes with vanishing speed of sound. Maxwell lattices comprise a subclass of such material which, owing to their critical coordination number (four, in 2D), necessarily possess such a uniform zero mode, often termed a Guest mode, and which may be topologically polarized, such that zero modes are moved from one edge to another. We show that activating the deformation can alter the shear/dilational character of the mode and topologically polarize the structure, thereby altering the bulk and surface properties at no significant energy cost. arXiv:1510.06389 [cond-mat.soft] NWO, Delta Institute of Physics, ICAM fellowship (DZR) and NSF Grant PHY-1402971 at University of Michigan (KS).

  9. Principles of Mechanical Excavation

    Energy Technology Data Exchange (ETDEWEB)

    Lislerud, A. [Tamrock Corp., Tampere (Finland)

    1997-12-01

    Mechanical excavation of rock today includes several methods such as tunnel boring, raiseboring, roadheading and various continuous mining systems. Of these raiseboring is one potential technique for excavating shafts in the repository for spent nuclear fuel and dry blind boring is promising technique for excavation of deposition holes, as demonstrated in the Research Tunnel at Olkiluoto. In addition, there is potential for use of other mechanical excavation techniques in different parts of the repository. One of the main objectives of this study was to analyze the factors which affect the feasibility of mechanical rock excavation in hard rock conditions and to enhance the understanding of factors which affect rock cutting so as to provide an improved basis for excavator performance prediction modeling. The study included the following four main topics: (a) phenomenological model based on similarity analysis for roller disk cutting, (b) rock mass properties which affect rock cuttability and tool life, (c) principles for linear and field cutting tests and performance prediction modeling and (d) cutter head lacing design procedures and principles. As a conclusion of this study, a test rig was constructed, field tests were planned and started up. The results of the study can be used to improve the performance prediction models used to assess the feasibility of different mechanical excavation techniques at various repository investigation sites. (orig.). 21 refs.

  10. Cracked fuel mechanics

    International Nuclear Information System (INIS)

    Fuel pellets undergo thermally induced cracking during normal reactor operation. Some fuel performance codes have included models that address the effects of fuel cracking on fuel rod thermal and mechanical behavior. However, models that rely too heavily on continuum mechanics formulations (annular gaps and solid cylindrical pellets) characteristically do not adequately predict cladding axial elongations. Calculations of bamboo ridging generally require many assumptions concerning fuel geometry, and some of the methods used are too complex and expensive to employ on a routine basis. Some of these difficulties originate from a lack of definition of suitable parameters which describe the cracked fuel medium. The methodology is being improved by models that describe cracked fuel behavior utilizing parameters with stronger physical foundations instead of classical continuum formulations. This paper presents a modelling concept and a set of measurable parameters that have been shown to improve the prediction of the mechanical behavior of cracked fuel/cladding systems without added computational expense. The transition from classical annular gap/cylindrical pellet models to modified bulk properties and further to local behavior for cracked fuel systems is discussed. The results of laboratory experiments to verify these modelling parameters are shown. Data are also presented from laboratory experiments on unirradiated and irradiated rods which show that fuel rod mechanical response depends on fuel fragment size. The impact of these data on cracked fuel behavior and failure modelling is also discussed. (author)

  11. Lectures on quantum mechanics

    International Nuclear Information System (INIS)

    Quantum mechanics represents the central revolution of modern natural science and reaches in its importance farely beyond physics. Neither chemistry nor biology on the molecular scale would be understandable without it. Modern information technology from the laptop over the mobile telephone and the flat screen until the supercomputer would be unthinkable without quantum-mechanical effects. It desribes the world on the atomic and subatomic scale and is by this the starting point of our modern worldview. The Nobel-prize carrier Steven Weinberg has done ever among others by his theory of the unification of the weak and the electromagnetic interaction one of the most important contributions to this revolution. In this book he reproduces his personal view of quantum mechanics, which captivates by its strictly logic construction, precise linguistic representation, and mathematical clearness and completeness. This book appeals to studyings of natural sciences, especially of physics. Accompanied is the test by exercise problems, which allow the studying to apply immediately the knowledge, but also test their understanding. Because of its precision and clearness ''Lectures on Quantum Mechanics'' by Weinberg is also essentially suited for the self-study.

  12. Structured Mechanical Collage.

    Science.gov (United States)

    Huang, Zhe; Wang, Jiang; Fu, Hongbo; Lau, Rynson W H

    2014-07-01

    We present a method to build 3D structured mechanical collages consisting of numerous elements from the database given artist-designed proxy models. The construction is guided by some graphic design principles, namely unity, variety and contrast. Our results are visually more pleasing than previous works as confirmed by a user study. PMID:26357362

  13. Fractures mechanics. Pt. 30

    International Nuclear Information System (INIS)

    This book results from lectures which the author held front of students in engineering, and it is aimed at giving an introduction into the linear elasticity fracture mechanics. A dominant part of the contents deals with theoretical elasticity solutions of fracture problems, the foundation of the theories of friffith and Irwin concerning crack expansion and fractures, respectively. Besides, the propects of development in the direction of general flow fracture mechanics are investigated, a development which cannot be regarded as conclusive yet. The reference - it is not claimed that they are comprehensive - contain some basic manuals and monographies on fractures, the elasticity theory and the science of strength of materials as well as related fields, and include also important original literature made reference to in the text. In order to comprehend the book it is necessary that the reader has a knowledge of technical mechanics, in particular of elastotatics and strength of materials. To remind the reader, the appendix contains the most important basics of the elasticity theory and some methods of solving problems in this connection. The book ends with a short survey on the finite element method which is considered to be the most important approximation method of continuum mechanics. (orig./LN)

  14. FUNCTIONAL MECHANISMS OF PROBIOTICS

    Directory of Open Access Journals (Sweden)

    Bijender Kumar Bajaj

    2015-02-01

    Full Text Available Probiotics are the live microorganisms which when ingested in adequate amounts confer health benefits. The strains most frequently used as probiotics include Lactic acid bacteria, bifidobacteria and yeast Saccharomyces boulardii. However, several other bacterial strains are being investigated for potential probiotic value viz. Enterococcus, Streptococcus, Bacillus, among others. Significant therapeutic potential of probiotics has been demonstrated in several in vitro studies and that involving animal models and humans. Despite intense focus on probiotics research the mechanisms responsible for health benefits are not yet completely understood. Several important mechanisms have been proposed such as improvement of gut epithelial barrier function, Immunomodulatory effects, degradation of toxin receptors, competition for nutrients, production of inhibitory substances, antiproliferative effects, blocking of adhesion sites and modulation of gut microbiota. Bacterial cell components such as DNA or peptidoglycan may also be involved in functional mechanism of probiotics. Effectiveness of a probiotic for potential application as prophylactic or treatment agent for certain ailment is determined by its ability to possess all or most of these characteristic features. The current article describes the general functional mechanisms of probiotics.

  15. Schwinger mechanism revisited

    CERN Document Server

    Gelis, Francois

    2015-01-01

    In this article, we review recent theoretical works on the Schwingermechanism of particle production in external electrical fields. Although the non-perturbative Schwinger mechanism is at the center of this discussion, many of the approaches that we discuss can cope with general time and space dependent fields, and therefore also capture the perturbative contributions to particle production.

  16. Mechanics with Matlab

    Czech Academy of Sciences Publication Activity Database

    Okrouhlík, Miloslav

    Praha : VŠCHT, 2000, s. 293-300. ISBN 80-7080-401-7. [Sborník příspěvků 8. ročníku konference Matlab 2000. Praha (CZ), 01.11.2000] R&D Projects: GA MŠk LB98202 Keywords : mechanics * using Matlab Subject RIV: BA - General Mathematics

  17. Mechanisms of multidrug transporters

    NARCIS (Netherlands)

    Bolhuis, Henk; Veen, Hendrik W. van; Poolman, Bert; Driessen, Arnold J.M.; Konings, Wil N.

    1997-01-01

    Drug resistance, mediated by various mechanisms, plays a crucial role in the failure of the drug-based treatment of various infectious diseases. As a result, these infectious diseases re-emerge rapidly and cause many victims every year. Another serious threat is imposed by the development of multidr

  18. Multidomain multiphase fluid mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sha, W.T.; Soo, S.L.

    1976-10-01

    A set of multiphase field equations--conversion of mass, momentum and energy--based on multiphase mechanics is developed. Multiphase mechanics applies to mixtures of phases which are separated by interfaces and are mutually exclusive. Based on the multiphase mechanics formulation, additional terms appear in the field equations when the physical size of the dispersed phase (bubble or droplet) is many times larger than the inter-molecular spacing. These terms are the inertial coupling due to virtual mass and the additional viscous coupling due to unsteadiness of the flow field. The multiphase formulation given here takes into account the discreteness of particles of dispersed phases and, at the same time, the necessity of the distributive representation of field variables via space-time averaging when handling a large number of particles. The provision for multidomain transition further permits us to treat dispersed phases which are large compared to the characteristic dimension of the flow system via interdomain relations. The multidomain multiphase approach provides a framework for us to model the various flow regimes. Because some of the transport parameters associated with the system equations are not well known at the present time, an idealized two-domain two-phase solution approach is proposed as a first step. Finally, comparisons are made between the field equations formulated based on the multidomain-multiphase fluid mechanics and the pertinent existing models, and their relative significances are discussed. The desirability of consistent approximation and simplifications possible for dilute suspensions are discussed.

  19. Manpower Implications of Mechanization.

    Science.gov (United States)

    Cargill, B. F.

    The fruit and vegetable industry is on the road to total mechanization. The scientific and social communities need to collaborate as technological innovations influence manpower development and utilization. An awareness of the implications of technological advancement and manpower problems is required so that the U. S. fruit and vegetable grower…

  20. Quantum mechanics gets real

    International Nuclear Information System (INIS)

    In 1929 Paul Dirac pronounced that 'the underlying physical laws necessary for the mathematical theory for a large part of physics and the whole of chemistry are ...completely known'. Indeed, the fundamental aspects of non-relativistic quantum mechanics have remained essentially unchanged ever since, while physics and chemistry have been driven largely by experiment. Since the time of Dirac, of course, we have entered the computer era. Increasingly fast computers have led to better, although still approximate, models for the quantum-mechanical equations that govern fundamental processes such as chemical reactions. So far, however, the goal of matching the accuracy of experiments for any chemical reaction has eluded computational scientists. Now Steven Miekle of the Pacific Northwest National Laboratory in the US and co-workers have performed quantum-mechanical calculations from first principles that reproduce the measured reaction rate of a chemical reaction for the first time (Phys. Rev. Lett. 91 063201). The team studied the gas-phase hydrogen exchange reaction H + H2 goes to H2 + H over temperatures ranging from -100 to 1900 C. This reaction has tantalized quantum chemists since the initial formulation of quantum- mechanics 75 years ago. In the November issue of Physics World Jonathan Tennyson in the Department of Physics and Astronomy at University College London explains how theory and experiment have converged to solve this problem. (U.K.)

  1. Lifetime of Mechanical Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Leland, K.

    1999-07-01

    The gas plant at Kaarstoe was built as part of the Statpipe gas transport system and went on stream in 1985. In 1993 another line was routed from the Sleipner field to carry condensate, and the plant was extended accordingly. Today heavy additional supply- and export lines are under construction, and the plant is extended more than ever. The main role of the factory is to separate the raw gas into commercial products and to pump or ship it to the markets. The site covers a large number of well-known mechanical equipment. This presentation deals with piping, mechanical and structural disciplines. The lifetime of mechanical equipment is often difficult to predict as it depends on many factors, and the subject is complex. Mechanical equipment has been kept in-house, which provides detailed knowledge of the stages from a new to a 14 years old plant. The production regularity has always been very high, as required. The standard of the equipment is well kept, support systems are efficient, and human improvisation is extremely valuable.

  2. Horticultural Mechanics Competencies

    Science.gov (United States)

    Shipley, W. Edward

    1974-01-01

    Ornamental horticulture teachers and managers of ornamental horticulture businesses were surveyed to determine which agricultural mechanics knowledges and skills are needed for entry-level employment in nursery, greenhouse, turf, and landscape management, which are common to the four areas, and the appropriate grade level at which they should be…

  3. Construction Mechanic 1 & C.

    Science.gov (United States)

    Seitz, Thomas E.

    This Rate Training Manual and Nonresident Career Course (RTM/NRCC) form a self-study package that will enable Naval Construction Mechanics First and Chief to fulfill the requirements of their rating. (Persons holding these ratings direct and coordinate efforts of individuals and crews in maintaining, repairing, and overhauling automotive,…

  4. Mechanical Measurements Laboratory

    CERN Multimedia

    Maximilien Brice

    2007-01-01

    The CERN mechanical measurements team check the sensors on one of the ATLAS inner detector end-caps using high precision measurement equipment. Remote checks like this must be made on these sensitive detector components before they can be transported to make sure that all systems are working correctly.

  5. Quantum Chaos and Statistical Mechanics

    OpenAIRE

    Srednicki, Mark

    1994-01-01

    We briefly review the well known connection between classical chaos and classical statistical mechanics, and the recently discovered connection between quantum chaos and quantum statistical mechanics.

  6. Mechanism for salt scaling

    Science.gov (United States)

    Valenza, John J., II

    Salt scaling is superficial damage caused by freezing a saline solution on the surface of a cementitious body. The damage consists of the removal of small chips or flakes of binder. The discovery of this phenomenon in the early 1950's prompted hundreds of experimental studies, which clearly elucidated the characteristics of this damage. In particular it was shown that a pessimum salt concentration exists, where a moderate salt concentration (˜3%) results in the most damage. Despite the numerous studies, the mechanism responsible for salt scaling has not been identified. In this work it is shown that salt scaling is a result of the large thermal expansion mismatch between ice and the cementitious body, and that the mechanism responsible for damage is analogous to glue-spalling. When ice forms on a cementitious body a bi-material composite is formed. The thermal expansion coefficient of the ice is ˜5 times that of the underlying body, so when the temperature of the composite is lowered below the melting point, the ice goes into tension. Once this stress exceeds the strength of the ice, cracks initiate in the ice and propagate into the surface of the cementitious body, removing a flake of material. The glue-spall mechanism accounts for all of the characteristics of salt scaling. In particular, a theoretical analysis is presented which shows that the pessimum concentration is a consequence of the effect of brine pockets on the mechanical properties of ice, and that the damage morphology is accounted for by fracture mechanics. Finally, empirical evidence is presented that proves that the glue-small mechanism is the primary cause of salt scaling. The primary experimental tool used in this study is a novel warping experiment, where a pool of liquid is formed on top of a thin (˜3 mm) plate of cement paste. Stresses in the plate, including thermal expansion mismatch, result in warping of the plate, which is easily detected. This technique revealed the existence of

  7. Quantum Mechanics As A Limiting Case of Classical Mechanics

    OpenAIRE

    Ghose, Partha

    2000-01-01

    In spite of its popularity, it has not been possible to vindicate the conventional wisdom that classical mechanics is a limiting case of quantum mechanics. The purpose of the present paper is to offer an alternative point of view in which quantum mechanics emerges as a limiting case of classical mechanics in which the classical system is decoupled from its environment.

  8. Mechanism of thymineless death

    International Nuclear Information System (INIS)

    Interest in the consequences of stressing the dUTPase and UrA-DNA glycosylase mechanisms in vivo led the authors to reconsider observations on the effects of thymidylate deprivation. A model of thymidylate deficiency was used produced by treatment of cultured animal cells (human lymphoblasts) with MTX in presence of purine and amino acid suppliments. The dUrd nucleotide pools were labeled under steady state conditions with tracer amounts of tritium-dUrd; unlabeled dUTP was added at the time of cid extraction of intracellular pools and re-isolated free of contaminants. The studies indicate that limiting deoxythymidylate unleashes the biosynthetic pathway for synthesis of deoxyuridylate, overcoming the dUTPase mechanism that ordinarily prevents Ura from entering DNA

  9. Physicalism versus quantum mechanics

    CERN Document Server

    Stapp, Henry P

    2008-01-01

    In the context of theories of the connection between mind and brain, physicalism is the demand that all is basically purely physical. But the concept of "physical" embodied in this demand is characterized essentially by the properties of the physical that hold in classical physical theories. Certain of these properties contradict the character of the physical in quantum mechanics, which provides a better, more comprehensive, and more fundamental account of phenomena. It is argued that the difficulties that have plaged physicalists for half a century, and that continue to do so, dissolve when the classical idea of the physical is replaced by its quantum successor. The argument is concretized in a way that makes it accessible to non-physicists by exploiting the recent evidence connecting our conscious experiences to macroscopic measurable synchronous oscillations occurring in well-separated parts of the brain. A specific new model of the mind-brain connection that is fundamentally quantum mechanical but that ti...

  10. Crude oil burning mechanisms

    DEFF Research Database (Denmark)

    van Gelderen, Laurens; Malmquist, L.M.V.; Jomaas, Grunde

    2015-01-01

    In order to improve predictions for the burning efficiency and the residue composition of in-situ burning of crude oil, the burning mechanism of crude oil was studied in relation to the composition of its hydrocarbon mixture, before, during and after the burning. The surface temperature, flame...... height, mass loss rate and residues of three hydrocarbon liquids (n-octane, dodecane and hexadecane), two crude oils (DUC and REBCO) and one hydrocarbon liquid mixture of the aforementioned hydrocarbon liquids were studied using the Crude Oil Flammability Apparatus. The experimental results were compared...... on the highest achievable oil slick temperature. Based on this mechanism, predictions can then be made depending on the hydrocarbon composition of the fuel and the measured surface temperature....

  11. Computation in Classical Mechanics

    CERN Document Server

    Timberlake, Todd

    2007-01-01

    There is a growing consensus that physics majors need to learn computational skills, but many departments are still devoid of computation in their physics curriculum. Some departments may lack the resources or commitment to create a dedicated course or program in computational physics. One way around this difficulty is to include computation in a standard upper-level physics course. An intermediate classical mechanics course is particularly well suited for including computation. We discuss the ways we have used computation in our classical mechanics courses, focusing on how computational work can improve students' understanding of physics as well as their computational skills. We present examples of computational problems that serve these two purposes. In addition, we provide information about resources for instructors who would like to include computation in their courses.

  12. Mechanics of collective unfolding

    CERN Document Server

    Caruel, M; Truskinovsky, L

    2015-01-01

    Mechanically induced unfolding of passive crosslinkers is a fundamental biological phenomenon encountered across the scales from individual macro-molecules to cytoskeletal actin networks. In this paper we study a conceptual model of athermal load-induced unfolding and use a minimalistic setting allowing one to emphasize the role of long-range interactions while maintaining full analytical transparency. Our model can be viewed as a description of a parallel bundle of N bistable units confined between two shared rigid backbones that are loaded through a series spring. We show that the ground states in this model correspond to synchronized, single phase configurations where all individual units are either folded or unfolded. We then study the fine structure of the wiggly energy landscape along the reaction coordinate linking the two coherent states and describing the optimal mechanism of cooperative unfolding. Quite remarkably, our study shows the fundamental difference in the size and structure of the folding-u...

  13. Optically defined mechanical geometry

    Science.gov (United States)

    Barasheed, Abeer Z.; Müller, Tina; Sankey, Jack C.

    2016-05-01

    In the field of optomechanics, radiation forces have provided a particularly high level of control over the frequency and dissipation of mechanical elements. Here we propose a class of optomechanical systems in which light exerts a similarly profound influence over two other fundamental parameters: geometry and mass. By applying an optical trap to one lattice site of an extended phononic crystal, we show it is possible to create a tunable, localized mechanical mode. Owing to light's simultaneous and constructive coupling with the structure's continuum of modes, we estimate that a trap power at the level of a single intracavity photon should be capable of producing a significant effect within a realistic, chip-scale device.

  14. Schwinger mechanism in QCD

    CERN Document Server

    Papavassiliou, Joannis

    2011-01-01

    The generation of a momentum-dependent gluon mass proceeds through a sophisticated implementation, at the level of the Schwinger-Dyson equation for the gluon propagator, of the Schwinger mechanism, whose central dynamical ingredient is the nonperturbative formation of longitudinally coupled massless bound-state excitations. In addition to triggering the aforementioned mechanism, these excitations introduce poles in the various off-shell Green's functions of the theory, in such a way as to maintain the Slavnov-Taylor identities intact in the presence of massive gluon propagators, acting effectively as composite Nambu-Goldstone bosons. In this work we focus on the dynamics leading to the actual formation of such bound states. Specifically, we derive and solve numerically an approximate version of the homogeneous Bethe-Salpeter equation governing the wave function of this special bound state. It is found that this integral equation admits physically meaningful non-trivial solutions, indicating that the QCD dynam...

  15. Inflammatory mechanisms of endometritis.

    Science.gov (United States)

    Woodward, E M; Troedsson, M H T

    2015-07-01

    Transient post breeding endometritis is a normal physiological reaction in the mare, as it is believed that an inflammatory response is necessary for the effective removal of contaminating bacteria and excess spermatozoa introduced into the uterus. While most mares can clear endometritis within a reasonable amount of time, persistent endometritis caused by either bacteria or spermatozoa can threaten the success of a pregnancy. A subpopulation of mares is susceptible to persistent endometritis, and these mares are a concern in equine reproductive medicine. Research has identified several factors that contribute to susceptibility; however, the exact mechanisms of the progression of the disease are still being elucidated. Current research focuses on endometrial gene expression during endometritis in an attempt to understand the timing of specific inflammatory processes involved with the development of susceptibility to persistent endometritis. With an increased understanding of the mechanisms involved with the disease, current treatments can be improved upon, and new treatments can be developed to target affected pathways. PMID:25537084

  16. Crude oil burning mechanisms

    DEFF Research Database (Denmark)

    van Gelderen, Laurens; Malmquist, Linus Mattias Valdemar; Jomaas, Grunde

    2015-01-01

    In order to improve predictions for the burning efficiency and the residue composition of in-situ burning of crude oil, the burning mechanism of crude oil was studied in relation to the composition of its hydrocarbon mixture, before, during and after the burning. The surface temperature, flame...... height, mass loss rate and residues of three hydrocarbon liquids (n-octane, dodecane and hexadecane), two crude oils (DUC and REBCO) and one hydrocarbon liquid mixture of the aforementioned hydrocarbon liquids were studied using the Crude Oil Flammability Apparatus. The experimental results were compared...... to the predictions of four conceptual models that describe the burning mechanism of multicomponent fuels. Based on the comparisons, hydrocarbon liquids were found to be best described by the Equilibrium Flash Vaporization model, showing a constant gas composition and gasification rate. The...

  17. NUT SCREW MECHANISMS

    Science.gov (United States)

    Glass, J.A.F.

    1958-07-01

    A reactor control mechanism is described wherein the control is achieved by the partial or total withdrawal of the fissile material which is in the form of a fuel rod. The fuel rod is designed to be raised and lowered from the reactor core area by means of two concentric ball nut and screw assemblies that may telescope one within the other. These screw mechanisms are connected through a magnetic clutch to a speed reduction gear and an accurately controllable prime motive source. With the clutch energized, the fuel rod may be moved into the reactor core area, and fine adjustments may be made through the reduction gearing. However, in the event of a power failure or an emergency signal, the magnetic clutch will become deenergized, and the fuel rod will drop out of the core area by the force of gravity, thus shutting down the operation of the reactor.

  18. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...... beam is \\SI{4\\times10}{mm}. It is reinforced with a \\SI{3}{mm} high steel band covering the full width of the beam. The experimental setup is described and results for this beam are presented. Furthermore, the results for three similar experiments with a \\SI{6}{mm} steel band reinforcement are briefly...

  19. Molecular mechanisms of cholangiocarcinoma.

    Science.gov (United States)

    Fava, Giammarco

    2010-04-15

    Cholangiocarcinoma (CC), the malignant tumor of the epithelial cells lining the biliary ducts, has undergone a worldwide increase in incidence and mortality. The malignant transformation of the biliary cells originates from a multistep process evolving through chronic inflammation of the biliary tract to CC. In the last few years several advances have been towards understanding and clarifying the molecular mechanisms implicated in the cholangiocarcinogenesis process. However, many pathophysiologic aspects governing the growth of CC are still undefined. The poor prognosis of this tumor underlines the urgent need to codify the underlying molecular mechanisms involved in the growth and progression of CC in order to design effective preventive measures and valid treatment regimens. This review reports on progresses made in the last few years in clarifying the molecular pathways involved in the process of cholangiocarcinogenesis. PMID:21607138

  20. Modelling Cochlear Mechanics

    Directory of Open Access Journals (Sweden)

    Guangjian Ni

    2014-01-01

    Full Text Available The cochlea plays a crucial role in mammal hearing. The basic function of the cochlea is to map sounds of different frequencies onto corresponding characteristic positions on the basilar membrane (BM. Sounds enter the fluid-filled cochlea and cause deflection of the BM due to pressure differences between the cochlear fluid chambers. These deflections travel along the cochlea, increasing in amplitude, until a frequency-dependent characteristic position and then decay away rapidly. The hair cells can detect these deflections and encode them as neural signals. Modelling the mechanics of the cochlea is of help in interpreting experimental observations and also can provide predictions of the results of experiments that cannot currently be performed due to technical limitations. This paper focuses on reviewing the numerical modelling of the mechanical and electrical processes in the cochlea, which include fluid coupling, micromechanics, the cochlear amplifier, nonlinearity, and electrical coupling.

  1. Mechanisms of immunological tolerance.

    Science.gov (United States)

    Waldmann, Herman

    2016-03-01

    There is increasing interest in establishing diagnostic markers of immunological tolerance applicable to efforts to minimize drug immunosuppression in transplantation and chronic immunological diseases. It is hoped that an understanding of the diverse mechanisms that can contribute to tolerance will guide efforts to establish diagnostic tolerance biomarkers. Not only would these be valuable for management of autoimmune diseases, transplants and allergies, but they might also guide efforts to override tolerance processes in cancer and vaccine development. Where tolerance is generated by deletion or inactivation of antigen reactive lymphocytes, it is unlikely that any long-term-valid blood biomarkers might be found. Where tolerance is mediated by active regulatory mechanisms, indicators that can be usefully measured may emerge, but these would likely show significant heterogeneity reflecting the diversity of active tolerance processes operating in different individuals. Given this, the most useful "kits" might be those "smart" enough to detect this diversity of tolerance players. PMID:26036868

  2. Mechanisms of arteriogenesis

    Institute of Scientific and Technical Information of China (English)

    Weijun Cai; Wolfgang Schaper

    2008-01-01

    Patients with occlusive atherosclerotic vascular diseases have frequently developed collateral blood vessels that bypass areas of arterial obstructions. The growth of these collateral arteries has been termed "arteriogenesis", which describes the process of a small arteriole's transformation into a much larger conductance artery.In recent years,intensive investi-gations using various animal models have been performed to unravel the molecular mechanisms of arteriogenesis.The increasing evidence suggests that arteriogenesis seems to be triggered mainly by fluid shear stress,which is induced by the altered blood flow conditions after an arterial occlusion.Arteriogenesis involves endothelial cell activation,basal membrane degradation,leukocyte invasion,proliferation of vascular cells,neonitima formation(in most species studied),changes of the extracellular matrix and cytokine participation.This paper is an in-depth review of the research critical to recent advaces in the field of arteriogenesis that have provided a better understanding of its mechanism.

  3. Responding to Mechanical Antigravity

    Science.gov (United States)

    Millis, Marc G.; Thomas, Nicholas E.

    2006-01-01

    Based on the experiences of the NASA Breakthrough Propulsion Physics Project, suggestions are offered for constructively responding to proposals that purport breakthrough propulsion using mechanical devices. Because of the relatively large number of unsolicited submissions received (about 1 per workday) and because many of these involve similar concepts, this report is offered to help the would-be submitters make genuine progress as well as to help reviewers respond to such submissions. Devices that use oscillating masses or gyroscope falsely appear to create net thrust through differential friction or by misinterpreting torques as linear forces. To cover both the possibility of an errant claim and a genuine discovery, reviews should require that submitters meet minimal thresholds of proof before engaging in further correspondence; such as achieving sustained deflection of a level-platform pendulum in the case of mechanical thrusters.

  4. PARALLEL MOVING MECHANICAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    Florian Ion Tiberius Petrescu

    2014-09-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Moving mechanical systems parallel structures are solid, fast, and accurate. Between parallel systems it is to be noticed Stewart platforms, as the oldest systems, fast, solid and precise. The work outlines a few main elements of Stewart platforms. Begin with the geometry platform, kinematic elements of it, and presented then and a few items of dynamics. Dynamic primary element on it means the determination mechanism kinetic energy of the entire Stewart platforms. It is then in a record tail cinematic mobile by a method dot matrix of rotation. If a structural mottoelement consists of two moving elements which translates relative, drive train and especially dynamic it is more convenient to represent the mottoelement as a single moving components. We have thus seven moving parts (the six motoelements or feet to which is added mobile platform 7 and one fixed.

  5. Statistical crack mechanics

    International Nuclear Information System (INIS)

    Although it is possible to simulate the ground blast from a single explosive shot with a simple computer algorithm and appropriate constants, the most commonly used modelling methods do not account for major changes in geology or shot energy because mechanical features such as tectonic stresses, fault structure, microcracking, brittle-ductile transition, and water content are not represented in significant detail. An alternative approach for modelling called Statistical Crack Mechanics is presented in this paper. This method, developed in the seventies as a part of the oil shale program, accounts for crack opening, shear, growth, and coalescence. Numerous photographs and micrographs show that shocked materials tend to involve arrays of planar cracks. The approach described here provides a way to account for microstructure and give a representation of the physical behavior of a material at the microscopic level that can account for phenomena such as permeability, fragmentation, shear banding, and hot-spot formation in explosives

  6. Mechanics of fretting fatigue

    Science.gov (United States)

    Hills, D. A.

    1994-06-01

    Several aspects of the mechanics of cracks originating at sites of fretting are considered. It is argued that the problem may be distilled into three separate parts: the contact problem itself in full or partial slip, the initiation of a crack from a surface suffering severe distress, and the propagation of a crack under combined contact and bulk loading. The first of these may be solved by either a classical or numerical means, while the last merely requires the careful use of fracture mechanics. However, it is the second element which remains elusive to quantify, and the influence of the intrinsic length scales in the problem, including contact length, surface roughness and amplitude of relative tangential displacement on initiation conditions, is discussed and explored.

  7. MECHANISMS OF BACTERIAL POLYHOSTALITY

    Directory of Open Access Journals (Sweden)

    Markova Yu.A.

    2007-12-01

    Full Text Available In the review data about factors of pathogenicity of the bacteria, capable to amaze both animals, and a plant are collected. Such properties of microorganisms as adhesion, secretion of some enzymes, mobility, a phenomenon of cooperative sensitivity - play an essential role at defeat of different organisms. They are used for many universal offensive strategy overcoming protection of an organism, irrespective of its evolutionary origin. Studying of these mechanisms, will allow to provide new approaches to monitoring illnesses.

  8. What Kind of Mechanism

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Yang: In recent years, under the new international security environment, multilateralism has gradually played greater roles in various international and regional topics, especially in the settlement of regional security issues. Theoretically, regional multi-lateral security cooperation can increase the cost of destroying the status quo or invasion while increasing mutual confidence, alleviating feeling of security threat, decreasing or eliminating security predicament. This is caused by the limitations of the mechanism and the consideration of cost.

  9. Quantum conformal mechanics

    CERN Document Server

    Andrzejewski, K

    2015-01-01

    The quantum mechanics of one degree of freedom exhibiting the exact conformal SL(2,R) symmetry is presented. The starting point is the classification of the unitary irreducible representations of the SL(2,R) group (or, to some extent, its universal covering). The coordinate representation is defined as the basis diagonalizing the special conformal generator K. It is indicated how the resulting theory emerges from the canonical/geometric quantization of the Hamiltonian dynamics on the relevant coadjoint orbits.

  10. Irreversibility and quantum mechanics

    International Nuclear Information System (INIS)

    Quantum mechanisms has a dual structure: while Schroedinger equation corresponds to a deterministic and time-reversible description, measurement introduces irreversibility and stochasticity. This contrasts with the Bohr-Sommerfeld-Einsten theory, in which transitions between quantum states are associated with spontaneous and induced transitions, defined in terms of a stochastic process. A new form of quantum theory is summarized here, which contains an intrinsic form of irreversibility, independent of observation

  11. Relational Quantum Mechanics

    OpenAIRE

    A. Nicolaidis

    2013-01-01

    I suggest that the common unease with taking quantum mechanics as a fundamental description of nature (the "measurement problem") could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer-independent time. I suggest that this incorrect notion is the notion of observer-independent state of a system (or observer-independent values of physical quantities). I reformulate the problem of the "interpretation o...

  12. Lung Parenchymal Mechanics

    OpenAIRE

    Suki, Béla; Stamenovic, Dimitrije; Hubmayr, Rolf

    2011-01-01

    The lung parenchyma comprises a large number of thin-walled alveoli, forming an enormous surface area, which serves to maintain proper gas exchange. The alveoli are held open by the transpulmonary pressure, or prestress, which is balanced by tissues forces and alveolar surface film forces. Gas exchange efficiency is thus inextricably linked to three fundamental features of the lung: parenchymal architecture, prestress, and the mechanical properties of the parenchyma. The prestress is a key de...

  13. Ontology and Quantum Mechanics

    OpenAIRE

    N. D. Hari Dass

    2014-01-01

    The issue of ontology in quantum mechanics, or equivalently the issue of the reality of the wave function is critically examined within standard quantum theory. It is argued that though no strict ontology is possible within quantum theory, ingenious measurement schemes may still make the notion of a \\emph{FAPP Ontology} i.e ontology for all practical purposes (a phrase coined by John Bell), meaningful and useful.

  14. Neural Mechanisms of Foraging

    OpenAIRE

    Kolling, Nils; Behrens, Timothy EJ; Mars, Rogier B.; Rushworth, Matthew FS

    2012-01-01

    Behavioural economic studies, involving limited numbers of choices, have provided key insights into neural decision-making mechanisms. By contrast, animals’ foraging choices arise in the context of sequences of encounters with prey/food. On each encounter the animal chooses to engage or whether the environment is sufficiently rich that searching elsewhere is merited. The cost of foraging is also critical. We demonstrate humans can alternate between two modes of choice, comparative decision-ma...

  15. Qualified voting mechanisms

    OpenAIRE

    Mart??nez Rico, Ricardo; Moreno, Bernardo

    2014-01-01

    We study voting mechanisms, which consist of two elements: a profile of sets of votes (this profile describes the votes that voters are allowed to cast) and a voting scheme (which explains how to aggregate those votes). To investigate how these two elements interact, we impose some properties on the sets of votes (i.e., regularity ) and on the voting scheme (i.e., candidate monotonicity, candidate anonymity, and weak neutrality ). We characterize the family of voting schemes that satisfy some...

  16. What is semiquantum mechanics?

    OpenAIRE

    Bracken, A. J.

    2006-01-01

    Semiclassical approximations to quantum dynamics are almost as old as quantum mechanics itself. In the approach pioneered by Wigner, the evolution of his quasiprobability density function on phase space is expressed as an asymptotic series in increasing powers of Planck's constant, with the classical Liouvillean evolution as leading term. Successive semiclassical approximations to quantum dynamics are defined by successive terms in the series. We consider a complementary approach, which explo...

  17. Mechanisms of Coronal Heating

    Indian Academy of Sciences (India)

    S. R. Verma

    2006-06-01

    The Sun is a mysterious star. The high temperature of the chromosphere and corona present one of the most puzzling problems of solar physics. Observations show that the solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in solar corona. Recent observations show that Magnetic Carpet is a potential candidate for solar coronal heating.

  18. Classical fracture mechanics methods

    International Nuclear Information System (INIS)

    Comprehensive Structural Integrity is a reference work which covers all activities involved in the assurance of structural integrity. It provides engineers and scientists with an unparalleled depth of knowledge in the disciplines involved. The new online Volume 11 is dedicated to the mechanical characteristics of materials. This paper contains the chapter 11.02 of this volume and is structured as follows: Test techniques; Analysis; Fracture behavior; Fracture toughness tests for nonmetals

  19. MECHANISMS OF PERCEPTUAL LEARNING

    OpenAIRE

    Lu, Zhong-Lin; Dosher, Barbara Anne

    2009-01-01

    What is learned in perceptual learning? How does perceptual learning change the perceptual system? We investigate these questions using a systems analysis of the perceptual system during the course of perceptual learning using psychophysical methods and models of the observer. Effects of perceptual learning on an observer’s performance are characterized by external noise tests within the framework of noisy observer models. We find evidence that two independent mechanisms, external noise exclu...

  20. Generalised Business Mechanics

    OpenAIRE

    Peter Johnson

    2007-01-01

    In this paper an analogy is established between a generalised system of point masses described by classical mechanics, and a set of discrete economic entities within a generalized resource framework. If the economic system is subject to a generalised variational Principle of Economy, the counterpart to Hamilton’s Principle Action, the evolution of the system will be governed by a set of canonical equations that relate defined system measures of fortune and prosperity to changes in prices, a...

  1. Semiclassical statistical mechanics

    International Nuclear Information System (INIS)

    On the basis of an approach devised by Miller, a formalism is developed which allows the nonperturbative incorporation of quantum effects into equilibrium classical statistical mechanics. The resulting expressions bear a close similarity to classical phase space integrals and, therefore, are easily molded into forms suitable for examining a wide variety of problems. As a demonstration of this, three such problems are briefly considered: the simple harmonic oscillator, the vibrational state distribution of HCl, and the density-independent radial distribution function of He4. A more detailed study is then made of two more general applications involving the statistical mechanics of nonanalytic potentials and of fluids. The former, which is a particularly difficult problem for perturbative schemes, is treated with only limited success by restricting phase space and by adding an effective potential. The problem of fluids, however, is readily found to yield to a semiclassical pairwise interaction approximation, which in turn permits any classical many-body model to be expressed in a convenient form. The remainder of the discussion concentrates on some ramifications of having a phase space version of quantum mechanics. To test the breadth of the formulation, the task of constructing quantal ensemble averages of phase space functions is undertaken, and in the process several limitations of the formalism are revealed. A rather different approach is also pursued. The concept of quantum mechanical ergodicity is examined through the use of numerically evaluated eigenstates of the Barbanis potential, and the existence of this quantal ergodicity - normally associated with classical phase space - is verified. 21 figures, 4 tables

  2. DARPA's Big Mechanism program

    Science.gov (United States)

    Cohen, Paul R.

    2015-07-01

    Reductionist science produces causal models of small fragments of complicated systems. Causal models of entire systems can be hard to construct because what is known of them is distributed across a vast amount of literature. The Big Mechanism program aims to have machines read the literature and assemble the causal fragments found in individual papers into huge causal models, automatically. The current domain of the program is cell signalling associated with Ras-driven cancers.

  3. Graduate Quantum Mechanics Reform

    OpenAIRE

    Carr, L. D.; McKagan, S. B.

    2008-01-01

    We address four main areas in which graduate quantum mechanics education can be improved: course content, textbook, teaching methods, and assessment tools. We report on a three year longitudinal study at the Colorado School of Mines using innovations in all these areas. In particular, we have modified the content of the course to reflect progress in the field in the last 50 years, used textbooks that include such content, incorporated a variety of teaching techniques based on physics educatio...

  4. Quantum mechanical Carnot engine

    OpenAIRE

    Bender, C. M.; Brody, D. C.; Meister, B. K.

    2000-01-01

    A cyclic thermodynamic heat engine runs most efficiently if it is reversible. Carnot constructed such a reversible heat engine by combining adiabatic and isothermal processes for a system containing an ideal gas. Here, we present an example of a cyclic engine based on a single quantum-mechanical particle confined to a potential well. The efficiency of this engine is shown to equal the Carnot efficiency because quantum dynamics is reversible. The quantum heat engine has a cycle consisting of a...

  5. The Mechanical Copula

    OpenAIRE

    Fusco, Maria

    2010-01-01

    The Mechanical Copula is a solo-authored collection of short stories. Stripping bare the accord of culture and commodity, this sequence of stories tracks the slimy path of social mobility with serious playfulness and an eye for the absurd. Tales of Donald Sutherland fucking a doll, two men eating a clown and how the obsessive searching of bins can transform trash into meaning, this is a book about the porous relationship between the extramundane and the average.

  6. Molecular mechanisms of cholangiocarcinoma

    OpenAIRE

    Fava, Giammarco

    2010-01-01

    Cholangiocarcinoma (CC), the malignant tumor of the epithelial cells lining the biliary ducts, has undergone a worldwide increase in incidence and mortality. The malignant transformation of the biliary cells originates from a multistep process evolving through chronic inflammation of the biliary tract to CC. In the last few years several advances have been towards understanding and clarifying the molecular mechanisms implicated in the cholangiocarcinogenesis process. However, many pathophysio...

  7. Computation in Classical Mechanics

    OpenAIRE

    Timberlake, Todd; Hasbun, Javier E.

    2007-01-01

    There is a growing consensus that physics majors need to learn computational skills, but many departments are still devoid of computation in their physics curriculum. Some departments may lack the resources or commitment to create a dedicated course or program in computational physics. One way around this difficulty is to include computation in a standard upper-level physics course. An intermediate classical mechanics course is particularly well suited for including computation. We discuss th...

  8. Mechanically modulated nozzles

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    Praha : Ústav termomechaniky AV ČR, v. v. i., 2015 - (Šimurda, D.; Bodnár, T.), s. 199-220 ISBN 978-80-87012-55-0. ISSN 2336-5781. [Topical Problems of Fluid Mechanics 2015. Praha (CZ), 11.02.2015-13.02.2015] R&D Projects: GA ČR GA13-23046S Institutional support: RVO:61388998 Keywords : nozzles * needle nozzles * flow separation Subject RIV: BK - Fluid Dynamics

  9. Mechanisms of Dyspnea

    OpenAIRE

    Burki, Nausherwan K; Lee, Lu-Yuan

    2010-01-01

    The mechanisms and pathways of the sensation of dyspnea are incompletely understood, but recent studies have provided some clarification. Studies of patients with cord transection or polio, induced spinal anesthesia, or induced respiratory muscle paralysis indicate that activation of the respiratory muscles is not essential for the perception of dyspnea. Similarly, reflex chemostimulation by CO2 causes dyspnea, even in the presence of respiratory muscle paralysis or cord transection, indicati...

  10. Relativistic viscoelastic fluid mechanics

    OpenAIRE

    Fukuma, Masafumi; Sakatani, Yuho

    2011-01-01

    A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by t...

  11. Acoustic Mechanical Feedthroughs

    Science.gov (United States)

    Sherrit, Stewart; Walkemeyer, Phillip; Bao, Xiaoqi; Bar-Cohen, Yoseph; Badescu, Mircea

    2013-01-01

    Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be

  12. Conventional mechanical ventilation

    OpenAIRE

    Tobias Joseph

    2010-01-01

    The provision of mechanical ventilation for the support of infants and children with respiratory failure or insufficiency is one of the most common techniques that are performed in the Pediatric Intensive Care Unit (PICU). Despite its widespread application in the PICUs of the 21st century, before the 1930s, respiratory failure was uniformly fatal due to the lack of equipment and techniques for airway management and ventilatory support. The operating rooms of the 1950s and 1960s provided the ...

  13. Epigenetic Mechanisms of Depression

    OpenAIRE

    Nestler, Eric J.

    2014-01-01

    Growing evidence supports the hypothesis that epigenetics is a key mechanism through which environmental exposures interact with an individual’s genetic constitution to determine risk for depression throughout life.1 Epigenetics, in its broadest meaning, refers to stable changes in gene expression that are mediated via altered chromatin structure without modification of DNA sequence. According to this hypothesis, severe stress triggers changes—in vulnerable individuals—in chromatin structure ...

  14. Probability in quantum mechanics

    Directory of Open Access Journals (Sweden)

    J. G. Gilson

    1982-01-01

    Full Text Available By using a fluid theory which is an alternative to quantum theory but from which the latter can be deduced exactly, the long-standing problem of how quantum mechanics is related to stochastic processes is studied. It can be seen how the Schrödinger probability density has a relationship to time spent on small sections of an orbit, just as the probability density has in some classical contexts.

  15. Mechanical beam isolator

    International Nuclear Information System (INIS)

    Back-reflections from a target, lenses, etc. can gain energy passing backwards through a laser just like the main beam gains energy passing forwards. Unless something blocks these back-reflections early in their path, they can seriously damage the laser. A Mechanical Beam Isolator is a device that blocks back-reflections early, relatively inexpensively, and without introducing aberrations to the laser beam

  16. The physio-mechanical

    Directory of Open Access Journals (Sweden)

    C.U. Atuanya

    2014-01-01

    Full Text Available This work presents a systematic approach to evaluate the physio-mechanical properties of bean pod ash particles (BPAp reinforced recycled polyethylene (RLDPE polymer based composites. The bean pod ash particles of 75 μm with a weight percentage of 0, 5, 10, 15, 20, 25, 30 (wt% and recycled polyethylene (RLDPE were prepared. The surface morphology, physical and the mechanical properties of the composites were examined. The results showed that the fair distribution of the bean pod ash particles in the microstructure of the polymer composites is the major factor responsible for the improvement in the mechanical properties. The bean pod ash particles added to the RLDPE polymer increased the percentage of water absorption and improved its rigidity, modulus and hardness values of the composites. The tensile and flexural strengths increased to a maximum of 20.1 and 39.0 N/mm2 at 20 wt% BPAp respectively. Based on the results obtained in this study, it is recommended that the composites can be used in the production of indoor and outdoor applications.

  17. Relational quantum mechanics

    International Nuclear Information System (INIS)

    I suggest that the common unease with taking quantum mechanics as a fundamental description of nature (the open-quotes measurement problemclose quotes) could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer-independent time. I suggest that this incorrect notion that generates the unease with quantum mechanics is the notion of open-quotes observer-independent stateclose quotes of a system, or open-quotes observer-independent values of physical quantities.close quotes I reformulate the problem of the open-quotes interpretation of quantum mechanicsclose quotes as the problem of deriving the formalism from a set of simple physical postulates. I consider a reformulation of quantum mechanics in terms of information theory. All systems are assumed to be equivalent, there is no observer-observed distinction, and the theory describes only the information that systems have about each other; nevertheless, the theory is complete

  18. Time Asymmetric Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Arno R. Bohm

    2011-09-01

    Full Text Available The meaning of time asymmetry in quantum physics is discussed. On the basis of a mathematical theorem, the Stone-von Neumann theorem, the solutions of the dynamical equations, the Schrödinger equation (1 for states or the Heisenberg equation (6a for observables are given by a unitary group. Dirac kets require the concept of a RHS (rigged Hilbert space of Schwartz functions; for this kind of RHS a mathematical theorem also leads to time symmetric group evolution. Scattering theory suggests to distinguish mathematically between states (defined by a preparation apparatus and observables (defined by a registration apparatus (detector. If one requires that scattering resonances of width Γ and exponentially decaying states of lifetime τ=h/Γ should be the same physical entities (for which there is sufficient evidence one is led to a pair of RHS's of Hardy functions and connected with it, to a semigroup time evolution t_0≤t<∞, with the puzzling result that there is a quantum mechanical beginning of time, just like the big bang time for the universe, when it was a quantum system. The decay of quasi-stable particles is used to illustrate this quantum mechanical time asymmetry. From the analysis of these processes, we show that the properties of rigged Hilbert spaces of Hardy functions are suitable for a formulation of time asymmetry in quantum mechanics.

  19. Mechanical Properties of Materials

    CERN Document Server

    Pelleg, Joshua

    2013-01-01

    The subject of mechanical behavior has been in the front line of basic studies in engineering curricula for many years.  This textbook was written for engineering students with the aim of presenting, in a relatively simple manner, the basic concepts of mechanical behavior in solid materials. A second aim of the book is to guide students in their laboratory experiments by helping them to understand their observations in parallel with the lectures of their various courses; therefore the first chapter of the book is devoted to mechanical testing. Another aim of the book is to provide practicing engineers with basic help to bridge the gap of time that has passed from their graduation up to their actual involvement in engineering work. The book also serves as the basis for more advanced studies and seminars when pursuing courses on a graduate level. The content of this textbook and the topics discussed correspond to courses that are usually taught in universities and colleges all over the world, but with a differ...

  20. Empirical quantum mechanics

    Science.gov (United States)

    Nishimura, Hirokazu

    1996-06-01

    Machida and Namiki developed a many-Hilbert-spaces formalism for dealing with the interaction between a quantum object and a measuring apparatus. Their mathematically rugged formalism was polished first by Araki from an operator-algebraic standpoint and then by Ozawa for Boolean quantum mechanics, which approaches a quantum system with a compatible family of continuous superselection rules from a notable and perspicacious viewpoint. On the other hand, Foulis and Randall set up a formal theory for the empirical foundation of all sciences, at the hub of which lies the notion of a manual of operations. They deem an operation as the set of possible outcomes and put down a manual of operations at a family of partially overlapping operations. Their notion of a manual of operations was incorporated into a category-theoretic standpoint into that of a manual of Boolean locales by Nishimura, who looked upon an operation as the complete Boolean algebra of observable events. Considering a family of Hilbert spaces not over a single Boolean locale but over a manual of Boolean locales as a whole, Ozawa's Boolean quantum mechanics is elevated into empirical quantum mechanics, which is, roughly speaking, the study of quantum systems with incompatible families of continuous superselection rules. To this end, we are obliged to develop empirical Hilbert space theory. In particular, empirical versions of the square root lemma for bounded positive operators, the spectral theorem for (possibly unbounded) self-adjoint operators, and Stone's theorem for one-parameter unitary groups are established.

  1. Relativistic viscoelastic fluid mechanics

    International Nuclear Information System (INIS)

    A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.

  2. Design on hopping locomotion mechanism

    Institute of Scientific and Technical Information of China (English)

    LU Yong-kui; WU Yue-hua; YANG Jie; Hisayuki AOYAMA

    2005-01-01

    A new type of locomotion mechanism is introduced in this paper. With vibrating motors used in controling the movement of the hopping locomotion mechanism, the simple hopping locomotion mechanism had two motors, when the current went through the vertical motor, the vertical motor would vibrate to cause the mechanism to go forward, and when the current went through the horizontal motor, the mechanism will go around itself. A spring was added to the mechanism to change the natural frequency of the mechanism, when the frequency of the motor was equal to the natural frequency of the mechanism, the mechanism would hop resonantly. With the resonant hopping, the load of the mechanism was greatly enlarged, and some sensors could be added to the mechanism. Optical sensors were used to detect the infrared source, the current that went through the sensors related to the distance between the infrared light. Three optical sensors was put on the left, right and the front the mechanism, when the mechanism detect the special infrared source, it would turn itself to the light, and go forward to the light. The experiments of the mechanism shown that the mechanism could work well on different surfaces freely, and the resonant hopping locomotion mechanism with infrared sensors could move to the special light by automatic regulation. Experimental results and theoretical studies demonstrate that the innovative design for hopping locomotion mechanism is superior.

  3. Understanding Bohmian mechanics: A dialogue

    OpenAIRE

    Tumulka, Roderich

    2004-01-01

    This paper is an introduction to the ideas of Bohmian mechanics, an interpretation of quantum mechanics in which the observer plays no fundamental role. Bohmian mechanics describes, instead of probabilities of measurement results, objective microscopic events. In recent years, Bohmian mechanics has attracted increasing attention by researchers. The form of a dialogue allows me to address questions about the Bohmian view that often arise.

  4. Advanced concepts in quantum mechanics

    CERN Document Server

    Esposito, Giampiero; Miele, Gennaro; Sudarshan, George

    2015-01-01

    Introducing a geometric view of fundamental physics, starting from quantum mechanics and its experimental foundations, this book is ideal for advanced undergraduate and graduate students in quantum mechanics and mathematical physics. Focusing on structural issues and geometric ideas, this book guides readers from the concepts of classical mechanics to those of quantum mechanics. The book features an original presentation of classical mechanics, with the choice of topics motivated by the subsequent development of quantum mechanics, especially wave equations, Poisson brackets and harmonic oscillators. It also presents new treatments of waves and particles and the symmetries in quantum mechanics, as well as extensive coverage of the experimental foundations.

  5. Thin film mechanics

    Science.gov (United States)

    Cooper, Ryan C.

    This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate

  6. On Foundations of Newtonian Mechanics

    CERN Document Server

    Cheremensky, Al

    2010-01-01

    Being based on V. Konoplev's axiomatic approach to continuum mechanics, the paper broadens its frontiers in order to bring together continuum mechanics with classical mechanics in a new theory of mechanical systems. There are derived motion equations of `abstract' mechanical systems specified for mass-points, multibody systems and continua: Newton-Euler equations, Lagrange equations of II kind and Navier-Stokes ones. Quasi-linear constitutive equations are introduced in conformity with V. Konoplev's definition of stress and strain (rate) matrices.

  7. [Mechanism of Cryptococcus Meningoencephalitis].

    Science.gov (United States)

    Miyazato, Akiko

    2016-01-01

    Cryptococcus neoformans and Cryptococcus gattii are fungal pathogens that cause diseases in humans. Cryptococcal species mainly enter the body by inhalation and in most cases are eliminated by host defense mechanisms. Some cases, however, progress to pneumonia and subsequent dissemination of the infection to the central nervous system (CNS), leading to meningoencephalitis. Cryptococcus can cross the blood-brain barrier transcellularly, paracellularly and through infected phagocytes (the Trojan horse mechanism). The reason for the tropism of Cryptococcus to the CNS could be partially explained by the abundance of inositol in the brain, which causes the hyaluronic acid in fungal cells to bind to host CD44 receptors. There are differences in the clinical characteristics of C. neoformans and C. gattii. HIV infection is the most common risk factor for cryptococcosis due to C. neoformans, whereas C. gattii infection with CNS involvement is frequently found in otherwise healthy individuals exposed to plant propagules found in tropical and subtropical regions. As the virulence traits of C. neoformans contributing to CNS disease, high macrophage uptake and laccase activity are associated with the fungal burden and the rate of clearance of the infection from the brain. Recent reports suggested that the C. gattii VGII strain suppresses host immune responses in the lung and causes more lung infections than CNS diseases. Furthermore, the anti-GM-CSF autoantibodies are a risk factor for CNS infection by the C. gattii VGI strain. To understand the mechanism by which Cryptococcus causes CNS disease, it is important to consider the specific characteristics of the species and the molecular types. PMID:26936349

  8. Fracture mechanics safety approaches

    International Nuclear Information System (INIS)

    Component integrity assessments require the knowledge of reliable fracture toughness parameters characterising the initiation of the failure process in the whole relevant temperature range. From a large number of fracture mechanics tests a statistically based procedure was derived allowing to quantify the initiation of fracture toughness as a function of temperature as a closed function as well as the temperature dependence of the cleavage instability parameters. Alternatively to the direct experimental determination one also can use a correlation between fracture toughness and notch impact energy. (orig.)

  9. Fracture mechanics safety approaches

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E.; Schuler, X.; Eisele, U. [Materials Testing Inst. (MPA), Univ. of Stuttgart (Germany)

    2004-07-01

    Component integrity assessments require the knowledge of reliable fracture toughness parameters characterising the initiation of the failure process in the whole relevant temperature range. From a large number of fracture mechanics tests a statistically based procedure was derived allowing to quantify the initiation of fracture toughness as a function of temperature as a closed function as well as the temperature dependence of the cleavage instability parameters. Alternatively to the direct experimental determination one also can use a correlation between fracture toughness and notch impact energy. (orig.)

  10. Engineering fluid mechanics

    CERN Document Server

    Yamaguchi, Hiroshi

    2008-01-01

    This book is intended to serve as a unique and comprehensive textbook for scientists and engineers as well as advanced students in thermo-fluid courses. It provides an intensive monograph essential for understanding dynamics of ideal fluid, Newtonian fluid, non-Newtonian fluid and magnetic fluid. These distinct, yet intertwined subjects are addressed in an integrated manner. It starts with coherent treatment of fundamental continuum mechanics, with an emphasis on the intrinsic angular momentum, by which the concepts of ferrohydrodynamics are progressively built up, and serve as a foundation fo

  11. Mechanics of micropolar media

    CERN Document Server

    Brulin, O

    1982-01-01

    This book is essentially made up of the lecture notes delivered by seven authors at the International Centre for Mechanical Sciences in Udine in June 1979. It attempts to provide an up-to-date and concise summary of the authors' understanding of micropolar materials. Both asymmetric elasticity and fluids are covered. The chapters range from the discussion of micropolar molecular models to the analysis of structure models, from linear to nonlinear theories and from electromagnetic, thermal, viscous effects to lattice defects. The subjects are treated from both theoretical and experimental point

  12. Radioactivity. Mechanisms and applications

    International Nuclear Information System (INIS)

    This work tells the discovery of radioactivity, by specifying the respective contributions of Becquerel, Pierre and marie Curie, Rutherford. It explains its mechanisms that begin in the heart of atom and it gives the principal laws. In the different uses are showed how the carbon 14 is a watch for history, to date rocks and solar system, the radioactivity and the spatial system, tracers and isotopic labelled compounds, for nuclear medicine how to make a diagnosis and how to cure, to end by radioactivity at the service of art and industry. (N.C.)

  13. Introduction to continuum mechanics

    CERN Document Server

    Rubin, David; Lai, W Michael

    1994-01-01

    Continuum mechanics studies the response of materials to different loading conditions. The concept of tensors is introduced through the idea of linear transformation in a self-contained chapter, and the interrelation of direct notation, indicial notation and matrix operations is clearly presented. A wide range of idealized materials are considered through simple static and dynamic problems, and the book contains an abundance of illustrative examples and problems, many with solutions. Through the addition of more advanced material (solution of classical elasticity problems, constitutive e

  14. Fluid Mechanics of Papermaking

    Science.gov (United States)

    Lundell, Fredrik; Söderberg, L. Daniel; Alfredsson, P. Henrik

    2011-01-01

    Papermaking is to a large extent a multiphase flow process in which the structure of the material and many of the relevant properties of the final product are determined by the interaction between water and the wood fibers. The dominant feature of a suspension composed of wood fibers and water is its inherent propensity to form bundles of mechanically entangled fibers, known as fiber flocs. However, the phenomena apparent throughout the papermaking process are not unique but in fact have a generic fluid dynamical nature.

  15. Quantum mechanical Carnot engine

    CERN Document Server

    Bender, C M; Meister, B K

    2000-01-01

    A cyclic thermodynamic heat engine runs most efficiently if it is reversible. Carnot constructed such a reversible heat engine by combining adiabatic and isothermal processes for a system containing an ideal gas. Here, we present an example of a cyclic engine based on a single quantum-mechanical particle confined to a potential well. The efficiency of this engine is shown to equal the Carnot efficiency because quantum dynamics is reversible. The quantum heat engine has a cycle consisting of adiabatic and isothermal quantum processes that are close analogues of the corresponding classical processes.

  16. Rock mechanics data package

    International Nuclear Information System (INIS)

    This data package provides a summary of available laboratory and in situ stress field test results from site characterization investigations by the Basalt Waste Isolation Project Modeling and Analysis Group. The objective is to furnish rock mechanics information for use by Rockwell Hanford Operations and their subcontractors in performance assessment and engineering studies. This release includes Reference Repository Location (RRL) site specific laboratory and field test data from boreholes RRL-2, RRL-6, and RRL-14 as well as previous Hanford wide data available as of April, 1985. 25 refs., 9 figs., 16 tabs

  17. Abstractions for Mechanical Systems

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Wisniewski, Rafael

    2012-01-01

    mechanical system. The tangential manifolds are generated using constants of motion, which can be derived from Noether's theorem. The transversal manifolds are subsequently generated on a reduced space, given by the Routhian, via action-angle coordinates. The method fully applies for integrable systems. We...... focus on a particular aspect of abstraction - partitioning the state space, as existing methods can be applied on the discretized state space to obtain an automata-based model. The contribution of the paper is to show that well-known reduction methods can be used to generate abstract models, which can...

  18. Incretin secretion: direct mechanisms

    DEFF Research Database (Denmark)

    Balk-Møller, Emilie; Holst, Jens Juul; Kuhre, Rune Ehrenreich

    2014-01-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are secreted from gastro-intestinal K- and L-cells, respectively, and play an important role in post-prandial blood glucose regulation. They do this by direct stimulation of the pancreatic β...... enzyme responsible for incretin degradation (dipeptidyl peptidase-4) is inhibited (drugs are already on the market) while the secretion of endogenous GLP-1 secretion is stimulated at the same time may prove particularly rewarding. In this section we review current knowledge on the mechanisms for direct...

  19. Mechanics of Generalized Continua

    CERN Document Server

    Altenbach, Holm; Erofeev, Vladimir

    2011-01-01

    This collection on auMechanics of Generalized Continua - from Micromechanical Basics to Engineering Applications" brings together leading scientists in this field from France, Russian Federation, and Germany. The attention in this publication is be focussed on the most recent research items, i.e., - new models, - application of well-known models to new problems, - micro-macro aspects, - computational effort, - possibilities to identify the constitutive equations, and - old problems with incorrect or non-satisfying solutions based on the classical continua assumptions.

  20. Mechanism of nanofiber crimp

    Directory of Open Access Journals (Sweden)

    Chen Rou-Xi

    2013-01-01

    Full Text Available Fabrication of crimped fibers has been caught much attention recently due to remarkable improvement surface-to-volume ratio. The precise mechanism of the fiber crimp is, however, rare and preliminary. This paper finds that pulsation of fibers is the key factor for fiber crimp, and its configuration (wave formation corresponds to its nature frequency after solidification. Crimping performance can be improved by temperature control of the uncrimped fibers. In the paper, polylactide/ dimethylfomamide solution is fabricated into crimped nanofibers by the bubble electrospinning, an approximate period- amplitude relationship of the wave formation is obtained.

  1. Nanoantenna using mechanical resonance

    KAUST Repository

    Chang Hwa Lee,

    2010-11-01

    Nanoantenna using mechanical resonance vibration is made from an indium tin oxide (ITO) coated vertically aligned nanorod array. Only this structure works as a radio with demodulator without any electrical circuit using field emission phenomenon. A top-down fabrication method of an ITO coated nanorod array is proposed using a modified UV lithography. The received radio frequency and the resonance frequency of nanoantenna can be controlled by the fabrication condition through the height of a nanorod array. The modulated signals are received successfully with the transmission carrier wave frequency (248MHz) and the proposed nanoantenna is expected to be used in communication system for ultra small scale sensor. ©2010 IEEE.

  2. Fundamental mechanisms of CVD

    International Nuclear Information System (INIS)

    A program of coordinated experimental and theoretical research on the fundamental chemistry and physics of VCD is described. The experimental work involves the development and use of laser diagnostic techniques for monitoring chemical species in the gas phase and measuring fluid-flow properties. The theoretical work applies state-of-the-art computational techniques to the coupled fluid mechanical and gas-phase chemical kinetics of CVD. The work has concentrated on the simple model system of silicon deposition from silane, although the concepts should be applicable to CVD in general. Some preliminary work on the chlorosilane and tungsten hexafluoride systems is also described

  3. Mechanical engineering principles

    CERN Document Server

    Bird, John

    2014-01-01

    A student-friendly introduction to core engineering topicsThis book introduces mechanical principles and technology through examples and applications, enabling students to develop a sound understanding of both engineering principles and their use in practice. These theoretical concepts are supported by 400 fully worked problems, 700 further problems with answers, and 300 multiple-choice questions, all of which add up to give the reader a firm grounding on each topic.The new edition is up to date with the latest BTEC National specifications and can also be used on undergraduate courses in mecha

  4. Mega Key Authentication Mechanism

    OpenAIRE

    Kloss, Guy

    2016-01-01

    For secure communication it is not just sufficient to use strong cryptography with good and strong keys, but to actually have the assurance, that the keys in use for it are authentic and from the contact one is expecting to communicate with. Without that, it is possible to be subject to impersonation or man-in-the-middle (MitM) attacks. Mega meets this problem by providing a hierarchical authentication mechanism for contacts and their keys. To avoid any hassle when using multiple types of key...

  5. Biochemical mechanisms underlying atherogenesis

    Directory of Open Access Journals (Sweden)

    Dr.P.V.L.N. Srinivasa Rao

    2012-02-01

    Full Text Available Atherosclerosis remains one of the major causes of death and premature disability in developed countries. Though atherosclerosis was formerly considered a bland lipid storage disease, substantial advances in basic and experimental sciences have illuminated the role of endothelium, inflammation and immune mechanisms in its pathogenesis. Current concept of atherosclerosis is that of a dynamic and progressive disease arising from in- jury to endothelium, also known as endothelial dysfunction and an inflammatory response to that injury. The lesions of atherosclerosis occur principally in large and medium sized arteries. Atherosclerosis affects various regions of the circulation preferentially and can lead to ischemia of heart, brain or extremities resulting in in- farction.This produces distinct clinical manifestations depending on the vessel involved. Several predisposing factors to cardiovascular diseases such as diabetes mellitus, hypertension, obesity, infections act as triggers to the devel- opment of atherosclerosis by causing endothelial dysfunction and/or promoting inflammatory response. The evolution of pathogenetic mechanisms has passed through various directions such as oxidative stress, inflam- mation and immune responses. It is now known that all these are not acting independently but are interrelated and getting unified in the current concept of atherogenesis. The following discussion aims at providing an in- sight into these developments which can help in a better comprehension of the disease and management of its clinical complications

  6. Fluid Mechanics: The Pamphlet

    Science.gov (United States)

    Variano, Evan

    2012-11-01

    One impediment to student learning in introductory fluid mechanics courses is that the fundamental laws of physics can become lost in the ``noise'' of dozens of semi-empirical equations describing special cases. This can be exacerbated by trends in textbooks and other teaching media. This talk will explore a minimalist approach, whereby the entire content of introductory fluids is distilled to a single 1-page pamphlet, designed to emphasize the governing equations and their near-universal applicability. We are particularly interested in hearing feedback from the audience on ways to further distill the content while keeping it accessible and useful. To further emphasize the difference between the fundamental laws and the many specific cases, we have begun assembling a complementary resource: a field guide to fluid phenomena, which mixes the approach of Van Dyke's book with a standard field guide. This is designed to emphasize that there is a ``zoology'' of fluid phenomena, to which the same small set of fundamental laws has been applied repeatedly. These materials may be useful in helping AP Physics teachers cover fluid mechanics, which is an under-utilized opportunity to introduce young scientists to our field of study.

  7. The French capacity mechanism

    International Nuclear Information System (INIS)

    The French capacity mechanism has been design to ensure security of supply in the context of the energy transition. This energy transition challenges the electricity market design with several features: peak load growth, the development of renewables, demand response,... To ensure security of supply in this context, a capacity mechanism is being implemented in France. It is a market wide capacity obligation on electricity suppliers, based on market principles. Suppliers are responsible for forecasting their obligation, which corresponds to their contribution to winter peak load, and must procure enough capacity certificates to meet their obligations. Capacity certificates are granted to capacities through a certification process, which assesses their contribution to security of supply on the basis of availability commitments. This certification process is technology neutral and performance based, associated with controls and penalties in case of non compliance. Demand Side is fully integrated in the market, either through the reduction of suppliers' capacity obligation or direct participation after certification. In addition to the expected benefits in terms of security of supply, the French capacity market will foster the development of demand response. The participation of foreign capacities will require adaptations which are scheduled in a road-map, and could pave the way for further European integration of energy policies. (authors)

  8. Quantum Mechanics as Dualism

    Science.gov (United States)

    Jones, Robert

    2011-03-01

    I do not agree with mind-body dualism. Today the consensus view is that thought and mind is a combination of processes like memory, generalization, comparison, deduction, organization, induction, classification, feature detection, analogy, etc. performed by computational machinery. (R. Jones, Trans. of the Kansas Acad. Sci., vol. 109, # 3/4, 2006 and www.robert-w-jones.com, philosopher, theory of thought) But I believe that quantum mechanics is a more plausible dualist theory of reality. The quantum mechanical wave function is nonphysical, it exists in a 3N space (for an N body system) not in (x,y,z,t) 4-space, and does not possess physical properties. But real physical things like energy (which do exist in our 4-space world) influence the wave function and the wave function, in its turn, influences real physical things, like where a particle can be found in 4-space. The coupling between the spirit-like wave function and things found in the real (4-space) world (like energy) is via mathematical equations like the Schrodinger equation and Born normalization.

  9. Mechanisms of cadmium carcinogenesis

    International Nuclear Information System (INIS)

    Cadmium (Cd), a heavy metal of considerable occupational and environmental concern, has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). The carcinogenic potential of Cd as well as the mechanisms underlying carcinogenesis following exposure to Cd has been studied using in vitro cell culture and in vivo animal models. Exposure of cells to Cd results in their transformation. Administration of Cd in animals results in tumors of multiple organs/tissues. Also, a causal relationship has been noticed between exposure to Cd and the incidence of lung cancer in human. It has been demonstrated that Cd induces cancer by multiple mechanisms and the most important among them are aberrant gene expression, inhibition of DNA damage repair, induction of oxidative stress, and inhibition of apoptosis. The available evidence indicates that, perhaps, oxidative stress plays a central role in Cd carcinogenesis because of its involvement in Cd-induced aberrant gene expression, inhibition of DNA damage repair, and apoptosis.

  10. Mechanisms of Plasma Therapeutics

    Science.gov (United States)

    Graves, David

    2015-09-01

    In this talk, I address research directed towards biomedical applications of atmospheric pressure plasma such as sterilization, surgery, wound healing and anti-cancer therapy. The field has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that plasmas readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. It is postulated that cold atmospheric plasma (CAP) can trigger a therapeutic shielding response in tissue in part by creating a time- and space-localized, burst-like form of oxy-nitrosative stress on near-surface exposed cells through the flux of plasma-generated RONS. RONS-exposed surface layers of cells communicate to the deeper levels of tissue via a form of the ``bystander effect,'' similar to responses to other forms of cell stress. In this proposed model of CAP therapeutics, the plasma stimulates a cellular survival mechanism through which aerobic organisms shield themselves from infection and other challenges.

  11. Lectures on Quantum Mechanics

    CERN Document Server

    Basdevant, Jean-Louis

    2007-01-01

    Beautifully illustrated and engagingly written, Lectures on Quantum Mechanics presents theoretical physics with a breathtaking array of examples and anecdotes. Basdevant's style is clear and stimulating, in the manner of a brisk classroom lecture that students can follow with ease and enjoyment. Here is a sample of the book's style, from the opening of Chapter 1: "If one were to ask a passer-by to quote a great formula of physics, chances are that the answer would be 'E = mc2'. Nevertheless, the formula 'E=hV' which was written in the same year 1905 by the same Albert Einstein, and which started quantum theory, concerns their daily life considerably more. In fact, of the three watershed years for physics toward the beginning of the 20th century - 1905: the Special Relativity of Einstein, Lorentz and Poincaré; 1915: the General Relativity of Einstein, with its extraordinary reflections on gravitation, space and time; and 1925: the full development of Quantum Mechanics - it is surely the last which has the mos...

  12. Mechanical shielded hot cell

    International Nuclear Information System (INIS)

    A plan to erect a mechanical shielded hot cell in the process hall of the Radiochemical Laboratory at Inchas is described. The hot cell is designed for safe handling of spent fuel bundles, from the Inchas reactor, and for dismantling and cutting the fuel rods in preparation for subsequent treatment. The biological shielding allows for the safe handling of a total radioactivity level up to 10,000 MeV-Ci. The hot cell consists of an α-tight stainless-steel box, connected to a γ-shielded SAS, through an air-lock containing a movable carriage. The α-box is tightly connected with six dry-storage cavities for adequate storage of the spent fuel bundles. Both the α-box, with the dry-storage cavities, and the SAS are surrounded by 200-mm thick biological lead shielding. The α-box is equipped with two master-slave manipulators, a lead-glass window, a monorail crane and Padirac and Minirag systems. The SAS is equipped with a lead-glass window, tong manipulator, a shielded pit and a mechanism for the entry of the spent fuel bundle. The hot cell is served by adequate ventilation and monitoring systems. (author)

  13. Control rod drive mechanisms

    International Nuclear Information System (INIS)

    Purpose: To accurately measure the loads generated upon scram and judge the absence or presence of deceleration in control rod drive mechanisms. Constitution: Control rod drive mechanisms for use in a BWR type reactor includes an index tube vertically movably, connected at the upper end to the control rod and having a drive piston at the lower end. A piezoelectric member for detecting the load generated upon uprise of the index tube is disposed and signals from the piezoelectric member is connected to a calculation processing device. A load exerted when the index tube uprises is measured by way of the piezoelectric member upon scram thereby judging the absence or presence of the decelerating operation. Therefore, the nuclear reactor can be shutdown only when it is required with no excess safety operation than required. As a result, the reactor availability can be improved and, in addition, it is also possible to mitigate the burden of in-service inspection and reduce the operators' exposure. (Kamimura, M.)

  14. Copenhagen Quantum Mechanics

    CERN Document Server

    Hollowood, Timothy J

    2015-01-01

    In our quantum mechanics courses, measurement is usually taught in passing, as an ad-hoc procedure involving the ugly collapse of the wave function. No wonder we search for more satisfying alternatives to the Copenhagen interpretation. But this overlooks the fact that the approach fits very well with modern measurement theory with its notions of the conditioned state and quantum trajectory. In addition, what we know of as the Copenhagen interpretation is a later 1950's development and some of the earlier pioneers like Bohr did not talk of wave function collapse. In fact, if one takes these earlier ideas and mixes them with later insights of decoherence, a much more satisfying version of Copenhagen quantum mechanics emerges, one for which the collapse of the wave function is seen to be a harmless book keeping device. Along the way, we explain why chaotic systems lead to wave functions that spread out quickly on macroscopic scales implying that Schrodinger cat states are the norm rather than curiosities generat...

  15. Submicroscopic Deterministic Quantum Mechanics

    CERN Document Server

    Krasnoholovets, V

    2002-01-01

    So-called hidden variables introduced in quantum mechanics by de Broglie and Bohm have changed their initial enigmatic meanings and acquired quite reasonable outlines of real and measurable characteristics. The start viewpoint was the following: All the phenomena, which we observe in the quantum world, should reflect structural properties of the real space. Thus the scale 10^{-28} cm at which three fundamental interactions (electromagnetic, weak, and strong) intersect has been treated as the size of a building block of the space. The appearance of a massive particle is associated with a local deformation of the cellular space, i.e. deformation of a cell. The mechanics of a moving particle that has been constructed is deterministic by its nature and shows that the particle interacts with cells of the space creating elementary excitations called "inertons". The further study has disclosed that inertons are a substructure of the matter waves which are described by the orthodox wave \\psi-function formalism. The c...

  16. Peripheral Auditory Mechanisms

    CERN Document Server

    Hall, J; Hubbard, A; Neely, S; Tubis, A

    1986-01-01

    How weIl can we model experimental observations of the peripheral auditory system'? What theoretical predictions can we make that might be tested'? It was with these questions in mind that we organized the 1985 Mechanics of Hearing Workshop, to bring together auditory researchers to compare models with experimental observations. Tbe workshop forum was inspired by the very successful 1983 Mechanics of Hearing Workshop in Delft [1]. Boston University was chosen as the site of our meeting because of the Boston area's role as a center for hearing research in this country. We made a special effort at this meeting to attract students from around the world, because without students this field will not progress. Financial support for the workshop was provided in part by grant BNS- 8412878 from the National Science Foundation. Modeling is a traditional strategy in science and plays an important role in the scientific method. Models are the bridge between theory and experiment. Tbey test the assumptions made in experim...

  17. Mechanical cornpicker hand injuries

    Directory of Open Access Journals (Sweden)

    Momčilović Dragan

    2005-01-01

    Full Text Available Mechanical cornpicker hand injuries are not frequent in comparison to general hand trauma, but they have a specific mechanism of occurrence and are very severe. This investigation included 221 hand injuries. The sex distribution shows a general male dominance (85.25% in their active age (84.44%. These are, seasonal injuries mostly occurring in October (75.11%. By type of injuries, mutilating crush injuries are most frequent (64.25%. After completing the treatment, in most cases the functional result were estimated as bad (50.68%. Data concerning education and training for operating agricultural machines (96.38% - patients without training and carrying out safety measures (63.35% of injured patients did not apply any protection measures are devastating. The number of these injuries, as well as consequent permanent disabilities, may be considerably reduced by preventive measures, including public health services and media. Use of contemporary agricultural machinery, as well as obligatory training for operating these machines and application of protective measures, may also reduce the incidence of hand injuries during corn picking.

  18. Principles of Quantum Mechanics

    Science.gov (United States)

    Landé, Alfred

    2013-10-01

    ödinger's equation for non-conservative systems; 46. Pertubation theory; 47. Orthogonality, normalization and Hermitian conjugacy; 48. General matrix elements; Part IV. The Principle of Correspondence: 49. Contact transformations in classical mechanics; 50. Point transformations; 51. Contact transformations in quantum mechanics; 52. Constants of motion and angular co-ordinates; 53. Periodic orbits; 54. De Broglie and Schrödinger function; correspondence to classical mechanics; 55. Packets of probability; 56. Correspondence to hydrodynamics; 57. Motion and scattering of wave packets; 58. Formal correspondence between classical and quantum mechanics; Part V. Mathematical Appendix: Principle of Invariance: 59. The general theorem of transformation; 60. Operator calculus; 61. Exchange relations; three criteria for conjugacy; 62. First method of canonical transformation; 63. Second method of canonical transformation; 64. Proof of the transformation theorem; 65. Invariance of the matrix elements against unitary transformations; 66. Matrix mechanics; Index of literature; Index of names and subjects.

  19. Kinetic Studies that Evaluate the Solvolytic Mechanisms of Allyl and Vinyl Chloroformate Esters

    Directory of Open Access Journals (Sweden)

    Malcolm J. D'Souza

    2013-04-01

    Full Text Available At 25.0 °C the specific rates of solvolysis for allyl and vinyl chloroformates have been determined in a wide mix of pure and aqueous organic mixtures. In all the solvents studied, vinyl chloroformate was found to react significantly faster than allyl chloroformate. Multiple correlation analyses of these rates are completed using the extended (two-term Grunwald-Winstein equation with incorporation of literature values for solvent nucleophilicity (NT and solvent ionizing power (YCl. Both substrates were found to solvolyze by similar dual bimolecular carbonyl-addition and unimolecular ionization channels, each heavily dependent upon the solvents nucleophilicity and ionizing ability.

  20. Hydro-mechanical processes

    International Nuclear Information System (INIS)

    This session gathers 13 articles dealing with: three-dimensional and time stepping modelling of the whole Meuse/Haute-Marne ANDRA URL (F. Laouafa, J.B. Kazmierczak, G. Armand, J. Vaunat, M. Jobmann, M. Polster); a constitutive model for a deep argillaceous rock using Hoek-Brown criteria (K. Su, C. Chavant, M. Souley); the long term behaviour of the Boom clay: influence of viscosity on the pore pressure distribution (C. Coll, R. Charlier, X.L. Li, F. Collin); the microstructural changes induced by viscoplastic deformations in argillaceous rocks (F.L. Pellet, G. Fabre, K. Su, P. Lebon); the engineered barrier experiment at Mont Terri rock laboratory (J.L. Garcia-Sineriz, M. Rey, J.C. Mayor); the chemical influence on the Hydro-Mechanical behaviour of high-density FEBEX bentonite (E. Castellanos, M.V. Villar, E. Romero, A. Lloret, A. Gens); the influence of water exchanges on the gallery convergence (P. Gerard, R. Charlier, R. Chambon, F. Collin); a new method for ageing resistant storage of argillaceous rock samples to achieve reproducible experimental results even after long intermediate storage times (O. Czaikowski, K.H. Lux); the installation and evaluation of a large-scale in-situ shaft seal experiment in Boom clay the RESEAL project M. Van Geet, W. Bastiaens, G. Volckaert, E. Weetjens, X. Sillen, A. Gens, M.V. Villar, Ch. Imbert, M. Filippi, F. Plas); the hydro-Mechanical response of the Callovo-Oxfordian mud-stone around a deep vertical drift (J. Vaunat, B. Garitte, A. Gens, K. Su, G. Armand); the sensitivity of total stress to changes in externally applied water pressure in KBS-3 buffer bentonite (J.F. Harrington, D.J. Birchall, P. Sellin); the comparison of the poro-elastic behavior of Meuse/Haute Marne and Tournemire argillites: effect of loading and saturation states (E. Bemer, A. Noiret, F. Homand, A. Rejeb); and the multi-scale modelling of the argillites mechanical behaviour (A. Abou-Chakra Guery, F. Cormery, K. Su, J.F. Shao, D. Kondo)

  1. Hydro-mechanical processes

    Energy Technology Data Exchange (ETDEWEB)

    Laouafa, F.; Kazmierczak, J.B. [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60 - Verneuil en Halatte (France); Armand, G. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Vaunat, J. [Catalonia UPC- Technical Univ., Barcelona (Spain); Jobmann, M.; Polster, M. [DBETEC- DBE Technology GmbH, Peine (Germany); Su, K.; Lebon, P.; Plas, F.; Armand, G.; Abou-Chakra Guery, A.; Cormery, F.; Shao, J.F.; Kondo, D. [ANDRA - Agence Nationale pour la Gestion des Dechets Radioactifs, 92 - Chatenay Malabry (France); Souley, M. [Institut National de l' Environnement Industriel et des Risques (INERIS), 54 - Nancy (France); Coll, C.; Charlier, R.; Collin, F.; Gerard, P. [Liege Univ., Dept. ArGEnCo (Belgium); Xiang Ling, Li [ESV EURIDICE, SCK.CEN, Belgian Nuclear Research Centre, Mol (Belgium); Collin, F. [Liege Univ., Charge de Recherches FNRS (Belgium); Pellet, F.L.; Fabre, G. [University Joseph Fourier, Laboratory 3S-R, 38 - Grenoble (France); Garcia-Sineriz, J.L.; Rey, M. [AITEMIN - Asociacion para la Investigacion y Desarrollo Industrial de los Recursos Naturales, Madrid (Spain); Mayor, J.C. [ENRESA - Empresa Nacional des Residuos Radioactivos, Madrid (Spain); Castellanos, E.; Romero, E.; Lloret, A.; Gens, A. [Catalunya Univ. Politecnica, UPC (Spain); Villar, M.V. [CIEMAT - Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain); Chambon, R. [Laboratoire 3S, UJF-INPG-CNRS, 38 - Grenoble (France); Czaikowski, O.; Lux, K.H. [Clausthal Univ. of Technology, Professorship for Waste Disposal and Geomechanics, Clausthal-Zellerfeld (Germany); Van Geet, M.; Bastiaens, W.; Volckaert, G.; Weetjens, E.; Sillen, X. [SCK-CEN, Waste and Disposal dept., Mol (Belgium); ONDRAF/NIRAS, Brussel (Belgium); Imbert, Ch. [CEA Saclay, Dept. de Physico-Chimie (DPC/SCCME/LECBA), 91 - Gif sur Yvette (France)] [and others

    2007-07-01

    This session gathers 13 articles dealing with: three-dimensional and time stepping modelling of the whole Meuse/Haute-Marne ANDRA URL (F. Laouafa, J.B. Kazmierczak, G. Armand, J. Vaunat, M. Jobmann, M. Polster); a constitutive model for a deep argillaceous rock using Hoek-Brown criteria (K. Su, C. Chavant, M. Souley); the long term behaviour of the Boom clay: influence of viscosity on the pore pressure distribution (C. Coll, R. Charlier, X.L. Li, F. Collin); the microstructural changes induced by viscoplastic deformations in argillaceous rocks (F.L. Pellet, G. Fabre, K. Su, P. Lebon); the engineered barrier experiment at Mont Terri rock laboratory (J.L. Garcia-Sineriz, M. Rey, J.C. Mayor); the chemical influence on the Hydro-Mechanical behaviour of high-density FEBEX bentonite (E. Castellanos, M.V. Villar, E. Romero, A. Lloret, A. Gens); the influence of water exchanges on the gallery convergence (P. Gerard, R. Charlier, R. Chambon, F. Collin); a new method for ageing resistant storage of argillaceous rock samples to achieve reproducible experimental results even after long intermediate storage times (O. Czaikowski, K.H. Lux); the installation and evaluation of a large-scale in-situ shaft seal experiment in Boom clay the RESEAL project M. Van Geet, W. Bastiaens, G. Volckaert, E. Weetjens, X. Sillen, A. Gens, M.V. Villar, Ch. Imbert, M. Filippi, F. Plas); the hydro-Mechanical response of the Callovo-Oxfordian mud-stone around a deep vertical drift (J. Vaunat, B. Garitte, A. Gens, K. Su, G. Armand); the sensitivity of total stress to changes in externally applied water pressure in KBS-3 buffer bentonite (J.F. Harrington, D.J. Birchall, P. Sellin); the comparison of the poro-elastic behavior of Meuse/Haute Marne and Tournemire argillites: effect of loading and saturation states (E. Bemer, A. Noiret, F. Homand, A. Rejeb); and the multi-scale modelling of the argillites mechanical behaviour (A. Abou-Chakra Guery, F. Cormery, K. Su, J.F. Shao, D. Kondo)

  2. Cellular mechanics and motility

    Science.gov (United States)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  3. Principles of discrete time mechanics

    CERN Document Server

    Jaroszkiewicz, George

    2014-01-01

    Could time be discrete on some unimaginably small scale? Exploring the idea in depth, this unique introduction to discrete time mechanics systematically builds the theory up from scratch, beginning with the historical, physical and mathematical background to the chronon hypothesis. Covering classical and quantum discrete time mechanics, this book presents all the tools needed to formulate and develop applications of discrete time mechanics in a number of areas, including spreadsheet mechanics, classical and quantum register mechanics, and classical and quantum mechanics and field theories. A consistent emphasis on contextuality and the observer-system relationship is maintained throughout.

  4. Odd coset quantum mechanics

    CERN Document Server

    Ivanov, E; Pashnev, A; Townsend, P K; Ivanov, Evgeny; Mezincescu, Luca; Pashnev, Anatoly; Townsend, Paul K.

    2003-01-01

    The standard quantum states of n complex Grassmann variables with a free-particle Lagrangian transform as a spinor of SO(2n). However, the same `free-fermion' model has a non-linearly realized SU(n|1) symmetry; it can be viewed as the mechanics of a `particle' on the Grassmann-odd coset space SU(n|1)/U(n). We implement a quantization of this model for which the states with non-zero norm transform as a representation of SU(n|1), the representation depending on the U(1) charge of the wave-function. For a natural charge assignment, the n=2 wave-function can be interpreted as a BRST superfield.

  5. Mechanics of moving materials

    CERN Document Server

    Banichuk, Nikolay; Neittaanmäki, Pekka; Saksa, Tytti; Tuovinen, Tero

    2014-01-01

    This book deals with theoretical aspects of modelling the mechanical behaviour of manufacturing, processing, transportation or other systems in which the processed or supporting material is travelling through the system. Examples of such applications include paper making, transmission cables, band saws, printing presses, manufacturing of plastic films and sheets, and extrusion of aluminium foil, textiles and other materials.   The work focuses on out-of-plane dynamics and stability analysis for isotropic and orthotropic travelling elastic and viscoelastic materials, with and without fluid-structure interaction, using analytical and semi-analytical approaches.  Also topics such as fracturing and fatigue are discussed in the context of moving materials. The last part of the book deals with optimization problems involving physical constraints arising from the stability and fatigue analyses, including uncertainties in the parameters.   The book is intended for researchers and specialists in the field, providin...

  6. CTD lowering mechanics

    Science.gov (United States)

    Berteaux, H. O.; Walden, R. G.

    1984-02-01

    The difficulties encountered in the deployment of CTD instruments, including the loss of an appreciable number of them, has prompted a comprehensive study of CTD lowering mechanics. Conditions causing large cyclic cable tensions, shock loads, or cable slack were to be investigated, modeled, and hopefully, measured in situ. The dynamic behaviour of the instrument package needed to be assessed. Methods to improve the path of the instruments as they travel through the water column and recommendations for safer and more efficient lowering procedures had to be formulated. This paper describes the study and presents salient findings and recommendations. We point out the limits of present CTD lowering systems and advocate that servo-controlled motion-compensating winches be used.

  7. Mechanisms of Phosphine Toxicity

    Directory of Open Access Journals (Sweden)

    Nisa S. Nath

    2011-01-01

    Full Text Available Fumigation with phosphine gas is by far the most widely used treatment for the protection of stored grain against insect pests. The development of high-level resistance in insects now threatens its continued use. As there is no suitable chemical to replace phosphine, it is essential to understand the mechanisms of phosphine toxicity to increase the effectiveness of resistance management. Because phosphine is such a simple molecule (PH3, the chemistry of phosphorus is central to its toxicity. The elements above and below phosphorus in the periodic table are nitrogen (N and arsenic (As, which also produce toxic hydrides, namely, NH3 and AsH3. The three hydrides cause related symptoms and similar changes to cellular and organismal physiology, including disruption of the sympathetic nervous system, suppressed energy metabolism and toxic changes to the redox state of the cell. We propose that these three effects are interdependent contributors to phosphine toxicity.

  8. PEBBLES Mechanics Simulation Speedup

    Energy Technology Data Exchange (ETDEWEB)

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2010-05-01

    Pebble bed reactors contain large numbers of spherical fuel elements arranged randomly. Determining the motion and location of these fuel elements is required for calculating certain parameters of pebble bed reactor operation. These simulations involve hundreds of thousands of pebbles and involve determining the entire core motion as pebbles are recirculated. Single processor algorithms for this are insufficient since they would take decades to centuries of wall-clock time. This paper describes the process of parallelizing and speeding up the PEBBLES pebble mechanics simulation code. Both shared memory programming with the Open Multi-Processing API and distributed memory programming with the Message Passing Interface API are used in simultaneously in this process. A new shared memory lock-less linear time collision detection algorithm is described. This method allows faster detection of pebbles in contact than generic methods. These combine to make full recirculations on AVR sized reactors possible in months of wall clock time.

  9. Mechanisms of postoperative pain

    Institute of Scientific and Technical Information of China (English)

    YUE Yun

    2007-01-01

    @@ The practice of modern anaesthesiology has extended into perioperative medicine. Due to their expertise in analgesic drug pharmacology and peripheral nerve blocking, anaesthesiologists have pioneered in the management of acute postoperative pain. Effective postoperative analgesia reduces the incidence of postoperative chronic pain, improves the functioning of organs following surgery and shortens the hospital stay.1,2 Although a variety of analgesic techniques and preventative approaches are at the disposal of modem aneasthesiologists, including patient controlled epidural analgesia (PCEA), patient controlled intravenous analgesia, multimodal analgesia and pre-empty analgesia.Despite this array of strategies, these predominantly opioid based techniques are still limited by side-effects such as vomiting, nausea, itching and urinary retention.To optimize further the management of acute postoperative pain, basic mechanisms of postoperative pain must be explored and new treatments must continue to be developed.

  10. Microcomputer quantum mechanics

    International Nuclear Information System (INIS)

    Chapter headings are: microcomputers and BASIC; tuning the instrument; the iterative approach; some finite-difference methods; numerical integration; Pade approximants and all that; a simple power series method; some matrix calculations; hypervirial-perturbation methods; finite-difference eigenvalue calculations; one-dimensional model problems; some case studies (a simple helium atom calculation; Monte-Carlo optimization; the charmonium problem; the quadratic Zeeman effect; quasi-bound states). While the first chapters deal with general ways of applying and testing microcomputers the later chapters concentrate on the use of microcomputers in quantum mechanics. Worked exercises are given in the text and provide concrete uses for the computing skills that are discussed. (U.K.)

  11. Payload Launch Lock Mechanism

    Science.gov (United States)

    Young, Ken (Inventor); Hindle, Timothy (Inventor)

    2014-01-01

    A payload launch lock mechanism includes a base, a preload clamp, a fastener, and a shape memory alloy (SMA) actuator. The preload clamp is configured to releasibly restrain a payload. The fastener extends, along an axis, through the preload clamp and into the base, and supplies a force to the preload clamp sufficient to restrain the payload. The SMA actuator is disposed between the base and the clamp. The SMA actuator is adapted to receive electrical current and is configured, upon receipt of the electrical current, to supply a force that causes the fastener to elongate without fracturing. The preload clamp, in response to the fastener elongation, either rotates or pivots to thereby release the payload.

  12. Dictionary of fracture mechanics

    International Nuclear Information System (INIS)

    7000 entries summarize the most important and frequently used terms in fracture mechanics: modes of fracture, concepts and criteria, cracks and crack growth, test methods, specimens etc. Some general terms that have a special meaning in the scope of this book are also included as are important abbreviations, acronyms, symbols and units. All entries are alphabetically ordered and, if appropriate, combined with groups of related words. Groups of word combinations are thought to be useful for the understanding of linguistic laws. Annotations in italics may be helpful in relating the entry to a special technical scope. Within the entries the source-language terms are bold-faced. In the German alphabet the mutated vowels ae, oe and ue are ordered as ae, oe and ue; ss is ordered as ss. (orig./HP)

  13. Quo Vadis Quantum Mechanics?

    CERN Document Server

    Dolev, S; Kolenda, N

    2005-01-01

    For more than a century, quantum mechanics has served as a very powerful theory that has expanded physics and technology far beyond their classical limits, yet it has also produced some of the most difficult paradoxes known to the human mind. This book represents the combined efforts of sixteen of today's most eminent theoretical physicists to lay out future directions for quantum physics. The authors include Yakir Aharonov, Anton Zeilinger; the Nobel laureates Anthony Leggett and Geradus 't Hooft; Basil Hiley, Lee Smolin and Henry Stapp. Following a foreword by Roger Penrose, the individual chapters address questions such as quantum non-locality, the measurement problem, quantum insights into relativity, cosmology and thermodynamics, and the possible bearing of quantum phenomena on biology and consciousness.

  14. What is semiquantum mechanics?

    CERN Document Server

    Bracken, A J

    2006-01-01

    Semiclassical approximations to quantum dynamics are almost as old as quantum mechanics itself. In the approach pioneered by Wigner, the evolution of his quasiprobability density function on phase space is expressed as an asymptotic series in increasing powers of Planck's constant, with the classical Liouvillean evolution as leading term. Successive semiclassical approximations to quantum dynamics are defined by successive terms in the series. We consider a complementary approach, which explores the quantum-clssical interface from the other direction. Classical dynamics is formulated in Hilbert space, with the Groenewold quasidensity operator as the image of the Liouville density on phase space. The evolution of the Groenewold operator is then expressed as an asymptotic series in increasing powers of Planck's constant. Successive semiquantum approximations to classical dynamics are defined by successive terms in this series, with the familiar quantum evolution as leading term.

  15. Mechanics of slide dams

    International Nuclear Information System (INIS)

    Studies which promote the use of nuclear energy for peaceful projects in engineering are sponsored by the Atomic Energy Commission under the Plowshare program. Specific projects being considered include the construction of harbors, canals, and dams. Of these projects, perhaps the most difficult to accomplish will be the latter. This paper which is in two parts considers the problems which are associated with the construction of slide dams with nuclear explosives. It examines first the characteristics of conventional earth and rock-fill dams which are based upon proven techniques developed after many years of experience. The characteristics of natural landslide dams are also briefly considered to identify potential problems that must be overcome by slide dam construction techniques. Second, the mechanics of slide dams as determined from small-scale laboratory studies are presented. It is concluded that slide dams can be constructed and that small-scale field tests and additional laboratory studies are justified. (author)

  16. Mechanical origin of aftershocks.

    Science.gov (United States)

    Lippiello, E; Giacco, F; Marzocchi, W; Godano, C; de Arcangelis, L

    2015-01-01

    Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering. PMID:26497720

  17. The mechanical components market

    International Nuclear Information System (INIS)

    Evolution of CANDU power station design is described and installed nuclear power in Canada to 2000 is forecast. The predicted value of various mechanical components is depicted. Improvements are being made in reliability and speed of repair, which reduce man-rem expenditure in concert with radiation field reduction. Actual reactor operating performance is very good; a significant portion of power plant downtime is associated with steam turbine and generator unreliability. Heavy water upkeep has been reduced by improved equipment layout, live loading of valve stem packing, improved flange seals, and improved leak detection techniques. Steam generator tube reliability is 1000 times better than that of light water reactors. Pump seal reliability has progressed to the point that current station design eliminates pump redundancy. Fuel bundle defect rates are now less than 0.03%. (E.C.B.)

  18. Probabilistic fracture mechanics

    International Nuclear Information System (INIS)

    It has been attempted to present the elements of probabilistic fracture mechanics in a self-contained way. First, for brittle fracture, damage theories are discussed which allow for the effects of both size and local strength of the structure on the probability of fracture. Second, combined crack and damage theories are presented. They provide insight into macro-crack formation and take into account the effects of crack orientation and multiaxial states of stress. For fatigue, both the two-phase theory of damage and crack extension as well as the cumulative theory (of damage or of crack extension) are presented. They give estimates for the lifetime of a structure under random load. The effect of random material properties may be included. Finally, an assessment of the probability of failure of reactor pressure vessels is discussed. There, brittle fracture and fatigue are taken into account and both fracture toughness and crack size are considered to be random quantities. (Auth.)

  19. Teaching Continuum Mechanics in a Mechanical Engineering Program

    Science.gov (United States)

    Liu, Yucheng

    2011-01-01

    This paper introduces a graduate course, continuum mechanics, which is designed for and taught to graduate students in a Mechanical Engineering (ME) program. The significance of continuum mechanics in engineering education is demonstrated and the course structure is described. Methods used in teaching this course such as topics, class…

  20. The Baroreflex Mechanism Revisited.

    Science.gov (United States)

    Rabinovitch, A; Friedman, M; Braunstein, D; Biton, Y; Aviram, I

    2015-08-01

    We state that the autonomic part of the brain controls the blood pressure (BP) and the heart rate (HR) via the baroreflex mechanism in all situations of human activity (at sleep, at rest, during exercise, fright etc.), in a way which is not, as was hitherto assumed, a mere homeostatic tool or even a resetting device, designed to bring these variables on the road to preset values. The baroreflex is rather a continuous feedback mechanism commanded by the autonomic part of the brain, leading to values appropriate to the situation at hand. Feasibility of this assertion is demonstrated here by using the Seidel-Herzel feedback system outside of its regular practice. Results show indeed that the brain can, and we claim that it does, control the HR and BP throughout life. New responses are demonstrated, e.g., to a sudden fear or apnea. In this event, large BP and HR overshoots are expected before the variables can relax to a new level. Response to abrupt downward change in the controlling parameter shows an undershoot in HR and just a gradual resetting in the BP. The relaxation from sudden external changes to various expected states are calculated and discussed and properties of the Rheos test are explained. Experimental findings for orthostatic tests and for babies under translations and rotations reveal complete qualitative agreement with our model and show no need to invoke the operation of additional body systems. Our method should be the preferred one by the Occam Razor approach. The outcomes may lead to beneficial clinical implication. PMID:26394627

  1. PT quantum mechanics.

    Science.gov (United States)

    Bender, Carl M; DeKieviet, Maarten; Klevansky, S P

    2013-04-28

    PT-symmetric quantum mechanics (PTQM) has become a hot area of research and investigation. Since its beginnings in 1998, there have been over 1000 published papers and more than 15 international conferences entirely devoted to this research topic. Originally, PTQM was studied at a highly mathematical level and the techniques of complex variables, asymptotics, differential equations and perturbation theory were used to understand the subtleties associated with the analytic continuation of eigenvalue problems. However, as experiments on PT-symmetric physical systems have been performed, a simple and beautiful physical picture has emerged, and a PT-symmetric system can be understood as one that has a balanced loss and gain. Furthermore, the PT phase transition can now be understood intuitively without resorting to sophisticated mathematics. Research on PTQM is following two different paths: at a fundamental level, physicists are attempting to understand the underlying mathematical structure of these theories with the long-range objective of applying the techniques of PTQM to understanding some of the outstanding problems in physics today, such as the nature of the Higgs particle, the properties of dark matter, the matter-antimatter asymmetry in the universe, neutrino oscillations and the cosmological constant; at an applied level, new kinds of PT-synthetic materials are being developed, and the PT phase transition is being observed in many physical contexts, such as lasers, optical wave guides, microwave cavities, superconducting wires and electronic circuits. The purpose of this Theme Issue is to acquaint the reader with the latest developments in PTQM. The articles in this volume are written in the style of mini-reviews and address diverse areas of the emerging and exciting new area of PT-symmetric quantum mechanics. PMID:23509390

  2. Mechanisms of chemical phototoxicity

    International Nuclear Information System (INIS)

    Psoralens in combination with ultraviolet light (PUVA) are phototoxic and potent modulators of epidermal cell growth and differentiation. Using an in vitro cell culture model, the effects of psoralens and UVA light on the growth of epidermal cells were investigated. It was found that psoralen and UVA light interact synergistically to inhibit the growth of cells in culture. This synergism was also observed in the ability of PUVA to inhibit DNA synthesis, decrease cell survival, cause mutations and form psoralen-DNA adducts. Using a cell culture model for the differentiation of melanocytes, PUVA was also found to be a potent inducer of melanogenesis as evidenced by its ability to increase cellular tyrosinase, the enzyme responsible for melanin biosynthesis. Results from these studies indicate that PUVA can induce dramatic alterations in the growth rate and differentiation state of cells at dosage levels which are associated with minimal DNA damage. These findings are in conflict with the general assumption that the biological effects of psoralens and UVA light are associated with their ability to bind covalently to and cross-link DNA. Therefore, the author investigated the possibility that sites of action, other than DNA, are involved in the mechanism(s) by which photoactivated psoralens modulate epidermal cell growth and differentiation. The author's laboratory has found that mammalian epidermal cells contain specific, saturable, high-affinity binding sites for the psoralens that are distinct from DNA. This receptor for the psoralens, photolabeled with [3H]-8-methoxysporalen, was visualized following sodium dodecyl sulfatepolyacrylamide gel electrophoresis. The psoralen receptor is shown to be a 22,000 dalton protein located in nonnuclear fractions of cell extracts

  3. Charging mechanisms in persistent phosphors

    OpenAIRE

    Smet, Philippe; Van den Eeckhout, Koen; Korthout, Katleen; Botterman, Jonas; van der Kolk, Erik; Bos, Adrie; Dorenbos, Pieter; Poelman, Dirk

    2011-01-01

    The development of novel persistent phosphors is currently hampered by a limited understanding of the charging mechanism. Using x-ray absorption and thermoluminescence spectroscopy we evaluate the validity of recently proposed models for the charging mechanism.

  4. 39th Aerospace Mechanisms Symposium

    Science.gov (United States)

    Boesiger, E. A. (Compiler)

    2008-01-01

    The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production, and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Education Association, NASA Marshall Space Flight Center (MSFC) and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for hosting the AMS. Now in its 39th symposium, the AMS continues to be well attended, attracting participants from both the United States and abroad. The 39th AMS was held in Huntsville, Alabama, May 7-9, 2008. During these 3 days, 34 papers were presented. Topics included gimbals and positioning mechanisms, tribology, actuators, deployment mechanisms, release mechanisms, and sensors. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components.

  5. Statistical mechanics of nonequilibrium liquids

    CERN Document Server

    Evans, Denis J; Craig, D P; McWeeny, R

    1990-01-01

    Statistical Mechanics of Nonequilibrium Liquids deals with theoretical rheology. The book discusses nonlinear response of systems and outlines the statistical mechanical theory. In discussing the framework of nonequilibrium statistical mechanics, the book explains the derivation of a nonequilibrium analogue of the Gibbsian basis for equilibrium statistical mechanics. The book reviews the linear irreversible thermodynamics, the Liouville equation, and the Irving-Kirkwood procedure. The text then explains the Green-Kubo relations used in linear transport coefficients, the linear response theory,

  6. MECHANISM TO DRAW MACLAURIN TRISECTRIX

    Directory of Open Access Journals (Sweden)

    Mirela CHERCIU

    2013-05-01

    Full Text Available It is used a geometrical method for generating Maclaurin trisectrix and based on it , thesynthesis of a mechanism that can draw it, is made. The structure of the found mechanism is R-RTRTtype, having two driving elements with correlated movements. This mechanism is analysedand the desired curve is obtained just for certain dimensions of the mechanism. The mechanism’smovement is studied based on some diagrams and different outputs are obtained for certain initialdimensions of the mechanism’s.

  7. Operator formalism of quantum mechanics

    OpenAIRE

    Naudts, Jan

    2000-01-01

    This is the first chapter of a new and unconventional textbook on quantum mechanics and quantum field theory. The chapter introduces standard quantum mechanics by means of a symmetry principle, without reference to classical mechanics. The mathematical foundation of this approach comes from a recent paper of Naudts and Kuna on covariance systems. The standard representation of quantum mechanics is derived. Next, spin and mass of a quantum particle are explained as labels of projective represe...

  8. Principles of Fractional Quantum Mechanics

    OpenAIRE

    Laskin, Nick

    2010-01-01

    A review of fundamentals and physical applications of fractional quantum mechanics has been presented. Fundamentals cover fractional Schr\\"odinger equation, quantum Riesz fractional derivative, path integral approach to fractional quantum mechanics, hermiticity of the Hamilton operator, parity conservation law and the current density. Applications of fractional quantum mechanics cover dynamics of a free particle, new representation for a free particle quantum mechanical kernel, infinite poten...

  9. Molecular dynamics investigation of mechanical mixing in mechanical alloying

    International Nuclear Information System (INIS)

    Molecular dynamic simulation is exploited to obtain a deep insight of atomic scale mixing and amorphization mechanisms happening during mechanical mixing. Impact-relaxation cycles are performed to simulate the mechanical alloying process. The results obtained by structural analysis shows that the final structure obtained through simulation of mechanical alloying is in an amorphous state. This analysis reveals that amorphization occurs concurrently with the attainment of a perfectly mixed alloy. The results indicate diffusion and deformation are two important mechanisms for mixing during mechanical alloying. The rate of diffusion is controlled by the temperature and by the density of defects in the structure. Deformation enhances mixing directly by sliding atomic layers on each other and increases the number of defects in the structure. The results agree with mechanical alloying experiments described in the literature

  10. Molecular dynamics investigation of mechanical mixing in mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Ali Nematollahi, Gh. [Department of Ceramic, Materials and Energy Research Center, Karaj, Tehran (Iran, Islamic Republic of)], E-mail: ali61gh@yahoo.com; Marzbanrad, E.; Aghaei, A.R. [Department of Ceramic, Materials and Energy Research Center, Karaj, Tehran (Iran, Islamic Republic of)

    2008-09-25

    Molecular dynamic simulation is exploited to obtain a deep insight of atomic scale mixing and amorphization mechanisms happening during mechanical mixing. Impact-relaxation cycles are performed to simulate the mechanical alloying process. The results obtained by structural analysis shows that the final structure obtained through simulation of mechanical alloying is in an amorphous state. This analysis reveals that amorphization occurs concurrently with the attainment of a perfectly mixed alloy. The results indicate diffusion and deformation are two important mechanisms for mixing during mechanical alloying. The rate of diffusion is controlled by the temperature and by the density of defects in the structure. Deformation enhances mixing directly by sliding atomic layers on each other and increases the number of defects in the structure. The results agree with mechanical alloying experiments described in the literature.

  11. 41st Aerospace Mechanisms Symposium

    Science.gov (United States)

    Boesiger, Edward A. (Editor)

    2012-01-01

    The proceedings of the 41st Aerospace Mechanisms Symposium are reported. JPL hosted the conference, which was held in Pasadena Hilton, Pasadena, California on May 16-18, 2012. Lockheed Martin Space Systems cosponsored the symposium. Technology areas covered include gimbals and positioning mechanisms, components such as hinges and motors, CubeSats, tribology, and Mars Science Laboratory mechanisms.

  12. A Primer on Geometric Mechanics

    OpenAIRE

    Lessig, Christian

    2012-01-01

    Geometric mechanics is usually studied in applied mathematics and most introductory texts are hence aimed at a mathematically minded audience. The present note tries to provide the intuition of geometric mechanics and to show the relevance of the subject for an understanding of "mechanics".

  13. Kinetics of template-directed pyrophosphate-linked dideoxyguanylate synthesis as a function of 2-MeImpdG and poly(C) concentration: insights into the mechanism

    Science.gov (United States)

    Kanavarioti, A.; Gangopadhyay, S.

    1999-01-01

    Aqueous solutions of deoxyguanosine 5'-monophosphate 2-methylimidazolide, 2-MeImpdG, yield primarily deoxyguanosine 5'-monophosphate, 5'dGMP, and pyrophosphate-linked dideoxyguanylate, dG5'ppdG, abbreviated G2p (see Chart 1). The initial rate of G2p formation, d[G2p]/dt in M h-1, determined at 23 degrees C, pH 7.8, 1.0 M NaCl and 0.2 M Mg2+ by timed high-performance liquid chromatography (HPLC) analysis, exhibits a second-order dependence on 2-MeImpdG concentration, [G]o, indicating a bimolecular mechanism of dimerization in the range 0.02 M function of both monomer and polymer concentration, expressed in C equivalents, were also determined under the above conditions and exhibited a complex behavior. Specifically, at a constant [poly(C)], values of d[G2p]/dt typically increased with [G]o with a parabolic upward curvature. At a constant [G]o, values of d[G2p]/dt increase with [poly(C)], but level off at the higher poly(C) concentrations. As [G]o increases this saturation occurs at a higher poly(C) concentration, a result opposite to expectation for a simple complexation of two reacting monomers with the catalyst prior to reaction. Nevertheless, these results are shown to be quantitatively consistent with a template-directed (TD) mechanism of dimerization where poly(C) acts as the template to bind 2-MeImpdG in a cooperative manner and lead, for the first time, to the formulation of principles that govern template-directed chemistry. Analysis of the kinetic data via a proposed TD cooperative model provides association constants for the affinity between polymer and monomer and the intrinsic reactivity of 2-MeImpdG toward pyrophosphate synthesis. To the best of our knowledge, poly(C)/2-MeImpdG is the first system that could serve as a textbook example of a TD reaction under conditions such that the template is fully saturated by monomers and under conditions that it is not.

  14. Quantum mechanics and experience

    CERN Document Server

    Albert, David Z

    1992-01-01

    The more science tells us about the world, the stranger it looks. Ever since physics first penetrated the atom, early in this century, what it found there has stood as a radical and unanswered challenge to many of our most cherished conceptions of nature. It has literally been called into question since then whether or not there are always objective matters of fact about the whereabouts of subatomic particles, or about the locations of tables and chairs, or even about the very contents of our thoughts. A new kind of uncertainty has become a principle of science. This book is an original and provocative investigation of that challenge, as well as a novel attempt at writing about science in a style that is simultaneously elementary and deep. It is a lucid and self-contained introduction to the foundations of quantum mechanics, accessible to anyone with a high school mathematics education, and at the same time a rigorous discussion of the most important recent advances in our understanding of that subject, some...

  15. Quantum mechanics probes superspace

    CERN Document Server

    Nicolis, S

    2014-01-01

    We study quantum mechanics in one space dimension in the stochastic formalism. We show that the partition function of the theory is, in fact, equivalent to that of a model, whose action is explicitly invariant (up to surface terms) under supersymmetry transformations--but whose invariance under the stochastic identities is not obvious, due to an apparent mismatch between fermions and bosons. The resolution of the riddle is that one "fermion" is a gauge artifact and, upon fixing the local, fermionic symmetry, called $\\kappa-$symmetry, we recover the stochastic partition function. The "fermions" do not propagate in the bulk, since their kinetic term is a total derivative. Their contribution to the action is through an ultra--local bilinear term, that may be exactly integrated out, as long as the superpotential has a unique minimum and we obtain a local action for the scalar. When the superpotential does not have a unique minimum, we use a Hubbard-Stratonovich transformation of the kinetic term to obtain an acti...

  16. Mechanical behavior of superalloys

    International Nuclear Information System (INIS)

    Recent developments affecting the mechanical behavior of superalloys over three ranges of operating temperatures are reviewed. At lower temperatures, activity has been focused on stress corrosion cracking susceptibility in light water reactor and sour gas well environments. The susceptibility to intergranular crack growth is critically dependent upon the grain boundary chemistry, and a method of minimizing the sensitivity of the boundaries to attack has been pursued. At intermediate temperatures, considerable effort has been directed toward increasing the tensile and fatigue strengths. The higher strength materials, however, show increased fracture sensitivity. In particular, embrittlement due to diffusion into the grain boundaries of aggressive species, such as oxygen or sulfur from the environments, becomes a problem. Minor element alloying additions of boron, zirconium, magnesium, etc., are helpful in retarding the degradation caused by the environment. At higher temperatures, the major thrust is toward improving the creep strength. The weak link in the materials, which is the transverse grain boundaries, has been eliminated by the use of specialized processing steps to produce either directionally solidified materials with minimum transverse grain boundaries, or single crystal materials. Single crystal materials permit alloying and heat treating modifications that further enhance the creep strength. The materials are very anisotropic in properties, but are successfully used in turbine blades and could be useful in other special applications

  17. Pseudohyperaldosteronism: pathogenetic mechanisms.

    Science.gov (United States)

    Armanini, Decio; Calò, Lorenzo; Semplicini, Andrea

    2003-06-01

    Pseudohyperaldosteronism is characterized by a clinical picture of hyperaldosteronism with suppression of plasma renin activity and aldosterone. Pseudohyperaldosteronism can be due to a direct mineralocorticoid effect, as with desoxycorticosterone, fluorohydrocortisone, fluoroprednisolone, estrogens, and the ingestion of high amounts of glycyrrhetinic acid. A block of 11-hydroxysteroid-dehydrogenase type 2 (11HSD2), the enzyme that converts cortisol into cortisone, at the level of epithelial target tissues of aldosterone, is involved in other cases. This mechanism is related either to a mutation of the gene, which encodes 11HSD2 (apparent mineralocorticoid excess syndrome and some cases of low renin hypertension) or to an acquired reduction of the activity of the enzyme due to glycyrrhetinic acid, carbenoxolone, and grapefruit juice. In other cases saturation of 11HSD2 may be involved as in severe Cushing's syndrome and chronic therapy with some corticosteroids. Recently, an activating mutation of the mineralocorticoid receptor gene has been described. Another genetic cause of pseudohyperaldosteronism is the syndrome of Liddle, which is due to a mutation of the gene encoding for beta and gamma subunits of the sodium channels. PMID:12892318

  18. Topics in statistical mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Elser, V.

    1984-05-01

    This thesis deals with four independent topics in statistical mechanics: (1) the dimer problem is solved exactly for a hexagonal lattice with general boundary using a known generating function from the theory of partitions. It is shown that the leading term in the entropy depends on the shape of the boundary; (2) continuum models of percolation and self-avoiding walks are introduced with the property that their series expansions are sums over linear graphs with intrinsic combinatorial weights and explicit dimension dependence; (3) a constrained SOS model is used to describe the edge of a simple cubic crystal. Low and high temperature results are derived as well as the detailed behavior near the crystal facet; (4) the microscopic model of the lambda-transition involving atomic permutation cycles is reexamined. In particular, a new derivation of the two-component field theory model of the critical behavior is presented. Results for a lattice model originally proposed by Kikuchi are extended with a high temperature series expansion and Monte Carlo simulation. 30 references.

  19. On the ENSO Mechanisms

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The El Nino-Southern Oscillation (ENSO) is an interannual phenomenon involved in the tropical Paci fic Ocean-atmosphere interactions. The oscillatory nature of ENSO requires both positive and negative ocean-atmosphere feedbacks. The positive feedback is dated back to Bjerknes' hypothesis in the 1960s, and different negative feedbacks have been proposed since the 1980s associated with the delayed oscillator, the western Pacific oscillator, the recharge-discharge oscillator, and the advective-reflective oscillator. The de layed oscillator assumes that wave reflection at the western boundary provides a negative feedback for the coupled system to oscillate. The western Pacific oscillator emphasizes equatorial wind in the western Pacific that provides a negative feedback for the coupled system. The recharge-discharge oscillator argues that discharge and recharge of equatorial heat content cause the coupled system to oscillate. The advective-re flective oscillator emphasizes the importance of zonal advection associated with wave reflection at both the western and eastern boundaries. All of these physics are summarized in a unified ENSO oscillator. The de layed oscillator, the western Pacific oscillator, the recharge-discharge oscillator, and the advective-reflec tive oscillator can be extracted as special cases of the unified oscillator. As suggested by this unified oscillator, all of the previous ENSO oscillator mechanisms may be operating in nature.

  20. Mechanics of the animate.

    Science.gov (United States)

    Killeen, P R

    1992-05-01

    Behavior is treated as basic physics. Dimensions are identified and their transformations from physical specification to axes in behavioral space are suggested. Responses are treated as action patterns arrayed along a continuum of activation energy. Behavior is seen as movement along a trajectory through this behavior space. Incentives or reinforcers are attractors in behavior space, at the centers of basins of lowered potential. Trajectories impinging on such basins may be captured; repeated capture will warp the trajectory toward a geodesic, a process called conditioning. Conditioning is enhanced by contiguity, the proximity between the measured behavior and the incentive at the end of the trajectory, and by contingency, the depth of the trajectory below the average level of the potential energy landscape. Motivation is seen as the potential of an organism for motion under the forces impinging on it. Degree of motivation is characterized by the depth of the potential field, with low motivation corresponding to a flat field and a flat gradient of activation energy. Drives are the forces of incentives propagated through behavior space. Different laws for the attenuation of drive with behavioral distance are discussed, as is the dynamics of action. The basic postulate of behavior mechanics is incentive-tracking in behavior space, the energy for which is provided by decreases in potential. The relation of temporal gradients to response differentiation and temporal discrimination is analyzed. Various two-body problems are sketched to illustrate the application of these ideas to association, choice, scalar timing, self-control, and freedom. PMID:1602272

  1. Warp Field Mechanics 101

    Science.gov (United States)

    White, H.

    This paper will begin with a short review of the Alcubierre warp drive metric and describes how the phenomenon might work based on the original paper. The canonical form of the metric was developed and published in [6] which provided key insight into the field potential and boost for the field which remedied a critical paradox in the original Alcubierre concept of operations. A modified concept of operations based on the canonical form of the metric that remedies the paradox is presented and discussed. The idea of a warp drive in higher dimensional space-time (manifold) will then be briefly considered by comparing the null-like geodesics of the Alcubierre metric to the Chung-Freese metric to illustrate the mathematical role of hyperspace coordinates. The net effect of using a warp drive "technology" coupled with conventional propulsion systems on an exploration mission will be discussed using the nomenclature of early mission planning. Finally, an overview of the warp field interferometer test bed being implemented in the Advanced Propulsion Physics Laboratory: Eagleworks (APPL:E) at the Johnson Space Center will be detailed. While warp field mechanics has not had a "Chicago Pile" moment, the tools necessary to detect a modest instance of the phenomenon are near at hand.

  2. Quantum mechanics of leptogenesis

    International Nuclear Information System (INIS)

    Leptogenesis is an attractive mechanism that simultaneously explains the matterantimatter asymmetry of the universe as well as the small masses of the standard model neutrinos. This is performed by naturally extending the standard model with the insertion of right handed neutrinos. Leptogenesis is usually studied via the semi-classical Boltzmann equations. However, these equations suffer from basic conceptual problems and they lack to include many quantum phenomena, such as memory effects and coherence oscillations. In order to fully describe leptogenesis, a full quantum treatment is required. In this work we show how to address leptogenesis systematically in a purely quantum way. We start by studying scalar and fermionic excitations in a plasma by solving the Kadanoff-Baym equations of motion for Green's functions, with significant emphasis on the initial and boundary conditions of the solutions. We compute analytically the asymmetry generated from the departure of equilibrium of a particle in a thermal bath. The comparison with the semi-classical Boltzmann approach is also analysed, leading to a qualitative difference between both methods. The non-locality of the Kadanoff-Baym equations shows how off-shell effects can have a huge impact on the generated asymmetry, effects that cannot be studied with the Boltzmann equations. The insertion of standard model interactions like the decay widths for the particles of the bath is also discussed. We explain how with a trivial insertion of these widths we regain locality on the processes, i.e. we regain the Boltzmann equations. (orig.)

  3. Respiratory Fluid Mechanics

    Science.gov (United States)

    Grotberg, James

    2005-11-01

    This brief overview of our groups activities includes liquid plug propagation in single and bifurcating tubes, a subject which pertains to surfactant delivery, liquid ventilation, pulmonary edema, and drowning. As the plug propagates, a variety of flow patterns may emerge depending on the parameters. It splits unevenly at airway bifurcations and can rupture, which reopens the airway to gas flow. Both propagation and rupture may damage the underlying airway wall cells. Another topic is surfactant dynamics and flow in a model of an oscillating alveolus. The analysis shows a nontrivial cycle-averaged surfactant concentration gradient along the interface that generates steady streaming. The steady streaming patterns particularly depend on the ratio of inspiration to expiration time periods and the sorption parameter. Vortices, single and multiple, may be achieved, as well as a saddle point configuration. Potential applications are pulmonary drug administration, cell-cell signaling pathways, and gene therapy. Finally, capillary instabilities which cause airway closure, and strategies for stabilization, will be presented. This involves the core-annular flow of a liquid-lined tube, where the core (air) is forced to oscillate axially. The stabilization mechanism is similar to that of a reversing butter knife, where the core shear wipes the growing liquid bulge, from the Rayleigh instability, back on to the tube wall during the main tidal volume stroke, but allows it to grow back as the stroke and shear turn around.

  4. Topics in statistical mechanics

    International Nuclear Information System (INIS)

    This thesis deals with four independent topics in statistical mechanics: (1) the dimer problem is solved exactly for a hexagonal lattice with general boundary using a known generating function from the theory of partitions. It is shown that the leading term in the entropy depends on the shape of the boundary; (2) continuum models of percolation and self-avoiding walks are introduced with the property that their series expansions are sums over linear graphs with intrinsic combinatorial weights and explicit dimension dependence; (3) a constrained SOS model is used to describe the edge of a simple cubic crystal. Low and high temperature results are derived as well as the detailed behavior near the crystal facet; (4) the microscopic model of the lambda-transition involving atomic permutation cycles is reexamined. In particular, a new derivation of the two-component field theory model of the critical behavior is presented. Results for a lattice model originally proposed by Kikuchi are extended with a high temperature series expansion and Monte Carlo simulation. 30 references

  5. Quantum mechanics over sets

    Science.gov (United States)

    Ellerman, David

    2014-03-01

    In models of QM over finite fields (e.g., Schumacher's ``modal quantum theory'' MQT), one finite field stands out, Z2, since Z2 vectors represent sets. QM (finite-dimensional) mathematics can be transported to sets resulting in quantum mechanics over sets or QM/sets. This gives a full probability calculus (unlike MQT with only zero-one modalities) that leads to a fulsome theory of QM/sets including ``logical'' models of the double-slit experiment, Bell's Theorem, QIT, and QC. In QC over Z2 (where gates are non-singular matrices as in MQT), a simple quantum algorithm (one gate plus one function evaluation) solves the Parity SAT problem (finding the parity of the sum of all values of an n-ary Boolean function). Classically, the Parity SAT problem requires 2n function evaluations in contrast to the one function evaluation required in the quantum algorithm. This is quantum speedup but with all the calculations over Z2 just like classical computing. This shows definitively that the source of quantum speedup is not in the greater power of computing over the complex numbers, and confirms the idea that the source is in superposition.

  6. Fluid mechanics. Vol. 2

    International Nuclear Information System (INIS)

    The second volume contains the chapter 4 to 6. Whereas chapter 1 deals with the introduction into the mechanics of fluids and chapter 2 with the fundamental laws of fluid and thermal fluid dynamics, in chapter 3 elementary flow phenomena in fluids with constant density are treated. Chapter 4 directly continues chapter 3 and describes elementary flow phenomena in fluids with varying density. Fluid statics again is treated as a special case. If compared with the first edition the treatment of unsteady laminar flow and of pipe flow for a fluid with varying density were subject to a substantial extension. In chapter 5 rotation-free and rotating potential flows are presented together. By this means it is achieved to explain the behaviour of the multidimensional fictionless flow in closed form. A subchapter describes some related problems of potential theory like the flow along a free streamline and seepage flow through a porous medium. The boundary layer flows in chapter 6 are concerned with the flow and temperature boundary layer in laminar and turbulent flows at a fired wall. In it differential and integral methods are applied of subchapter reports on boundary layer flows without a fixed boundary, occurring e.g. in an open jet and in a wake flow. The problems of intermittence and of the Coanda effect are briefly mentioned. (orig./MH)

  7. Quantum mechanics of leptogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Mendizabal Cofre, Sebastian

    2010-08-15

    Leptogenesis is an attractive mechanism that simultaneously explains the matterantimatter asymmetry of the universe as well as the small masses of the standard model neutrinos. This is performed by naturally extending the standard model with the insertion of right handed neutrinos. Leptogenesis is usually studied via the semi-classical Boltzmann equations. However, these equations suffer from basic conceptual problems and they lack to include many quantum phenomena, such as memory effects and coherence oscillations. In order to fully describe leptogenesis, a full quantum treatment is required. In this work we show how to address leptogenesis systematically in a purely quantum way. We start by studying scalar and fermionic excitations in a plasma by solving the Kadanoff-Baym equations of motion for Green's functions, with significant emphasis on the initial and boundary conditions of the solutions. We compute analytically the asymmetry generated from the departure of equilibrium of a particle in a thermal bath. The comparison with the semi-classical Boltzmann approach is also analysed, leading to a qualitative difference between both methods. The non-locality of the Kadanoff-Baym equations shows how off-shell effects can have a huge impact on the generated asymmetry, effects that cannot be studied with the Boltzmann equations. The insertion of standard model interactions like the decay widths for the particles of the bath is also discussed. We explain how with a trivial insertion of these widths we regain locality on the processes, i.e. we regain the Boltzmann equations. (orig.)

  8. Mechanical properties of ceramics

    CERN Document Server

    Pelleg, Joshua

    2014-01-01

    This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work.  Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated technique...

  9. Ecological transfer mechanisms - Terrestrial

    International Nuclear Information System (INIS)

    Radionuclides produced by nuclear excavation detonations and released to the environment may enter a variety of biogeochemical cycles and follow essentially the same transfer pathways as their stable-element counterparts. Estimation of potential internal radiation doses to individuals and/or populations living in or near fallout-contaminated areas requires analysis of the food-chain and other ecological pathways by which radionuclides released to the environment may be returned to man. A generalized materials transfer diagram, applicable to the forest, agricultural, freshwater and marine ecosystems providing food and water to the indigenous population of Panama and Colombia in regions that could be affected by nuclear excavation of a sea-level canal between the Atlantic and Pacific Oceans, is presented. Transfer mechanisms effecting the movement of stable elements and radionuclides in terrestrial ecosystems are discussed, and methods used to simulate these processes by means of mathematical models are described to show how intake values are calculated for different radionuclides in the major ecological pathways leading to man. These data provide a basis for estimating potential internal radiation doses for comparison with the radiation protection criteria established by recognized authorities; and this, in turn, provides a basis for recommending measures to insure the radiological safety of the nuclear operation plan. (author)

  10. Warp Field Mechanics 101

    Science.gov (United States)

    White, Harold

    2011-01-01

    This paper will begin with a short review of the Alcubierre warp drive metric and describes how the phenomenon might work based on the original paper. The canonical form of the metric was developed and published in [6] which provided key insight into the field potential and boost for the field which remedied a critical paradox in the original Alcubierre concept of operations. A modified concept of operations based on the canonical form of the metric that remedies the paradox is presented and discussed. The idea of a warp drive in higher dimensional space-time (manifold) will then be briefly considered by comparing the null-like geodesics of the Alcubierre metric to the Chung-Freese metric to illustrate the mathematical role of hyperspace coordinates. The net effect of using a warp drive technology coupled with conventional propulsion systems on an exploration mission will be discussed using the nomenclature of early mission planning. Finally, an overview of the warp field interferometer test bed being implemented in the Advanced Propulsion Physics Laboratory: Eagleworks (APPL:E) at the Johnson Space Center will be detailed. While warp field mechanics has not had a Chicago Pile moment, the tools necessary to detect a modest instance of the phenomenon are near at hand.

  11. Mechanical Impedance of Cerebral Material

    Directory of Open Access Journals (Sweden)

    Hédi Ben Ghozlen

    2012-03-01

    Full Text Available The tentative variation of the mechanical impedance, of a cylindrical sample of cerebral material, has been achieved by Vibrometer Laser according to the frequency. The studied matter is supposed homogeneous, isotropic and stationary. A multilayered mechanical model has been associated to the studied sample to simulate its vibration. The theoretical expression of mechanical impedance has been determined while taking the mechanical/electric analogy as a basis. A good adjustment of theoretical model parameters permitted us to have a good agreement theory/experience of the mechanical impedance variation according to the sample vibration frequency.

  12. DYNAMIC MODELING OF METAMORPHIC MECHANISM

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The concept of metamorphic mechanism is put forward according to the change of configurations from one state to another. Different configurations of metamorphic mechanism are described through the method of Huston lower body arrays. Kinematics analyses for metamorphic mechanism with generalized topological structure, including the velocity, angular velocity, acceleration and angular acceleration, are given. Dynamic equations for an arbitrary configuration, including close-loop constraints, are formed by using Kane's equations. For an arbitrary metamorphic mechanism, the transformation matrix of generalized speeds between configuration (*)and(*)+1 is obtained for the first time. Furthermore, configuration-complete dynamic modeling of metamorphic mechanism including all configurations is completely established.

  13. Theoretical physics 2 analytical mechanics

    CERN Document Server

    Nolting, Wolfgang

    2016-01-01

    This textbook offers a clear and comprehensive introduction to analytical mechanics, one of the core components of undergraduate physics courses.It follows on naturally from the previous volumes in this series, thus expanding the knowledge in classical mechanics. The book starts with a thorough introduction into Lagrangian mechanics, detailing the d’Alembert principle, Hamilton’s principle and conservation laws. It continues with an in-depth explanation of Hamiltonian mechanics, illustrated by canonical and Legendre transformation, the generalization to quantum mechanics through Poisson brackets and all relevant variational principles. Finally, the Hamilton-Jacobi theory and the transition to wave mechanics are presented in detail. Ideally suited to undergraduate students with some grounding in classical mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by ...

  14. The Mechanism of Dishabituation

    Directory of Open Access Journals (Sweden)

    Genevieve Z. Steiner

    2014-02-01

    Full Text Available The dual-process theory of habituation attributes dishabituation, an increase in responding to a habituated stimulus after an interpolated deviant, to sensitisation, a change in arousal. Our previous investigations into elicitation and habituation of the electrodermal Orienting Reflex (OR showed that dishabituation is independent of sensitisation for indifferent stimuli, arguing against dual-process theory’s explanation. However, this could not be tested for significant stimuli in that study, because sensitisation was confounded with incomplete resolution of the preceding OR. This study aimed to clarify the mechanism of dishabituation for significant stimuli by extending the stimulus onset asynchrony (SOA beyond the time required for the phasic response to resolve. Participants completed an auditory dishabituation task with a random SOA of 13-15 s while their electrodermal activity was recorded. The stimulus sequence was 10 standards, 1 deviant, 2-4 standards; counterbalanced innocuous tones. Two counterbalanced conditions were used: silently count all stimuli (significant and no task (indifferent. Skin conductance responses (SCRs and pre-stimulus skin conductance levels (SCLs both decremented over trials 1-10. In both conditions, SCRs showed response recovery and dishabituation, indicating habituation, and post-deviant SCL sensitisation was apparent. Across all trials, phasic ORs were dependent on the pre-stimulus SCL (arousal level; this did not differ with condition. Importantly, dishabituation was independent of sensitisation for both conditions. Findings indicate that sensitisation, the change in state, is a process separate from phasic response resolution, and that arousal consistently predicts OR magnitude, including the dishabituation response. This argues against dual-process theory’s explanation, and instead suggests that dishabituation is a disruption of the habituation process, with magnitude determined by the current arousal

  15. Remote mechanical C line

    International Nuclear Information System (INIS)

    Westinghouse Hanford Company is developing a desk-top simulation based training program on the operation of the Remote Mechanical C (RMC) Line process in the Plutonium Finishing Plant on the Hanford site, Richland, Washington. Simulations display aod contioually update current values of system parameters on computer graphics of RMC line equipment. Students are able to operate a variety of controllers to maintain proper system status. Programmed faults, selectable by the course instructor, can be used to test student responses to off-normal events. Prior to operation of the simulation, students are given computer-based tutorials on the function, processes, operation, and error conditions associated with individual components. By including the capability of operating each individual component - valves, heaters, agitators, etc. - the computer-based training (CBT) lessons become an interactive training manual. From one perspective RMC represents one step in the diffusion of the well-known and well-documented simulator training activities for nuclear reactor operators to other training programs, equally critical, perhaps, but less well scrutinized in the past. Because of the slowly responding nature of the actual process, RMC can retain many of the capabilities of practice and testing in a simulated work environment while avoiding the cost of a full scale simulator and the exposure and waste developed by practice runs of the RMC line. From another perspective RMC suggests training advances even beyond the most faithful simulators. For example, by integrating CBT lessons with the simulation, RMC permits students to focus in on specific processes occurring inside chosen components. In effect, the interactive training manual is available on-line with the simulation itself. Cost are also discussed

  16. Remarks on the conservation of mechanical energy in introductory mechanics

    OpenAIRE

    Santos, F C; Soares, V.; Tort, A C

    2005-01-01

    We discuss the work-kinetic energy theorem and the mechanical energy conservation theorem in the context of general physics courses. The motivation is the fact that all modern texts on introductory mechanics show the same conceptually dangerous statement that besides obliterating the concept of mechanical work, diminishing the importance of the work-kinetic energy theorem, leads to erroneous applications of the energy conservation theorem and at the same eliminates its relationship with the p...

  17. Analogies between classical statistical mechanics and quantum mechanics

    International Nuclear Information System (INIS)

    Some analogies between nonequilibrium classical statistical mechanics and quantum mechanics, at the level of the Liouville equation and at the kinetic level, are commented on. A theorem, related to the Vlasov equation applied to a plasma, is proved. The theorem presents an analogy with Ehrenfest's theorem of quantum mechanics. An analogy between the plasma kinetic theory and Bohm's quantum theory with 'hidden variables' is also shown. (Author)

  18. $PT$-symmetric quantum mechanics is a Hermitian quantum mechanics

    OpenAIRE

    Lee, Sungwook

    2013-01-01

    The author discusses a different kind of Hermitian quantum mechanics, called $J$-Hermitian quantum mechanics. He shows that $PT$-symmetric quantum mechanics is indeed $J$-Hermitian quantum mechanics, and that time evolution (in the Krein space of states) is unitary if and only if Hamiltonian is $J$-Hermitian (or equivalently $PT$-symmetric). An issue with unitarity comes up when time evolution is considered in the Hilbert space of states rather than in the Krein space of states. The author of...

  19. Molecular Electrical Doping of Organic Semiconductors: Fundamental Mechanisms and Emerging Dopant Design Rules.

    Science.gov (United States)

    Salzmann, Ingo; Heimel, Georg; Oehzelt, Martin; Winkler, Stefanie; Koch, Norbert

    2016-03-15

    Today's information society depends on our ability to controllably dope inorganic semiconductors, such as silicon, thereby tuning their electrical properties to application-specific demands. For optoelectronic devices, organic semiconductors, that is, conjugated polymers and molecules, have emerged as superior alternative owing to the ease of tuning their optical gap through chemical variability and their potential for low-cost, large-area processing on flexible substrates. There, the potential of molecular electrical doping for improving the performance of, for example, organic light-emitting devices or organic solar cells has only recently been established. The doping efficiency, however, remains conspicuously low, highlighting the fact that the underlying mechanisms of molecular doping in organic semiconductors are only little understood compared with their inorganic counterparts. Here, we review the broad range of phenomena observed upon molecularly doping organic semiconductors and identify two distinctly different scenarios: the pairwise formation of both organic semiconductor and dopant ions on one hand and the emergence of ground state charge transfer complexes between organic semiconductor and dopant through supramolecular hybridization of their respective frontier molecular orbitals on the other hand. Evidence for the occurrence of these two scenarios is subsequently discussed on the basis of the characteristic and strikingly different signatures of the individual species involved in the respective doping processes in a variety of spectroscopic techniques. The critical importance of a statistical view of doping, rather than a bimolecular picture, is then highlighted by employing numerical simulations, which reveal one of the main differences between inorganic and organic semiconductors to be their respective density of electronic states and the doping induced changes thereof. Engineering the density of states of doped organic semiconductors, the Fermi

  20. Fluid mechanics fundamentals and applications

    CERN Document Server

    Cengel, Yunus

    2013-01-01

    Cengel and Cimbala's Fluid Mechanics Fundamentals and Applications, communicates directly with tomorrow's engineers in a simple yet precise manner. The text covers the basic principles and equations of fluid mechanics in the context of numerous and diverse real-world engineering examples. The text helps students develop an intuitive understanding of fluid mechanics by emphasizing the physics, using figures, numerous photographs and visual aids to reinforce the physics. The highly visual approach enhances the learning of Fluid mechanics by students. This text distinguishes itself from others by the way the material is presented - in a progressive order from simple to more difficult, building each chapter upon foundations laid down in previous chapters. In this way, even the traditionally challenging aspects of fluid mechanics can be learned effectively. McGraw-Hill is also proud to offer ConnectPlus powered by Maple with the third edition of Cengel/Cimbabla, Fluid Mechanics. This innovative and powerful new sy...

  1. Nonequilibrium Statistical Mechanics in One Dimension

    Science.gov (United States)

    Privman, Vladimir

    2005-08-01

    Part I. Reaction-Diffusion Systems and Models of Catalysis; 1. Scaling theories of diffusion-controlled and ballistically-controlled bimolecular reactions S. Redner; 2. The coalescence process, A+A->A, and the method of interparticle distribution functions D. ben-Avraham; 3. Critical phenomena at absorbing states R. Dickman; Part II. Kinetic Ising Models; 4. Kinetic ising models with competing dynamics: mappings, correlations, steady states, and phase transitions Z. Racz; 5. Glauber dynamics of the ising model N. Ito; 6. 1D Kinetic ising models at low temperatures - critical dynamics, domain growth, and freezing S. Cornell; Part III. Ordering, Coagulation, Phase Separation; 7. Phase-ordering dynamics in one dimension A. J. Bray; 8. Phase separation, cluster growth, and reaction kinetics in models with synchronous dynamics V. Privman; 9. Stochastic models of aggregation with injection H. Takayasu and M. Takayasu; Part IV. Random Sequential Adsorption and Relaxation Processes; 10. Random and cooperative sequential adsorption: exactly solvable problems on 1D lattices, continuum limits, and 2D extensions J. W. Evans; 11. Lattice models of irreversible adsorption and diffusion P. Nielaba; 12. Deposition-evaporation dynamics: jamming, conservation laws and dynamical diversity M. Barma; Part V. Fluctuations In Particle and Surface Systems; 13. Microscopic models of macroscopic shocks S. A. Janowsky and J. L. Lebowitz; 14. The asymmetric exclusion model: exact results through a matrix approach B. Derrida and M. R. Evans; 15. Nonequilibrium surface dynamics with volume conservation J. Krug; 16. Directed walks models of polymers and wetting J. Yeomans; Part VI. Diffusion and Transport In One Dimension; 17. Some recent exact solutions of the Fokker-Planck equation H. L. Frisch; 18. Random walks, resonance, and ratchets C. R. Doering and T. C. Elston; 19. One-dimensional random walks in random environment K. Ziegler; Part VII. Experimental Results; 20. Diffusion

  2. Mechanics in Steels through Microscopy

    OpenAIRE

    Tirumalasetty, G.K.

    2013-01-01

    The goal of the study consolidated in this thesis is to understand the mechanics in steels using microscopy. In particular, the mechanical response of Transformation Induced Plasticity (TRIP) steels is correlated with their microstructures. Chapter 1 introduces the current state of the art of TRIP steels, highlighting the importance of microstructure - mechanical properties - applications relationships. In Chapter 2 the material properties and material processing are described into more detai...

  3. Biocontrol mechanisms of Thrichoderma strains

    OpenAIRE

    Benítez Fernández, Concepción Tahía; Rincón Romero, Ana María; Limón Mirón, María del Carmen; Carballo Codón, Antonio

    2004-01-01

    The genus Trichoderma comprises a great number of fungal strains that act as biological control agents, the antagonistic properties of which are based on the activation of multiple mechanisms. Trichoderma strains exert biocontrol against fungal phytopathogens either indirectly, by competing for nutrients and space, modifying the environmental conditions, or promoting plant growth and plant defensive mechanisms and antibiosis, or directly, by mechanisms such as mycoparasitism. These indirect a...

  4. Mechanical ventilation in neurosurgical patients

    Directory of Open Access Journals (Sweden)

    Keshav Goyal

    2013-01-01

    Full Text Available Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical patient requiring artificial support of the respiration.

  5. Statistical Mechanics of Nonequilbrium Liquids

    OpenAIRE

    Morriss, Gary P.; Evans, Denis J.

    2007-01-01

    During the 1980’s there were many developments regarding the nonequilibrium statistical mechanics of dense classical atomic fluids. These developments have had a major impact on the computer simulation methods used to model nonequilibrium fluids. The present volume is, in part, an attempt to provide a pedagogical discussion of the statistical mechanical justification of these algorithms. There is a symbiotic relationship between theoretical nonequilibrium statistical mechanics on the one ...

  6. Mechanical ventilation in neurosurgical patients

    OpenAIRE

    Keshav Goyal; Ranadhir Mitra; Shweta Kedia

    2013-01-01

    Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical pa...

  7. Microscopic mechanism for cold denaturation

    OpenAIRE

    Dias, CL; Ala-Nissila, T.; Karttunen, MEJ Mikko; Vattulainen, I.; Grant, M.

    2008-01-01

    We elucidate the mechanism of cold denaturation through constant-pressure simulations for a model of hydrophobic molecules in an explicit solvent. We find that the temperature dependence of the hydrophobic effect induces, facilitates, and is the driving force for cold denaturation. The physical mechanism underlying this phenomenon is identified as the destabilization of hydrophobic contact in favor of solvent-separated configurations, the same mechanism seen in pressure-induced denaturation. ...

  8. A textbook of quantum mechanics

    International Nuclear Information System (INIS)

    After briefly surveying the inadequacy of the classical ideas and elementary older quantum theory, the ideas of wave mechanics, the postulates of quantum mechanics, exactly soluble problems, approximation techniques, scattering theory, angular momentum, time dependent problems and the basic ideas of relativistic quantum mechanics are discussed. The book is meant for the Master of Science degree course students of Indian Universities. (M.G.B.)

  9. Quantum Mechanics in the Infrared

    CERN Document Server

    Radicevic, Djordje

    2016-01-01

    This paper presents an algebraic formulation of the renormalization group flow in quantum mechanics on flat target spaces. For any interacting quantum mechanical theory, the fixed point of this flow is a theory of classical probability, not a different effective quantum mechanics. Each energy eigenstate of the UV Hamiltonian flows to a probability distribution whose entropy is a natural diagnostic of quantum ergodicity of the original state. These conclusions are supported by various examples worked out in detail.

  10. Gamification of Quantum Mechanics Teaching

    CERN Document Server

    Bjælde, Ole Eggers; Sherson, Jacob

    2015-01-01

    In this small scale study we demonstrate how a gamified teaching setup can be used effectively to support student learning in a quantum mechanics course. The quantum mechanics games were research games, which were played during lectures and the learning was measured with a pretest/posttest method with promising results. The study works as a pilot study to guide the planning of quantum mechanics courses in the future at Aarhus University in Denmark.

  11. Learn new mechanisms from life

    International Nuclear Information System (INIS)

    On the basis of the important experimental results of molecular motors, it was pointed out that the moving process of molecular motors is a coupling biological process of chemical-electrical-mechanical processes. This clever mechanism of energy conversion on the molecular level with several processes coupled together had never been observed before. The understanding of this new mechanism is an important step towards the understanding of life and an important content of what we can learn from life. The authors introduced here the status of the investigations on the mechanism for the force generation of kinesin and the studies of the authors in this field. (authors)

  12. Focal mechanism estimation by classification

    CERN Document Server

    Lasscock, Ben G; Glinsky, Michael E

    2014-01-01

    A classification technique for identifying focal mechanism type and fault plane orientation based on the polarity of P-wave "first motion" data is derived. A support vector machine is used to classify the polarity data in the space of spherical harmonic functions. The classification is non-parametric in the sense that there is no requirement to make a priori assumptions source mechanism. A metric of similarity potentially able to distinguish shear versus tensile dislocation without requiring estimation of the fault plane orientation is a natural consequence of this procedure. Going further, correlation functions between template source mechanism is derived, gives an estimate of fault plane orientation assuming a particular source mechanism.

  13. Mechanisms of HSP72 release

    Indian Academy of Sciences (India)

    Alexzander Asea

    2007-04-01

    Currently two mechanisms are recognized by which heat shock proteins (HSP) are released from cells; a passive release mechanism, including necrotic cell death, severe blunt trauma, surgery and following infection with lytic viruses, and an active release mechanism which involves the non classical protein release pathway. HSPs are released both as free HSP and within exosomes. This review covers recent findings on the mechanism by which stress induces the release of HSP72 into the circulation and the biological significance of circulating HSP72 to host defense against disease.

  14. Statistical mechanics in a nutshell

    CERN Document Server

    Peliti, Luca

    2011-01-01

    Statistical mechanics is one of the most exciting areas of physics today, and it also has applications to subjects as diverse as economics, social behavior, algorithmic theory, and evolutionary biology. Statistical Mechanics in a Nutshell offers the most concise, self-contained introduction to this rapidly developing field. Requiring only a background in elementary calculus and elementary mechanics, this book starts with the basics, introduces the most important developments in classical statistical mechanics over the last thirty years, and guides readers to the very threshold of today

  15. Mathematical foundations of quantum mechanics

    CERN Document Server

    Mackey, George W

    2004-01-01

    Designed for students familiar with abstract mathematical concepts but possessing little knowledge of physics, this text focuses on generality and careful formulation rather than problem-solving. Its author, a member of the distinguished National Academy of Science, based this graduate-level text on the course he taught at Harvard University.Opening chapters on classical mechanics examine the laws of particle mechanics; generalized coordinates and differentiable manifolds; oscillations, waves, and Hilbert space; and statistical mechanics. A survey of quantum mechanics covers the old quantum

  16. Mechanics lectures on theoretical physics

    CERN Document Server

    Sommerfeld, Arnold Johannes Wilhelm

    1952-01-01

    Mechanics: Lectures on Theoretical Physics, Volume I covers a general course on theoretical physics. The book discusses the mechanics of a particle; the mechanics of systems; the principle of virtual work; and d'alembert's principle. The text also describes oscillation problems; the kinematics, statics, and dynamics of a rigid body; the theory of relative motion; and the integral variational principles of mechanics. Lagrange's equations for generalized coordinates and the theory of Hamilton are also considered. Physicists, mathematicians, and students taking Physics courses will find the book

  17. Novel mechanisms in functional dyspepsia

    Institute of Scientific and Technical Information of China (English)

    Rok Son Choung; Nicholas J Talley

    2006-01-01

    Functional dyspepsia (FD) is a highly prevalent but heterogeneous disorder in which multiple pathogenetic mechanisms are involved. Although there are many studies that have investigated various pathophysiologic mechanisms, the underlying casual pathways associated with FD remain obscure. The currently proposed pathophysiologic mechanisms associated with FD include genetic susceptibility, delayed as well as accelerated gastric emptying, visceral hypersensitivity to acid or mechanical distention, impaired gastric accommodation,abnormal fundic phasic contractions, abnormal antroduodenal motility, acute and chronic infections, and psychosocial comorbidity. A greater understanding of the abnormalities underlying FD may lead to improved management. The aim of this editorial is to provide a critical overview of current pathophysiologic concepts in functional dyspepsia.

  18. Mechanical behavior of steels: from fundamental mechanisms to macroscopic deformation

    OpenAIRE

    Allain, Sebastien

    2014-01-01

    My scientific activities aim at understand and predict the mechanical behaviour of steels, from fundamental mechanisms to macroscopic deformation. This manuscript is dedicated to the TWIP effect (TWinning Induced Plasticity) of high manganese austenitic steels and DP effect (Dual-Phase) in more conventional Ferrite-Martensite steels.

  19. Teaching Psychological Defense Mechanisms: "The Defense Mechanisms Game."

    Science.gov (United States)

    Waugh, Charles G.

    1980-01-01

    Presents the rules for an educational game in which students reinforce psychology lecture material by creating and dramatizing defense mechanisms such as reaction formation, displacement, and fantasy. Provides definitions and examples of the various defense mechanisms that can be portrayed. (JP)

  20. Mechanical Behaviour of Materials Volume II Fracture Mechanics and Damage

    CERN Document Server

    François, Dominique; Zaoui, André

    2013-01-01

    Designing new structural materials, extending lifetimes and guarding against fracture in service are among the preoccupations of engineers, and to deal with these they need to have command of the mechanics of material behaviour. This ought to reflect in the training of students. In this respect, the first volume of this work deals with elastic, elastoplastic, elastoviscoplastic and viscoelastic behaviours; this second volume continues with fracture mechanics and damage, and with contact mechanics, friction and wear. As in Volume I, the treatment links the active mechanisms on the microscopic scale and the laws of macroscopic behaviour. Chapter I is an introduction to the various damage phenomena. Chapter II gives the essential of fracture mechanics. Chapter III is devoted to brittle fracture, chapter IV to ductile fracture and chapter V to the brittle-ductile transition. Chapter VI is a survey of fatigue damage. Chapter VII is devoted to hydogen embrittlement and to environment assisted cracking, chapter VIII...