Insight into the kinetics and thermodynamics of the hydride transfer reactions between quinones and lumiflavin: a density functional theory study.

PubMed

Reinhardt, Clorice R; Jaglinski, Tanner C; Kastenschmidt, Ashly M; Song, Eun H; Gross, Adam K; Krause, Alyssa J; Gollmar, Jonathan M; Meise, Kristin J; Stenerson, Zachary S; Weibel, Tyler J; Dison, Andrew; Finnegan, Mackenzie R; Griesi, Daniel S; Heltne, Michael D; Hughes, Tom G; Hunt, Connor D; Jansen, Kayla A; Xiong, Adam H; Hati, Sanchita; Bhattacharyya, Sudeep

2016-09-01

The kinetics and equilibrium of the hydride transfer reaction between lumiflavin and a number of substituted quinones was studied using density functional theory. The impact of electron withdrawing/donating substituents on the redox potentials of quinones was studied. In addition, the role of these substituents on the kinetics of the hydride transfer reaction with lumiflavin was investigated in detail under the transition state (TS) theory assumption. The hydride transfer reactions were found to be more favorable for an electron-withdrawing substituent. The activation barrier exhibited a quadratic relationship with the driving force of these reactions as derived under the formalism of modified Marcus theory. The present study found a significant extent of electron delocalization in the TS that is stabilized by enhanced electrostatic, polarization, and exchange interactions. Analysis of geometry, bond-orders, and energetics revealed a predominant parallel (Leffler-Hammond) effect on the TS. Closer scrutiny reveals that electron-withdrawing substituents, although located on the acceptor ring, reduce the N-H bond order of the donor fragment in the precursor complex. Carried out in the gas-phase, this is the first ever report of a theoretical study of flavin's hydride transfer reactions with quinones, providing an unfiltered view of the electronic effect on the nuclear reorganization of donor-acceptor complexes.

Parents' experiences of neonatal transfer. A meta-study of qualitative research 2000-2017.

PubMed

Aagaard, Hanne; Hall, Elisabeth O C; Ludvigsen, Mette S; Uhrenfeldt, Lisbeth; Fegran, Liv

2018-02-15

Transfers of critically ill neonates are frequent phenomena. Even though parents' participation is regarded as crucial in neonatal care, a transfer often means that parents and neonates are separated. A systematic review of the parents' experiences of neonatal transfer is lacking. This paper describes a meta-study addressing qualitative research about parents' experiences of neonatal transfer. Through deconstruction and reflections of theories, methods, and empirical data, the aim was to achieve a deeper understanding of theoretical, empirical, contextual, historical, and methodological issues of qualitative studies concerning parents' experiences of neonatal transfer over the course of this meta-study (2000-2017). Meta-theory and meta-method analyses showed that caring, transition, and family-centered care were main theoretical frames applied and that interviewing with a small number of participants was the preferred data collection method. The meta-data-analysis showed that transfer was a scary, unfamiliar, and threatening experience for the parents; they were losing familiar context, were separated from their neonate, and could feel their parenthood disrupted. We identified 'wavering and wandering' as a metaphoric representation of the parents' experiences. The findings add knowledge about meta-study as an approach for comprehensive qualitative research and point at the value of meta-theory and meta-method analyses. © 2018 John Wiley & Sons Ltd.

Initialization of Formation Flying Using Primer Vector Theory

NASA Technical Reports Server (NTRS)

Mailhe, Laurie; Schiff, Conrad; Folta, David

2002-01-01

In this paper, we extend primer vector analysis to formation flying. Optimization of the classical rendezvous or free-time transfer problem between two orbits using primer vector theory has been extensively studied for one spacecraft. However, an increasing number of missions are now considering flying a set of spacecraft in close formation. Missions such as the Magnetospheric MultiScale (MMS) and Leonardo-BRDF (Bidirectional Reflectance Distribution Function) need to determine strategies to transfer each spacecraft from the common launch orbit to their respective operational orbit. In addition, all the spacecraft must synchronize their states so that they achieve the same desired formation geometry over each orbit. This periodicity requirement imposes constraints on the boundary conditions that can be used for the primer vector algorithm. In this work we explore the impact of the periodicity requirement in optimizing each spacecraft transfer trajectory using primer vector theory. We first present our adaptation of primer vector theory to formation flying. Using this method, we then compute the AV budget for each spacecraft subject to different formation endpoint constraints.

Did you have an impact? A theory-based method for planning and evaluating knowledge-transfer and exchange activities in occupational health and safety.

PubMed

Kramer, Desré M; Wells, Richard P; Carlan, Nicolette; Aversa, Theresa; Bigelow, Philip P; Dixon, Shane M; McMillan, Keith

2013-01-01

Few evaluation tools are available to assess knowledge-transfer and exchange interventions. The objective of this paper is to develop and demonstrate a theory-based knowledge-transfer and exchange method of evaluation (KEME) that synthesizes 3 theoretical frameworks: the promoting action on research implementation of health services (PARiHS) model, the transtheoretical model of change, and a model of knowledge use. It proposes a new term, keme, to mean a unit of evidence-based transferable knowledge. The usefulness of the evaluation method is demonstrated with 4 occupational health and safety knowledge transfer and exchange (KTE) implementation case studies that are based upon the analysis of over 50 pre-existing interviews. The usefulness of the evaluation model has enabled us to better understand stakeholder feedback, frame our interpretation, and perform a more comprehensive evaluation of the knowledge use outcomes of our KTE efforts.

The Mediating Role of Insight for Long-Term Improvements in Psychodynamic Therapy

ERIC Educational Resources Information Center

Johansson, Paul; Hoglend, Per; Ulberg, Randi; Amlo, Svein; Marble, Alice; Bogwald, Kjell-Petter; Sorbye, Oystein; Sjaastad, Mary Cosgrove; Heyerdahl, Oscar

2010-01-01

Objective: According to psychoanalytic theory, interpretation of transference leads to increased insight that again leads to improved interpersonal functioning over time. In this study, we performed a full mediational analysis to test whether insight gained during treatment mediates the long-term effects of transference interpretation in dynamic…

Transfer of Training: Adding Insight through Social Network Analysis

ERIC Educational Resources Information Center

Van den Bossche, Piet; Segers, Mien

2013-01-01

This article reviews studies which apply a social network perspective to examine transfer of training. The theory behind social networks focuses on the interpersonal mechanisms and social structures that exist among interacting units such as people within an organization. A premise of this perspective is that individual's behaviors and outcomes…

Lattice Methods and the Nuclear Few- and Many-Body Problem

NASA Astrophysics Data System (ADS)

Lee, Dean

This chapter builds upon the review of lattice methods and effective field theory of the previous chapter. We begin with a brief overview of lattice calculations using chiral effective field theory and some recent applications. We then describe several methods for computing scattering on the lattice. After that we focus on the main goal, explaining the theory and algorithms relevant to lattice simulations of nuclear few- and many-body systems. We discuss the exact equivalence of four different lattice formalisms, the Grassmann path integral, transfer matrix operator, Grassmann path integral with auxiliary fields, and transfer matrix operator with auxiliary fields. Along with our analysis we include several coding examples and a number of exercises for the calculations of few- and many-body systems at leading order in chiral effective field theory.

Thermal microwave emissions from vegetated fields: A comparison between theory and experiment. [Agricultural Research Center, Beltsville, MD.

NASA Technical Reports Server (NTRS)

Wang, J. R.; Shiue, J.; Chuang, S. L.; Dombrowski, M.

1980-01-01

The radiometric measurements over bare field and fields covered with grass, soybean, corn, and alfalfa were made with 1.4 GHz and 5 GHz microwave radiometers during August - October 1978. The measured results are compared with radiative transfer theory treating the vegetated fields as a two layer random medium. It is found that the presence of a vegetation cover generally gives a higher brightness temperature T(B) than that expected from a bare soil. The amount of this T(B) excess increases in the vegetation biomass and in the frequency of the observed radiation. The results of radiative transfer calculations generally match well with the experimental data, however, a detailed analysis also strongly suggests the need of incorporating soil surface roughness effect into the radiative transfer theory in order to better interpret the experimental data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Megala, M.; Rajkumar, Beulah J. M., E-mail: beulah-rajkumar@yahoo.co.in

The electronic and optical transfer properties of Benzene, Benzoic Acid (BA), Nitrobenzene (NB) and Para Nitro Benzoic Acid (PNBA) at ground and first excited state has been investigated by the Density functional theory (DFT)and Time Dependent Density Functional Theory (TDDFT) using SVWN functional/3-21G basis set respectively. Possible intra-molecular charge transfer and n to π* transitions in the ground and the first excitation states have been predicted by the molecular orbitals and the Natural Bond Orbital (NBO) analysis. The simulated absorption spectra have been generated and the result compared with existing experimental results.

Research on Intellectual Property Conflicts Identification in Knowledge Transferring among EC Enterprises

NASA Astrophysics Data System (ADS)

Su, Shibin

As the lacks of existing research about intellectual property conflicts management of EC enterprise, the paper analysis the intellectual property conflicts in knowledge transferring among EC enterprises by intellectual property types, then, the paper makes research on intellectual property conflicts identification in knowledge transferring among EC enterprises, and gives relative assumption, meanwhile, the paper makes quantities identification of intellectual property conflicts in knowledge transferring among EC enterprises by evidential theory, finally, the paper gives the further research orientations.

Nurses' participation in personal knowledge transfer: the role of leader-member exchange (LMX) and structural empowerment.

PubMed

Davies, Alicia; Wong, Carol A; Laschinger, Heather

2011-07-01

The purpose of this study was to test Kanter's theory by examining relationships among structural empowerment, leader-member exchange (LMX) quality and nurses' participation in personal knowledge transfer activities. Despite the current emphasis on evidence-based practice in health care, research suggests that implementation of research findings in everyday clinical practice is unsystematic at best with mixed outcomes. This study was a secondary analysis of data collected using a non-experimental, predictive mailed survey design. A random sample of 400 registered nurses who worked in urban tertiary care hospitals in Ontario yielded a final sample of 234 for a 58.5% response rate. Hierarchical multiple linear regression analysis revealed that the combination of LMX and structural empowerment accounted for 9.1% of the variance in personal knowledge transfer but only total empowerment was a significant independent predictor of knowledge transfer (β=0.291, t=4.012, P<0.001). Consistent with Kanter's Theory, higher levels of empowerment and leader-member exchange quality resulted in increased participation in personal knowledge transfer in practice. The results reinforce the pivotal role of nurse managers in supporting empowering work environments that are conducive to transfer of knowledge in practice to provide evidence-based care. © 2011 The Authors. Journal compilation © 2011 Blackwell Publishing Ltd.

Factors Affecting Training Transfer: Participants' Motivation to Transfer Training, Literature Review

ERIC Educational Resources Information Center

Alawneh, Muhammad K.

2008-01-01

This article investigates factors that motivate participants in learning and training activities to transfer skills, knowledge and attitude from the learning setting to the workplace. Based on training transfer theories hypothesized by Holton (1996), one of the major theories that affect an organization's learning is motivation to transfer theory.…

Does Harcus-Hush theory really work The solvent dependence of intervalence charge-transfer energetics in (NH[sub 3])[sub 5]Ru[sup II]-4,4'-bipyridine-Ru[sup III](NH[sub 3] )[sub 5][sup 5+] in the limit of infinite dilution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hupp, J.T.; Dong, Y.; Blackbourn, R.L.

1993-04-01

Because of concern about ion-pairing artifacts, the solvent dependence of the intervalence charge-transfer absorption energy for a prototypical mixed-valence system, (NH[sub 3])[sub 5]Ru[sup III]-4,4'-bipyridine-Ru[sup II](NH[sub 3])[sub 5][sup 5+], has been reexamined in the limit of infinite dilution. New data are reported for 14 solvents. While one of these (hexamethylphosphoramide) yields anomalous energetics, the absorption energies for the remaining 13 solvents agree qualitatively with the predictions of the Marcus-Hush theory (i.e., two-sphere dielectric continuum theory). On a quantitative basis, however, there is substantial disagreement with theory, at least when the charge-transfer distance is equated with the metal-to-metal separation distance (as conventionallymore » done). Replacement of this distance with a much shorter distance inferred from by electronic Stark-effect spectroscopy leads to a 3-fold decrease in the magnitude of calculated solvent reorganizational contributions to the overall intervalence energy (and therefore, very good agreement with experiment). Unfortunately, the use of such a short charge-transfer distance (d = 5.1 [+-] 0.7 A) also leads to a violation of one of the boundary conditions for use of the two-sphere model. Reformulation of the problem in terms of a generalized dipole-inversion, dielectric cavity problem, however, leads to nearly perfect agreement between theory and experiment. Additional analysis shows that experiment now also agrees reasonably well with theory regarding the magnitude of solvent-independent energy contributions. Finally, it is noted that downward revision in the estimated charge-transfer distance (from 11.3 to 5.1 A) leads to a substantial upward revision in the experimental (i.e., oscillator-strength based) estimate of the electronic coupling element, H[sub if], for intervalence transfer. 33 refs., 3 figs., 2 tabs.« less

Information compression in the context model

NASA Technical Reports Server (NTRS)

Gebhardt, Joerg; Kruse, Rudolf; Nauck, Detlef

1992-01-01

The Context Model provides a formal framework for the representation, interpretation, and analysis of vague and uncertain data. The clear semantics of the underlying concepts make it feasible to compare well-known approaches to the modeling of imperfect knowledge like that given in Bayes Theory, Shafer's Evidence Theory, the Transferable Belief Model, and Possibility Theory. In this paper we present the basic ideas of the Context Model and show its applicability as an alternative foundation of Possibility Theory and the epistemic view of fuzzy sets.

Educational Policy Transfer in an Era of Globalization: Theory--History--Comparison. Comparative Studies Series. Volume 23

ERIC Educational Resources Information Center

Rappleye, Jeremy

2012-01-01

As education becomes increasingly global, the processes and politics of transfer have become a central focus of research. This study provides a comprehensive analysis of contemporary theoretical and analytical work aimed at exploring international educational reform and reveals the myriad ways that globalization is now fundamentally altering our…

Alpha-transfer reactions with large energy transfers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Froehlich, H.; Shimoda, T.; Ishihara, M.

1979-06-04

Alpha-transfer reactions (/sup 20/Ne,/sup 16/O), (/sup 14/N,/sup 10/B), and (/sup 13/C,/sup 9/Be) on a /sup 40/Ca target were studied at 262, 153, 149 MeV, respectively. Analysis in terms of the direction-reaction theory reproduced the observed continuum spectra and angular distributions well, except for the cross section of the reaction (/sup 20/Ne,/sup 16/O) at small angles, which is attributed to a projectile breakup process.

Super-Planckian far-field radiative heat transfer

NASA Astrophysics Data System (ADS)

Fernández-Hurtado, V.; Fernández-Domínguez, A. I.; Feist, J.; García-Vidal, F. J.; Cuevas, J. C.

2018-01-01

We present here a theoretical analysis that demonstrates that the far-field radiative heat transfer between objects with dimensions smaller than the thermal wavelength can overcome the Planckian limit by orders of magnitude. To guide the search for super-Planckian far-field radiative heat transfer, we make use of the theory of fluctuational electrodynamics and derive a relation between the far-field radiative heat transfer and the directional absorption efficiency of the objects involved. Guided by this relation, and making use of state-of-the-art numerical simulations, we show that the far-field radiative heat transfer between highly anisotropic objects can largely overcome the black-body limit when some of their dimensions are smaller than the thermal wavelength. In particular, we illustrate this phenomenon in the case of suspended pads made of polar dielectrics like SiN or SiO2. These structures are widely used to measure the thermal transport through nanowires and low-dimensional systems and can be employed to test our predictions. Our work illustrates the dramatic failure of the classical theory to predict the far-field radiative heat transfer between micro- and nanodevices.

Analysis of neutral beam driven impurity flow reversal in PLT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malik, M.A.; Stacey, W.M. Jr.; Thomas, C.E.

1986-10-01

The Stacey-Sigmar impurity transport theory for tokamak plasmas is applied to the analysis of experimental data from the PLT tokamak with a tungsten limiter. The drag term, which is a central piece in the theory, is evaluated from the recently developed gyroviscous theory for radial momentum transfer. An effort is made to base the modeling of the experiment on measured quantities. Where measured data is not available, recourse is made to extrapolation or numerical modeling. The theoretical and the experimental tungsten fluxes are shown to agree very closely within the uncertainties of the experimental data.

Theory and experimental results of transfer-NOE experiments. 1. The influence of the off rate versus cross-relaxation rates

NASA Astrophysics Data System (ADS)

Lippens, R. M.; Cerf, C.; Hallenga, K.

The theory of the transferred nuclear Overhauser effect is presented in the framework of an extended relaxation matrix representation. This matrix representation allows a coherent description of all one- and two-dimensional experiments. We present analytical solutions for the buildup of magnetization in the 2D transfer-NOE experiment, for all ratios of the off rate k to the cross-relaxation rates R involved. We show that systematic deviations in distance determination occur when the off rate becomes comparable to or smaller than the relaxation rates. Experimental results on the peptide/protein system oxytocin/neurophysin confirming this analysis are presented. The importance of residual mobility in the bound ligand, as demonstrated by the experimental data, is also discussed.

Redox reaction characteristics of riboflavin: a fluorescence spectroelectrochemical analysis and density functional theory calculation.

PubMed

Chen, Wei; Chen, Jie-Jie; Lu, Rui; Qian, Chen; Li, Wen-Wei; Yu, Han-Qing

2014-08-01

Riboflavin (RF), the primary redox active component of flavin, is involved in many redox processes in biogeochemical systems. Despite of its wide distribution and important roles in environmental remediation, its redox behaviors and reaction mechanisms in hydrophobic sites remain unclear yet. In this study, spectroelectrochemical analysis and density functional theory (DFT) calculation were integrated to explore the redox behaviors of RF in dimethyl sulfoxide (DMSO), which was used to create a hydrophobic environment. Specifically, cyclic voltafluorometry (CVF) and derivative cyclic voltafluorometry (DCVF) were employed to track the RF concentration changing profiles. It was found that the reduction contained a series of proton-coupled electron transfers dependent of potential driving force. In addition to the electron transfer-chemical reaction-electron transfer process, a disproportionation (DISP1) process was also identified to be involved in the reduction. The redox potential and free energy of each step obtained from the DFT calculations further confirmed the mechanisms proposed based on the experimental results. The combination of experimental and theoretical approaches yields a deep insight into the characteristics of RF in environmental remediation and better understanding about the proton-coupled electron transfer mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

PubMed

Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

2015-08-11

The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

Analysis of S2QA- charge recombination with the Arrhenius, Eyring and Marcus theories.

PubMed

Rantamäki, Susanne; Tyystjärvi, Esa

2011-01-01

The Q band of photosynthetic thermoluminescence, measured in the presence of a herbicide that blocks electron transfer from PSII, is associated with recombination of the S(2)Q(A)(-) charge pair. The same charge recombination reaction can be monitored with chlorophyll fluorescence. It has been shown that the recombination occurs via three competing routes of which one produces luminescence. In the present study, we measured the thermoluminescence Q band and the decay of chlorophyll fluorescence yield after a single turnover flash at different temperatures from spinach thylakoids. The data were analyzed using the commonly used Arrhenius theory, the Eyring rate theory and the Marcus theory of electron transfer. The fitting error was minimized for both thermoluminescence and fluorescence by adjusting the global, phenomenological constants obtained when the reaction rate theories were applied to the multi-step recombination reaction. For chlorophyll fluorescence, all three theories give decent fits. The peak position of the thermoluminescence Q band is correct by all theories but the form of the Q band is somewhat different in curves predicted by the three theories. The Eyring and Marcus theories give good fits for the decreasing part of the thermoluminescence curve and Marcus theory gives the closest fit for the rising part. Copyright © 2011 Elsevier B.V. All rights reserved.

The security energy encryption in wireless power transfer

NASA Astrophysics Data System (ADS)

Sadzali, M. N.; Ali, A.; Azizan, M. M.; Albreem, M. A. M.

2017-09-01

This paper presents a concept of security in wireless power transfer (WPT) by applying chaos theory. Chaos theory is applied as a security system in order to safeguard the transfer of energy from a transmitter to the intended receiver. The energy encryption of the wireless power transfer utilizes chaos theory to generate the possibility of a logistic map for the chaotic security key. The simulation for energy encryption wireless power transfer system was conducted by using MATLAB and Simulink. By employing chaos theory, the chaotic key ensures the transmission of energy from transmitter to its intended receiver.

Turbine blade tip durability analysis

NASA Technical Reports Server (NTRS)

Mcknight, R. L.; Laflen, J. H.; Spamer, G. T.

1981-01-01

An air-cooled turbine blade from an aircraft gas turbine engine chosen for its history of cracking was subjected to advanced analytical and life-prediction techniques. The utility of advanced structural analysis techniques and advanced life-prediction techniques in the life assessment of hot section components are verified. Three dimensional heat transfer and stress analyses were applied to the turbine blade mission cycle and the results were input into advanced life-prediction theories. Shortcut analytical techniques were developed. The proposed life-prediction theories are evaluated.

Internal energy transfer phenomenon and light-emission properties of γ-LiAlO2 phosphor doped with Mn2+

NASA Astrophysics Data System (ADS)

Wang, Bai-Bin; Chang, Chi-Fen; Yang, Wein-Duo

2013-07-01

γ-LiAlO2:Mn2+ phosphor was synthesized using the cellulose-citric acid sol-gel method, and its light emission and energy transfer properties were investigated. Excitation and emission spectrum analysis revealed a decrease in intensity of the spectrum as the amount of Mn2+ doping increased. Blasse's equation determined the maximum distance for energy transfer between Mn2+ ions as 4.3142 nm. Dexter's theory verifies that the mechanism of energy transfer between Mn2+ ions conforms to an electric dipole and electric quadrupole interaction.

Theory of light transfer in food and biological materials

USDA-ARS?s Scientific Manuscript database

In this chapter, we first define the basic radiometric quantities that are needed for describing light propagation in food and biological materials. Radiative transfer theory is then derived, according to the principle of the conservation of energy. Because the radiative transfer theory equation is ...

NO-sensing performance of vacancy defective monolayer MoS2 predicted by density function theory

NASA Astrophysics Data System (ADS)

Li, Feifei; Shi, Changmin

2018-03-01

Using density functional theory (DFT), we predict the NO-sensing performance of monolayer MoS2 (MoS2-MLs) with and without MoS3-vacancy/S-vacancy defects. Our theoretical results demonstrate that MoS3- and S-vacancy defective MoS2-MLs show stronger chemisorption and greater electron transfer effects than pure MoS2-MLs. The charge transfer analysis showed pure and defective MoS2-MLs all act as donors. Both MoS3-vacancy and S-vacancy defects induce dramatic changes of electronic properties of MoS2-MLs, which have direct relationship with gas sensing performance. In addition, S-vacancy defect leads to more electrons transfer to NO molecule than MoS3-vacancy defect. The H2O molecule urges more electrons transfer from MoS3- or S-vacancy defective MoS2-MLs to NO molecule. We believe that this calculation results will provide some information for future experiment.

Deep-inelastic multinucleon transfer processes in the 16O+27Al reaction

NASA Astrophysics Data System (ADS)

Roy, B. J.; Sawant, Y.; Patwari, P.; Santra, S.; Pal, A.; Kundu, A.; Chattopadhyay, D.; Jha, V.; Pandit, S. K.; Parkar, V. V.; Ramachandran, K.; Mahata, K.; Nayak, B. K.; Saxena, A.; Kailas, S.; Nag, T. N.; Sahoo, R. N.; Singh, P. P.; Sekizawa, K.

2018-03-01

The reaction mechanism of deep-inelastic multinucleon transfer processes in the 16O+27Al reaction at an incident 16O energy (Elab=134 MeV) substantially above the Coulomb barrier has been studied both experimentally and theoretically. Elastic-scattering angular distribution, total kinetic energy loss spectra, and angular distributions for various transfer channels have been measured. The Q -value- and angle-integrated isotope production cross sections have been deduced. To obtain deeper insight into the underlying reaction mechanism, we have carried out a detailed analysis based on the time-dependent Hartree-Fock (TDHF) theory. A recently developed method, TDHF+GEMINI, has been applied to evaluate production cross sections for secondary products. From a comparison between the experimental and theoretical cross sections, we find that the theory qualitatively reproduces the experimental data. Significant effects of secondary light-particle emissions are demonstrated. Possible interplay among fusion-fission, deep-inelastic, multinucleon transfer, and particle evaporation processes is discussed.

Three-dimensional representations of photo-induced electron transfer rates in pyrene-(CH2)n-N,N'-dimethylaniline systems obtained by three electron transfer theories.

PubMed

Rujkorakarn, Rong; Tanaka, Fumio

2009-01-01

The observed rates of photo-induced electron transfer (ET) from N,N'-dimethylaniline (DMA) to the excited pyrene (Py) in confined systems of pyrene-(CH(2))(n)-N,N'- dimethylaniline (PnD: n=1-3) were studied by molecular dynamic simulation (MD) and three kinds of electron transfer theories. ET parameters contained in Marcus theory (M theory), Bixon and Jortner theory (BJ theory) and Kakitani and Mataga theory (KM theory) were determined so as to fit the calculated fluorescence intensities with those obtained by the observed ET rates, according to a non-linear least squares method. Three-dimensional profiles of logarithm of calculated ET rates depending on two of three ET parameters, R, epsilon(0) and -DeltaG degrees were systematically examined with best-fit ET parameters of P1D. Bell shape dependencies of ET rate were predicted on R and on epsilon(0), and on -DeltaG degrees as well, by M theory and KM theory. The profiles of logarithm of ET rate calculated by BJ theory exhibited oscillatory dependencies not only on -DeltaG degrees , but also on R and on epsilon(0). Relationship between ET state and charge transfer complex was discussed with BJ theory.

Charge transfer efficiency improvement of 4T pixel for high speed CMOS image sensor

NASA Astrophysics Data System (ADS)

Jin, Xiangliang; Liu, Weihui; Yang, Hongjiao; Tang, Lizhen; Yang, Jia

2015-03-01

The charge transfer efficiency improvement method is proposed by optimizing the electrical potential distribution along the transfer path from the PPD to the FD. In this work, we present a non-uniform doped transfer transistor channel, with the adjustments to the overlap length between the CPIA layer and the transfer gate, and the overlap length between the SEN layer and transfer gate. Theory analysis and TCAD simulation results show that the density of the residual charge reduces from 1e11 /cm3 to 1e9 /cm3, and the transfer time reduces from 500 ns to 143 ns, and the charge transfer efficiency is about 77 e-/ns. This optimizing design effectively improves the charge transfer efficiency of 4T pixel and the performance of 4T high speed CMOS image sensor.

The mediating role of insight for long-term improvements in psychodynamic therapy.

PubMed

Johansson, Paul; Høglend, Per; Ulberg, Randi; Amlo, Svein; Marble, Alice; Bøgwald, Kjell-Petter; Sørbye, Oystein; Sjaastad, Mary Cosgrove; Heyerdahl, Oscar

2010-06-01

According to psychoanalytic theory, interpretation of transference leads to increased insight that again leads to improved interpersonal functioning over time. In this study, we performed a full mediational analysis to test whether insight gained during treatment mediates the long-term effects of transference interpretation in dynamic psychotherapy. This study is a randomized clinical trial with a dismantling design. One hundred outpatients seeking psychotherapy for depression, anxiety, personality disorders, and interpersonal problems were randomly assigned to 1 year of weekly sessions of dynamic psychotherapy with transference interpretation or to the same type and duration of treatment with the same therapists but without the use of transference interpretation. Interpersonal functioning and insight were measured pretreatment, posttreatment, and 1 year and 3 years after treatment termination. Contrary to common expectation, patients with a life-long pattern of low quality of object relations and personality disorder pathology profited more from therapy with transference interpretation than from therapy with no transference interpretation. This long-term effect was mediated by an increase in the level of insight during treatment. Insight seems to be a key mechanism of change in dynamic psychotherapy. Our results bridge the gap between clinical theory and empirical research.

Primer vector theory applied to the linear relative-motion equations. [for N-impulse space trajectory optimization

NASA Technical Reports Server (NTRS)

Jezewski, D.

1980-01-01

Prime vector theory is used in analyzing a set of linear relative-motion equations - the Clohessy-Wiltshire (C/W) equations - to determine the criteria and necessary conditions for an optimal N-impulse trajectory. The analysis develops the analytical criteria for improving a solution by: (1) moving any dependent or independent variable in the initial and/or final orbit, and (2) adding intermediate impulses. If these criteria are violated, the theory establishes a sufficient number of analytical equations. The subsequent satisfaction of these equations will result in the optimal position vectors and times of an N-impulse trajectory. The solution is examined for the specific boundary conditions of: (1) fixed-end conditions, two impulse, and time-open transfer; (2) an orbit-to-orbit transfer; and (3) a generalized renezvous problem.

Evolution of the transfer function characterization of surface scatter phenomena

NASA Astrophysics Data System (ADS)

Harvey, James E.; Pfisterer, Richard N.

2016-09-01

Based upon the empirical observation that BRDF measurements of smooth optical surfaces exhibited shift-invariant behavior when plotted versus    o , the original Harvey-Shack (OHS) surface scatter theory was developed as a scalar linear systems formulation in which scattered light behavior was characterized by a surface transfer function (STF) reminiscent of the optical transfer function (OTF) of modern image formation theory (1976). This shift-invariant behavior combined with the inverse power law behavior when plotting log BRDF versus log   o was quickly incorporated into several optical analysis software packages. Although there was no explicit smooth-surface approximation in the OHS theory, there was a limitation on both the incident and scattering angles. In 1988 the modified Harvey-Shack (MHS) theory removed the limitation on the angle of incidence; however, a moderate-angle scattering limitation remained. Clearly for large incident angles the BRDF was no longer shift-invariant as a different STF was now required for each incident angle. In 2011 the generalized Harvey-Shack (GHS) surface scatter theory, characterized by a two-parameter family of STFs, evolved into a practical modeling tool to calculate BRDFs from optical surface metrology data for situations that violate the smooth surface approximation inherent in the Rayleigh-Rice theory and/or the moderate-angle limitation of the Beckmann-Kirchhoff theory. And finally, the STF can be multiplied by the classical OTF to provide a complete linear systems formulation of image quality as degraded by diffraction, geometrical aberrations and surface scatter effects from residual optical fabrication errors.

Data-Driven Model Reduction and Transfer Operator Approximation

NASA Astrophysics Data System (ADS)

Klus, Stefan; Nüske, Feliks; Koltai, Péter; Wu, Hao; Kevrekidis, Ioannis; Schütte, Christof; Noé, Frank

2018-06-01

In this review paper, we will present different data-driven dimension reduction techniques for dynamical systems that are based on transfer operator theory as well as methods to approximate transfer operators and their eigenvalues, eigenfunctions, and eigenmodes. The goal is to point out similarities and differences between methods developed independently by the dynamical systems, fluid dynamics, and molecular dynamics communities such as time-lagged independent component analysis, dynamic mode decomposition, and their respective generalizations. As a result, extensions and best practices developed for one particular method can be carried over to other related methods.

Predicting Autonomous and Controlled Motivation to Transfer Training

ERIC Educational Resources Information Center

Gegenfurtner, Andreas; Festner, Dagmar; Gallenberger, Wolfgang; Lehtinen, Erno; Gruber, Hans

2009-01-01

In spite of a broad consensus on the importance of motivation for the transfer of learning from training to the job in work organizations, studies investigating motivation to transfer are limited. This study combines the self-determination theory, the expectancy theory and the theory of planned behaviour to provide a theoretical framework for…

Theoretical insights of proton transfer and hydrogen bonded charge transfer complex of 1,2-dimethylimidazolium-3,5-dinitrobenzoate crystal

NASA Astrophysics Data System (ADS)

Afroz, Ziya; Faizan, Mohd.; Alam, Mohammad Jane; Ahmad, Shabbir; Ahmad, Afaq

2018-04-01

Proton transfer (PT) and hydrogen bonded charge transfer (HBCT) 1:1 complex of 1,2-dimethylimidazole (DMI) and 3,5-dinitrobenzoic acid (DNBA) have been theoretically analyzed and compared with reported experimental results. Both the structures in the isolated gaseous state have been optimized at DFT/B3LYP/6-311G(d,p) level of theory and further, the PT energy barrier has been calculated from potential energy surface scan. Along with structural investigations, theoretical vibrational spectra have been inspected and compared with the FTIR spectrum. Moreover, frontier molecular analysis has also been carried out.

Radiative Transfer in Stellar Atmospheres

NASA Astrophysics Data System (ADS)

Rutten, Robert J.

2003-05-01

The main topic treated in these graduate course notes is the classical theory of radiative transfer for explaining stellar spectra. It needs relatively much attention to be mastered. Radiative transfer in gaseous media that are neither optically thin nor fully opaque and scatter to boot is a key part of astrophysics but not a transparent subject. These course notes represent a middle road between Mihalas' "Stellar Atmospheres" (graduate level and up) and the books by Novotny and Boehm-Vitense (undergraduate level). They are at about the level of Gray's "The observation and analysis of stellar photospheres" but emphasize NLTE radiative transfer rather than observational techniques and data interpretation.

The Contributions of Applied Behavior Analysis and Behavior Theory to Innovative Research and Practice Cultures in Social Work.

PubMed

Briggs, Harold Eugene; Sharkey, Caroline; Briggs, Adam Christopher

2016-01-01

In this article the authors tie the emergence of an empirical practice research culture, which enabled the rise in evidence-based practice in social work to the introduction of applied behavior analysis and behavioral theory to social work practice and research. The authors chronicle the: (1) scientific foundations of social work, (2) influence and push by corporatized university cultures for higher scholarship productivity among faculty, (3) significance of theory in general, (4) importance of behavioral theory in particular as a major trigger of the growth in research on effective social work practice approaches, and (5) commonalities between applied behavior analysis and evidence-based practice. The authors conclude with implications for addressing the dual challenges of building an enhanced research culture in schools of social work and the scholarship of transferring practice research to adoption in real world practice settings.

Modeling Choice Under Uncertainty in Military Systems Analysis

DTIC Science & Technology

1991-11-01

operators rather than fuzzy operators. This is suggested for further research. 4.3 ANALYTIC HIERARCHICAL PROCESS ( AHP ) In AHP , objectives, functions and...14 4.1 IMPRECISELY SPECIFIED MULTIPLE A’ITRIBUTE UTILITY THEORY... 14 4.2 FUZZY DECISION ANALYSIS...14 4.3 ANALYTIC HIERARCHICAL PROCESS ( AHP ) ................................... 14 4.4 SUBJECTIVE TRANSFER FUNCTION APPROACH

Metaphors--Messengers of Meaning: A Contribution to an Evolutionary Sociology of Science.

ERIC Educational Resources Information Center

Maasen, Sabine; Weingart, Peter

1995-01-01

Presents the idea that the central link between science and society is established by a diffusion of knowledge. Suggests knowledge transfers may be analyzed in a metaphorical context and that a metaphorical analysis should be combined with discourse analysis and central concepts of evolutionary theory. (50 references) (Author/AEF)

A Social Network Analysis of the National Materials Competency at Naval Air Systems Command

DTIC Science & Technology

2002-09-01

language held by individuals within the structure. (Lesser, 2000, p. 4) Bourdieu defines social capital as decomposable into two elements: first, the...The fundamental proposition of social capital theory is that the network ties provide access to resources and that social relations constitute...transferring knowledge are being identified as a central element of organizational advantage. Social capital theory provides a sounds basis for explaining

Situational and Demographic Influences on Transfer System Characteristics in Organizations

ERIC Educational Resources Information Center

Chen, Hsin-Chih; Holton, Elwood F., III; Bates, Reid A.

2006-01-01

Transfer theories, which are closely related to evaluation theory, have been developed from a holistic perspective, but most of empirical transfer research has not effectively utilized holistic models to investigate transfer of learning until the late 1990s. Additionally, little has been done in examining the relationship between situational…

An integrated reweighting theory of perceptual learning

PubMed Central

Dosher, Barbara Anne; Jeter, Pamela; Liu, Jiajuan; Lu, Zhong-Lin

2013-01-01

Improvements in performance on visual tasks due to practice are often specific to a retinal position or stimulus feature. Many researchers suggest that specific perceptual learning alters selective retinotopic representations in early visual analysis. However, transfer is almost always practically advantageous, and it does occur. If perceptual learning alters location-specific representations, how does it transfer to new locations? An integrated reweighting theory explains transfer over retinal locations by incorporating higher level location-independent representations into a multilevel learning system. Location transfer is mediated through location-independent representations, whereas stimulus feature transfer is determined by stimulus similarity at both location-specific and location-independent levels. Transfer to new locations/positions differs fundamentally from transfer to new stimuli. After substantial initial training on an orientation discrimination task, switches to a new location or position are compared with switches to new orientations in the same position, or switches of both. Position switches led to the highest degree of transfer, whereas orientation switches led to the highest levels of specificity. A computational model of integrated reweighting is developed and tested that incorporates the details of the stimuli and the experiment. Transfer to an identical orientation task in a new position is mediated via more broadly tuned location-invariant representations, whereas changing orientation in the same position invokes interference or independent learning of the new orientations at both levels, reflecting stimulus dissimilarity. Consistent with single-cell recording studies, perceptual learning alters the weighting of both early and midlevel representations of the visual system. PMID:23898204

Van der Waals corrected DFT study of adsorption of groups VA and VIA hydrides on graphene monoxide

NASA Astrophysics Data System (ADS)

Notash, M. Yaghoobi; Ebrahimzadeh, A. Rastkar

2016-06-01

Adsorption properties of H2O, H2S, NH3 and PH3 on graphene monoxide (GMO) nano flack are investigated using density functional theory (DFT). Calculations were carried out by van der Waals correction and general gradient approximation. The adsorption energies and charge transfer between species are obtained and discussed for the considered positions of adsorbate molecules. Charge transfer analysis show that the gas molecules act as an electron acceptor in all cases. The analysis of the adsorption energies suggest GMO can be a good candidate for the adsorption of these molecules.

Toda theories as contractions of affine Toda theories

NASA Astrophysics Data System (ADS)

Aghamohammadi, A.; Khorrami, M.; Shariati, A.

1996-02-01

Using a contraction procedure, we obtain Toda theories and their structures, from affine Toda theories and their corresponding structures. By structures, we mean the equation of motion, the classical Lax pair, the boundary term for half line theories, and the quantum transfer matrix. The Lax pair and the transfer matrix so obtained, depend nontrivially on the spectral parameter.

Implausibility of the vibrational theory of olfaction

DOE PAGES

Block, Eric; Ertem, Mehmed Z.; Jang, Seogjoo; ...

2015-04-21

The vibrational theory of olfaction assumes that electron transfer occurs across odorants at the active sites of odorant receptors (ORs), serving as a sensitive measure of odorant vibrational frequencies, ultimately leading to olfactory perception. A previous study reported that human subjects differentiated hydrogen/deuterium isotopomers (isomers with isotopic atoms) of the musk compound cyclopentadecanone as evidence supporting the theory. Here, we find no evidence for such differentiation at the molecular level. In fact, we find that the human musk-recognizing receptor, OR5AN1, identified using a heterologous OR expression system and robustly responding to cyclopentadecanone and muscone, fails to distinguish isotopomers of thesemore » compounds in vitro. Furthermore, the mouse (methylthio)methanethiol (MTMT)-recognizing receptor, MOR244-3, and other selected human and mouse ORs, responded similarly to normal, deuterated, and ¹³C isotopomers of their respective ligands, paralleling our results with the musk receptor OR5AN1. These findings suggest that the proposed vibration theory does not apply to the human musk receptor OR5AN1, mouse thiol receptor MOR244-3, or other ORs examined. Also, contrary to the vibration theory predictions, muscone-d₃₀ lacks the 1,380-1,550 cm⁻¹ IR bands claimed to be essential for musk odor. Furthermore, our theoretical analysis shows that the proposed electron transfer mechanism of the vibrational frequencies of odorants could be easily suppressed by quantum effects of non-odorant molecular vibrational modes. As a result, these and other concerns about electron transfer at ORs, together with our extensive experimental data, argue against the plausibility of the vibration theory.« less

Implausibility of the vibrational theory of olfaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Block, Eric; Ertem, Mehmed Z.; Jang, Seogjoo

The vibrational theory of olfaction assumes that electron transfer occurs across odorants at the active sites of odorant receptors (ORs), serving as a sensitive measure of odorant vibrational frequencies, ultimately leading to olfactory perception. A previous study reported that human subjects differentiated hydrogen/deuterium isotopomers (isomers with isotopic atoms) of the musk compound cyclopentadecanone as evidence supporting the theory. Here, we find no evidence for such differentiation at the molecular level. In fact, we find that the human musk-recognizing receptor, OR5AN1, identified using a heterologous OR expression system and robustly responding to cyclopentadecanone and muscone, fails to distinguish isotopomers of thesemore » compounds in vitro. Furthermore, the mouse (methylthio)methanethiol (MTMT)-recognizing receptor, MOR244-3, and other selected human and mouse ORs, responded similarly to normal, deuterated, and ¹³C isotopomers of their respective ligands, paralleling our results with the musk receptor OR5AN1. These findings suggest that the proposed vibration theory does not apply to the human musk receptor OR5AN1, mouse thiol receptor MOR244-3, or other ORs examined. Also, contrary to the vibration theory predictions, muscone-d₃₀ lacks the 1,380-1,550 cm⁻¹ IR bands claimed to be essential for musk odor. Furthermore, our theoretical analysis shows that the proposed electron transfer mechanism of the vibrational frequencies of odorants could be easily suppressed by quantum effects of non-odorant molecular vibrational modes. As a result, these and other concerns about electron transfer at ORs, together with our extensive experimental data, argue against the plausibility of the vibration theory.« less

In the eye of the beholder: Helmholtzian perception and the origins of Freud's 1900 theory of transference.

PubMed

Makari, G J

1994-01-01

Freud's 1900 theory of transference was indebted to the convergence of philosophy and physiology found in nineteenth-century theories of visual perception. The author maps out the post-Kantian philosophical and German physiological currents that gave rise to Hermann von Helmholtz's influential work on perception, and proposes that Freud's 1900 theory of transference was a creative synthesis of novel notions like unconscious wishing and psychic defense with a Helmholtzian model of visual illusion.

Transfer reactions induced by lithium ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogloblin, A.A.

The review deals with nuclear reactions induced by /sup 6/Li and /sup 7/ Li io ns having energies between 10 and 30 MeV. Due to the cluster structure of / sup 6/Li (/sup 6/Li= alpha +d) and /sup 7/Li (/sup 7/Li= alpha +t) and the low bindi ng energy of these nuclei, one of the clustcr is directly transferred in (/ sup 6/Li, d), (/sup 7/Li, t) (/sup 6/Li alpha ) and (/sup 7/Li, alpha ) reactions, i.e., the alpha p article, the deuteron, or the triton is directly transferred. Particular attention is paid to the (/sup 6/Li, d) andmore » (/sup 7/Li, t) reactions, in which the cluster-transfe r mechanism (alpha-particle transfer) appear in ita purest fomn. These reactions can be used to study the alpha- particle or quartet states of light nuclei, which are difficult or impossible to excite in any other way. The present state of the theory of multinucleon transfcr reactions is considered and the application of the theory to thc analysis of reactions induced by lithium atoms is discussed. (auth)« less

Health insurance theory: the case of the missing welfare gain.

PubMed

Nyman, John A

2008-11-01

An important source of value is missing from the conventional welfare analysis of moral hazard, namely, the effect of income transfers (from those who purchase insurance and remain healthy to those who become ill) on purchases of medical care. Income transfers are contained within the price reduction that is associated with standard health insurance. However, in contrast to the income effects contained within an exogenous price decrease, these income transfers act to shift out the demand for medical care. As a result, the consumer's willingness to pay for medical care increases and the resulting additional consumption is welfare increasing.

Information Acquisition, Analysis and Integration

DTIC Science & Technology

2016-08-03

of sensing and processing, theory, applications, signal processing, image and video processing, machine learning , technology transfer. 16. SECURITY... learning . 5. Solved elegantly old problems like image and video debluring, intro- ducing new revolutionary approaches. 1 DISTRIBUTION A: Distribution...Polatkan, G. Sapiro, D. Blei, D. B. Dunson, and L. Carin, “ Deep learning with hierarchical convolution factor analysis,” IEEE 6 DISTRIBUTION A

Application of Electron-Transfer Theory to Several Systems of Biological Interest

DOE R&D Accomplishments Database

Marcus, R. A.; Sutin, N.

1985-03-23

Electron-transfer reaction rates are compared with theoretically calculated values for several reactions in the bacterial photosynthetic reaction center. A second aspect of the theory, the cross-relation, is illustrated using protein-protein electron transfers.

Theory for electron transfer from a mixed-valence dimer with paramagnetic sites to a mononuclear acceptor

NASA Astrophysics Data System (ADS)

Bominaar, E. L.; Achim, C.; Borshch, S. A.

1999-06-01

Polynuclear transition-metal complexes, such as Fe-S clusters, are the prosthetic groups in a large number of metalloproteins and serve as temporary electron storage units in a number of important redox-based biological processes. Polynuclearity distinguishes clusters from mononuclear centers and confers upon them unique properties, such as spin ordering and the presence of thermally accessible excited spin states in clusters with paramagnetic sites, and fractional valencies in clusters of the mixed-valence type. In an earlier study we presented an effective-mode (EM) analysis of electron transfer from a binuclear mixed-valence donor with paramagnetic sites to a mononuclear acceptor which revealed that the cluster-specific attributes have an important impact on the kinetics of long-range electron transfer. In the present study, the validity of these results is tested in the framework of more detailed theories which we have termed the multimode semiclassical (SC) model and the quantum-mechanical (QM) model. It is found that the qualitative trends in the rate constant are the same in all treatments and that the semiclassical models provide a good approximation of the more rigorous quantum-mechanical description of electron transfer under physiologically relevant conditions. In particular, the present results corroborate the importance of electron transfer via excited spin states in reactions with a low driving force and justify the use of semiclassical theory in cases in which the QM model is computationally too demanding. We consider cases in which either one or two donor sites of a dimer are electronically coupled to the acceptor. In the case of multiconnectivity, the rate constant for electron transfer from a valence-delocalized (class-III) donor is nonadditive with respect to transfer from individual metal sites of the donor and undergoes an order-of-magnitude change by reversing the sign of the intradimer metal-metal resonance parameter (β). In the case of single connectivity, the rate constant for electron transfer from a valence-localized (class-II) donor can readily be tuned over several orders of magnitude by introducing differences in the electronic potentials at the two metal sites of the donor. These results indicate that theories of cluster-based electron transfer, in order to be realistic, need to consider both intrinsic electronic structure and extrinsic interactions of the cluster with the protein environment.

Photoinduced electron transfer process on emission spectrum of N,N‧-bis(salicylidene)-1,2-phenylenediamine as a Mg2+ cation chemosensor: A first principle DFT and TDDFT study

NASA Astrophysics Data System (ADS)

Taherpour, Avat (Arman); Jamshidi, Morteza; Rezaei, Omid; Belverdi, Ali Rezaei

2018-06-01

The electronic and optical properties of N,N‧-bis(salicylidene)-1,2-phenylenediamine (SPDA) ligand were studied as a chemical sensor of Mg2+ cation in two solvents (water and DMSO) using the ab initio theory through Density Functional Theory (DFT) and Time Dependent Density Functional theory (TDDFT) methods. The results show that the SPDA ligand has a high ability for chemical sensing of Mg2+. The results has also represented that HOMO-LUMO energy gap decreases 0.941 eV after the complex formation between SPDA and Mg2+. In addition, obvious changes are found in the UV-Vis absorption spectrum, optical analyses SPDA ligand and [SPDA.Mg]2+ complex, which it has the capability of detecting Mg2+ via the adsorptive UV-Vis and colorimetric methods. Emission spectrum calculations and photoinduced electron transfer (PET) process in water solution shows different wavelength emission spectrum in amount of 4.6 nm. An analysis of NBO (natural bond orbital) data indicates tangible changes in the electron transfers data from the electron pairs of ligand to the conjugated system, both prior and subsequent to Mg2+addition.

Expertise facilitates the transfer of anticipation skill across domains.

PubMed

Rosalie, Simon M; Müller, Sean

2014-02-01

It is unclear whether perceptual-motor skill transfer is based upon similarity between the learning and transfer domains per identical elements theory, or facilitated by an understanding of underlying principles in accordance with general principle theory. Here, the predictions of identical elements theory, general principle theory, and aspects of a recently proposed model for the transfer of perceptual-motor skill with respect to expertise in the learning and transfer domains are examined. The capabilities of expert karate athletes, near-expert karate athletes, and novices to anticipate and respond to stimulus skills derived from taekwondo and Australian football were investigated in ecologically valid contexts using an in situ temporal occlusion paradigm and complex whole-body perceptual-motor skills. Results indicated that the karate experts and near-experts are as capable of using visual information to anticipate and guide motor skill responses as domain experts and near-experts in the taekwondo transfer domain, but only karate experts could perform like domain experts in the Australian football transfer domain. Findings suggest that transfer of anticipation skill is based upon expertise and an understanding of principles but may be supplemented by similarities that exist between the stimulus and response elements of the learning and transfer domains.

A Critical Review of Heat Transfer Enhancement Techniques for Use in Marine Condensers.

DTIC Science & Technology

1982-09-01

horizontal tube, the Nusselt theory predicts that the condensate film is thinnest at the top of the tube, and thickens around the tube until at the...transfer coefficient. As pointed out above, the Nusselt analysis assumes that the condensate film drains from a horizontal tube in a continuous sheet...the condensate falling on the lower tubes does not deteriorate the thermal performance of these tubes because the helically - wrapped wires draw the

Heat Transfer in the Turbulent Boundary Layer of a Compressible Gas at High Speeds

NASA Technical Reports Server (NTRS)

Frankl, F.

1942-01-01

The Reynolds law of heat transfer from a wall to a turbulent stream is extended to the case of flow of a compressible gas at high speeds. The analysis is based on the modern theory of the turbulent boundary layer with laminar sublayer. The investigation is carried out for the case of a plate situated in a parallel stream. The results are obtained independently of the velocity distribution in the turbulent boundar layer.

Charge Transfer Enhancement in the D-π-A Type Porphyrin Dyes: A Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) Study.

PubMed

Kang, Guo-Jun; Song, Chao; Ren, Xue-Feng

2016-11-25

The electronic geometries and optical properties of two D-π-A type zinc porphyrin dyes (NCH₃-YD2 and TPhe-YD) were systematically investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to reveal the origin of significantly altered charge transfer enhancement by changing the electron donor of the famous porphyrin-based sensitizer YD2-o-C8. The molecular geometries and photophysical properties of dyes before and after binding to the TiO₂ cluster were fully investigated. From the analyses of natural bond orbital (NBO), extended charge decomposition analysis (ECDA), and electron density variations (Δρ) between the excited state and ground state, it was found that the introduction of N(CH₃)₂ and 1,1,2-triphenylethene groups enhanced the intramolecular charge-transfer (ICT) character compared to YD2-o-C8. The absorption wavelength and transition possess character were significantly influenced by N(CH₃)₂ and 1,1,2-triphenylethene groups. NCH₃-YD2 with N(CH₃)₂ groups in the donor part is an effective way to improve the interactions between the dyes and TiO₂ surface, light having efficiency (LHE), and free energy change (ΔG inject ), which is expected to be an efficient dye for use in dye-sensitized solar cells (DSSCs).

A detailed study of intermolecular interactions, electronic and vibrational properties of the metal complex bis(uracilato)diammine copper(ii) dihydrate

NASA Astrophysics Data System (ADS)

Gramajo Feijoo, M.; Fernández-Liencres, M. P.; Gil, D. M.; Gómez, M. I.; Ben Altabef, A.; Navarro, A.; Tuttolomondo, M. E.

2018-03-01

Density Functional Theory (DFT) calculations were performed with the aim of investigating the vibrational, electronic and structural properties of [Cu(uracilato-N1)2 (NH3)2]ṡ2H2O complex. The IR and Raman spectra were recorded leading to a complete analysis of the normal modes of vibration of the metal complex. A careful study of the intermolecular interactions observed in solid state was performed by using the Hirshfeld surface analysis and their associated 2D fingerprint plots. The results indicated that the crystal packing is stabilized by Nsbnd H⋯O hydrogen bonds and π-stacking interactions. In addition, Csbnd H···π interactions were also observed. Time-dependent density functional theory (TD-DFT) calculations revealed that all the low-lying electronic states correspond to a mixture of intraligand charge transfer (ILCT) and ligand-to-metal charge transfer (LMCT) transitions. Finally, Natural Bond Orbital (NBO) and Atoms in Molecules (AIM) analysis were performed to shed light on the intermolecular interactions in the coordination sphere.

An upper bound on the radius of a highly electrically conducting lunar core

NASA Technical Reports Server (NTRS)

Hobbs, B. A.; Hood, L. L.; Herbert, F.; Sonett, C. P.

1983-01-01

Parker's (1980) nonlinear inverse theory for the electromagnetic sounding problem is converted to a form suitable for analysis of lunar day-side transfer function data by: (1) transforming the solution in plane geometry to that in spherical geometry; and (2) transforming the theoretical lunar transfer function in the dipole limit to an apparent resistivity function. The theory is applied to the revised lunar transfer function data set of Hood et al. (1982), which extends in frequency from 10 to the -5th to 10 to the -3rd Hz. On the assumption that an iron-rich lunar core, whether molten or solid, can be represented by a perfect conductor at the minimum sampled frequency, an upper bound of 435 km on the maximum radius of such a core is calculated. This bound is somewhat larger than values of 360-375 km previously estimated from the same data set via forward model calculations because the prior work did not consider all possible mantle conductivity functions.

Design of optimal impulse transfers from the Sun-Earth libration point to asteroid

NASA Astrophysics Data System (ADS)

Wang, Yamin; Qiao, Dong; Cui, Pingyuan

2015-07-01

The lunar probe, Chang'E-2, is the first one to successfully achieve both the transfer to Sun-Earth libration point orbit and the flyby of near-Earth asteroid Toutatis. This paper, taking the Chang'E-2's asteroid flyby mission as an example, provides a method to design low-energy transfers from the libration point orbit to an asteroid. The method includes the analysis of transfer families and the design of optimal impulse transfers. Firstly, the one-impulse transfers are constructed by correcting the initial guesses, which are obtained by perturbing in the direction of unstable eigenvector. Secondly, the optimality of one-impulse transfers is analyzed and the optimal impulse transfers are built by using the primer vector theory. After optimization, the transfer families, including the slow and the fast transfers, are refined to be continuous and lower-cost transfers. The method proposed in this paper can be also used for designing transfers from an arbitrary Sun-Earth libration point orbit to a near-Earth asteroid in the Sun-Earth-Moon system.

Energy decomposition analysis for exciplexes using absolutely localized molecular orbitals

NASA Astrophysics Data System (ADS)

Ge, Qinghui; Mao, Yuezhi; Head-Gordon, Martin

2018-02-01

An energy decomposition analysis (EDA) scheme is developed for understanding the intermolecular interaction involving molecules in their excited states. The EDA utilizes absolutely localized molecular orbitals to define intermediate states and is compatible with excited state methods based on linear response theory such as configuration interaction singles and time-dependent density functional theory. The shift in excitation energy when an excited molecule interacts with the environment is decomposed into frozen, polarization, and charge transfer contributions, and the frozen term can be further separated into Pauli repulsion and electrostatics. These terms can be added to their counterparts obtained from the ground state EDA to form a decomposition of the total interaction energy. The EDA scheme is applied to study a variety of systems, including some model systems to demonstrate the correct behavior of all the proposed energy components as well as more realistic systems such as hydrogen-bonding complexes (e.g., formamide-water, pyridine/pyrimidine-water) and halide (F-, Cl-)-water clusters that involve charge-transfer-to-solvent excitations.

Proceedings: international conference on transfer of forest science knowledge and technology.

Treesearch

Cynthia Miner; Ruth Jacobs; Dennis Dykstra; Becky Bittner

2007-01-01

This proceedings compiles papers presented by extensionists, natural resource specialists, scientists, technology transfer specialists, and others at an international conference that examined knowledge and technology transfer theories, methods, and case studies. Theory topics included adult education, applied science, extension, diffusion of innovations, social...

Nonequilibrium Energy Transfer at Nanoscale: A Unified Theory from Weak to Strong Coupling

NASA Astrophysics Data System (ADS)

Wang, Chen; Ren, Jie; Cao, Jianshu

2015-07-01

Unraveling the microscopic mechanism of quantum energy transfer across two-level systems provides crucial insights to the optimal design and potential applications of low-dimensional nanodevices. Here, we study the non-equilibrium spin-boson model as a minimal prototype and develop a fluctuation-decoupled quantum master equation approach that is valid ranging from the weak to the strong system-bath coupling regime. The exact expression of energy flux is analytically established, which dissects the energy transfer as multiple boson processes with even and odd parity. Our analysis provides a unified interpretation of several observations, including coherence-enhanced heat flux and negative differential thermal conductance. The results will have broad implications for the fine control of energy transfer in nano-structural devices.

A reagent for safe and efficient diazo-transfer to primary amines: 2-azido-1,3-dimethylimidazolinium hexafluorophosphate.

PubMed

Kitamura, Mitsuru; Kato, So; Yano, Masakazu; Tashiro, Norifumi; Shiratake, Yuichiro; Sando, Mitsuyoshi; Okauchi, Tatsuo

2014-07-07

Organic azides were prepared from primary amines in high yields by a metal free diazo-transfer reaction using 2-azido-1,3-dimethylimidazolinium hexafluorophosphate (ADMP), which is safe and stable crystalline. The choice of base was important in the diazo-transfer reaction. In general, 4-(N,N-dimethyl)aminopyridine (DMAP) was efficient, but a stronger base such as alkylamine or DBU was more appropriate for the reaction of nucleophilic primary amines. X-ray single crystal structural analysis and geometry optimization using density functional theory (B3LYP/6-31G**) were conducted to study the ADMP structure, and the diazo-transfer reaction mechanism was explained with the help of the results of these analyses.

Local control theory using trajectory surface hopping and linear-response time-dependent density functional theory.

PubMed

Curchod, Basile F E; Penfold, Thomas J; Rothlisberger, Ursula; Tavernelli, Ivano

2013-01-01

The implementation of local control theory using nonadiabatic molecular dynamics within the framework of linear-response time-dependent density functional theory is discussed. The method is applied to study the photoexcitation of lithium fluoride, for which we demonstrate that this approach can efficiently generate a pulse, on-the-fly, able to control the population transfer between two selected electronic states. Analysis of the computed control pulse yields insights into the photophysics of the process identifying the relevant frequencies associated to the curvature of the initial and final state potential energy curves and their energy differences. The limitations inherent to the use of the trajectory surface hopping approach are also discussed.

Bridge-mediated hopping or superexchange electron-transfer processes in bis(triarylamine) systems

NASA Astrophysics Data System (ADS)

Lambert, Christoph; Nöll, Gilbert; Schelter, Jürgen

2002-09-01

Hopping and superexchange are generally considered to be alternative electron-transfer mechanisms in molecular systems. In this work we used mixed-valence radical cations as model systems for the investigation of electron-transfer pathways. We show that substituents attached to a conjugated bridge connecting two triarylamine redox centres have a marked influence on the near-infrared absorption spectra of the corresponding cations. Spectral analysis, followed by evaluation of the electron-transfer parameters using the Generalized Mulliken-Hush theory and simulation of the potential energy surfaces, indicate that hopping and superexchange are not alternatives, but are both present in the radical cation with a dimethoxybenzene bridge. We found that the type of electron-transfer mechanism depends on the bridge-reorganization energy as well as on the bridge-state energy. Because superexchange and hopping follow different distance laws, our findings have implications for the design of new molecular and polymeric electron-transfer materials.

Integrated analysis of energy transfers in elastic-wave turbulence.

PubMed

Yokoyama, Naoto; Takaoka, Masanori

2017-08-01

In elastic-wave turbulence, strong turbulence appears in small wave numbers while weak turbulence does in large wave numbers. Energy transfers in the coexistence of these turbulent states are numerically investigated in both the Fourier space and the real space. An analytical expression of a detailed energy balance reveals from which mode to which mode energy is transferred in the triad interaction. Stretching energy excited by external force is transferred nonlocally and intermittently to large wave numbers as the kinetic energy in the strong turbulence. In the weak turbulence, the resonant interactions according to the weak turbulence theory produce cascading net energy transfer to large wave numbers. Because the system's nonlinearity shows strong temporal intermittency, the energy transfers are investigated at active and moderate phases separately. The nonlocal interactions in the Fourier space are characterized by the intermittent bundles of fibrous structures in the real space.

On the transferability of electron density in binary vanadium borides VB, V3B4 and VB2.

PubMed

Terlan, Bürgehan; Akselrud, Lev; Baranov, Alexey I; Borrmann, Horst; Grin, Yuri

2015-12-01

Binary vanadium borides are suitable model systems for a systematic analysis of the transferability concept in intermetallic compounds due to chemical intergrowth in their crystal structures. In order to underline this structural relationship, topological properties of the electron density in VB, V3B4 and VB2 reconstructed from high-resolution single-crystal X-ray diffraction data as well as derived from quantum chemical calculations, are analysed in terms of Bader's Quantum Theory of Atoms in Molecules [Bader (1990). Atoms in Molecules: A Quantum Theory, 1st ed. Oxford: Clarendon Press]. The compounds VB, V3B4 and VB2 are characterized by a charge transfer from the metal to boron together with two predominant atomic interactions, the shared covalent B-B interactions and the polar covalent B-M interactions. The resembling features of the crystal structures are well reflected by the respective B-B interatomic distances as well as by ρ(r) values at the B-B bond critical points. The latter decrease with an increase in the corresponding interatomic distances. The B-B bonds show transferable electron density properties at bond critical points depending on the respective bond distances.

Extending Transfer of Learning Theory to Transformative Learning Theory: A Model for Promoting Teacher Leadership

ERIC Educational Resources Information Center

Harris, Sandra; Lowery-Moore, Hollis; Farrow, Vicky

2008-01-01

This article describes collaborative efforts to frame university teacher preparation program activities within transfer of learning and transformative learning theories to promote teacher leadership. Specifically, we describe (a) a community sponsored, public school, campus-based experience during an introductory teacher preparation course; (b) a…

A Comparison of Theory and Experiment for High-speed Free-molecule Flow

NASA Technical Reports Server (NTRS)

Stalder, Jackson R; Goodwin, Glen; Creager, Marcus O

1951-01-01

A comparison is made of free-molecule-flow theory with the results of wind-tunnel tests performed to determine the drag and temperature-rise characteristics of a transverse circular cylinder. The measured values of the cylinder center-point temperature confirmed the salient point of the heat-transfer analysis which was the prediction that an insulated cylinder would attain a temperature higher than the stagnation temperature of the stream. Good agreement was obtained between the theoretical and the experimental values for the drag coefficient.

Cross talk analysis in multicore optical fibers by supermode theory.

PubMed

Szostkiewicz, Lukasz; Napierala, Marek; Ziolowicz, Anna; Pytel, Anna; Tenderenda, Tadeusz; Nasilowski, Tomasz

2016-08-15

We discuss the theoretical aspects of core-to-core power transfer in multicore fibers relying on supermode theory. Based on a dual core fiber model, we investigate the consequences of this approach, such as the influence of initial excitation conditions on cross talk. Supermode interpretation of power coupling proves to be intuitive and thus may lead to new concepts of multicore fiber-based devices. As a conclusion, we propose a definition of a uniform cross talk parameter that describes multicore fiber design.

A Short Account of RRKM Theory of Unimolecular Reactions and of Marcus Theory of Electron Transfer in a Historical Perspective

ERIC Educational Resources Information Center

Di Giacomo, Francesco

2015-01-01

The RRKM Theory of Unimolecular Reactions and Marcus Theory of Electron Transfer are here briefly discussed in a historical perspective. In the final section, after a general discussion on the educational usefulness of teaching chemistry in a historical framework, hints are given on how some characteristics of Marcus' work could be introduced in…

Coherence, Energy and Charge Transfers in De-Excitation Pathways of Electronic Excited State of Biomolecules in Photosynthesis

NASA Astrophysics Data System (ADS)

Bohr, Henrik G.; Malik, F. Bary

2013-11-01

The observed multiple de-excitation pathways of photo-absorbed electronic excited state in the peridinin-chlorophyll complex, involving both energy and charge transfers among its constituents, are analyzed using the bio-Auger (B-A) theory. It is also shown that the usually used Förster-Dexter theory, which does not allow for charge transfer, is a special case of B-A theory. The latter could, under appropriate circumstances, lead to excimers.

The Myth of Fair Prices: A Graphical Analysis.

ERIC Educational Resources Information Center

Yanchus, Dennis; de Vanssay, Xavier

2003-01-01

Illustrates how fair price policies can be explained to undergraduate students by applying simple graphical methods normally used in general equilibrium trade theory. Indicates that fair price strategies can be looked upon as a suboptimal device for redistributing the gains from trade as compared with a transfer of funds. (JEH)

Longitudinal Analysis of Teacher Education: The Case of History Teachers

ERIC Educational Resources Information Center

Martell, Christopher Charles

2011-01-01

In the United States, learning history has traditionally been rooted in a transmission-oriented view of teaching and learning. From this perspective, teachers transfer their historical knowledge to their students. Alternatively, this dissertation positions itself within constructivist theories of teaching and learning, where learning is a process…

Developing a framework for transferring knowledge into action: a thematic analysis of the literature

PubMed Central

Ward, Vicky; House, Allan; Hamer, Susan

2010-01-01

Objectives Although there is widespread agreement about the importance of transferring knowledge into action, we still lack high quality information about what works, in which settings and with whom. Whilst there are a large number of models and theories for knowledge transfer interventions, they are untested meaning that their applicability and relevance is largely unknown. This paper describes the development of a conceptual framework of translating knowledge into action and discusses how it can be used for developing a useful model of the knowledge transfer process. Methods A narrative review of the knowledge transfer literature identified 28 different models which explained all or part of the knowledge transfer process. The models were subjected to a thematic analysis to identify individual components and the types of processes used when transferring knowledge into action. The results were used to build a conceptual framework of the process. Results Five common components of the knowledge transfer process were identified: problem identification and communication; knowledge/research development and selection; analysis of context; knowledge transfer activities or interventions; and knowledge/research utilization. We also identified three types of knowledge transfer processes: a linear process; a cyclical process; and a dynamic multidirectional process. From these results a conceptual framework of knowledge transfer was developed. The framework illustrates the five common components of the knowledge transfer process and shows that they are connected via a complex, multidirectional set of interactions. As such the framework allows for the individual components to occur simultaneously or in any given order and to occur more than once during the knowledge transfer process. Conclusion Our framework provides a foundation for gathering evidence from case studies of knowledge transfer interventions. We propose that future empirical work is designed to test and refine the relevant importance and applicability of each of the components in order to build more useful models of knowledge transfer which can serve as a practical checklist for planning or evaluating knowledge transfer activities. PMID:19541874

Vibrational study and Natural Bond Orbital analysis of serotonin in monomer and dimer states by density functional theory

NASA Astrophysics Data System (ADS)

Borah, Mukunda Madhab; Devi, Th. Gomti

2018-06-01

The vibrational spectral analysis of Serotonin and its dimer were carried out using the Fourier Transform Infrared (FTIR) and Raman techniques. The equilibrium geometrical parameters, harmonic vibrational wavenumbers, Frontier orbitals, Mulliken atomic charges, Natural Bond orbitals, first order hyperpolarizability and some optimized energy parameters were computed by density functional theory with 6-31G(d,p) basis set. The detailed analysis of the vibrational spectra have been carried out by computing Potential Energy Distribution (PED, %) with the help of Vibrational Energy Distribution Analysis (VEDA) program. The second order delocalization energies E(2) confirms the occurrence of intramolecular Charge Transfer (ICT) within the molecule. The computed wavenumbers of Serotonin monomer and dimer were found in good agreement with the experimental Raman and IR values.

BPF Theory-Based Design Method for Wireless Power Transfer System by Use of Magnetically Coupled Resonators

NASA Astrophysics Data System (ADS)

Awai, Ikuo

A wireless power transfer system based on two coupled resonators is analyzed by the filter design theory. Many useful relations between the equivalent circuit components are derived to comply with the change of power transfer condition along with the basic design of the system. Some design examples are given to deepen understanding of the theory and thus to stimulate using it for the system design. The effect of the resonator losses is also addressed to show the robustness of the theory, indicating the circuit loss of almost 10 dB does not deteriorate the matching condition too much.

Numerical simulations of electromagnetic scattering by Solar system objects

NASA Astrophysics Data System (ADS)

Dlugach, Janna M.

2016-11-01

Having been profoundly stimulated by the seminal work of Viktor V. Sobolev, I have been involved in multi-decadal research in the fields of radiative transfer, electromagnetic scattering by morphologically complex particles and particulate media, and planetary remote sensing. Much of this research has been done in close collaboration with other "descendants" of Academician Sobolev. This tutorial paper gives a representative overview of the results of extensive numerical simulations (in the vast majority carried out in collaboration with Michael Mishchenko) used to analyze remote-sensing observations of Solar system objects and based on highly accurate methods of the radiative transfer theory and direct computer solvers of the Maxwell equations. Using the atmosphere of Jupiter as a proving ground and performing T-matrix and radiative-transfer calculations helps demonstrate the strong effect of aerosol-particle shapes on the accuracy of remote-sensing retrievals. I then discuss the application of the T-matrix method, a numerically exact solution of the vector radiative transfer equation, and the theory of coherent backscattering to an analysis of polarimetric radar observations of Saturn's rings. Numerical modeling performed by using the superposition T-matrix method in application to cometary dust in the form of aggregates serves to reproduce the results of polarimetric observations of the distant comet C/2010 S1. On the basis of direct computer solutions of the Maxwell equations, it is demonstrated that all backscattering effects predicted by the low-density theories of radiative transfer and coherent backscattering can also be identified for media with volume packing densities typically encountered in natural and artificial environments. This result implies that spectacular opposition effects observed for some high-albedo atmoshereless Solar system bodies can be attributed to coherent backscattering of sunlight by regolith layers composed of microscopic particles.

Marcus Theory: Thermodynamics CAN Control the Kinetics of Electron Transfer Reactions

ERIC Educational Resources Information Center

Silverstein, Todd P.

2012-01-01

Although it is generally true that thermodynamics do not influence kinetics, this is NOT the case for electron transfer reactions in solution. Marcus Theory explains why this is so, using straightforward physical chemical principles such as transition state theory, Arrhenius' Law, and the Franck-Condon Principle. Here the background and…

Knowledge-for-Action Theories in Evaluation: Knowledge Utilization, Diffusion, Implementation, Transfer, and Translation

ERIC Educational Resources Information Center

Ottoson, Judith M.

2009-01-01

Five knowledge-for-action theories are summarized and compared in this chapter for their evaluation implications: knowledge utilization, diffusion, implementation, transfer, and translation. Usually dispersed across multiple fields and disciplines, these theories are gathered here for a common focus on knowledge and change. Knowledge in some form…

Rudolph A. Marcus and His Theory of Electron Transfer Reactions

Science.gov Websites

early 1950s and soon discovered ... a strong experimental program at Brookhaven on electron-transfer experimental work provided the first verification of several of the predictions of his theory. This, in turn Marcus theory, namely, experimental evidence for the so-called "inverted region" where rates

Optical rectenna operation: where Maxwell meets Einstein

NASA Astrophysics Data System (ADS)

Joshi, Saumil; Moddel, Garret

2016-07-01

Optical rectennas are antenna-coupled diode rectifiers that receive and convert optical-frequency electromagnetic radiation into DC output. The analysis of rectennas is carried out either classically using Maxwell’s wave-like approach, or quantum-mechanically using Einstein’s particle-like approach for electromagnetic radiation. One of the characteristics of classical operation is that multiple photons transfer their energy to individual electrons, whereas in quantum operation each photon transfers its energy to each electron. We analyze the correspondence between the two approaches by comparing rectenna response first to monochromatic illumination obtained using photon-assisted tunnelling theory and classical theory. Applied to broadband rectenna operation, this correspondence provides clues to designing a rectenna solar cell that has the potential to exceed the 44% quantum-limited conversion efficiency. The comparison of operating regimes shows how optical rectenna operation differs from microwave rectenna operation.

Finite Element Analysis of Poroelastic Composites Undergoing Thermal and Gas Diffusion

NASA Technical Reports Server (NTRS)

Salamon, N. J. (Principal Investigator); Sullivan, Roy M.; Lee, Sunpyo

1995-01-01

A theory for time-dependent thermal and gas diffusion in mechanically time-rate-independent anisotropic poroelastic composites has been developed. This theory advances previous work by the latter two authors by providing for critical transverse shear through a three-dimensional axisymmetric formulation and using it in a new hypothesis for determining the Biot fluid pressure-solid stress coupling factor. The derived governing equations couple material deformation with temperature and internal pore pressure and more strongly couple gas diffusion and heat transfer than the previous theory. Hence the theory accounts for the interactions between conductive heat transfer in the porous body and convective heat carried by the mass flux through the pores. The Bubnov Galerkin finite element method is applied to the governing equations to transform them into a semidiscrete finite element system. A numerical procedure is developed to solve the coupled equations in the space and time domains. The method is used to simulate two high temperature tests involving thermal-chemical decomposition of carbon-phenolic composites. In comparison with measured data, the results are accurate. Moreover unlike previous work, for a single set of poroelastic parameters, they are consistent with two measurements in a restrained thermal growth test.

Nonequilibrium Energy Transfer at Nanoscale: A Unified Theory from Weak to Strong Coupling

PubMed Central

Wang, Chen; Ren, Jie; Cao, Jianshu

2015-01-01

Unraveling the microscopic mechanism of quantum energy transfer across two-level systems provides crucial insights to the optimal design and potential applications of low-dimensional nanodevices. Here, we study the non-equilibrium spin-boson model as a minimal prototype and develop a fluctuation-decoupled quantum master equation approach that is valid ranging from the weak to the strong system-bath coupling regime. The exact expression of energy flux is analytically established, which dissects the energy transfer as multiple boson processes with even and odd parity. Our analysis provides a unified interpretation of several observations, including coherence-enhanced heat flux and negative differential thermal conductance. The results will have broad implications for the fine control of energy transfer in nano-structural devices. PMID:26152705

Phylogenetics.

PubMed

Sleator, Roy D

2011-04-01

The recent rapid expansion in the DNA and protein databases, arising from large-scale genomic and metagenomic sequence projects, has forced significant development in the field of phylogenetics: the study of the evolutionary relatedness of the planet's inhabitants. Advances in phylogenetic analysis have greatly transformed our view of the landscape of evolutionary biology, transcending the view of the tree of life that has shaped evolutionary theory since Darwinian times. Indeed, modern phylogenetic analysis no longer focuses on the restricted Darwinian-Mendelian model of vertical gene transfer, but must also consider the significant degree of lateral gene transfer, which connects and shapes almost all living things. Herein, I review the major tree-building methods, their strengths, weaknesses and future prospects.

Attachment theory as a guide to understanding and working with transference and the real relationship in psychotherapy.

PubMed

Gelso, Charles J; Palma, Beatriz; Bhatia, Avantika

2013-11-01

Recent decades have witnessed an extraordinary amount of conceptual and empirical work on attachment theory in psychology and psychotherapy. Attachment theory is discussed in the present article as a way of understanding and fostering therapeutic work with 2 other key relationship constructs that have been theorized to be elements of all psychotherapies: client transference and the real relationship existing between the therapist and patient. Fundamental features of attachment, transference, and the real relationship are summarized. Particular emphasis is given to the role of the therapist as a secure base and a safe haven within the real relationship, and to the patient's internal working model as it relates to transference. A case of long-term psychodynamic psychotherapy conducted by the first author is presented to illuminate the 3 main constructs. The case demonstrates both the usefulness of attachment theory and the fact that any single theory cannot explain all of the complex features of a given treatment. © 2013 Wiley Periodicals, Inc.

Examination of the teaching styles of nursing professional development specialists, part I: best practices in adult learning theory, curriculum development, and knowledge transfer.

PubMed

Curran, Mary K

2014-05-01

The American Nurses Association advocates for nursing professional development (NPD) specialists to have an earned graduate degree, as well as educational and clinical expertise. However, many NPD specialists have limited exposure to adult learning theory. Limited exposure to adult learning theory may affect NPD educational practices, learning outcomes, organizational knowledge transfer, and subsequently, the professional development of the nurses they serve and quality of nursing care. An examination of current teaching practices may reveal opportunities for NPD specialists to enhance educational methods to promote learning, learning transfer, and organizational knowledge and excellence. This article, the first in a two-part series, examines best practices of adult learning theories, nursing professional development, curriculum design, and knowledge transfer. Part II details the results of a correlational study that examined the effects of four variables on the use of adult learning theory to guide curriculum development for NPD specialists in hospitals. Copyright 2014, SLACK Incorporated.

Teaching for Transfer: Insights from Theory and Practices in Primary-Level French-Second-Language Classrooms

ERIC Educational Resources Information Center

Thomas, Reed; Mady, Callie

2014-01-01

This paper illustrates teaching for transfer across languages by synthesizing key insights from theory and previously published research alongside our case study data from primary-level teachers in core French-second-language (CF) classrooms in Ontario, Canada. Drawing on research that redefines language transfer as a resource, this study drew on…

Year 7 Students, Information Literacy, and Transfer: A Grounded Theory

ERIC Educational Resources Information Center

Herring, James E.

2011-01-01

This study examined the views of year 7 students, teacher librarians, and teachers in three state secondary schools in rural New South Wales, Australia, on information literacy and transfer. The aims of the study included the development of a grounded theory in relation to information literacy and transfer in these schools. The study's perspective…

Features of control systems analysis with discrete control devices using mathematical packages

NASA Astrophysics Data System (ADS)

Yakovleva, E. M.; Faerman, V. A.

2017-02-01

The article contains presentation of basic provisions of the theory of automatic pulse control systems as well as methods of analysis of such systems using the mathematical software widespread in the academic environment. The pulse systems under research are considered as analogues systems interacting among themselves, including sensors, amplifiers, controlled objects, and discrete parts. To describe such systems, one uses a mathematical apparatus of difference equations as well as discrete transfer functions. To obtain a transfer function of the open-loop system, being important from the point of view of the analysis of control systems, one uses mathematical packages Mathcad and Matlab. Despite identity of the obtained result, the way of its achievement from the point of view of user’s action is various for the specified means. In particular, Matlab uses a structural model of the control system while Mathcad allows only execution of a chain of operator transforms. It is worth noting that distinctions taking place allow considering transformation of signals during interaction of the linear and continuous parts of the control system from different sides. The latter can be used in an educational process for the best assimilation of the course of the control system theory by students.

Origin of attraction in p-benzoquinone complexes with benzene and p-hydroquinone.

PubMed

Tsuzuki, Seiji; Uchimaru, Tadafumi; Ono, Taizo

2017-08-30

The origin of the attraction in charge-transfer complexes (a p-hydroquinone-p-benzoquinone complex and benzene complexes with benzoquinone, tetracyanoethylene and Br 2 ) was analyzed using distributed multipole analysis and symmetry-adapted perturbation theory. Both methods show that the dispersion interactions are the primary source of the attraction in these charge-transfer complexes followed by the electrostatic interactions. The natures of the intermolecular interactions in these complexes are close to the π/π interactions of neutral aromatic molecules. The electrostatic interactions play important roles in determining the magnitude of the attraction. The contribution of charge-transfer interactions to the attraction is not large compared with the dispersion interactions in these complexes.

Quantum chemical characterization of N-(2-hydroxybenzylidene)acetohydrazide (HBAH): a detailed vibrational and NLO analysis.

PubMed

Tamer, Ömer; Avcı, Davut; Atalay, Yusuf

2014-01-03

The molecular modeling of N-(2-hydroxybenzylidene)acetohydrazide (HBAH) was carried out using B3LYP, CAMB3LYP and PBE1PBE levels of density functional theory (DFT). The molecular structure of HBAH was solved by means of IR, NMR and UV-vis spectroscopies. In order to find the stable conformers, conformational analysis was performed based on B3LYP level. A detailed vibrational analysis was made on the basis of potential energy distribution (PED). HOMO and LUMO energies were calculated, and the obtained energies displayed that charge transfer occurs in HBAH. NLO analysis indicated that HBAH can be used as an effective NLO material. NBO analysis also proved that charge transfer, conjugative interactions and intramolecular hydrogen bonding interactions occur through HBAH. Additionally, major contributions from molecular orbitals to the electronic transitions were investigated theoretically. Copyright © 2013 Elsevier B.V. All rights reserved.

Charge-transfer channel in quantum dot-graphene hybrid materials

NASA Astrophysics Data System (ADS)

Cao, Shuo; Wang, Jingang; Ma, Fengcai; Sun, Mengtao

2018-04-01

The energy band theory of a classical semiconductor can qualitatively explain the charge-transfer process in low-dimensional hybrid colloidal quantum dot (QD)-graphene (GR) materials; however, the definite charge-transfer channels are not clear. Using density functional theory (DFT) and time-dependent DFT, we simulate the hybrid QD-GR nanostructure, and by constructing its orbital interaction diagram, we show the quantitative coupling characteristics of the molecular orbitals (MOs) of the hybrid structure. The main MOs are derived from the fragment MOs (FOs) of GR, and the Cd13Se13 QD FOs merge with the GR FOs in a certain proportion to afford the hybrid system. Upon photoexcitation, electrons in the GR FOs jump to the QD FOs, leaving holes in the GR FOs, and the definite charge-transfer channels can be found by analyzing the complex MOs coupling. The excited electrons and remaining holes can also be localized in the GR or the QD or transfer between the QD and GR with different absorption energies. The charge-transfer process for the selected excited states of the hybrid QD-GR structure are testified by the charge difference density isosurface. The natural transition orbitals, charge-transfer length analysis and 2D site representation of the transition density matrix also verify the electron-hole delocalization, localization, or coherence chacracteristics of the selected excited states. Therefore, our research enhances understanding of the coupling mechanism of low-dimensional hybrid materials and will aid in the design and manipulation of hybrid photoelectric devices for practical application in many fields.

Charge-transfer channel in quantum dot-graphene hybrid materials.

PubMed

Cao, Shuo; Wang, Jingang; Ma, Fengcai; Sun, Mengtao

2018-04-06

The energy band theory of a classical semiconductor can qualitatively explain the charge-transfer process in low-dimensional hybrid colloidal quantum dot (QD)-graphene (GR) materials; however, the definite charge-transfer channels are not clear. Using density functional theory (DFT) and time-dependent DFT, we simulate the hybrid QD-GR nanostructure, and by constructing its orbital interaction diagram, we show the quantitative coupling characteristics of the molecular orbitals (MOs) of the hybrid structure. The main MOs are derived from the fragment MOs (FOs) of GR, and the Cd 13 Se 13 QD FOs merge with the GR FOs in a certain proportion to afford the hybrid system. Upon photoexcitation, electrons in the GR FOs jump to the QD FOs, leaving holes in the GR FOs, and the definite charge-transfer channels can be found by analyzing the complex MOs coupling. The excited electrons and remaining holes can also be localized in the GR or the QD or transfer between the QD and GR with different absorption energies. The charge-transfer process for the selected excited states of the hybrid QD-GR structure are testified by the charge difference density isosurface. The natural transition orbitals, charge-transfer length analysis and 2D site representation of the transition density matrix also verify the electron-hole delocalization, localization, or coherence chacracteristics of the selected excited states. Therefore, our research enhances understanding of the coupling mechanism of low-dimensional hybrid materials and will aid in the design and manipulation of hybrid photoelectric devices for practical application in many fields.

Information theory and robotics meet to study predator-prey interactions

NASA Astrophysics Data System (ADS)

Neri, Daniele; Ruberto, Tommaso; Cord-Cruz, Gabrielle; Porfiri, Maurizio

2017-07-01

Transfer entropy holds promise to advance our understanding of animal behavior, by affording the identification of causal relationships that underlie animal interactions. A critical step toward the reliable implementation of this powerful information-theoretic concept entails the design of experiments in which causal relationships could be systematically controlled. Here, we put forward a robotics-based experimental approach to test the validity of transfer entropy in the study of predator-prey interactions. We investigate the behavioral response of zebrafish to a fear-evoking robotic stimulus, designed after the morpho-physiology of the red tiger oscar and actuated along preprogrammed trajectories. From the time series of the positions of the zebrafish and the robotic stimulus, we demonstrate that transfer entropy correctly identifies the influence of the stimulus on the focal subject. Building on this evidence, we apply transfer entropy to study the interactions between zebrafish and a live red tiger oscar. The analysis of transfer entropy reveals a change in the direction of the information flow, suggesting a mutual influence between the predator and the prey, where the predator adapts its strategy as a function of the movement of the prey, which, in turn, adjusts its escape as a function of the predator motion. Through the integration of information theory and robotics, this study posits a new approach to study predator-prey interactions in freshwater fish.

Carotenoid-to-bacteriochlorophyll energy transfer through vibronic coupling in LH2 from Phaeosprillum molischianum.

PubMed

Thyrhaug, Erling; Lincoln, Craig N; Branchi, Federico; Cerullo, Giulio; Perlík, Václav; Šanda, František; Lokstein, Heiko; Hauer, Jürgen

2018-03-01

The peripheral light-harvesting antenna complex (LH2) of purple photosynthetic bacteria is an ideal testing ground for models of structure-function relationships due to its well-determined molecular structure and ultrafast energy deactivation. It has been the target for numerous studies in both theory and ultrafast spectroscopy; nevertheless, certain aspects of the convoluted relaxation network of LH2 lack a satisfactory explanation by conventional theories. For example, the initial carotenoid-to-bacteriochlorophyll energy transfer step necessary on visible light excitation was long considered to follow the Förster mechanism, even though transfer times as short as 40 femtoseconds (fs) have been observed. Such transfer times are hard to accommodate by Förster theory, as the moderate coupling strengths found in LH2 suggest much slower transfer within this framework. In this study, we investigate LH2 from Phaeospirillum (Ph.) molischianum in two types of transient absorption experiments-with narrowband pump and white-light probe resulting in 100 fs time resolution, and with degenerate broadband 10 fs pump and probe pulses. With regard to the split Q x band in this system, we show that vibronically mediated transfer explains both the ultrafast carotenoid-to-B850 transfer, and the almost complete lack of transfer to B800. These results are beyond Förster theory, which predicts an almost equal partition between the two channels.

A Conceptual Framework for Educational Design at Modular Level to Promote Transfer of Learning

ERIC Educational Resources Information Center

Botma, Yvonne; Van Rensburg, G. H.; Coetzee, I. M.; Heyns, T.

2015-01-01

Students bridge the theory-practice gap when they apply in practice what they have learned in class. A conceptual framework was developed that can serve as foundation to design for learning transfer at modular level. The framework is based on an adopted and adapted systemic model of transfer of learning, existing learning theories, constructive…

Arms Transfers: A System Dynamics Analysis Focusing on Regional Stability.

DTIC Science & Technology

1983-12-01

tive manner fails. 48 The following illustrates a part of the nature and effects of change on individuals in society. Emile Durkheinm undertook a study...a system, and that not all societal groups are the same. Durkheim insisted that his theory of anowia must be interpreted frorr a contingency point of

Valuing the Adult Learner in E-Learning: A Conceptual Model for Corporate Settings

ERIC Educational Resources Information Center

Waight, Consuelo L.; Stewart, Barbara

2005-01-01

The framework describes that e-Learning engagement, learning and transfer within corporate settings can possibly be achieved if antecedents such as needs assessment, learner analysis, for example, and moderators such as return on investment, learning theories, for example, are adhered. The realization of antecedents and moderators, however, are…

Predictors of Music Sight-Reading Ability in High School Wind Players

ERIC Educational Resources Information Center

Gromko, Joyce Eastlund

2004-01-01

The purpose of this study, grounded in near-transfer theory, was to investigate relationships among music sight-reading and tonal and rhythmic audiation, visual field articulation, spatial orientation and visualization, and achievement in math concepts and reading comprehension. A regression analysis with data from four high schools (N = 98) in…

A Critical Analysis of Hypermedia and Virtual Learning Environments.

ERIC Educational Resources Information Center

Oliver, Kevin M.

The use of hypermedia in education is supported by cognitive flexibility theory which indicates transfer of knowledge to real-world settings is improved when that material is learned in a case-based, associative network emphasizing complexity and links to related information. Hypermedia is further assumed to benefit education, because it resembles…

The primer vector in linear, relative-motion equations. [spacecraft trajectory optimization

NASA Technical Reports Server (NTRS)

1980-01-01

Primer vector theory is used in analyzing a set of linear, relative-motion equations - the Clohessy-Wiltshire equations - to determine the criteria and necessary conditions for an optimal, N-impulse trajectory. Since the state vector for these equations is defined in terms of a linear system of ordinary differential equations, all fundamental relations defining the solution of the state and costate equations, and the necessary conditions for optimality, can be expressed in terms of elementary functions. The analysis develops the analytical criteria for improving a solution by (1) moving any dependent or independent variable in the initial and/or final orbit, and (2) adding intermediate impulses. If these criteria are violated, the theory establishes a sufficient number of analytical equations. The subsequent satisfaction of these equations will result in the optimal position vectors and times of an N-impulse trajectory. The solution is examined for the specific boundary conditions of (1) fixed-end conditions, two-impulse, and time-open transfer; (2) an orbit-to-orbit transfer; and (3) a generalized rendezvous problem. A sequence of rendezvous problems is solved to illustrate the analysis and the computational procedure.

Transverse Vibration of Tapered Single-Walled Carbon Nanotubes Embedded in Viscoelastic Medium

NASA Astrophysics Data System (ADS)

Lei, Y. J.; Zhang, D. P.; Shen, Z. B.

2017-12-01

Based on the nonlocal theory, Euler-Bernoulli beam theory and Kelvin viscoelastic foundation model, free transverse vibration is studied for a tapered viscoelastic single-walled carbon nanotube (visco-SWCNT) embedded in a viscoelastic medium. Firstly, the governing equations for vibration analysis are established. And then, we derive the natural frequencies in closed form for SWCNTs with arbitrary boundary conditions by applying transfer function method and perturbation method. Numerical results are also presented to discuss the effects of nonlocal parameter, relaxation time and taper parameter of SWCNTs, and material property parameters of the medium. This study demonstrates that the proposed model is available for vibration analysis of the tapered SWCNTs-viscoelastic medium coupling system.

Impact of charge-transfer excitons in regioregular polythiophene on the charge separation at polythiophene-fullerene heterojunctions

NASA Astrophysics Data System (ADS)

Polkehn, M.; Tamura, H.; Burghardt, I.

2018-01-01

This study addresses the mechanism of ultrafast charge separation in regioregular oligothiophene-fullerene assemblies representative of poly-3-hexylthiophene (P3HT)-[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) heterojunctions, with special emphasis on the inclusion of charge transfer excitons in the oligothiophene phase. The formation of polaronic inter-chain charge separated species in highly ordered oligothiophene has been demonstrated in recent experiments and could have a significant impact on the net charge transfer to the fullerene acceptor. The present approach combines a first-principles parametrized multi-site Hamiltonian, based on time-dependent density functional theory calculations, with accurate quantum dynamics simulations using the multi-layer multi-configuration time-dependent Hartree method. Quantum dynamical studies are carried out for up to 182 electronic states and 112 phonon modes. The present analysis follows up on our previous study of (Huix-Rotllant et al 2015 J. Phys. Chem. Lett. 6 1702) and significantly expands the scope of this analysis by including the dynamical role of charge transfer excitons. Our investigation highlights the pronounced mixing of photogenerated Frenkel excitons with charge transfer excitons in the oligothiophene domain, and the opening of new transfer channels due the creation of such charge-separated species. As a result, it turns out that the interfacial donor/acceptor charge transfer state can be largely circumvented due to the presence of charge transfer excitons. However, the latter states in turn act as a trap, such that the free carrier yield observed on ultrafast time scales is tangibly reduced. The present analysis underscores the complexity of the transfer pathways at P3HT-PCBM type junctions.

Fragment-orbital tunneling currents and electronic couplings for analysis of molecular charge-transfer systems.

PubMed

Hwang, Sang-Yeon; Kim, Jaewook; Kim, Woo Youn

2018-04-04

In theoretical charge-transfer research, calculation of the electronic coupling element is crucial for examining the degree of the electronic donor-acceptor interaction. The tunneling current (TC), representing the magnitudes and directions of electron flow, provides a way of evaluating electronic couplings, along with the ability of visualizing how electrons flow in systems. Here, we applied the TC theory to π-conjugated organic dimer systems, in the form of our fragment-orbital tunneling current (FOTC) method, which uses the frontier molecular-orbitals of system fragments as diabatic states. For a comprehensive test of FOTC, we assessed how reasonable the computed electronic couplings and the corresponding TC densities are for the hole- and electron-transfer databases HAB11 and HAB7. FOTC gave 12.5% mean relative unsigned error with regard to the high-level ab initio reference. The shown performance is comparable with that of fragment-orbital density functional theory, which gave the same error by 20.6% or 13.9% depending on the formulation. In the test of a set of nucleobase π stacks, we showed that the original TC expression is also applicable to nondegenerate cases under the condition that the overlap between the charge distributions of diabatic states is small enough to offset the energy difference. Lastly, we carried out visual analysis on the FOTC densities of thiophene dimers with different intermolecular alignments. The result depicts an intimate topological connection between the system geometry and electron flow. Our work provides quantitative and qualitative grounds for FOTC, showing it to be a versatile tool in characterization of molecular charge-transfer systems.

Comparison of classical reaction paths and tunneling paths studied with the semiclassical instanton theory.

PubMed

Meisner, Jan; Markmeyer, Max N; Bohner, Matthias U; Kästner, Johannes

2017-08-30

Atom tunneling in the hydrogen atom transfer reaction of the 2,4,6-tri-tert-butylphenyl radical to 3,5-di-tert-butylneophyl, which has a short but strongly curved reaction path, was investigated using instanton theory. We found the tunneling path to deviate qualitatively from the classical intrinsic reaction coordinate, the steepest-descent path in mass-weighted Cartesian coordinates. To perform that comparison, we implemented a new variant of the predictor-corrector algorithm for the calculation of the intrinsic reaction coordinate. We used the reaction force analysis method as a means to decompose the reaction barrier into structural and electronic components. Due to the narrow energy barrier, atom tunneling is important in the abovementioned reaction, even above room temperature. Our calculated rate constants between 350 K and 100 K agree well with experimental values. We found a H/D kinetic isotope effect of almost 10 6 at 100 K. Tunneling dominates the protium transfer below 400 K and the deuterium transfer below 300 K. We compared the lengths of the tunneling path and the classical path for the hydrogen atom transfer in the reaction HCl + Cl and quantified the corner cutting in this reaction. At low temperature, the tunneling path is about 40% shorter than the classical path.

Excited State Charge Transfer reaction with dual emission from 5-(4-dimethylamino-phenyl)-penta-2,4-dienenitrile: Spectral measurement and theoretical density functional theory calculation

NASA Astrophysics Data System (ADS)

Jana, Sankar; Dalapati, Sasanka; Ghosh, Shalini; Kar, Samiran; Guchhait, Nikhil

2011-07-01

The excited state intramolecular charge transfer process in donor-chromophore-acceptor system 5-(4-dimethylamino-phenyl)-penta-2,4-dienenitrile (DMAPPDN) has been investigated by steady state absorption and emission spectroscopy in combination with Density Functional Theory (DFT) calculations. This flexible donor acceptor molecule DMAPPDN shows dual fluorescence corresponding to emission from locally excited and charge transfer state in polar solvent. Large solvatochromic emission shift, effect of variation of pH and HOMO-LUMO molecular orbital pictures support excited state intramolecular charge transfer process. The experimental findings have been correlated with the calculated structure and potential energy surfaces based on the Twisted Intramolecular Charge Transfer (TICT) model obtained at DFT level using B3LYP functional and 6-31+G( d, p) basis set. The theoretical potential energy surfaces for the excited states have been generated in vacuo and acetonitrile solvent using Time Dependent Density Functional Theory (TDDFT) and Time Dependent Density Functional Theory Polarized Continuum Model (TDDFT-PCM) method, respectively. All the theoretical results show well agreement with the experimental observations.

Study on transport packages used for food freshness preservation based on thermal analysis

NASA Astrophysics Data System (ADS)

Yu, Ying

2016-12-01

In recent time, as the Chinese consumption level increases, the consumption quantity of high-value fruits, vegetables and seafood products have been increasing year by year. As a consequence, the traffic volume of refrigerated products also increases yearly and the popularization degree of the cold-chain transportation enhances. A low-temperature environment should be guaranteed during transportation, thus there is about 40% of diesel oil should be consumed by the refrigerating system and the cold-chain transportation becomes very costly. This study aimed to explore methods that could reduce the cost of transport packages of refrigerated products. On the basis of the heat transfer theory and the fluid mechanics theory, the heat exchanging process of corrugated cases during the operation of refrigerating system was analyzed, the heat transfer process of corrugated cases and refrigerator van was theoretically analyzed and the heat balance equation of corrugated cases was constructed.

On Two-Scale Modelling of Heat and Mass Transfer

NASA Astrophysics Data System (ADS)

Vala, J.; Št'astník, S.

2008-09-01

Modelling of macroscopic behaviour of materials, consisting of several layers or components, whose microscopic (at least stochastic) analysis is available, as well as (more general) simulation of non-local phenomena, complicated coupled processes, etc., requires both deeper understanding of physical principles and development of mathematical theories and software algorithms. Starting from the (relatively simple) example of phase transformation in substitutional alloys, this paper sketches the general formulation of a nonlinear system of partial differential equations of evolution for the heat and mass transfer (useful in mechanical and civil engineering, etc.), corresponding to conservation principles of thermodynamics, both at the micro- and at the macroscopic level, and suggests an algorithm for scale-bridging, based on the robust finite element techniques. Some existence and convergence questions, namely those based on the construction of sequences of Rothe and on the mathematical theory of two-scale convergence, are discussed together with references to useful generalizations, required by new technologies.

Origin of the X-Hal (Hal = Cl, Br) bond-length change in the halogen-bonded complexes.

PubMed

Wang, Weizhou; Hobza, Pavel

2008-05-01

The origin of the X-Hal bond-length change in the halogen bond of the X-Hal...Y type has been investigated at the MP2(full)/6-311++G(d,p) level of theory using a natural bond orbital analysis, atoms in molecules procedure, and electrostatic potential fitting methods. Our results have clearly shown that various theories explaining the nature of the hydrogen bond cannot be applied to explain the origin of the X-Hal bond-length change in the halogen bond. We provide a new explanation for this change. The elongation of the X-Hal bond length is caused by the electron-density transfer to the X-Hal sigma* antibonding orbital. For the blue-shifting halogen bond, the electron-density transfer to the X-Hal sigma* antibonding orbital is only of minor importance; it is the electrostatic attractive interaction that causes the X-Hal bond contraction.

Neural field theory of perceptual echo and implications for estimating brain connectivity

NASA Astrophysics Data System (ADS)

Robinson, P. A.; Pagès, J. C.; Gabay, N. C.; Babaie, T.; Mukta, K. N.

2018-04-01

Neural field theory is used to predict and analyze the phenomenon of perceptual echo in which random input stimuli at one location are correlated with electroencephalographic responses at other locations. It is shown that this echo correlation (EC) yields an estimate of the transfer function from the stimulated point to other locations. Modal analysis then explains the observed spatiotemporal structure of visually driven EC and the dominance of the alpha frequency; two eigenmodes of similar amplitude dominate the response, leading to temporal beating and a line of low correlation that runs from the crown of the head toward the ears. These effects result from mode splitting and symmetry breaking caused by interhemispheric coupling and cortical folding. It is shown how eigenmodes obtained from functional magnetic resonance imaging experiments can be combined with temporal dynamics from EC or other evoked responses to estimate the spatiotemporal transfer function between any two points and hence their effective connectivity.

Optical properties, excitation energy and primary charge transfer in photosystem II: theory meets experiment.

PubMed

Renger, Thomas; Schlodder, Eberhard

2011-01-01

In this review we discuss structure-function relationships of the core complex of photosystem II, as uncovered from analysis of optical spectra of the complex and its subunits. Based on descriptions of optical difference spectra including site directed mutagenesis we propose a revision of the multimer model of the symmetrically arranged reaction center pigments, described by an asymmetric exciton Hamiltonian. Evidence is provided for the location of the triplet state, the identity of the primary electron donor, the localization of the cation and the secondary electron transfer pathway in the reaction center. We also discuss the stationary and time-dependent optical properties of the CP43 and CP47 subunits and the excitation energy transfer and trapping-by-charge-transfer kinetics in the core complex. Copyright © 2011 Elsevier B.V. All rights reserved.

Progress Towards the Vindication of Panspermia

NASA Astrophysics Data System (ADS)

Wickramasinghe, N. C.; Wainwright, M.; Narlikar, J. V.; Rajaratnam, P.; Harris, M. J.; Lloyd, D.

Theories of panspermia are rapidly coming into vogue, with the possibility of the transfer of viable bacterial cells from one planetary abode to another being generally accepted as inevitable. The panspermia models of Hoyle and Wickramasinghe require the transfer of viable bacterial cells from interstellar dust to comets and back into interplanetary and interstellar space. In such a cycle a viable fraction of as little as 10-18 at the inception of a newly formed comet/planet system suffices for cometary panspermia to dominate over competing processes for the origin and transfer of life. The well-attested survival attributes of microbes under extreme conditions, which have recently been discovered, gives credence to the panspermia hypothesis. The prediction of the theory that comets bring microbes onto the Earth at the present time is testable if aseptic collections of stratospheric air above the tropopause can be obtained. We describe a recent collection of this kind and report microbiological analysis that shows the existence of viable cells at 41km, falling to Earth at the rate of a few tonnes per day over the entire globe. Some of these cells have been cultured in the laboratory and found to include microorganisms that are not too different from related species on the Earth. This is in fact what the Hoyle-Wickramasinghe theory predicts. The weight of evidence goes against the more conservative explanation that organisms are being lofted to the high atmosphere from the ground.

Density-based Energy Decomposition Analysis for Intermolecular Interactions with Variationally Determined Intermediate State Energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Q.; Ayers, P.W.; Zhang, Y.

2009-10-28

The first purely density-based energy decomposition analysis (EDA) for intermolecular binding is developed within the density functional theory. The most important feature of this scheme is to variationally determine the frozen density energy, based on a constrained search formalism and implemented with the Wu-Yang algorithm [Q. Wu and W. Yang, J. Chem. Phys. 118, 2498 (2003) ]. This variational process dispenses with the Heitler-London antisymmetrization of wave functions used in most previous methods and calculates the electrostatic and Pauli repulsion energies together without any distortion of the frozen density, an important fact that enables a clean separation of these twomore » terms from the relaxation (i.e., polarization and charge transfer) terms. The new EDA also employs the constrained density functional theory approach [Q. Wu and T. Van Voorhis, Phys. Rev. A 72, 24502 (2005)] to separate out charge transfer effects. Because the charge transfer energy is based on the density flow in real space, it has a small basis set dependence. Applications of this decomposition to hydrogen bonding in the water dimer and the formamide dimer show that the frozen density energy dominates the binding in these systems, consistent with the noncovalent nature of the interactions. A more detailed examination reveals how the interplay of electrostatics and the Pauli repulsion determines the distance and angular dependence of these hydrogen bonds.« less

Transfer potentials shape and equilibrate monetary systems

NASA Astrophysics Data System (ADS)

Fischer, Robert; Braun, Dieter

2003-04-01

We analyze a monetary system of random money transfer on the basis of double entry bookkeeping. Without boundary conditions, we do not reach a price equilibrium and violate text-book formulas of economist's quantity theory ( MV= PQ). To match the resulting quantity of money with the model assumption of a constant price, we have to impose boundary conditions. They either restrict specific transfers globally or impose transfers locally. Both connect through a general framework of transfer potentials. We show that either restricted or imposed transfers can shape Gaussian, tent-shape exponential, Boltzmann-exponential, pareto or periodic equilibrium distributions. We derive the master equation and find its general time-dependent approximate solution. An equivalent of quantity theory for random money transfer under the boundary conditions of transfer potentials is given.

Electrode redox reactions with polarizable molecules.

PubMed

Matyushov, Dmitry V

2018-04-21

A theory of redox reactions involving electron transfer between a metal electrode and a polarizable molecule in solution is formulated. Both the existence of molecular polarizability and its ability to change due to electron transfer distinguish this problem from classical theories of interfacial electrochemistry. When the polarizability is different between the oxidized and reduced states, the statistics of thermal fluctuations driving the reactant over the activation barrier becomes non-Gaussian. The problem of electron transfer is formulated as crossing of two non-parabolic free energy surfaces. An analytical solution for these free energy surfaces is provided and the activation barrier of electrode electron transfer is given in terms of two reorganization energies corresponding to the oxidized and reduced states of the molecule in solution. The new non-Gaussian theory is, therefore, based on two theory parameters in contrast to one-parameter Marcus formulation for electrode reactions. The theory, which is consistent with the Nernst equation, predicts asymmetry between the cathodic and anodic branches of the electrode current. They show different slopes at small electrode overpotentials and become curved at larger overpotentials. However, the curvature of the Tafel plot is reduced compared to the Marcus-Hush model and approaches the empirical Butler-Volmer form with different transfer coefficients for the anodic and cathodic currents.

Electrode redox reactions with polarizable molecules

NASA Astrophysics Data System (ADS)

Matyushov, Dmitry V.

2018-04-01

A theory of redox reactions involving electron transfer between a metal electrode and a polarizable molecule in solution is formulated. Both the existence of molecular polarizability and its ability to change due to electron transfer distinguish this problem from classical theories of interfacial electrochemistry. When the polarizability is different between the oxidized and reduced states, the statistics of thermal fluctuations driving the reactant over the activation barrier becomes non-Gaussian. The problem of electron transfer is formulated as crossing of two non-parabolic free energy surfaces. An analytical solution for these free energy surfaces is provided and the activation barrier of electrode electron transfer is given in terms of two reorganization energies corresponding to the oxidized and reduced states of the molecule in solution. The new non-Gaussian theory is, therefore, based on two theory parameters in contrast to one-parameter Marcus formulation for electrode reactions. The theory, which is consistent with the Nernst equation, predicts asymmetry between the cathodic and anodic branches of the electrode current. They show different slopes at small electrode overpotentials and become curved at larger overpotentials. However, the curvature of the Tafel plot is reduced compared to the Marcus-Hush model and approaches the empirical Butler-Volmer form with different transfer coefficients for the anodic and cathodic currents.

Basic theory for polarized, astrophysical maser radiation in a magnetic field

NASA Technical Reports Server (NTRS)

Watson, William D.

1994-01-01

Fundamental alterations in the theory and resulting behavior of polarized, astrophysical maser radiation in the presence of a magnetic field have been asserted based on a calculation of instabilities in the radiative transfer. I reconsider the radiative transfer and find that the relevant instabilities do not occur. Calculational errors in the previous investigation are identified. In addition, such instabilities would have appeared -- but did not -- in the numerous numerical solutions to the same radiative transfer equations that have been presented in the literature. As a result, all modifications that have been presented in a recent series of papers (Elitzur 1991, 1993) to the theory for polarized maser radiation in the presence of a magnetic field are invalid. The basic theory is thus clarified.

Charge transfer interactions and nonlinear optical properties of push pull chromophore benzaldehyde phenylhydrazone: A vibrational approach

NASA Astrophysics Data System (ADS)

Ravikumar, C.; Joe, I. Hubert; Jayakumar, V. S.

2008-07-01

FT Raman and IR spectra of the crystallized nonlinear optic (NLO) molecule, benzaldehyde phenylhydrazone (BPH) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies of BPH have been investigated with the help of B3LYP density functional theory (DFT) method. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology (SQMFF). From the optimized geometry, the decrease in C-N bond length indicates the electron delocalization over the region of the molecule. The vibrational analysis confirm the charge transfer interaction between the phenyl rings through ≻Cdbnd N-N≺ skeleton.

The more total cognitive load is reduced by cues, the better retention and transfer of multimedia learning: A meta-analysis and two meta-regression analyses.

PubMed

Xie, Heping; Wang, Fuxing; Hao, Yanbin; Chen, Jiaxue; An, Jing; Wang, Yuxin; Liu, Huashan

2017-01-01

Cueing facilitates retention and transfer of multimedia learning. From the perspective of cognitive load theory (CLT), cueing has a positive effect on learning outcomes because of the reduction in total cognitive load and avoidance of cognitive overload. However, this has not been systematically evaluated. Moreover, what remains ambiguous is the direct relationship between the cue-related cognitive load and learning outcomes. A meta-analysis and two subsequent meta-regression analyses were conducted to explore these issues. Subjective total cognitive load (SCL) and scores on a retention test and transfer test were selected as dependent variables. Through a systematic literature search, 32 eligible articles encompassing 3,597 participants were included in the SCL-related meta-analysis. Among them, 25 articles containing 2,910 participants were included in the retention-related meta-analysis and the following retention-related meta-regression, while there were 29 articles containing 3,204 participants included in the transfer-related meta-analysis and the transfer-related meta-regression. The meta-analysis revealed a statistically significant cueing effect on subjective ratings of cognitive load (d = -0.11, 95% CI = [-0.19, -0.02], p < 0.05), retention performance (d = 0.27, 95% CI = [0.08, 0.46], p < 0.01), and transfer performance (d = 0.34, 95% CI = [0.12, 0.56], p < 0.01). The subsequent meta-regression analyses showed that dSCL for cueing significantly predicted dretention for cueing (β = -0.70, 95% CI = [-1.02, -0.38], p < 0.001), as well as dtransfer for cueing (β = -0.60, 95% CI = [-0.92, -0.28], p < 0.001). Thus in line with CLT, adding cues in multimedia materials can indeed reduce SCL and promote learning outcomes, and the more SCL is reduced by cues, the better retention and transfer of multimedia learning.

The more total cognitive load is reduced by cues, the better retention and transfer of multimedia learning: A meta-analysis and two meta-regression analyses

PubMed Central

Hao, Yanbin; Chen, Jiaxue; An, Jing; Wang, Yuxin; Liu, Huashan

2017-01-01

Cueing facilitates retention and transfer of multimedia learning. From the perspective of cognitive load theory (CLT), cueing has a positive effect on learning outcomes because of the reduction in total cognitive load and avoidance of cognitive overload. However, this has not been systematically evaluated. Moreover, what remains ambiguous is the direct relationship between the cue-related cognitive load and learning outcomes. A meta-analysis and two subsequent meta-regression analyses were conducted to explore these issues. Subjective total cognitive load (SCL) and scores on a retention test and transfer test were selected as dependent variables. Through a systematic literature search, 32 eligible articles encompassing 3,597 participants were included in the SCL-related meta-analysis. Among them, 25 articles containing 2,910 participants were included in the retention-related meta-analysis and the following retention-related meta-regression, while there were 29 articles containing 3,204 participants included in the transfer-related meta-analysis and the transfer-related meta-regression. The meta-analysis revealed a statistically significant cueing effect on subjective ratings of cognitive load (d = −0.11, 95% CI = [−0.19, −0.02], p < 0.05), retention performance (d = 0.27, 95% CI = [0.08, 0.46], p < 0.01), and transfer performance (d = 0.34, 95% CI = [0.12, 0.56], p < 0.01). The subsequent meta-regression analyses showed that dSCL for cueing significantly predicted dretention for cueing (β = −0.70, 95% CI = [−1.02, −0.38], p < 0.001), as well as dtransfer for cueing (β = −0.60, 95% CI = [−0.92, −0.28], p < 0.001). Thus in line with CLT, adding cues in multimedia materials can indeed reduce SCL and promote learning outcomes, and the more SCL is reduced by cues, the better retention and transfer of multimedia learning. PMID:28854205

Energy decomposition analysis of single bonds within Kohn-Sham density functional theory.

PubMed

Levine, Daniel S; Head-Gordon, Martin

2017-11-28

An energy decomposition analysis (EDA) for single chemical bonds is presented within the framework of Kohn-Sham density functional theory based on spin projection equations that are exact within wave function theory. Chemical bond energies can then be understood in terms of stabilization caused by spin-coupling augmented by dispersion, polarization, and charge transfer in competition with destabilizing Pauli repulsions. The EDA reveals distinguishing features of chemical bonds ranging across nonpolar, polar, ionic, and charge-shift bonds. The effect of electron correlation is assessed by comparison with Hartree-Fock results. Substituent effects are illustrated by comparing the C-C bond in ethane against that in bis(diamantane), and dispersion stabilization in the latter is quantified. Finally, three metal-metal bonds in experimentally characterized compounds are examined: a [Formula: see text]-[Formula: see text] dimer, the [Formula: see text]-[Formula: see text] bond in dizincocene, and the Mn-Mn bond in dimanganese decacarbonyl.

Infrared laser driven double proton transfer. An optimal control theory study

NASA Astrophysics Data System (ADS)

Abdel-Latif, Mahmoud K.; Kühn, Oliver

2010-02-01

Laser control of ultrafast double proton transfer is investigated for a two-dimensional model system describing stepwise and concerted transfer pathways. The pulse design has been done by employing optimal control theory in combination with the multiconfiguration time-dependent Hartree wave packet propagation. The obtained laser fields correspond to multiple pump-dump pulse sequences. Special emphasis is paid to the relative importance of stepwise and concerted transfer pathways for the driven wave packet and its dependence on the parameters of the model Hamiltonian as well as on the propagation time. While stepwise transfer is dominating in all cases considered, for high barrier systems concerted transfer proceeding via tunneling can make a contribution.

Wireless Power Transfer for Space Applications

NASA Technical Reports Server (NTRS)

Ramos, Gabriel Vazquez; Yuan, Jiann-Shiun

2011-01-01

This paper introduces an implementation for magnetic resonance wireless power transfer for space applications. The analysis includes an equivalent impedance study, loop material characterization, source/load resonance coupling technique, and system response behavior due to loads variability. System characterization is accomplished by executing circuit design from analytical equations and simulations using Matlab and SPICE. The theory was validated by a combination of different experiments that includes loop material consideration, resonance coupling circuits considerations, electric loads considerations and a small scale proof-of-concept prototype. Experiment results shows successful wireless power transfer for all the cases studied. The prototype provided about 4.5 W of power to the load at a separation of -5 cm from the source using a power amplifier rated for 7 W.

Diagnostic criteria for the characterization of quasireversible electron transfer reactions by cyclic square wave voltammetry.

PubMed

Mann, Megan A; Helfrick, John C; Bottomley, Lawrence A

2014-08-19

Theory for cyclic square wave voltammetry of quasireversible electron transfer reactions is presented and experimentally verified. The impact of empirical parameters on the shape of the current-voltage curve is examined. From the trends, diagnostic criteria enabling the use of this waveform as a tool for mechanistic analysis of electrode reaction processes are presented. These criteria were experimentally confirmed using Eu(3+)/Eu(2+), a well-established quasireversible analyte. Using cyclic square wave voltammetry, both the electron transfer coefficient and rate were calculated for this analyte and found to be in excellent agreement with literature. When properly applied, these criteria will enable nonexperts in voltammetry to assign the electrode reaction mechanism and accurately measure electrode reaction kinetics.

Mechanistic information from the first volume profile analysis for a reversible intermolecular electron-transfer reaction involving pentaammine(isonicotinamide)ruthenium and cytochrome c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baensch, B.; Meier, M.; Martinez, P.

1994-10-12

The reversible intermolecular electron-transfer reaction between pentaammine(isonicotinamide)ruthenium(II/III) and horse-heart cytochrome c iron(III/II) was subjected to a detailed kinetic and thermodynamic study as a function of temperature and pressure. Theoretical calculations based on the Marcus-Hush theory were employed to predict all rate and equilibrium constants as well as activation parameters. There is an excellent agreement between the kinetically and thermodynamically determined equilibrium constants and associated pressure parameters. These data are used to construct a volume profile for the overall process, from which it follows that the transition state lies halfway between the reactant and product states on a volume basis. Themore » reorganization in the transition state has reached a similar degree in both directions of the electron-transfer process and corresponds to a {lambda}{sup {double_dagger}} value of 0.44 for this reversible reaction. This is the first complete volume profile analysis for a reversible intermolecular electron-transfer reaction.« less

Electrostatic properties of the pyrimethamine-2,4-dihydroxybenzoic acid cocrystal in methanol studied using transferred electron-density parameters.

PubMed

Faroque, Muhammad Umer; Noureen, Sajida; Ahmed, Maqsood; Tahir, Muhammad Nawaz

2018-01-01

The crystal structure of the cocrystal salt form of the antimalarial drug pyrimethamine with 2,4-dihydroxybenzoic acid in methanol [systematic name: 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimidin-1-ium 2,4-dihydroxybenzoate methanol monosolvate, C 12 H 14 ClN 4 + ·C 7 H 5 O 4 - ·CH 3 OH] has been studied using X-ray diffraction data collected at room temperature. The crystal structure was refined using the classical Independent Atom Model (IAM) and the Multipolar Atom Model by transferring electron-density parameters from the ELMAM2 database. The Cl atom was refined anharmonically. The results of both refinement methods have been compared. The intermolecular interactions have been characterized on the basis of Hirshfeld surface analysis and topological analysis using Bader's theory of Atoms in Molecules. The results show that the molecular assembly is built primarily on the basis of charge transfer between 2,4-dihydroxybenzoic acid and pyrimethamine, which results in strong intermolecular hydrogen bonds. This fact is further validated by the calculation of the electrostatic potential based on transferred electron-density parameters.

Molecular reorganization of selected quinoline derivatives in the ground and excited states—Investigations via static DFT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Błaziak, Kacper; Panek, Jarosław J.; Jezierska, Aneta, E-mail: aneta.jezierska@chem.uni.wroc.pl

2015-07-21

Quinoline derivatives are interesting objects to study internal reorganizations due to the observed excited-state-induced intramolecular proton transfer (ESIPT). Here, we report on computations for selected 12 quinoline derivatives possessing three kinds of intramolecular hydrogen bonds. Density functional theory was employed for the current investigations. The metric and electronic structure simulations were performed for the ground state and first excited singlet and triplet states. The computed potential energy profiles do not show a spontaneous proton transfer in the ground state, whereas excited states exhibit this phenomenon. Atoms in Molecules (AIM) theory was applied to study the nature of hydrogen bonding, whereasmore » Harmonic Oscillator Model of aromaticity index (HOMA) provided data of aromaticity evolution as a derivative of the bridge proton position. The AIM-based topological analysis confirmed the presence of the intramolecular hydrogen bonding. In addition, using the theory, we were able to provide a quantitative illustration of bonding transformation: from covalent to the hydrogen. On the basis of HOMA analysis, we showed that the aromaticity of both rings is dependent on the location of the bridge proton. Further, the computed results were compared with experimental data available. Finally, ESIPT occurrence was compared for the three investigated kinds of hydrogen bridges, and competition between two bridges in one molecule was studied.« less

The Real World of the Ivory Tower: Linking Classroom and Practice via Pedagogical Modeling

ERIC Educational Resources Information Center

Campbell, Carolyn; Scott-Lincourt, Rose; Brennan, Kimberley

2008-01-01

The authors explore the pedagogical principles of congruency, modeling, and transfer of learning through the description and analysis of a course entitled "The Theory and Practice of Anti-oppressive Social Work." Initially reviewing the literature related to the above concepts, they describe an instructor's attempt to explicitly model, via a range…

Alternative Theoretical Bases for the Study of Human Communication: The Rules Perspective.

ERIC Educational Resources Information Center

Cushman, Donald P.

Three potentially useful perspectives for the scientific development of human communication theory are the law model, the systems approach, and the rules paradigm. It is the purpose of this paper to indicate the utility of the rules perspective. For the purposes of this analysis, human communication is viewed as the successful transfer of symbolic…

Biomimetics: its practice and theory.

PubMed

Vincent, Julian F V; Bogatyreva, Olga A; Bogatyrev, Nikolaj R; Bowyer, Adrian; Pahl, Anja-Karina

2006-08-22

Biomimetics, a name coined by Otto Schmitt in the 1950s for the transfer of ideas and analogues from biology to technology, has produced some significant and successful devices and concepts in the past 50 years, but is still empirical. We show that TRIZ, the Russian system of problem solving, can be adapted to illuminate and manipulate this process of transfer. Analysis using TRIZ shows that there is only 12% similarity between biology and technology in the principles which solutions to problems illustrate, and while technology solves problems largely by manipulating usage of energy, biology uses information and structure, two factors largely ignored by technology.

Quantum theory for 1D X-ray free electron laser

DOE PAGES

Anisimov, Petr Mikhaylovich

2017-09-19

Classical 1D X-ray Free Electron Laser (X-ray FEL) theory has stood the test of time by guiding FEL design and development prior to any full-scale analysis. Future X-ray FELs and inverse-Compton sources, where photon recoil approaches an electron energy spread value, push the classical theory to its limits of applicability. After substantial efforts by the community to find what those limits are, there is no universally agreed upon quantum approach to design and development of future X-ray sources. We offer a new approach to formulate the quantum theory for 1D X-ray FELs that has an obvious connection to the classicalmore » theory, which allows for immediate transfer of knowledge between the two regimes. In conclusion, we exploit this connection in order to draw quantum mechanical conclusions about the quantum nature of electrons and generated radiation in terms of FEL variables.« less

Quantum theory for 1D X-ray free electron laser

NASA Astrophysics Data System (ADS)

Anisimov, Petr M.

2018-06-01

Classical 1D X-ray Free Electron Laser (X-ray FEL) theory has stood the test of time by guiding FEL design and development prior to any full-scale analysis. Future X-ray FELs and inverse-Compton sources, where photon recoil approaches an electron energy spread value, push the classical theory to its limits of applicability. After substantial efforts by the community to find what those limits are, there is no universally agreed upon quantum approach to design and development of future X-ray sources. We offer a new approach to formulate the quantum theory for 1D X-ray FELs that has an obvious connection to the classical theory, which allows for immediate transfer of knowledge between the two regimes. We exploit this connection in order to draw quantum mechanical conclusions about the quantum nature of electrons and generated radiation in terms of FEL variables.

Theory of transformation thermal convection for creeping flow in porous media: Cloaking, concentrating, and camouflage

NASA Astrophysics Data System (ADS)

Dai, Gaole; Shang, Jin; Huang, Jiping

2018-02-01

Heat can transfer via thermal conduction, thermal radiation, and thermal convection. All the existing theories of transformation thermotics and optics can treat thermal conduction and thermal radiation, respectively. Unfortunately, thermal convection has seldom been touched in transformation theories due to the lack of a suitable theory, thus limiting applications associated with heat transfer through fluids (liquid or gas). Here, we develop a theory of transformation thermal convection by considering the convection-diffusion equation, the equation of continuity, and the Darcy law. By introducing porous media, we get a set of equations keeping their forms under coordinate transformation. As model applications, the theory helps to show the effects of cloaking, concentrating, and camouflage. Our finite-element simulations confirm the theoretical findings. This work offers a transformation theory for thermal convection, thus revealing novel behaviors associated with potential applications; it not only provides different hints on how to control heat transfer by combining thermal conduction, thermal convection, and thermal radiation, but also benefits mass diffusion and other related fields that contain a set of equations and need to transform velocities at the same time.

Ultrafast energy transfer with competing channels: Non-equilibrium Förster and Modified Redfield theories

NASA Astrophysics Data System (ADS)

Seibt, Joachim; Mančal, Tomáš

2017-05-01

We derive equations of motion for the reduced density matrix of a molecular system which undergoes energy transfer dynamics competing with fast internal conversion channels. Environmental degrees of freedom of such a system have no time to relax to quasi-equilibrium in the electronic excited state of the donor molecule, and thus the conditions of validity of Förster and Modified Redfield theories in their standard formulations do not apply. We derive non-equilibrium versions of the two well-known rate theories and apply them to the case of carotenoid-chlorophyll energy transfer. Although our reduced density matrix approach does not account for the formation of vibronic excitons, it still confirms the important role of the donor ground-state vibrational states in establishing the resonance energy transfer conditions. We show that it is essential to work with a theory valid in a strong system-bath interaction regime to obtain correct dependence of the rates on donor-acceptor energy gap.

Horizontal gene transfer of microbial cellulases into nematode genomes is associated with functional assimilation and gene turnover

PubMed Central

2011-01-01

Background Natural acquisition of novel genes from other organisms by horizontal or lateral gene transfer is well established for microorganisms. There is now growing evidence that horizontal gene transfer also plays important roles in the evolution of eukaryotes. Genome-sequencing and EST projects of plant and animal associated nematodes such as Brugia, Meloidogyne, Bursaphelenchus and Pristionchus indicate horizontal gene transfer as a key adaptation towards parasitism and pathogenicity. However, little is known about the functional activity and evolutionary longevity of genes acquired by horizontal gene transfer and the mechanisms favoring such processes. Results We examine the transfer of cellulase genes to the free-living and beetle-associated nematode Pristionchus pacificus, for which detailed phylogenetic knowledge is available, to address predictions by evolutionary theory for successful gene transfer. We used transcriptomics in seven Pristionchus species and three other related diplogastrid nematodes with a well-defined phylogenetic framework to study the evolution of ancestral cellulase genes acquired by horizontal gene transfer. We performed intra-species, inter-species and inter-genic analysis by comparing the transcriptomes of these ten species and tested for cellulase activity in each species. Species with cellulase genes in their transcriptome always exhibited cellulase activity indicating functional integration into the host's genome and biology. The phylogenetic profile of cellulase genes was congruent with the species phylogeny demonstrating gene longevity. Cellulase genes show notable turnover with elevated birth and death rates. Comparison by sequencing of three selected cellulase genes in 24 natural isolates of Pristionchus pacificus suggests these high evolutionary dynamics to be associated with copy number variations and positive selection. Conclusion We could demonstrate functional integration of acquired cellulase genes into the nematode's biology as predicted by theory. Thus, functional assimilation, remarkable gene turnover and selection might represent key features of horizontal gene transfer events in nematodes. PMID:21232122

Horizontal gene transfer of microbial cellulases into nematode genomes is associated with functional assimilation and gene turnover.

PubMed

Mayer, Werner E; Schuster, Lisa N; Bartelmes, Gabi; Dieterich, Christoph; Sommer, Ralf J

2011-01-13

Natural acquisition of novel genes from other organisms by horizontal or lateral gene transfer is well established for microorganisms. There is now growing evidence that horizontal gene transfer also plays important roles in the evolution of eukaryotes. Genome-sequencing and EST projects of plant and animal associated nematodes such as Brugia, Meloidogyne, Bursaphelenchus and Pristionchus indicate horizontal gene transfer as a key adaptation towards parasitism and pathogenicity. However, little is known about the functional activity and evolutionary longevity of genes acquired by horizontal gene transfer and the mechanisms favoring such processes. We examine the transfer of cellulase genes to the free-living and beetle-associated nematode Pristionchus pacificus, for which detailed phylogenetic knowledge is available, to address predictions by evolutionary theory for successful gene transfer. We used transcriptomics in seven Pristionchus species and three other related diplogastrid nematodes with a well-defined phylogenetic framework to study the evolution of ancestral cellulase genes acquired by horizontal gene transfer. We performed intra-species, inter-species and inter-genic analysis by comparing the transcriptomes of these ten species and tested for cellulase activity in each species. Species with cellulase genes in their transcriptome always exhibited cellulase activity indicating functional integration into the host's genome and biology. The phylogenetic profile of cellulase genes was congruent with the species phylogeny demonstrating gene longevity. Cellulase genes show notable turnover with elevated birth and death rates. Comparison by sequencing of three selected cellulase genes in 24 natural isolates of Pristionchus pacificus suggests these high evolutionary dynamics to be associated with copy number variations and positive selection. We could demonstrate functional integration of acquired cellulase genes into the nematode's biology as predicted by theory. Thus, functional assimilation, remarkable gene turnover and selection might represent key features of horizontal gene transfer events in nematodes.

The potential role of sea spray droplets in facilitating air-sea gas transfer

NASA Astrophysics Data System (ADS)

Andreas, E. L.; Vlahos, P.; Monahan, E. C.

2016-05-01

For over 30 years, air-sea interaction specialists have been evaluating and parameterizing the role of whitecap bubbles in air-sea gas exchange. To our knowledge, no one, however, has studied the mirror image process of whether sea spray droplets can facilitate air-sea gas exchange. We are therefore using theory, data analysis, and numerical modeling to quantify the role of spray on air-sea gas transfer. In this, our first formal work on this subject, we seek the rate-limiting step in spray-mediated gas transfer by evaluating the three time scales that govern the exchange: τ air , which quantifies the rate of transfer between the atmospheric gas reservoir and the surface of the droplet; τ int , which quantifies the exchange rate across the air-droplet interface; and τ aq , which quantifies gas mixing within the aqueous solution droplet.

Spectroscopic analysis and efficient diode-pumped 2.0 μm emission in Ho3+/Tm3+ codoped fluoride glass

NASA Astrophysics Data System (ADS)

Tian, Ying; Jing, Xufeng; Xu, Shiqing

2013-11-01

Intense 2.0 μm emission has been obtained in Ho3+/Tm3+ codoped ZBLAY glass pumped by common laser diode. Three intensity parameters and radiative properties have been determined from the absorption spectrum based on the Judd-Ofelt theory. The 2 μm emission characteristics and the energy transfer mechanism upon excitation of a conventional 800 nm laser diode are investigated. Efficient Tm3+ to Ho3+ energy transfer processes have been observed in present glass and investigated using steady-state and time-resolved optical spectroscopy measurement. The energy transfer microscopic parameter has been calculated with the Inokuti-Hirayama and Förster-Dexter models. High quantum efficiency of 2 μm emission (80.35%) and large energy transfer coefficient from Tm3+ to Ho3+ indicates this Ho3+/Tm3+ codoped ZBLAY glass is a promising material for 2.0 μm laser.

Advanced statistical energy analysis

NASA Astrophysics Data System (ADS)

Heron, K. H.

1994-09-01

A high-frequency theory (advanced statistical energy analysis (ASEA)) is developed which takes account of the mechanism of tunnelling and uses a ray theory approach to track the power flowing around a plate or a beam network and then uses statistical energy analysis (SEA) to take care of any residual power. ASEA divides the energy of each sub-system into energy that is freely available for transfer to other sub-systems and energy that is fixed within the sub-systems that are physically separate and can be interpreted as a series of mathematical models, the first of which is identical to standard SEA and subsequent higher order models are convergent on an accurate prediction. Using a structural assembly of six rods as an example, ASEA is shown to converge onto the exact results while SEA is shown to overpredict by up to 60 dB.

Tools for Atmospheric Radiative Transfer: Streamer and FluxNet. Revised

NASA Technical Reports Server (NTRS)

Key, Jeffrey R.; Schweiger, Axel J.

1998-01-01

Two tools for the solution of radiative transfer problems are presented. Streamer is a highly flexible medium spectral resolution radiative transfer model based on the plane-parallel theory of radiative transfer. Capable of computing either fluxes or radiances, it is suitable for studying radiative processes at the surface or within the atmosphere and for the development of remote-sensing algorithms. FluxNet is a fast neural network-based implementation of Streamer for computing surface fluxes. It allows for a sophisticated treatment of radiative processes in the analysis of large data sets and potential integration into geophysical models where computational efficiency is an issue. Documentation and tools for the development of alternative versions of Fluxnet are available. Collectively, Streamer and FluxNet solve a wide variety of problems related to radiative transfer: Streamer provides the detail and sophistication needed to perform basic research on most aspects of complex radiative processes while the efficiency and simplicity of FluxNet make it ideal for operational use.

An ab-initio coupled mode theory for near field radiative thermal transfer.

PubMed

Chalabi, Hamidreza; Hasman, Erez; Brongersma, Mark L

2014-12-01

We investigate the thermal transfer between finite-thickness planar slabs which support surface phonon polariton modes (SPhPs). The thickness-dependent dispersion of SPhPs in such layered materials provides a unique opportunity to manipulate and enhance the near field thermal transfer. The key accomplishment of this paper is the development of an ab-initio coupled mode theory that accurately describes all of its thermal transfer properties. We illustrate how the coupled mode parameters can be obtained in a direct fashion from the dispersion relation of the relevant modes of the system. This is illustrated for the specific case of a semi-infinite SiC substrate placed in close proximity to a thin slab of SiC. This is a system that exhibits rich physics in terms of its thermal transfer properties, despite the seemingly simple geometry. This includes a universal scaling behavior of the thermal conductance with the slab thickness and spacing. The work highlights and further increases the value of coupled mode theories in rapidly calculating and intuitively understanding near-field transfer.

Shell Thickness Dependence of Interparticle Energy Transfer in Core-Shell ZnSe/ZnSe Quantum Dots Doping with Europium

NASA Astrophysics Data System (ADS)

Liu, Ni; Li, Shuxin; Wang, Caifeng; Li, Jie

2018-04-01

Low-toxic core-shell ZnSe:Eu/ZnS quantum dots (QDs) were prepared through two steps in water solution: nucleation doping and epitaxial shell grown. The structural and morphological characteristics of ZnSe/ZnS:Eu QDs with different shell thickness were explored by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The characteristic photoluminescence (PL) intensity of Eu ions was enhanced whereas that of band-edge luminescence and defect-related luminescence of ZnSe QDs was decreased with increasing shell thickness. The transformation of PL intensity revealed an efficient energy transfer process between ZnSe and Eu. The PL intensity ratio of Eu ions ( I 613) to ZnSe QDs ( I B ) under different shell thickness was systemically analyzed by PL spectra and time-resolved PL spectra. The obtained results were in agreement with the theory analysis results by the kinetic theory of energy transfer, revealing that energy was transmitted in the form of dipole-electric dipole interaction. This particular method of adjusting luminous via changing the shell thickness can provide valuable insights towards the fundamental understanding and application of QDs in the field of optoelectronics.

UV-Vis spectroscopy and density functional study of solvent effect on the charge transfer band of the n → σ* complexes of 2-Methylpyridine and 2-Chloropyridine with molecular iodine

NASA Astrophysics Data System (ADS)

Gogoi, Pallavi; Mohan, Uttam; Borpuzari, Manash Protim; Boruah, Abhijit; Baruah, Surjya Kumar

2017-03-01

UV-Vis spectroscopy has established that Pyridine substitutes form n→σ* charge transfer (CT) complexes with molecular Iodine. This study is a combined approach of purely experimental UV-Vis spectroscopy, Multiple linear regression theory and Computational chemistry to analyze the effect of solvent upon the charge transfer band of 2-Methylpyridine-I2 and 2-Chloropyridine-I2 complexes. Regression analysis verifies the dependence of the CT band upon different solvent parameters. Dielectric constant and refractive index are considered among the bulk solvent parameters and Hansen, Kamlet and Catalan parameters are taken into consideration at the molecular level. Density Functional Theory results explain well the blue shift of the CT bands in polar medium as an outcome of stronger donor acceptor interaction. A logarithmic relation between the bond length of the bridging atoms of the donor and the acceptor with the dielectric constant of the medium is established. Tauc plot and TDDFT study indicates a non-vertical electronic transition in the complexes. Buckingham and Lippert Mataga equations are applied to check the Polarizability effect on the CT band.

Theory and design of variable conductance heat pipes

NASA Technical Reports Server (NTRS)

Marcus, B. D.

1972-01-01

A comprehensive review and analysis of all aspects of heat pipe technology pertinent to the design of self-controlled, variable conductance devices for spacecraft thermal control is presented. Subjects considered include hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, materials compatibility and variable conductance control techniques. The report includes a selected bibliography of pertinent literature, analytical formulations of various models and theories describing variable conductance heat pipe behavior, and the results of numerous experiments on the steady state and transient performance of gas controlled variable conductance heat pipes. Also included is a discussion of VCHP design techniques.

Thermal Analysis Methods and Basic Heat-Transfer Data for a Turbulent Heating Flight Experiment at Mach 20 (Reentry F)

NASA Technical Reports Server (NTRS)

Howard, Floyd G.

1971-01-01

A heat-transfer experiment was flight conducted on a 5 deg half-angle cone, 396.2 cm (13 ft) in length, as it entered the sensible atmosphere under laminar, transitional, and turbulent boundary-layer conditions at a free-stream Mach number of about 20. Accurate turbulent-heat-transfer data with natural transition were obtained for correlation with theories in regions of simultaneous high Mach number, Reynolds number, enthalpy, and total-to-wall temperature ratio. Temperatures were measured at four depths through the 15.24-mm-thick (0.600-in.) beryllium wall. Experimental heating rates at 20 stations on the cone were determined independently from the outermost temperature measurement and from the temperature measurement at the second depth by a single-thermocouple inverse method and also from the temperature histories at all four depths by an integral method. The thermal data analysis procedure, associated problems, and results are presented herein.

Analysis of biological time-lapse microscopic experiment from the point of view of the information theory.

PubMed

Štys, Dalibor; Urban, Jan; Vaněk, Jan; Císař, Petr

2011-06-01

We report objective analysis of information in the microscopic image of the cell monolayer. The process of transfer of information about the cell by the microscope is analyzed in terms of the classical Shannon information transfer scheme. The information source is the biological object, the information transfer channel is the whole microscope including the camera chip. The destination is the model of biological system. The information contribution is analyzed as information carried by a point to overall information in the image. Subsequently we obtain information reflection of the biological object. This is transformed in the biological model which, in information terminology, is the destination. This, we propose, should be constructed as state transitions in individual cells modulated by information bonds between the cells. We show examples of detected cell states in multidimensional state space. This space is reflected as colour channel intensity phenomenological state space. We have also observed information bonds and show examples of them.

Analysis of biological time-lapse microscopic experiment from the point of view of the information theory.

PubMed

Stys, Dalibor; Urban, Jan; Vanek, Jan; Císar, Petr

2010-07-01

We report objective analysis of information in the microscopic image of the cell monolayer. The process of transfer of information about the cell by the microscope is analyzed in terms of the classical Shannon information transfer scheme. The information source is the biological object, the information transfer channel is the whole microscope including the camera chip. The destination is the model of biological system. The information contribution is analyzed as information carried by a point to overall information in the image. Subsequently we obtain information reflection of the biological object. This is transformed in the biological model which, in information terminology, is the destination. This, we propose, should be constructed as state transitions in individual cells modulated by information bonds between the cells. We show examples of detected cell states in multidimensional state space reflected in space an colour channel intensity phenomenological state space. We have also observed information bonds and show examples of them. Copyright 2010 Elsevier Ltd. All rights reserved.

Preservice Biology Teachers' Conceptions About the Tentative Nature of Theories and Models in Biology

NASA Astrophysics Data System (ADS)

Reinisch, Bianca; Krüger, Dirk

2018-02-01

In research on the nature of science, there is a need to investigate the role and status of different scientific knowledge forms. Theories and models are two of the most important knowledge forms within biology and are the focus of this study. During interviews, preservice biology teachers ( N = 10) were asked about their understanding of theories and models. They were requested to give reasons why they see theories and models as either tentative or certain constructs. Their conceptions were then compared to philosophers' positions (e.g., Popper, Giere). A category system was developed from the qualitative content analysis of the interviews. These categories include 16 conceptions for theories ( n tentative = 11; n certai n = 5) and 18 conceptions for models ( n tentative = 10; n certain = 8). The analysis of the interviews showed that the preservice teachers gave reasons for the tentativeness or certainty of theories and models either due to their understanding of the terms or due to their understanding of the generation or evaluation of theories and models. Therefore, a variety of different terminology, from different sources, should be used in learning-teaching situations. Additionally, an understanding of which processes lead to the generation, evaluation, and refinement or rejection of theories and models should be discussed with preservice teachers. Within philosophy of science, there has been a shift from theories to models. This should be transferred to educational contexts by firstly highlighting the role of models and also their connections to theories.

Theory and practice in the construction of professional identity in nursing students: a qualitative study.

PubMed

Arreciado Marañón, Antonia; Isla Pera, Ma Pilar

2015-07-01

The problem of nurses' professional identity continues to be seen in the disjunction between theoretical training and clinical placements. Moreover, it is not known how nursing students perceive these contradictions or how this discrepancy influences the construction of professional identity. To gain insight into nursing students' perception of their theoretical and practical training and how this training influences the process of constructing their professional identity. Qualitative, ethnographic study. Third-year nursing students at the l'Escola Universitària d'Infermeria Vall d'Hebron de Barcelona. Participant observation was conducted in the hospital setting and primary care. Discussion groups were held. The constant comparative method was used for the analysis. The study adhered to the criteria of credibility, transferability, dependability and confirmability. Students believed that both theoretical and practical trainings were indispensable. Nevertheless, clinical placements were considered essential to confer sense to the theory and to shape their identity, as they helped student nurses to experience their future professional reality and to compare it with what they had been taught in theoretical and academic classes. The role of the clinical placement mentor was essential. With regard to theory, the skills developed in problem-based learning gave novice nurses' confidence to approach the problems of daily practice and new situations. Equally, this approach taught them to reflect on what they did and what they were taught and this ability was transferred to the clinical setting. For students, both strategies (theory and practice) are vital to nursing education and the construction of a professional identity, although pride of place is given to clinical placements and mentors. The skills developed with problem-based learning favor active and reflective learning and are transferred to learning in the clinical setting. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transfer of knowledge and skills: some implications for nursing and nurse education.

PubMed

Lauder, W; Reynolds, W; Angus, N

1999-08-01

The construct of transfer has enormous importance to nursing as it begins to highlight potential problems in the transfer of knowledge and skills from the campus to the clinical area, from one part of the clinical area to another (e.g. surgical to medical), and from community to the clinical area. Thus, any adequate conceptualization of transfer must account for problems of practice-practice transfer as well as theory-practice transfer. These potential problems are the concern of educators, students and managers who have a responsibility for agency nurses and bank nurses who may find themselves in different specialities on a regular basis. Transfer has relevance to a whole raft of other issues ranging from the application of theories to nursing practice, through to the validity of claims that courses which develop intellectual skills prepare nurses for lifelong learning.

The study of structures and properties of PdnHm(n=1-10, m=1,2) clusters by density functional theory

NASA Astrophysics Data System (ADS)

Wen, Jun-Qing; Chen, Guo-Xiang; Zhang, Jian-Min; Wu, Hua

2018-04-01

The geometrical evolution, local relative stability, magnetism and charge transfer characteristics of PdnHm(n = 1-10, m = 1,2) have been systematically calculated by using density functional theory. The studied results show that the most stable geometries of PdnH and PdnH2 (n = 1-10) can be got by doping one or two H atoms on the sides of Pdn clusters except Pd6H and Pd6H2. It is found that doping one or two H atoms on Pdn clusters cannot change the basic framework of Pdn. The analysis of stability shows that Pd2H, Pd4H, Pd7H, Pd2H2, Pd4H2 and Pd7H2 clusters have higher local relative stability than neighboring clusters. The analysis of magnetic properties demonstrates that absorption of hydrogen atoms decreases the average atomic magnetic moments compared with pure Pdn clusters. More charges transfer from H atoms to Pd atoms for Pd6H and Pd6H2 clusters, demonstrating the adsorption of hydrogen atoms change from side adsorption to surface adsorption.

First-principles calculation of photo-induced electron transfer rate constants in phthalocyanine-C60 organic photovoltaic materials: Beyond Marcus theory

NASA Astrophysics Data System (ADS)

Lee, Myeong H.; Dunietz, Barry D.; Geva, Eitan

2014-03-01

Classical Marcus theory is commonly adopted in solvent-mediated charge transfer (CT) process to obtain the CT rate constant, but it can become questionable when the intramolecular vibrational modes dominate the CT process as in OPV devices because Marcus theory treats these modes classically and therefore nuclear tunneling is not accounted for. We present a computational scheme to obtain the electron transfer rate constant beyond classical Marcus theory. Within this approach, the nuclear vibrational modes are treated quantum-mechanically and a short-time approximation is avoided. Ab initio calculations are used to obtain the basic parameters needed for calculating the electron transfer rate constant. We apply our methodology to phthalocyanine(H2PC)-C60 organic photovoltaic system where one C60 acceptor and one or two H2PC donors are included to model the donor-acceptor interface configuration. We obtain the electron transfer and recombination rate constants for all accessible charge transfer (CT) states, from which the CT exciton dynamics is determined by employing a master equation. The role of higher lying excited states in CT exciton dynamics is discussed. This work is pursued as part of the Center for Solar and Thermal Energy Conversion, an Energy Frontier Research Center funded by the US Department of Energy Office of Science, Office of Basic Energy Sciences under 390 Award No. DE-SC0000957.

Bands dispersion and charge transfer in β-BeH2

NASA Astrophysics Data System (ADS)

Trivedi, D. K.; Galav, K. L.; Joshi, K. B.

2018-04-01

Predictive capabilities of ab-initio method are utilised to explore bands dispersion and charge transfer in β-BeH2. Investigations are carried out using the linear combination of atomic orbitals method at the level of density functional theory. The crystal structure and related parameters are settled by coupling total energy calculations with the Murnaghan equation of state. Electronic bands dispersion from PBE-GGA is reported. The PBE-GGA, and PBE0 hybrid functional, show that β-BeH2 is a direct gap semiconductor with 1.18 and 2.40 eV band gap. The band gap slowly decreases with pressure and beyond l00 GPa overlap of conduction and valence bands at the r point is observed. Charge transfer is studied by means of Mullikan population analysis.

Study of the cross-market effects of Brexit based on the improved symbolic transfer entropy GARCH model—An empirical analysis of stock–bond correlations

PubMed Central

Chen, Xiurong; Zhao, Rubo

2017-01-01

In this paper, we study the cross-market effects of Brexit on the stock and bond markets of nine major countries in the world. By incorporating information theory, we introduce the time-varying impact weights based on symbolic transfer entropy to improve the traditional GARCH model. The empirical results show that under the influence of Brexit, flight-to-quality not only commonly occurs between the stocks and bonds of each country but also simultaneously occurs among different countries. We also find that the accuracy of the time-varying symbolic transfer entropy GARCH model proposed in this paper has been improved compared to the traditional GARCH model, which indicates that it has a certain practical application value. PMID:28817712

Master surgeons' operative teaching philosophies: a qualitative analysis of parallels to learning theory.

PubMed

Pernar, Luise I M; Ashley, Stanley W; Smink, Douglas S; Zinner, Michael J; Peyre, Sarah E

2012-01-01

Practicing within the Halstedian model of surgical education, academic surgeons serve dual roles as physicians to their patients and educators of their trainees. Despite this significant responsibility, few surgeons receive formal training in educational theory to inform their practice. The goal of this work was to gain an understanding of how master surgeons approach teaching uncommon and highly complex operations and to determine the educational constructs that frame their teaching philosophies and approaches. Individuals included in the study were queried using electronically distributed open-ended, structured surveys. Responses to the surveys were analyzed and grouped using grounded theory and were examined for parallels to concepts of learning theory. Academic teaching hospital. Twenty-two individuals identified as master surgeons. Twenty-one (95.5%) individuals responded to the survey. Two primary thematic clusters were identified: global approach to teaching (90.5% of respondents) and approach to intraoperative teaching (76.2%). Many of the emergent themes paralleled principles of transfer learning theory outlined in the psychology and education literature. Key elements included: conferring graduated responsibility (57.1%), encouraging development of a mental set (47.6%), fostering or expecting deliberate practice (42.9%), deconstructing complex tasks (38.1%), vertical transfer of information (33.3%), and identifying general principles to structure knowledge (9.5%). Master surgeons employ many of the principles of learning theory when teaching uncommon and highly complex operations. The findings may hold significant implications for faculty development in surgical education. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Interlayer‐State‐Coupling Dependent Ultrafast Charge Transfer in MoS2/WS2 Bilayers

PubMed Central

Zhang, Jin; Hong, Hao; Lian, Chao; Ma, Wei; Xu, Xiaozhi; Zhou, Xu; Fu, Huixia

2017-01-01

Light‐induced interlayer ultrafast charge transfer in 2D heterostructures provides a new platform for optoelectronic and photovoltaic applications. The charge separation process is generally hypothesized to be dependent on the interlayer stackings and interactions, however, the quantitative characteristic and detailed mechanism remain elusive. Here, a systematical study on the interlayer charge transfer in model MoS2/WS2 bilayer system with variable stacking configurations by time‐dependent density functional theory methods is demonstrated. The results show that the slight change of interlayer geometry can significantly modulate the charge transfer time from 100 fs to 1 ps scale. Detailed analysis further reveals that the transfer rate in MoS2/WS2 bilayers is governed by the electronic coupling between specific interlayer states, rather than the interlayer distances, and follows a universal dependence on the state‐coupling strength. The results establish the interlayer stacking as an effective freedom to control ultrafast charge transfer dynamics in 2D heterostructures and facilitate their future applications in optoelectronics and light harvesting. PMID:28932669

Emerging Trends of Research on Transfer of Learning

ERIC Educational Resources Information Center

Subedi, Bhawani Shankar

2004-01-01

The terms "transfer of learning" and "transfer of training" are usually found mutually exclusive in training and development literature. Transfer is a key concept in adult learning theories because most education and training aspires to transfer. The end goals of training and education are not achieved unless transfer occurs. Emerging trends of…

Toward Construct Validation of a Transfer Climate Instrument. [and] Improving Positive Transfer: A Test of Relapse Prevention Training on Transfer Outcomes.

ERIC Educational Resources Information Center

Holton, Elwood F., III; And Others

1997-01-01

Includes "Toward Construct Validation of a Transfer Climate Instrument" (Holton et al.); "Improving Positive Transfer: A Test of Relapse Prevention Training on Transfer Outcomes" (Burke); "Invited Reaction: Progress or Relapse?" (Newstrom); "Invited Reaction: Theory, Research, and Practice" (Tang);…

Radiative transfer theory for active remote sensing of a layer of small ellipsoidal scatterers. [of vegetation

NASA Technical Reports Server (NTRS)

Tsang, L.; Kubacsi, M. C.; Kong, J. A.

1981-01-01

The radiative transfer theory is applied within the Rayleigh approximation to calculate the backscattering cross section of a layer of randomly positioned and oriented small ellipsoids. The orientation of the ellipsoids is characterized by a probability density function of the Eulerian angles of rotation. The radiative transfer equations are solved by an iterative approach to first order in albedo. In the half space limit the results are identical to those obtained via the approach of Foldy's and distorted Born approximation. Numerical results of the theory are illustrated using parameters encountered in active remote sensing of vegetation layers. A distinctive characteristic is the strong depolarization shown by vertically aligned leaves.

A formal derivation of the local energy transfer (LET) theory of homogeneous turbulence

NASA Astrophysics Data System (ADS)

McComb, W. D.; Yoffe, S. R.

2017-09-01

A statistical closure of the Navier-Stokes hierarchy which leads to equations for the two-point, two-time covariance of the velocity field for stationary, homogeneous isotropic turbulence is presented. It is a generalisation of the self-consistent field method due to Edwards (1964) for the stationary, single-time velocity covariance. The probability distribution functional P≤ft[\\mathbf{u},t\\right] is obtained, in the form of a series, from the Liouville equation by means of a perturbation expansion about a Gaussian distribution, which is chosen to give the exact two-point, two-time covariance. The triple moment is calculated in terms of an ensemble-averaged infinitesimal velocity-field propagator, and shown to yield the Edwards result as a special case. The use of a Gaussian zero-order distribution has been found to justify the introduction of a fluctuation-response relation, which is in accord with modern dynamical theories. In a sense this work completes the analogy drawn by Edwards between turbulence and Brownian motion. Originally Edwards had shown that the noise input was determined by the correlation of the velocity field with the externally applied stirring forces but was unable to determine the system response. Now we find that the system response is determined by the correlation of the velocity field with internal quasi-entropic forces. This analysis is valid to all orders of perturbation theory, and allows the recovery of the local energy transfer (LET) theory, which had previously been derived by more heuristical methods. The LET theory is known to be in good agreement with experimental results. It is also unique among two-point statistical closures in displaying an acceptable (i.e. non-Markovian) relationship between the transfer spectrum and the system response, in accordance with experimental results. As a result of the latter property, it is compatible with the Kolmogorov (K41) spectral phenomenology. In memory of Professor Sir Sam Edwards F.R.S. 1928-2015.

Emittance Theory for Thin Film Selective Emitter

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

1994-01-01

Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

Efficient Transfer Entropy Analysis of Non-Stationary Neural Time Series

PubMed Central

Vicente, Raul; Díaz-Pernas, Francisco J.; Wibral, Michael

2014-01-01

Information theory allows us to investigate information processing in neural systems in terms of information transfer, storage and modification. Especially the measure of information transfer, transfer entropy, has seen a dramatic surge of interest in neuroscience. Estimating transfer entropy from two processes requires the observation of multiple realizations of these processes to estimate associated probability density functions. To obtain these necessary observations, available estimators typically assume stationarity of processes to allow pooling of observations over time. This assumption however, is a major obstacle to the application of these estimators in neuroscience as observed processes are often non-stationary. As a solution, Gomez-Herrero and colleagues theoretically showed that the stationarity assumption may be avoided by estimating transfer entropy from an ensemble of realizations. Such an ensemble of realizations is often readily available in neuroscience experiments in the form of experimental trials. Thus, in this work we combine the ensemble method with a recently proposed transfer entropy estimator to make transfer entropy estimation applicable to non-stationary time series. We present an efficient implementation of the approach that is suitable for the increased computational demand of the ensemble method's practical application. In particular, we use a massively parallel implementation for a graphics processing unit to handle the computationally most heavy aspects of the ensemble method for transfer entropy estimation. We test the performance and robustness of our implementation on data from numerical simulations of stochastic processes. We also demonstrate the applicability of the ensemble method to magnetoencephalographic data. While we mainly evaluate the proposed method for neuroscience data, we expect it to be applicable in a variety of fields that are concerned with the analysis of information transfer in complex biological, social, and artificial systems. PMID:25068489

Stochastic Analysis of the Efficiency of a Wireless Power Transfer System Subject to Antenna Variability and Position Uncertainties

PubMed Central

Rossi, Marco; Stockman, Gert-Jan; Rogier, Hendrik; Vande Ginste, Dries

2016-01-01

The efficiency of a wireless power transfer (WPT) system in the radiative near-field is inevitably affected by the variability in the design parameters of the deployed antennas and by uncertainties in their mutual position. Therefore, we propose a stochastic analysis that combines the generalized polynomial chaos (gPC) theory with an efficient model for the interaction between devices in the radiative near-field. This framework enables us to investigate the impact of random effects on the power transfer efficiency (PTE) of a WPT system. More specifically, the WPT system under study consists of a transmitting horn antenna and a receiving textile antenna operating in the Industrial, Scientific and Medical (ISM) band at 2.45 GHz. First, we model the impact of the textile antenna’s variability on the WPT system. Next, we include the position uncertainties of the antennas in the analysis in order to quantify the overall variations in the PTE. The analysis is carried out by means of polynomial-chaos-based macromodels, whereas a Monte Carlo simulation validates the complete technique. It is shown that the proposed approach is very accurate, more flexible and more efficient than a straightforward Monte Carlo analysis, with demonstrated speedup factors up to 2500. PMID:27447632

Stochastic Analysis of the Efficiency of a Wireless Power Transfer System Subject to Antenna Variability and Position Uncertainties.

PubMed

Rossi, Marco; Stockman, Gert-Jan; Rogier, Hendrik; Vande Ginste, Dries

2016-07-19

The efficiency of a wireless power transfer (WPT) system in the radiative near-field is inevitably affected by the variability in the design parameters of the deployed antennas and by uncertainties in their mutual position. Therefore, we propose a stochastic analysis that combines the generalized polynomial chaos (gPC) theory with an efficient model for the interaction between devices in the radiative near-field. This framework enables us to investigate the impact of random effects on the power transfer efficiency (PTE) of a WPT system. More specifically, the WPT system under study consists of a transmitting horn antenna and a receiving textile antenna operating in the Industrial, Scientific and Medical (ISM) band at 2.45 GHz. First, we model the impact of the textile antenna's variability on the WPT system. Next, we include the position uncertainties of the antennas in the analysis in order to quantify the overall variations in the PTE. The analysis is carried out by means of polynomial-chaos-based macromodels, whereas a Monte Carlo simulation validates the complete technique. It is shown that the proposed approach is very accurate, more flexible and more efficient than a straightforward Monte Carlo analysis, with demonstrated speedup factors up to 2500.

Theoretical Investigation of Charge Transfer in Metal Organic Frameworks for Electrochemical Device Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patwardhan, Sameer; Schatz, George C.

For electrochemical device applications metal organic frameworks (MOFs) must exhibit suitable conduction properties. To this end, we have performed computational studies of intermolecular charge transfer in MOFs consisting of hexa-ZrIV nodes and tetratopic carboxylate linkers. This includes an examination of the electronic structure of linkers that are derived from tetraphenyl benzene 1, tetraphenyl pyrene 2, and tetraphenyl porphyrin 3 molecules. These results are used to determine charge transfer propensities in MOFs, within the framework of Marcus theory, including an analysis of the key parameters (charge transfer integral t, reorganization energy λ, and free energy change ΔG0) and evaluation of figuresmore » of merit for charge transfer based on the chemical structures of the linkers. This qualitative analysis indicates that delocalization of the HOMO/LUMO on terminal substituents increases t and decreases λ, while weaker binding to counterions decreases ΔG0, leading to better charge transfer propensity. Subsequently, we study hole transfer in the linker 2 containing MOFs, NU-901 and NU-1000, in detail and describe mechanisms (hopping and superexchange) that may be operative under different electrochemical conditions. Comparisons with experiment are provided where available. On the basis of the redox and catalytic activity of nodes and linkers, we propose three possible schemes for constructing electrochemical devices for catalysis. We believe that the results of this study will lay the foundation for future experimental work on this topic.« less

On the calculation of charge transfer transitions with standard density functionals using constrained variational density functional theory.

PubMed

Ziegler, Tom; Krykunov, Mykhaylo

2010-08-21

It is well known that time-dependent density functional theory (TD-DFT) based on standard gradient corrected functionals affords both a quantitative and qualitative incorrect picture of charge transfer transitions between two spatially separated regions. It is shown here that the well known failure can be traced back to the use of linear response theory. Further, it is demonstrated that the inclusion of higher order terms readily affords a qualitatively correct picture even for simple functionals based on the local density approximation. The inclusion of these terms is done within the framework of a newly developed variational approach to excitation energies called constrained variational density functional theory (CV-DFT). To second order [CV(2)-DFT] this theory is identical to adiabatic TD-DFT within the Tamm-Dancoff approximation. With inclusion of fourth order corrections [CV(4)-DFT] it affords a qualitative correct description of charge transfer transitions. It is finally demonstrated that the relaxation of the ground state Kohn-Sham orbitals to first order in response to the change in density on excitation together with CV(4)-DFT affords charge transfer excitations in good agreement with experiment. The new relaxed theory is termed R-CV(4)-DFT. The relaxed scheme represents an effective way in which to introduce double replacements into the description of single electron excitations, something that would otherwise require a frequency dependent kernel.

Teacher Transfer Policy and the Implications for Equity in Urban School Districts.

ERIC Educational Resources Information Center

Krei, Melinda Scott

Policies and practices associated with intra-district teacher transfers in urban school districts were examined, exploring the implications for educational equity of this aspect of teacher mobility. Human capital theory and the theory of internal labor markets and their institutional rules provided the primary theoretical focus of the research.…

Biomimetics: its practice and theory

PubMed Central

Vincent, Julian F.V; Bogatyreva, Olga A; Bogatyrev, Nikolaj R; Bowyer, Adrian; Pahl, Anja-Karina

2006-01-01

Biomimetics, a name coined by Otto Schmitt in the 1950s for the transfer of ideas and analogues from biology to technology, has produced some significant and successful devices and concepts in the past 50 years, but is still empirical. We show that TRIZ, the Russian system of problem solving, can be adapted to illuminate and manipulate this process of transfer. Analysis using TRIZ shows that there is only 12% similarity between biology and technology in the principles which solutions to problems illustrate, and while technology solves problems largely by manipulating usage of energy, biology uses information and structure, two factors largely ignored by technology. PMID:16849244

Phonon-electron coupling and tunneling effect on charge transport in organic semi-conductor crystals of Cn-BTBT.

PubMed

Zhou, Yecheng; Deng, Wei-Qiao; Zhang, Hao-Li

2016-09-14

Cn-[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) crystals show very high hole mobilities in experiments. These high mobilities are beyond existing theory prediction. Here, we employed different quantum chemistry methods to investigate charge transfer in Cn-BTBT crystals and tried to find out the reasons for the underestimation in the theory. It was found that the hopping rate estimated by the Fermi Golden Rule is higher than that of the Marcus theory due to the high temperature approximation and failure at the classic limit. More importantly, molecular dynamics simulations revealed that the phonon induced fluctuation of electronic transfer integral is much larger than the average of the electronic transfer integral itself. Mobilities become higher if simulations implement the phonon-electron coupling. This conclusion indicates that the phonon-electron coupling promotes charge transfer in organic semi-conductors at room temperature.

Phonon-electron coupling and tunneling effect on charge transport in organic semi-conductor crystals of Cn-BTBT

NASA Astrophysics Data System (ADS)

Zhou, Yecheng; Deng, Wei-Qiao; Zhang, Hao-Li

2016-09-01

Cn-[1]benzothieno[3,2-b][1]-benzothiophene (BTBT) crystals show very high hole mobilities in experiments. These high mobilities are beyond existing theory prediction. Here, we employed different quantum chemistry methods to investigate charge transfer in Cn-BTBT crystals and tried to find out the reasons for the underestimation in the theory. It was found that the hopping rate estimated by the Fermi Golden Rule is higher than that of the Marcus theory due to the high temperature approximation and failure at the classic limit. More importantly, molecular dynamics simulations revealed that the phonon induced fluctuation of electronic transfer integral is much larger than the average of the electronic transfer integral itself. Mobilities become higher if simulations implement the phonon-electron coupling. This conclusion indicates that the phonon-electron coupling promotes charge transfer in organic semi-conductors at room temperature.

Time dependence of triplet-singlet excitation transfer from compact poly rA to bound dye at 77 K.

PubMed Central

Pearlstein, R M; Van Nostrand, F; Nairn, J A

1979-01-01

The nonexponential phosphorescence decay of a highly folded form of poly-riboadenylic acid (poly rA) with noncovalently bound dye is explained by a novel application of a well-known theory of electronic excitation transfer based on the Förster mechanism. This theory, originally used to describe singlet-singlet energy transfer from donor molecules to an acceptor in a solution, is here applied to the transfer of triplet excitation from the adenine (in poly rA) to the singlet manifold of either of the bound dyes, ethidium bromide or proflavine. New experimental data are presented that allow straight-forward theoretical interpretation. These data fit the form predicted by the theory, U(t) exp(-Bt1/2), where U(t) is the decay of the poly rA phosphorescence in the absence of dye, for a range of relative concentrations of either dye. The self-consistency of these theoretical fits is demonstrated by the proportionality of B to the square root of the Förster triplet-singlet overlap integrals for transfer from poly rA to each of the dyes, as demanded by the theory. From these self-consistent values of B, the theory enables one to deduce the mean packing density of nucleotides in this folded poly rA, which we estimate to be approximately 1 nm-3. We conclude that some variations of the method described here may be useful for deducing packing densities of nucleotides in other compact nucleic acid structures. PMID:262411

An approximate classical unimolecular reaction rate theory

NASA Astrophysics Data System (ADS)

Zhao, Meishan; Rice, Stuart A.

1992-05-01

We describe a classical theory of unimolecular reaction rate which is derived from the analysis of Davis and Gray by use of simplifying approximations. These approximations concern the calculation of the locations of, and the fluxes of phase points across, the bottlenecks to fragmentation and to intramolecular energy transfer. The bottleneck to fragment separation is represented as a vibration-rotation state dependent separatrix, which approximation is similar to but extends and improves the approximations for the separatrix introduced by Gray, Rice, and Davis and by Zhao and Rice. The novel feature in our analysis is the representation of the bottlenecks to intramolecular energy transfer as dividing surfaces in phase space; the locations of these dividing surfaces are determined by the same conditions as locate the remnants of robust tori with frequency ratios related to the golden mean (in a two degree of freedom system these are the cantori). The flux of phase points across each dividing surface is calculated with an analytic representation instead of a stroboscopic mapping. The rate of unimolecular reaction is identified with the net rate at which phase points escape from the region of quasiperiodic bounded motion to the region of free fragment motion by consecutively crossing the dividing surfaces for intramolecular energy exchange and the separatrix. This new theory generates predictions of the rates of predissociation of the van der Waals molecules HeI2, NeI2 and ArI2 which are in very good agreement with available experimental data.

Charge Transfer and Orbital Level Alignment at Inorganic/Organic Interfaces: The Role of Dielectric Interlayers.

PubMed

Hollerer, Michael; Lüftner, Daniel; Hurdax, Philipp; Ules, Thomas; Soubatch, Serguei; Tautz, Frank Stefan; Koller, Georg; Puschnig, Peter; Sterrer, Martin; Ramsey, Michael G

2017-06-27

It is becoming accepted that ultrathin dielectric layers on metals are not merely passive decoupling layers, but can actively influence orbital energy level alignment and charge transfer at interfaces. As such, they can be important in applications ranging from catalysis to organic electronics. However, the details at the molecular level are still under debate. In this study, we present a comprehensive analysis of the phenomenon of charge transfer promoted by a dielectric interlayer with a comparative study of pentacene adsorbed on Ag(001) with and without an ultrathin MgO interlayer. Using scanning tunneling microscopy and photoemission tomography supported by density functional theory, we are able to identify the orbitals involved and quantify the degree of charge transfer in both cases. Fractional charge transfer occurs for pentacene adsorbed on Ag(001), while the presence of the ultrathin MgO interlayer promotes integer charge transfer with the lowest unoccupied molecular orbital transforming into a singly occupied and singly unoccupied state separated by a large gap around the Fermi energy. Our experimental approach allows a direct access to the individual factors governing the energy level alignment and charge-transfer processes for molecular adsorbates on inorganic substrates.

Quantifying highly efficient incoherent energy transfer in perylene-based multichromophore arrays.

PubMed

Webb, James E A; Chen, Kai; Prasad, Shyamal K K; Wojciechowski, Jonathan P; Falber, Alexander; Thordarson, Pall; Hodgkiss, Justin M

2016-01-21

Multichromophore perylene arrays were designed and synthesized to have extremely efficient resonance energy transfer. Using broadband ultrafast photoluminescence and transient absorption spectroscopies, transfer timescales of approximately 1 picosecond were resolved, corresponding to efficiencies of up to 99.98%. The broadband measurements also revealed spectra corresponding to incoherent transfer between localized states. Polarization resolved spectroscopy was used to measure the dipolar angles between donor and acceptor chromophores, thereby enabling geometric factors to be fixed when assessing the validity of Förster theory in this regime. Förster theory was found to predict the correct magnitude of transfer rates, with measured ∼2-fold deviations consistent with the breakdown of the point-dipole approximation at close approach. The materials presented, along with the novel methods for quantifying ultrahigh energy transfer efficiencies, will be valuable for applications demanding extremely efficient energy transfer, including fluorescent solar concentrators, optical gain, and photonic logic devices.

Analysis of the critical step in catalytic carbodiimide transformation: proton transfer from amines, phosphines, and alkynes to guanidinates, phosphaguanidinates, and propiolamidinates with Li and Al catalysts.

PubMed

Rowley, Christopher N; Ong, Tiow-Gan; Priem, Jessica; Richeson, Darrin S; Woo, Tom K

2008-12-15

While lithium amides supported by tetramethylethylenediamine (TMEDA) are efficient catalysts in the synthesis of substituted guanidines via the guanylation of an amine with carbodiimide, as well as the guanylation of phosphines and conversion of alkynes into propiolamidines, aluminum amides are only efficient catalysts for the guanylation of amides. Density functional theory (DFT) calculations were used to explain this difference in activity. The origin of this behavior is apparent in the critical step where a proton is transferred from the substrate to a metal guanidinate. The activation energies of these steps are modest for amines, phosphines, and alkynes when a lithium catalyst was used, but are prohibitively high for the analogous reactions with phosphines and alkynes for aluminum amide catalysts. Energy decomposition analysis (EDA) indicates that these high activations energies are due to the high energetic cost of the detachment of a chelating guanidinate nitrogen from the aluminum in the proton transfer transition state. Amines are able to adopt an ideal geometry for facile proton transfer to the aluminum guanidinate and concomitant Al-N bond formation, while phosphines and alkynes are not.

Inside the Green House "Black Box": Opportunities for High-Quality Clinical Decision Making.

PubMed

Bowers, Barbara; Roberts, Tonya; Nolet, Kimberly; Ryther, Brenda

2016-02-01

To develop a conceptual model that explained common and divergent care processes in Green House (GH) nursing homes with high and low hospital transfer rates. Eighty-four face-to-face, semistructured interviews were conducted with direct care, professional, and administrative staff with knowledge of care processes in six GH organizations in six states. The qualitative grounded theory method was used for data collection and analysis. Data were analyzed using open, axial, and selective coding. Data collection and analysis occurred iteratively. Elements of the GH model created significant opportunities to identify, communicate, and respond to early changes in resident condition. Staff in GH homes with lower hospital transfer rates employed care processes that maximized these opportunities. Staff in GH homes with higher transfer rates failed to maximize, or actively undermined, these opportunities. Variations in how the GH model was implemented across GH homes suggest possible explanations for inconsistencies found in past research on the care outcomes, including hospital transfer rates, in culture change models. The findings further suggest that the details of culture change implementation are important considerations in model replication and policies that create incentives for care improvements. © Health Research and Educational Trust.

Electronic Coupling Calculations for Bridge-Mediated Charge Transfer Using Constrained Density Functional Theory (CDFT) and Effective Hamiltonian Approaches at the Density Functional Theory (DFT) and Fragment-Orbital Density Functional Tight Binding (FODFTB) Level

DOE PAGES

Gillet, Natacha; Berstis, Laura; Wu, Xiaojing; ...

2016-09-09

In this paper, four methods to calculate charge transfer integrals in the context of bridge-mediated electron transfer are tested. These methods are based on density functional theory (DFT). We consider two perturbative Green's function effective Hamiltonian methods (first, at the DFT level of theory, using localized molecular orbitals; second, applying a tight-binding DFT approach, using fragment orbitals) and two constrained DFT implementations with either plane-wave or local basis sets. To assess the performance of the methods for through-bond (TB)-dominated or through-space (TS)-dominated transfer, different sets of molecules are considered. For through-bond electron transfer (ET), several molecules that were originally synthesizedmore » by Paddon-Row and co-workers for the deduction of electronic coupling values from photoemission and electron transmission spectroscopies, are analyzed. The tested methodologies prove to be successful in reproducing experimental data, the exponential distance decay constant and the superbridge effects arising from interference among ET pathways. For through-space ET, dedicated p-stacked systems with heterocyclopentadiene molecules were created and analyzed on the basis of electronic coupling dependence on donor-acceptor distance, structure of the bridge, and ET barrier height. The inexpensive fragment-orbital density functional tight binding (FODFTB) method gives similar results to constrained density functional theory (CDFT) and both reproduce the expected exponential decay of the coupling with donor-acceptor distances and the number of bridging units. Finally, these four approaches appear to give reliable results for both TB and TS ET and present a good alternative to expensive ab initio methodologies for large systems involving long-range charge transfers.« less

Electronic Coupling Calculations for Bridge-Mediated Charge Transfer Using Constrained Density Functional Theory (CDFT) and Effective Hamiltonian Approaches at the Density Functional Theory (DFT) and Fragment-Orbital Density Functional Tight Binding (FODFTB) Level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillet, Natacha; Berstis, Laura; Wu, Xiaojing

In this paper, four methods to calculate charge transfer integrals in the context of bridge-mediated electron transfer are tested. These methods are based on density functional theory (DFT). We consider two perturbative Green's function effective Hamiltonian methods (first, at the DFT level of theory, using localized molecular orbitals; second, applying a tight-binding DFT approach, using fragment orbitals) and two constrained DFT implementations with either plane-wave or local basis sets. To assess the performance of the methods for through-bond (TB)-dominated or through-space (TS)-dominated transfer, different sets of molecules are considered. For through-bond electron transfer (ET), several molecules that were originally synthesizedmore » by Paddon-Row and co-workers for the deduction of electronic coupling values from photoemission and electron transmission spectroscopies, are analyzed. The tested methodologies prove to be successful in reproducing experimental data, the exponential distance decay constant and the superbridge effects arising from interference among ET pathways. For through-space ET, dedicated p-stacked systems with heterocyclopentadiene molecules were created and analyzed on the basis of electronic coupling dependence on donor-acceptor distance, structure of the bridge, and ET barrier height. The inexpensive fragment-orbital density functional tight binding (FODFTB) method gives similar results to constrained density functional theory (CDFT) and both reproduce the expected exponential decay of the coupling with donor-acceptor distances and the number of bridging units. Finally, these four approaches appear to give reliable results for both TB and TS ET and present a good alternative to expensive ab initio methodologies for large systems involving long-range charge transfers.« less

Electronic Coupling Calculations for Bridge-Mediated Charge Transfer Using Constrained Density Functional Theory (CDFT) and Effective Hamiltonian Approaches at the Density Functional Theory (DFT) and Fragment-Orbital Density Functional Tight Binding (FODFTB) Level.

PubMed

Gillet, Natacha; Berstis, Laura; Wu, Xiaojing; Gajdos, Fruzsina; Heck, Alexander; de la Lande, Aurélien; Blumberger, Jochen; Elstner, Marcus

2016-10-11

In this article, four methods to calculate charge transfer integrals in the context of bridge-mediated electron transfer are tested. These methods are based on density functional theory (DFT). We consider two perturbative Green's function effective Hamiltonian methods (first, at the DFT level of theory, using localized molecular orbitals; second, applying a tight-binding DFT approach, using fragment orbitals) and two constrained DFT implementations with either plane-wave or local basis sets. To assess the performance of the methods for through-bond (TB)-dominated or through-space (TS)-dominated transfer, different sets of molecules are considered. For through-bond electron transfer (ET), several molecules that were originally synthesized by Paddon-Row and co-workers for the deduction of electronic coupling values from photoemission and electron transmission spectroscopies, are analyzed. The tested methodologies prove to be successful in reproducing experimental data, the exponential distance decay constant and the superbridge effects arising from interference among ET pathways. For through-space ET, dedicated π-stacked systems with heterocyclopentadiene molecules were created and analyzed on the basis of electronic coupling dependence on donor-acceptor distance, structure of the bridge, and ET barrier height. The inexpensive fragment-orbital density functional tight binding (FODFTB) method gives similar results to constrained density functional theory (CDFT) and both reproduce the expected exponential decay of the coupling with donor-acceptor distances and the number of bridging units. These four approaches appear to give reliable results for both TB and TS ET and present a good alternative to expensive ab initio methodologies for large systems involving long-range charge transfers.

Vibrational spectroscopy and density functional theory analysis of 3-O-caffeoylquinic acid

NASA Astrophysics Data System (ADS)

Mishra, Soni; Tandon, Poonam; Eravuchira, Pinkie J.; El-Abassy, Rasha M.; Materny, Arnulf

2013-03-01

Density functional theory (DFT) calculations are being performed to investigate the geometric, vibrational, and electronic properties of the chlorogenic acid isomer 3-CQA (1R,3R,4S,5R)-3-{[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-1,4,5-trihydroxycyclohexanecarboxylic acid), a major phenolic compound in coffee. DFT calculations with the 6-311G(d,p) basis set produce very good results. The electrostatic potential mapped onto an isodensity surface has been obtained. A natural bond orbital analysis (NBO) has been performed in order to study intramolecular bonding, interactions among bonds, and delocalization of unpaired electrons. HOMO-LUMO studies give insights into the interaction of the molecule with other species. The calculated HOMO and LUMO energies indicate that a charge transfer occurs within the molecule.

SAFSIM theory manual: A computer program for the engineering simulation of flow systems

NASA Astrophysics Data System (ADS)

Dobranich, Dean

1993-12-01

SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program for simulating the integrated performance of complex flow systems. SAFSIM provides sufficient versatility to allow the engineering simulation of almost any system, from a backyard sprinkler system to a clustered nuclear reactor propulsion system. In addition to versatility, speed and robustness are primary SAFSIM development goals. SAFSIM contains three basic physics modules: (1) a fluid mechanics module with flow network capability; (2) a structure heat transfer module with multiple convection and radiation exchange surface capability; and (3) a point reactor dynamics module with reactivity feedback and decay heat capability. Any or all of the physics modules can be implemented, as the problem dictates. SAFSIM can be used for compressible and incompressible, single-phase, multicomponent flow systems. Both the fluid mechanics and structure heat transfer modules employ a one-dimensional finite element modeling approach. This document contains a description of the theory incorporated in SAFSIM, including the governing equations, the numerical methods, and the overall system solution strategies.

Comparison of Several Methods of Predicting the Pressure Loss at Altitude Across a Baffled Aircraft-Engine Cylinder

NASA Technical Reports Server (NTRS)

Neustein, Joseph; Schafer, Louis J , Jr

1946-01-01

Several methods of predicting the compressible-flow pressure loss across a baffled aircraft-engine cylinder were analytically related and were experimentally investigated on a typical air-cooled aircraft-engine cylinder. Tests with and without heat transfer covered a wide range of cooling-air flows and simulated altitudes from sea level to 40,000 feet. Both the analysis and the test results showed that the method based on the density determined by the static pressure and the stagnation temperature at the baffle exit gave results comparable with those obtained from methods derived by one-dimensional-flow theory. The method based on a characteristic Mach number, although related analytically to one-dimensional-flow theory, was found impractical in the present tests because of the difficulty encountered in defining the proper characteristic state of the cooling air. Accurate predictions of altitude pressure loss can apparently be made by these methods, provided that they are based on the results of sea-level tests with heat transfer.

Ambiguity in knowledge transfer: The role of theory-practice gap.

PubMed

Cheraghi, Mohammad Ali; Salsali, Mahvash; Safari, Mahmoud

2010-01-01

In spite of much literature written about the theory-practice gap in the international nursing journals, there is evidence that indicates this subject has not been probed comprehensively since nursing education was transferred to universities in Iran. In the recent years, the public and the government have criticized Iranian nurses because of poor quality of patient care. Although this subject has been lamented by some researchers, there is no comprehensive work on how this gap resulted. In the process of a larger study on "nursing knowledge translation to practice", of one PhD thesis, this process was explored. Using grounded theory analysis, indepth interviews were undertaken with a purposive sample of 29 nurses, with different levels of experience, from the school of nursing in Tehran University of Medical Sciences in 2006 from January to August. Data were analyzed using the constant comparative method. Three main themes emerging from this study included clinical behavior structure, paradoxical knowledge and practice, and divergent nursing organization. It seems that nursing education with some praxis and paradoxes in the realm of nursing knowledge and practice, along with divergent organizational structure have decreased nurses' ability in applying their professional knowledge and skills in order to bridge the gap between theory and practice. Moreover, in spite of increased academic input into nursing education, clinical behaviors of both education and practice settings was perceived as "traditional routine-based".

Computational studies of molecular charge transfer complexes of heterocyclic 4-methylepyridine-2-azomethine-p-benzene derivatives with picric acid and m-dinitrobenzene.

PubMed

Al-Harbi, L M; El-Mossalamy, E H; Obaid, A Y; Al-Jedaani, A H

2014-01-01

Charge transfer complexes of substituted aryl Schiff bases as donors with picric acid and m-dinitrobenzene as acceptors were investigated by using computational analysis calculated by Configuration Interaction Singles Hartree-Fock (CIS-HF) at standard 6-31G∗ basis set and Time-Dependent Density-Functional Theory (TD-DFT) levels of theory at standard 6-31G∗∗ basis set, infrared spectra, visible and nuclear magnetic resonance spectra are investigated. The optimized geometries and vibrational frequencies were evaluated. The energy and oscillator strength were calculated by Configuration Interaction Singles Hartree-Fock method (CIS-HF) and the Time-Dependent Density-Functional Theory (TD-DFT) results. Electronic properties, such as HOMO and LUMO energies and band gaps of CTCs set, were studied by the Time-Dependent density functional theory with Becke-Lee-Young-Parr (B3LYP) composite exchange correlation functional and by Configuration Interaction Singles Hartree-Fock method (CIS-HF). The ionization potential Ip and electron affinity EA were calculated by PM3, HF and DFT methods. The columbic force was calculated theoretically by using (CIS-HF and TD-DFT) methods. This study confirms that the theoretical calculation of vibrational frequencies for (aryl Schiff bases--(m-dinitrobenzene and picric acid)) complexes are quite useful for the vibrational assignment and for predicting new vibrational frequencies. Copyright © 2013 Elsevier B.V. All rights reserved.

Vibrational spectroscopic investigation and normal coordinate analysis of the fibrate hypolipidemic agent 5-(2,5-dimethylphenoxy)-2,2-dimethyl pentanoic acid (Gemfibrozil)

NASA Astrophysics Data System (ADS)

Priya, M. Siva; Benitta, T. Asenath; James, C.

2011-03-01

Colorless crystals of 5-(2,5-dimethylphenoxy)-2,2-dimethyl pentanoic acid were grown by slow evaporation method and the FT-IR and FT-Raman spectra of the sample were recorded in the region 4000-450 cm -1 and 4000-50 cm -1 respectively. Molecular structure is optimized with the help of B3LYP/6-31G (d) density functional theory method. Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the σ ∗ antibonding orbitals and E (2) energies confirms the occurrence of intra-molecular charge transfer (ICT) within the molecule. The assignments of the vibrational spectra have been carried out with the help of Normal coordinate analysis following the scaled quantum mechanical force field (SQMFF) methodology. Mulliken population analysis on atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule.

Modeling thermal infrared (2-14 micrometer) reflectance spectra of frost and snow

NASA Technical Reports Server (NTRS)

Wald, Andrew E.

1994-01-01

Existing theories of radiative transfer in close-packed media assume that each particle scatters independently of its neighbors. For opaque particles, such as are common in the thermal infrared, this assumption is not valid, and these radiative transfer theories will not be accurate. A new method is proposed, called 'diffraction subtraction', which modifies the scattering cross section of close-packed large, opaque spheres to account for the effect of close packing on the diffraction cross section of a scattering particle. This method predicts the thermal infrared reflectance of coarse (greater than 50 micrometers radius), disaggregated granular snow. However, such coarse snow is typically old and metamorphosed, with adjacent grains welded together. The reflectance of such a welded block can be described as partly Fresnel in nature and cannot be predicted using Mie inputs to radiative transfer theory. Owing to the high absorption coefficient of ice in the thermal infrared, a rough surface reflectance model can be used to calculate reflectance from such a block. For very small (less than 50 micrometers), disaggregated particles, it is incorrect in principle to treat diffraction independently of reflection and refraction, and the theory fails. However, for particles larger than 50 micrometers, independent scattering is a valid assumption, and standard radiative transfer theory works.

A Modern Picture of Barred Galaxy Dynamics

NASA Astrophysics Data System (ADS)

Petersen, Michael; Weinberg, Martin; Katz, Neal

2018-01-01

Observations of disk galaxies suggest that bars are responsible for altering global galaxy parameters (e.g. structures, gas fraction, star formation rate). The canonical understanding of the mechanisms underpinning bar-driven secular dynamics in disk galaxies has been largely built upon the analysis of linear theory, despite galactic bars being clearly demonstrated to be nonlinear phenomena in n-body simulations. We present simulations of barred Milky Way-like galaxy models designed to elucidate nonlinear barred galaxy dynamics. We have developed two new methodologies for analyzing n-body simulations that give the best of both powerful analytic linear theory and brute force simulation analysis: orbit family identification and multicomponent torque analysis. The software will be offered publicly to the community for their own simulation analysis.The orbit classifier reveals that the details of kinematic components in galactic disks (e.g. the bar, bulge, thin disk, and thick disk components) are powerful discriminators of evolutionary paradigms (i.e. violent instabilities and secular evolution) as well as the basic parameters of the dark matter halo (mass distribution, angular momentum distribution). Multicomponent torque analysis provides a thorough accounting of the transfer of angular momentum between orbits, global patterns, and distinct components in order to better explain the underlying physics which govern the secular evolution of barred disk galaxies.Using these methodologies, we are able to identify the successes and failures of linear theory and traditional n-body simulations en route to a detailed understanding of the control bars exhibit over secular evolution in galaxies. We present explanations for observed physical and velocity structures in observations of barred galaxies alongside predictions for how structures will vary with dynamical properties from galaxy to galaxy as well as over the lifetime of a galaxy, finding that the transfer of angular momentum through previously unidentified channels can more fully explain the observed dynamics.

Information transfer in auditoria and room-acoustical quality.

PubMed

Summers, Jason E

2013-04-01

It is hypothesized that room-acoustical quality correlates with the information-transfer rate. Auditoria are considered as multiple-input multiple-output communication channels and a theory of information-transfer is outlined that accounts for time-variant multipath, spatial hearing, and distributed directional sources. Source diversity and spatial hearing are shown to be the mechanisms through which multipath increases the information-transfer rate by overcoming finite spatial resolution. In addition to predictions that are confirmed by recent and historical findings, the theory provides explanations for the influence of factors such as musical repertoire and ensemble size on subjective preference and the influence of multisource, multichannel auralization on perceived realism.

Power allocation for SWIPT in K-user interference channels using game theory

NASA Astrophysics Data System (ADS)

Wen, Zhigang; Liu, Ying; Liu, Xiaoqing; Li, Shan; Chen, Xianya

2018-12-01

A simultaneous wireless information and power transfer system in interference channels of multi-users is considered. In this system, each transmitter sends one data stream to its targeted receiver, which causes interference to other receivers. Since all transmitter-receiver links want to maximize their own average transmission rate, a power allocation problem under the transmit power constraints and the energy-harvesting constraints is developed. To solve this problem, we propose a game theory framework. Then, we convert the game into a variational inequalities problem by establishing the connection between game theory and variational inequalities and solve the variational inequalities problem. Through theoretical analysis, the existence and uniqueness of Nash equilibrium are both guaranteed by the theory of variational inequalities. A distributed iterative alternating optimization water-filling algorithm is derived, which is proved to converge. Numerical results show that the proposed algorithm reaches fast convergence and achieves a higher sum rate than the unaided scheme.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anisimov, Petr Mikhaylovich

Classical 1D X-ray Free Electron Laser (X-ray FEL) theory has stood the test of time by guiding FEL design and development prior to any full-scale analysis. Future X-ray FELs and inverse-Compton sources, where photon recoil approaches an electron energy spread value, push the classical theory to its limits of applicability. After substantial efforts by the community to find what those limits are, there is no universally agreed upon quantum approach to design and development of future X-ray sources. We offer a new approach to formulate the quantum theory for 1D X-ray FELs that has an obvious connection to the classicalmore » theory, which allows for immediate transfer of knowledge between the two regimes. In conclusion, we exploit this connection in order to draw quantum mechanical conclusions about the quantum nature of electrons and generated radiation in terms of FEL variables.« less

The role of community mental health nurses caring for people with schizophrenia in Taiwan: a substantive grounded theory.

PubMed

Huang, Xuan-Yi; Yen, Wen-Jiuan; Liu, Shwu-Jiuan; Lin, Chouh-Jiuan

2008-03-01

The aim was to develop a practice theory that can be used to guide the direction of community nursing practice to help clients with schizophrenia and those who care for them. Substantive grounded theory was developed through use of grounded theory method of Strauss and Corbin. Two groups of participants in Taiwan were selected using theoretical sampling: one group consisted of community mental health nurses and the other group was clients with schizophrenia and those who cared for them. The number of participants in each group was determined by theoretical saturation. Semi-structured one-to-one in-depth interviews and unstructured non-participant observation were utilized for data collection. Data analysis involved three stages: open, axial and selective coding. During the process of coding and analysis, both inductive and deductive thinking were utilized and the constant comparative analysis process continued until data saturation occurred. To establish trustworthiness, the four criteria of credibility, transferability, dependability and confirmability were followed along with field trial, audit trial, member check and peer debriefing for reliability and validity. A substantive grounded theory, the role of community mental health nurses caring for people with schizophrenia in Taiwan, was developed through utilization of grounded theory method of Strauss and Corbin. In this paper, results and discussion focus on causal conditions, context, intervening conditions, consequences and phenomenon. The theory is the first to contribute knowledge about the field of mental health home visiting services in Taiwan to provide guidance for the delivery of quality care to assist people in the community with schizophrenia and their carers.

Proton transfer complexes based on some π-acceptors having acidic protons with 3-amino-6-[2-(2-thienyl)vinyl]-1,2,4-triazin-5(4 H)-one donor: Synthesis and spectroscopic characterizations

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; Saad, Hosam A.; Adam, Abdel Majid A.

2011-05-01

Charge transfer complexes based on 3-amino-6-[2-(2-thienyl)vinyl]-1,2,4-triazin-5(4 H)-one (ArNH 2) organic basic donor and pi-acceptors having acidic protons such as picric acid (PiA), hydroquinone (Q(OH) 2) and 3,5-dinitrobenzene (DNB) have been synthesized and spectroscopically studied. The sbnd NH3+ ammonium ion was formed under the acid-base theory through proton transfer from an acidic to basic centers in all charge transfer complexes resulted. The values of formation constant ( KCT) and molar extinction coefficient ( ɛCT) which were estimated from the spectrophotometric studies have a dramatic effect for the charge transfer complexes with differentiation of pi-acceptors. For further studies the vibrational spectroscopy of the [( ArNH3+)(PiA -)] (1), [( ArNH3+)(Q (OH)2-)] (2) and [( ArNH3+)(DNB -)] (3) of (1:1) charge transfer complexes of (donor: acceptor) were characterized by elemental analysis, infrared spectra, Raman spectra, 1H and 13CNMR spectra. The experimental data of elemental analyses of the charge transfer complexes (1), (2) and (3) were in agreement with calculated data. The IR and Raman spectra of (1), (2) and (3) are indicated to the presence of bands around 3100 and 1600 cm -1 distinguish to sbnd NH3+. The thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) techniques were performed to give knowledge about thermal stability behavior of the synthesized charge transfer complexes. The morphological features of start materials and charge transfer complexes were investigated using scanning electron microscopy (SEM) and optical microscopy.

Analysis of Heat Transfer Phenomenon in Magnetohydrodynamic Casson Fluid Flow Through Cattaneo-Christov Heat Diffusion Theory

NASA Astrophysics Data System (ADS)

Ramesh, G. K.; Gireesha, B. J.; Shehzad, S. A.; Abbasi, F. M.

2017-07-01

Heat transport phenomenon of two-dimensional magnetohydrodynamic Casson fluid flow by employing Cattaneo-Christov heat diffusion theory is described in this work. The term of heat absorption/generation is incorporated in the mathematical modeling of present flow problem. The governing mathematical expressions are solved for velocity and temperature profiles using RKF 45 method along with shooting technique. The importance of arising nonlinear quantities namely velocity, temperature, skin-friction and temperature gradient are elaborated via plots. It is explored that the Casson parameter retarded the liquid velocity while it enhances the fluid temperature. Further, we noted that temperature and thickness of temperature boundary layer are weaker in case of Cattaneo-Christov heat diffusion model when matched with the profiles obtained for Fourier’s theory of heat flux.

An experimental/computational study of sharp fin induced shock wave/turbulent boundary layer interactions at Mach 5 - Experimental results

NASA Technical Reports Server (NTRS)

Rodi, Patrick E.; Dolling, David S.

1992-01-01

A combined experimental/computational study has been performed of sharp fin induced shock wave/turbulent boundary layer interactions at Mach 5. The current paper focuses on the experiments and analysis of the results. The experimental data include mean surface heat transfer, mean surface pressure distributions and surface flow visualization for fin angles of attack of 6, 8, 10, 12, 14 and 16-degrees at Mach 5 under a moderately cooled wall condition. Comparisons between the results and correlations developed earlier show that Scuderi's correlation for the upstream influence angle (recast in a conical form) is superior to other such correlations in predicting the current results, that normal Mach number based correlations for peak pressure heat transfer are adequate and that the initial heat transfer peak can be predicted using pressure-interaction theory.

Ultrashort hybrid metal-insulator plasmonic directional coupler.

PubMed

Noghani, Mahmoud Talafi; Samiei, Mohammad Hashem Vadjed

2013-11-01

An ultrashort plasmonic directional coupler based on the hybrid metal-insulator slab waveguide is proposed and analyzed at the telecommunication wavelength of 1550 nm. It is first analyzed using the supermode theory based on mode analysis via the transfer matrix method in the interaction region. Then the 2D model of the coupler, including transition arms, is analyzed using a commercial finite-element method simulator. The hybrid slab waveguide is composed of a metallic layer of silver and two dielectric layers of silica (SiO2) and silicon (Si). The coupler is optimized to have a minimum coupling length and to transfer maximum power considering the layer thicknesses as optimization variables. The resulting coupling length in the submicrometer region along with a noticeable power transfer efficiency are advantages of the proposed coupler compared to previously reported plasmonic couplers.

Density functional theory studies on molecular structure and vibrational spectra of NLO crystal L-phenylalanine phenylalanium nitrate for THz application

NASA Astrophysics Data System (ADS)

Amalanathan, M.; Hubert Joe, I.; Rastogi, V. K.

2011-12-01

Molecular structure, FT-IR and Raman spectra of L-phenylalanine phenylalanium nitrate have been investigated using density functional theory calculation. The polarizability and hyperpolarizability value of the crystal is also calculated. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction. Simultaneous activation of ring C sbnd C stretching modes shows the non-centrosymmetric symmetry. Terahertz time-domain spectroscopy has been used to detect the absorption spectra in the frequency range from 0.05 to 1.3 THz. Theoretically predicted β value exhibits the high nonlinear optical activity.

Quantum chemical calculations of Cr2O3/SnO2 using density functional theory method

NASA Astrophysics Data System (ADS)

Jawaher, K. Rackesh; Indirajith, R.; Krishnan, S.; Robert, R.; Das, S. Jerome

2018-03-01

Quantum chemical calculations have been employed to study the molecular effects produced by Cr2O3/SnO2 optimised structure. The theoretical parameters of the transparent conducting metal oxides were calculated using DFT / B3LYP / LANL2DZ method. The optimised bond parameters such as bond lengths, bond angles and dihedral angles were calculated using the same theory. The non-linear optical property of the title compound was calculated using first-order hyperpolarisability calculation. The calculated HOMO-LUMO analysis explains the charge transfer interaction between the molecule. In addition, MEP and Mulliken atomic charges were also calculated and analysed.

Linear control theory for gene network modeling.

PubMed

Shin, Yong-Jun; Bleris, Leonidas

2010-09-16

Systems biology is an interdisciplinary field that aims at understanding complex interactions in cells. Here we demonstrate that linear control theory can provide valuable insight and practical tools for the characterization of complex biological networks. We provide the foundation for such analyses through the study of several case studies including cascade and parallel forms, feedback and feedforward loops. We reproduce experimental results and provide rational analysis of the observed behavior. We demonstrate that methods such as the transfer function (frequency domain) and linear state-space (time domain) can be used to predict reliably the properties and transient behavior of complex network topologies and point to specific design strategies for synthetic networks.

Transference, Counter-Transference, and Reflexivity in Intercultural Education

ERIC Educational Resources Information Center

Shim, Jenna Min

2015-01-01

The article addresses the contributions psychoanalytic theory, particularly its concepts of "transference and counter-transference," can make to our understanding of reflexivity in intercultural education (IE). After the introduction, the article is organized into three parts. The first part is a psychoanalytic discussion that focuses on…

Multiconfiguration Pair-Density Functional Theory Is as Accurate as CASPT2 for Electronic Excitation.

PubMed

Hoyer, Chad E; Ghosh, Soumen; Truhlar, Donald G; Gagliardi, Laura

2016-02-04

A correct description of electronically excited states is critical to the interpretation of visible-ultraviolet spectra, photochemical reactions, and excited-state charge-transfer processes in chemical systems. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory and a new kind of density functional called an on-top density functional. Here, we show that MC-PDFT with a first-generation on-top density functional performs as well as CASPT2 for an organic chemistry database including valence, Rydberg, and charge-transfer excitations. The results are very encouraging for practical applications.

Nonadiabatic dynamics of electron transfer in solution: Explicit and implicit solvent treatments that include multiple relaxation time scales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwerdtfeger, Christine A.; Soudackov, Alexander V.; Hammes-Schiffer, Sharon, E-mail: shs3@illinois.edu

2014-01-21

The development of efficient theoretical methods for describing electron transfer (ET) reactions in condensed phases is important for a variety of chemical and biological applications. Previously, dynamical dielectric continuum theory was used to derive Langevin equations for a single collective solvent coordinate describing ET in a polar solvent. In this theory, the parameters are directly related to the physical properties of the system and can be determined from experimental data or explicit molecular dynamics simulations. Herein, we combine these Langevin equations with surface hopping nonadiabatic dynamics methods to calculate the rate constants for thermal ET reactions in polar solvents formore » a wide range of electronic couplings and reaction free energies. Comparison of explicit and implicit solvent calculations illustrates that the mapping from explicit to implicit solvent models is valid even for solvents exhibiting complex relaxation behavior with multiple relaxation time scales and a short-time inertial response. The rate constants calculated for implicit solvent models with a single solvent relaxation time scale corresponding to water, acetonitrile, and methanol agree well with analytical theories in the Golden rule and solvent-controlled regimes, as well as in the intermediate regime. The implicit solvent models with two relaxation time scales are in qualitative agreement with the analytical theories but quantitatively overestimate the rate constants compared to these theories. Analysis of these simulations elucidates the importance of multiple relaxation time scales and the inertial component of the solvent response, as well as potential shortcomings of the analytical theories based on single time scale solvent relaxation models. This implicit solvent approach will enable the simulation of a wide range of ET reactions via the stochastic dynamics of a single collective solvent coordinate with parameters that are relevant to experimentally accessible systems.« less

Comparison of connectivity analyses for resting state EEG data

NASA Astrophysics Data System (ADS)

Olejarczyk, Elzbieta; Marzetti, Laura; Pizzella, Vittorio; Zappasodi, Filippo

2017-06-01

Objective. In the present work, a nonlinear measure (transfer entropy, TE) was used in a multivariate approach for the analysis of effective connectivity in high density resting state EEG data in eyes open and eyes closed. Advantages of the multivariate approach in comparison to the bivariate one were tested. Moreover, the multivariate TE was compared to an effective linear measure, i.e. directed transfer function (DTF). Finally, the existence of a relationship between the information transfer and the level of brain synchronization as measured by phase synchronization value (PLV) was investigated. Approach. The comparison between the connectivity measures, i.e. bivariate versus multivariate TE, TE versus DTF, TE versus PLV, was performed by means of statistical analysis of indexes based on graph theory. Main results. The multivariate approach is less sensitive to false indirect connections with respect to the bivariate estimates. The multivariate TE differentiated better between eyes closed and eyes open conditions compared to DTF. Moreover, the multivariate TE evidenced non-linear phenomena in information transfer, which are not evidenced by the use of DTF. We also showed that the target of information flow, in particular the frontal region, is an area of greater brain synchronization. Significance. Comparison of different connectivity analysis methods pointed to the advantages of nonlinear methods, and indicated a relationship existing between the flow of information and the level of synchronization of the brain.

[Research on Participation in Working Life: On the Transfer from Theory into Practice].

PubMed

Bartel, Susanne; Ohlbrecht, Heike

2018-06-01

This study focuses on the theory-practice transfer in the field of research on participation in working life (LTA). The aim was to determine what expectations are prevalent on the part of service providers, how they access scientific knowledge, how the transfer into practice takes place and what research gaps exist. At the same time, representatives of the German Statutory Pension Insurance were asked about internal structures for identifying research topics and evaluating research results as well as for knowledge transfer. The aim of the article is to address the relationship between research and practice in the field of LTA and to create a sensitivity for this topic. The results of this study are based on a written survey of 28 Vocational Training Institutes (BFW) of the Federal Association of Vocational Rehabilitation Centres (BV BFW) and on three expert interviews with representatives of pension insurance companies (federal and regional). The response rate of the BFW survey was approximately 54% (N=15). For the evaluation of data primarily qualitative content analysis was applied, which included a step by step coding of the data. The results of the survey indicate a pronounced need for translation processes and a culture of cooperation between research and practice. At the same time, a tension between the preservation of the autonomy of research and an increasing transfer orientation became evident. In addition, a wide range of approaches for structuring possible transfer activities could be identified. In the area of research on services for participation in working life, the development of a strategy for research transfer represents a future task. It is necessary to explore new communication structures and participatory research formats in which research groups and sponsors as well as practitioners can jointly carry out research in this field. © Georg Thieme Verlag KG Stuttgart · New York.

Molecular conformational analysis, vibrational spectra, NBO analysis and first hyperpolarizability of (2E)-3-(3-chlorophenyl)prop-2-enoic anhydride based on density functional theory calculations.

PubMed

Mary, Y Sheena; Raju, K; Panicker, C Yohannan; Al-Saadi, Abdulaziz A; Thiemann, Thies

2014-10-15

The conformational behavior and structural stability of (2E)-3-(3-chlorophenyl)prop-2-enoic anhydride were investigated by using density functional theory. The optimized molecular structure, vibrational wavenumbers, corresponding vibrational assignments of (2E)-3-(3-chlorophenyl)prop-2-enoic anhydride have been investigated experimentally and theoretically. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated first hyperpolarizability of the title compound is 15.8×10(-30)esu, and is 121.54 times that of the standard NLO material urea and the title compound is an attractive object for future studies of nonlinear optical properties. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. Copyright © 2014 Elsevier B.V. All rights reserved.

Time dependence of triplet--singlet excitation transfer from compact poly rA to bound dye at 77 k

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pearlstein, R.M.; Nostrand, F.V.; Nairn, J.A.

1979-04-01

The nonexponential phosphorescence decay of a highly folded form of polyriboadenylic acid (poly rA) with noncovalently bound dye is explained by a novel application of a well-known theory of electronic excitation transfer based on the Forster mechanism. This theory, originally used to describe singlet-singlet energy transfer from donor molecules to an acceptor in a solution, is here applied to the transfer of triplet excitation from the adenine (in poly rA) to the singlet manifold of either of the bound dyes, ethidium bromide or proflavine. New experimental data are presented that allow straight-forward theoretical interpretation. These data fit the form predictedmore » by the theory, U(t)exp(-Bt/sup 1/2/), where U(t) is the decay of the poly rA phosphorescence in the absence of dye, for a range of relative concentrations of either dye. The self-consistency of these theoretical fits is demonstrated by the proportionality of B to the square root of the Forster triplet-singlet overlap integrals for transfer from poly rA to each of the dyes, as demanded by the theory. From these self-consistent values of B, the theory enables one to deduce the mean packing density of nucleotides in this folded poly rA, which we estimate to be approx. 1 nm/sup -3/. We conclude that some variation of the method described here may be useful for deducing packing densities of nucleotides in other compact nucleic acid structures.« less

Transfer of learning between 2D and 3D sources during infancy: Informing theory and practice

PubMed Central

Barr, Rachel

2010-01-01

The ability to transfer learning across contexts is an adaptive skill that develops rapidly during early childhood. Learning from television is a specific instance of transfer of learning between a 2-Dimensional (2D) representation and a 3-Dimensional (3D) object. Understanding the conditions under which young children might accomplish this particular kind of transfer is important because by 2 years of age 90% of US children are viewing television on a daily basis. Recent research shows that children can imitate actions presented on television using the corresponding real-world objects, but this same research also shows that children learn less from television than they do from live demonstrations until they are at least 3 years old; termed the video deficit effect. At present, there is no coherent theory to account for the video deficit effect; how learning is disrupted by this change in context is poorly understood. The aims of the present review are (1) to review the conditions under which children transfer learning between 2D images and 3D objects during early childhood, and (2) to integrate developmental theories of memory processing into the transfer of learning from media literature using Hayne’s (2004) developmental representational flexibility account. The review will conclude that studies on the transfer of learning between 2D and 3D sources have important theoretical implications for general developmental theories of cognitive development, and in particular the development of a flexible representational system, as well as policy implications for early education regarding the potential use and limitations of media as effective teaching tools during early childhood. PMID:20563302

Influences of system uncertainties on the numerical transfer path analysis of engine systems

NASA Astrophysics Data System (ADS)

Acri, A.; Nijman, E.; Acri, A.; Offner, G.

2017-10-01

Practical mechanical systems operate with some degree of uncertainty. In numerical models uncertainties can result from poorly known or variable parameters, from geometrical approximation, from discretization or numerical errors, from uncertain inputs or from rapidly changing forcing that can be best described in a stochastic framework. Recently, random matrix theory was introduced to take parameter uncertainties into account in numerical modeling problems. In particular in this paper, Wishart random matrix theory is applied on a multi-body dynamic system to generate random variations of the properties of system components. Multi-body dynamics is a powerful numerical tool largely implemented during the design of new engines. In this paper the influence of model parameter variability on the results obtained from the multi-body simulation of engine dynamics is investigated. The aim is to define a methodology to properly assess and rank system sources when dealing with uncertainties. Particular attention is paid to the influence of these uncertainties on the analysis and the assessment of the different engine vibration sources. Examples of the effects of different levels of uncertainties are illustrated by means of examples using a representative numerical powertrain model. A numerical transfer path analysis, based on system dynamic substructuring, is used to derive and assess the internal engine vibration sources. The results obtained from this analysis are used to derive correlations between parameter uncertainties and statistical distribution of results. The derived statistical information can be used to advance the knowledge of the multi-body analysis and the assessment of system sources when uncertainties in model parameters are considered.

Charge-transfer mechanism for electrophilic aromatic nitration and nitrosation via the convergence of (ab initio) molecular-orbital and Marcus-Hush theories with experiments.

PubMed

Gwaltney, Steven R; Rosokha, Sergiy V; Head-Gordon, Martin; Kochi, Jay K

2003-03-19

The highly disparate rates of aromatic nitrosation and nitration, despite the very similar (electrophilic) properties of the active species: NO(+) and NO(2)(+) in Chart 1, are quantitatively reconciled. First, the thorough mappings of the potential-energy surfaces by high level (ab initio) molecular-orbital methodologies involving extensive coupled-cluster CCSD(T)/6-31G optimizations establish the intervention of two reactive intermediates in nitration (Figure 8) but only one in nitrosation (Figure 7). Second, the same distinctive topologies involving double and single potential-energy minima (Figures 6 and 5) also emerge from the semiquantitative application of the Marcus-Hush theory to the transient spectral data. Such a striking convergence from quite different theoretical approaches indicates that the molecular-orbital and Marcus-Hush (potential-energy) surfaces are conceptually interchangeable. In the resultant charge-transfer mechanism, the bimolecular interactions of arene donors with both NO(+) and NO(2)(+) spontaneously lead (barrierless) to pi-complexes in which electron transfer is concurrent with complexation. Such a pi-complex in nitration is rapidly converted to the sigma-complex, whereas this Wheland adduct in nitrosation merely represents a high energy (transition-state) structure. Marcus-Hush analysis thus demonstrates how the strongly differentiated (arene) reactivities toward NO(+) and NO(2)(+) can actually be exploited in the quantitative development of a single coherent (electron-transfer) mechanism for both aromatic nitrosation and nitration.

Nuclear magnetic relaxation by the dipolar EMOR mechanism: Multi-spin systems

NASA Astrophysics Data System (ADS)

Chang, Zhiwei; Halle, Bertil

2017-08-01

In aqueous systems with immobilized macromolecules, including biological tissues, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. Starting from the stochastic Liouville equation, we have previously developed a rigorous EMOR relaxation theory for dipole-coupled two-spin and three-spin systems. Here, we extend the stochastic Liouville theory to four-spin systems and use these exact results as a guide for constructing an approximate multi-spin theory, valid for spin systems of arbitrary size. This so-called generalized stochastic Redfield equation (GSRE) theory includes the effects of longitudinal-transverse cross-mode relaxation, which gives rise to an inverted step in the relaxation dispersion profile, and coherent spin mode transfer among solid-like spins, which may be regarded as generalized spin diffusion. The GSRE theory is compared to an existing theory, based on the extended Solomon equations, which does not incorporate these phenomena. Relaxation dispersion profiles are computed from the GSRE theory for systems of up to 16 protons, taken from protein crystal structures. These profiles span the range from the motional narrowing limit, where the coherent mode transfer plays a major role, to the ultra-slow motion limit, where the zero-field rate is closely related to the strong-collision limit of the dipolar relaxation rate. Although a quantitative analysis of experimental data is beyond the scope of this work, it is clear from the magnitude of the predicted relaxation rate and the shape of the relaxation dispersion profile that the dipolar EMOR mechanism is the principal cause of water-1H low-field longitudinal relaxation in aqueous systems of immobilized macromolecules, including soft biological tissues. The relaxation theory developed here therefore provides a basis for molecular-level interpretation of endogenous soft-tissue image contrast obtained by the emerging low-field magnetic resonance imaging techniques.

Heat Exchange in “Human body - Thermal protection - Environment” System

NASA Astrophysics Data System (ADS)

Khromova, I. V.

2017-11-01

This article is devoted to the issues of simulation and calculation of thermal processes in the system called “Human body - Thermal protection - Environment” under low temperature conditions. It considers internal heat sources and convective heat transfer between calculated elements. Overall this is important for the Heat Transfer Theory. The article introduces complex heat transfer calculation method and local thermophysical parameters calculation method in the system called «Human body - Thermal protection - Environment», considering passive and active thermal protections, thermophysical and geometric properties of calculated elements in a wide range of environmental parameters (water, air). It also includes research on the influence that thermal resistance of modern materials, used in special protective clothes development, has on heat transfer in the system “Human body - Thermal protection - Environment”. Analysis of the obtained results allows adding of the computer research data to experiments and optimizing of individual life-support system elements, which are intended to protect human body from exposure to external factors.

An investigation of rotor noise generation by aerodynamic disturbance. [aeroacoustic transfer functions

NASA Technical Reports Server (NTRS)

Whitfield, C. E.

1977-01-01

An open rotor was considered as a process for converting an unsteady velocity inflow into sound radiation. With the aid of crude assumptions, aero-acoustic transfer functions were defined theoretically for both discrete frequency and broad band noise. A study of the validity of these transfer functions yielded results which show good agreement at discrete frequencies though slightly less good for broad band noise. Agreement in both cases holds over three or more decades of the relevant parameters. A rotating hot wire anemometry system consisting of a single hot wire probe mounted in the nose cone of the rotor was used to quantify fluctuations in the airflow onto a single rotor blade for the transfer function results. Further theoretical analysis revealed that the sound field can be expressed in terms of blade-to-blade correlations in the airflow, and results from two probes rotating simultaneously were modelled mathematically and inserted in the theory. Preliminary results snow encouraging agreement with experimental data.

Partially-irreversible sorption of formaldehyde in five polymers

NASA Astrophysics Data System (ADS)

Ye, Wei; Cox, Steven S.; Zhao, Xiaomin; Frazier, Charles E.; Little, John C.

2014-12-01

Due to its environmental ubiquity and concern over its potential toxicity, the mass-transfer characteristics of formaldehyde are of critical importance to indoor air quality research. Previous studies have suggested that formaldehyde mass transfer in polymer is partially irreversible. In this study, mechanisms that could cause the observed irreversibility were investigated. Polycarbonate and four other polymeric matrices were selected and subjected to formaldehyde sorption/desorption cycles. Mass transfer of formaldehyde was partially irreversible in all cases, and three potential mechanisms were evaluated. First, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis was used to investigate possible formaldehyde polymerization on polymer surfaces. ATR-FTIR showed no detectable paraformaldehyde or formaldehyde on the film surfaces that had been exposed to formaldehyde and air. ATR-FTIR did detect aliphatic acids suggesting oxidation had occurred on film surfaces as a result of exposure to formaldehyde. However, additional study suggested that air is not the primary cause for irreversibility. Second, statistical physics theory was tested as a possible explanation. According to this theory, reversible and irreversible sorption could be taking place simultaneously. The irreversible fraction should be constant during sorption and the fraction could be determined by performing a complete sorption/desorption test. The sorption/desorption data was consistent with this theory. Third, chemisorption was considered as another possible cause for irreversibility. Extraction/fluorimetry testing of post-sorption and post-desorption polymer films showed measurable quantities of formaldehyde suggesting that some of the chemisorbed formaldehyde was reversible at the higher extraction temperature. Further quantitative study on chemical reaction products is needed.

Measuring the Effectiveness of Transfer of Learning Constructs and Intent to Transfer in a Simulation-Based Leadership Training Program

ERIC Educational Resources Information Center

Hix, Joanne W.

2013-01-01

The purpose of business training programs is to improve performance, which improved performance changes leadership behaviors based on the knowledge, skills, and abilities (KSAs) learned in training. One of the most common criticisms of leadership training is the tendency to focus on teaching theory but not on applying theory into practice, that…

"Parallel Leadership in an "Unparallel" World"--Cultural Constraints on the Transferability of Western Educational Leadership Theories across Cultures

ERIC Educational Resources Information Center

Goh, Jonathan Wee Pin

2009-01-01

With the global economy becoming more integrated, the issues of cross-cultural relevance and transferability of leadership theories and practices have become increasingly urgent. Drawing upon the concept of parallel leadership in schools proposed by Crowther, Kaagan, Ferguson, and Hann as an example, the purpose of this paper is to examine the…

Performance Assessment of Counseling Skills Based on Specific Theories: Acquisition, Retention and Transfer to Actual Counseling Sessions

ERIC Educational Resources Information Center

Schaefle, Scott; Smaby, Marlowe H.; Packman, Jill; Maddux, Cleborne D.

2007-01-01

The purposes of the present study were to determine if (a) students trained to demonstrate specific skills learn these skills and transfer them to actual counseling sessions; (b) mastery of counseling skills differs by students' adherence to one of four general counseling theories; (c) mastery of counseling skills is related to counseling goal…

[Mathematical apparatus of the circuit theory in modeling of heat transfer upon extreme heating of an organism].

PubMed

2010-01-01

The mathematical model of heat transfer in whole-body hyperthermia, developed earlier by the author, has been refined using the mathematical apparatus of the circuit theory. The model can be used to calculate the temperature of each organ, which can increase the efficacy and safety of the immersion-convection technique of whole-body hyperthermia.

Theory of Prejudice and American Identity Threat Transfer for Latino and Asian Americans.

PubMed

Sanchez, Diana T; Chaney, Kimberly E; Manuel, Sara K; Remedios, Jessica D

2018-03-01

Latinos and Asian Americans confront similar stereotypes as they are often presumed to be foreigners and subjected to American identity denial. Across six studies (total N = 992), we demonstrate that Latinos and Asians anticipate ingroup prejudice and specific types of subordination (e.g., American identity threat) in the face of outgroup threats that target one another (i.e., stigma transfer). The studies explore whether stigma transfer occurred primarily when shared Latino and Asian stereotype content was a salient component of the prejudice remark (e.g., foreigner stereotypes; Study 3), or when outgroup prejudice targeted a social group with shared stereotype content (Study 4), though neither appeared to substantively moderate stigma transfer. Minority group members who conceptualize prejudiced people as holding multiple biases (i.e., a monolithic prejudice theory) were more susceptible to stigma transfer suggesting that stereotype content is not necessary for stigma transfer because people assume that prejudice is not singular.

Combined TDDFT and AIM Insights into Photoinduced Excited State Intramolecular Proton Transfer (ESIPT) Mechanism in Hydroxyl- and Amino-Anthraquinone Solution.

PubMed

Zheng, Daoyuan; Zhang, Mingzhen; Zhao, Guangjiu

2017-10-23

Time-dependent density functional theory (TDDFT) and atoms in molecules (AIM) theory are combined to study the photoinduced excited state intramolecular proton transfer (ESIPT) dynamics for eight anthraquinones (AQs) derivatives in solution. The calculated absorption and emission spectra are consistent with the available experimental data, verifying the suitability of the theory selected. The systems with the excited-state exothermic proton transfer, such as 1-HAQ, 1,5-DHAQ and TFAQ, emit completely from transfer structure (T), while the reactions for those without ESIPT including 1,4-DHAQ and AAAQ appear to be endothermic. Three reaction properties of three systems (1,8-DHAQ, DCAQ and CAAQ) are between the exothermic and endothermic, sensitive to the solvent. Energy scanning shows that 1,4-DHAQ and AAAQ exhibit the higher ESIPT energy barriers compared to 1-HAQ, 1,5-DHAQ and TFAQ with the "barrierless" ESIPT process. The ESIPT process is facilitated by the strengthening of hydrogen bonds in excited state. With AIM theory, it is observed that the change in electrons density ρ(r) and potential energy density V(r) at BCP position between ground state and excited state are crucial factors to quantitatively elucidate the ESIPT.

Quantum gravity and the holographic principle

NASA Astrophysics Data System (ADS)

de Haro Ollé, S.

2001-06-01

In this thesis we study two different approaches to holography, and comment on the possible relation between them. The first approach is an analysis of the high-energy regime of quantum gravity in the eikonal approximation, where the theory reduces to a topological field theory. This is the regime where particles interact at high energies but with small momentum transfer. We do this for the cases of asymptotically dS and AdS geometries and find that in both cases the theory is topological. We discuss the relation of our solutions in AdS to those of Horowitz and Itzhaki. We also consider quantum gravity away from the extreme eikonal limit and explain the sense in which the covariance of the theory is equivalent to taking into account transfer of momentum. The second approach we pursue is the AdS/CFT correspondence. We provide a holographic reconstruction of the bulk space-time metric and of bulk fields on this space-time, out of conformal field theory data. Knowing which sources are turned on is sufficient in order to obtain an asymptotic expansion of the bulk metric and of bulk fields near the boundary to high enough order so that all infrared divergences of the on-shell action are obtained. We provide explicit formulae for the holographic stress-energy tensors associated with an arbitrary asymptotically AdS geometry. We also study warped compactifications, where our d-dimensional world is regarded as a slice of a (d+1)-dimensional space-time, and analyse in detail the question as to where the d-dimensional observer can find the information about the extra dimension.

Group Differences in California Community College Transfers

ERIC Educational Resources Information Center

Budd, Deborah; Stowers, Genie N. L.

2015-01-01

This study explores the extent to which community colleges succeed in assisting students to transfer to four-year colleges. The study uses data from the California Community College system to test hypotheses about overall transfers and transfers of underrepresented students, It utilizes a framework based upon social reproduction theory (Bowles…

Flight Simulation for the Study of Skill Transfer.

ERIC Educational Resources Information Center

Lintern, Gavan

1992-01-01

Discusses skill transfer as a human performance issue based on experiences with computerized flight simulators. Highlights include the issue of similarity; simulation and the design of training devices; an information theory of transfer; invariants for flight control; and experiments involving the transfer of flight skills. (21 references) (LRW)

Comparison of Theoretical and Experimental Heat-Transfer Characteristics of Bodies of Revolution at Supersonic Speeds

NASA Technical Reports Server (NTRS)

Scherrer, Richard

1951-01-01

An investigation of the three important factors that determine convective heat-transfer characteristics at supersonic speeds, location boundary-layer transition, recovery factor, and heat-transfer parameter has been performed at Mach numbers from 1.49 to 1.18. The bodies of revolution that were tested had, in most cases, laminar boundary layers, and the test results have been compared with available theory. Boundary-layer transition was found to be affected by heat transfer. Adding heat to a laminar boundary layer caused transition to move forward on the test body, while removing heat caused transition to move rearward. These experimental results and the implications of boundary-layer-stability theory are in qualitative agreement.

A molecular Debye-Hückel approach to the reorganization energy of electron transfer reactions in an electric cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Tiejun; Department of Chemistry, Iowa State University, Ames, Iowa 50011; Song, Xueyu

2014-10-07

Electron transfer near an electrode immersed in ionic fluids is studied using the linear response approximation, namely, mean value of the vertical energy gap can be used to evaluate the reorganization energy, and hence any linear response model that can treat Coulomb interactions successfully can be used for the reorganization energy calculation. Specifically, a molecular Debye-Hückel theory is used to calculate the reorganization energy of electron transfer reactions in an electric cell. Applications to electron transfer near an electrode in molten salts show that the reorganization energies from our molecular Debye-Hückel theory agree well with the results from MD simulations.

Investigation of ground state charge transfer complex between paracetamol and p-chloranil through DFT and UV-visible studies

NASA Astrophysics Data System (ADS)

Shukla, Madhulata; Srivastava, Nitin; Saha, Satyen

2012-08-01

The present report deals with the theoretical investigation on ground state structure and charge transfer (CT) transitions in paracetamol (PA)/p-chloranil (CA) complex using Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) method. It is found that Cdbnd O bond length of p-chloranil increases on complexation with paracetamol along with considerable amount of charge transfer from PA to CA. TD-DFT calculations have been performed to analyse the observed UV-visible spectrum of PA-CA charge transferred complex. Interestingly, in addition to expected CT transition, a weak symmetry relieved π-π* transition in the chloranil is also observed.

Theoretical and experimental evaluation of a new organic proton transfer crystal aminoguanidinium p-nitrobenzoate monohydrate for optical limiting applications

NASA Astrophysics Data System (ADS)

Shanmugavadivu, T.; Senthilkumar, K.; Dhandapani, M.; Muthuraja, P.; Balachandar, S.; Sethu Raman, M.

2017-12-01

Aminoguanidinium p-nitrobenzoate monohydrate (AGPNB), an organic third order nonlinear crystal, was successfully grown by the slow evaporation technique. Single crystal XRD analysis reveals that the grown crystal belongs to monoclinic system with P21/n space group. FT-IR, 1H and 13C NMR spectroscopic studies were carried out to confirm the proton transfer. Optical and thermal suitability were assessed by UV-NIR and TG-DTA studies. Hirshfeld surface analysis predicts that the O⋯H/H⋯O interactions dominated over the crystal structure. Third order nonlinearity was studied by Z-scan analysis and it is found that AGPNB can be used as a reverse satuarble absorption (RSA) based optical limiter at 632.8 nm. Computational studies, such as geometry optimization, Natural bond orbital (NBO) analysis, Mulliken population analysis and Molecular electrostatic potential (MEP) were performed at B3LYP/6-311G(d,p) level of theory. The calculated first order hyperpolarizability of AGPNB is found to be 35 times that of urea.

Priority design parameters of industrialized optical fiber sensors in civil engineering

NASA Astrophysics Data System (ADS)

Wang, Huaping; Jiang, Lizhong; Xiang, Ping

2018-03-01

Considering the mechanical effects and the different paths for transferring deformation, optical fiber sensors commonly used in civil engineering have been systematically classified. Based on the strain transfer theory, the relationship between the strain transfer coefficient and allowable testing error is established. The proposed relationship is regarded as the optimal control equation to obtain the optimal value of sensors that satisfy the requirement of measurement precision. Furthermore, specific optimization design methods and priority design parameters of the classified sensors are presented. This research indicates that (1) strain transfer theory-based optimization design method is much suitable for the sensor that depends on the interfacial shear stress to transfer the deformation; (2) the priority design parameters are bonded (sensing) length, interfacial bonded strength, elastic modulus and radius of protective layer and thickness of adhesive layer; (3) the optimization design of sensors with two anchor pieces at two ends is independent of strain transfer theory as the strain transfer coefficient can be conveniently calibrated by test, and this kind of sensors has no obvious priority design parameters. Improved calibration test is put forward to enhance the accuracy of the calibration coefficient of end-expanding sensors. By considering the practical state of sensors and the testing accuracy, comprehensive and systematic analyses on optical fiber sensors are provided from the perspective of mechanical actions, which could scientifically instruct the application design and calibration test of industrialized optical fiber sensors.

Exergoeconomic analysis and optimization of an evaporator for a binary mixture of fluids in an organic Rankine cycle

NASA Astrophysics Data System (ADS)

Li, You-Rong; Du, Mei-Tang; Wang, Jian-Ning

2012-12-01

This paper focuses on the research of an evaporator with a binary mixture of organic working fluids in the organic Rankine cycle. Exergoeconomic analysis and performance optimization were performed based on the first and second laws of thermodynamics, and the exergoeconomic theory. The annual total cost per unit heat transfer rate was introduced as the objective function. In this model, the exergy loss cost caused by the heat transfer irreversibility and the capital cost were taken into account; however, the exergy loss due to the frictional pressure drops, heat dissipation to surroundings, and the flow imbalance were neglected. The variation laws of the annual total cost with respect to the number of transfer units and the temperature ratios were presented. Optimal design parameters that minimize the objective function had been obtained, and the effects of some important dimensionless parameters on the optimal performances had also been discussed for three types of evaporator flow arrangements. In addition, optimal design parameters of evaporators were compared with those of condensers.

Numerical study focusing on the entropy analysis of MHD squeezing flow of a nanofluid model using Cattaneo–Christov theory

NASA Astrophysics Data System (ADS)

Akmal, N.; Sagheer, M.; Hussain, S.

2018-05-01

The present study gives an account of the heat transfer characteristics of the squeezing flow of a nanofluid between two flat plates with upper plate moving vertically and the lower in the horizontal direction. Tiwari and Das nanofluid model has been utilized to give a comparative analysis of the heat transfer in the Cu-water and Al2O3-water nanofluids with entropy generation. The modeling is carried out with the consideration of Lorentz forces to observe the effect of magnetic field on the flow. The Joule heating effect is included to discuss the heat dissipation in the fluid and its effect on the entropy of the system. The nondimensional ordinary differential equations are solved using the Keller box method to assess the numerical results which are presented by the graphs and tables. An interesting observation is that the entropy is generated more near the lower plate as compared with that at the upper plate. Also, the heat transfer rate is found to be higher for the Cu nanoparticles in comparison with the Al2O3 nanoparticles.

Electronic and magnetic properties of transition metal doped graphyne

NASA Astrophysics Data System (ADS)

Gangan, Abhijeet Sadashiv; Yadav, Asha S.; Chakraborty, Brahmananda; Ramaniah, Lavanya M.

2017-05-01

We have theoretically investigated the interaction of few 3d (V,Mn) and 4d (Y,Zr) transition metals with the γ-graphyne structure using the spin-polarized density functional theory for its potentials application in Hydrogen storage, spintronics and nano-electronics. By doping different TMs we have observed that the system can be either metallic(Y), semi-conducting or half metallic. The system for Y and Zr doped graphyne becomes non-magnetic while V and Mn doped graphyne have a magnetic moments of l μB and 3 μB respectively From bader charge analysis it is seen that there is a charge transfer from the TM atom to the graphyne. Zr and Y have a net charge transfer of 2.15e and 1.73e respectively. Charge density analysis also shows the polarization on the carbon skeleton which becomes larger as the charge transfer for the TM atom increases. Thus we see Y and Zr are better candidates for hydrogen storage devices since they are non-magnetic and have less d electrons which is ideal for kubas-type interactions between hydrogen molecule and TM.

An inventory-theory-based interval-parameter two-stage stochastic programming model for water resources management

NASA Astrophysics Data System (ADS)

Suo, M. Q.; Li, Y. P.; Huang, G. H.

2011-09-01

In this study, an inventory-theory-based interval-parameter two-stage stochastic programming (IB-ITSP) model is proposed through integrating inventory theory into an interval-parameter two-stage stochastic optimization framework. This method can not only address system uncertainties with complex presentation but also reflect transferring batch (the transferring quantity at once) and period (the corresponding cycle time) in decision making problems. A case of water allocation problems in water resources management planning is studied to demonstrate the applicability of this method. Under different flow levels, different transferring measures are generated by this method when the promised water cannot be met. Moreover, interval solutions associated with different transferring costs also have been provided. They can be used for generating decision alternatives and thus help water resources managers to identify desired policies. Compared with the ITSP method, the IB-ITSP model can provide a positive measure for solving water shortage problems and afford useful information for decision makers under uncertainty.

Practice teaching and the importance of feedback.

PubMed

Lally, Sheila

2013-01-01

Practice teachers play a key role in ensuring health visitors, school nurses and occupational health nurses are capable of delivering safe and effective practice to the public. The practice teacher is a significant member of the learning team during the specialist community public health nursing programme. This paper discusses the role of feedback in facilitating students' learning while in practice. Its purpose is to raise awareness for those working as practice teachers to the issues they may experience when giving feedback and discusses the theories of transactional analysis, transference and counter-transference and the impact these may have on the practice teachers' ability to give constructive feedback to specialist community public health nursing students.

Maxwell's second- and third-order equations of transfer for non-Maxwellian gases

NASA Technical Reports Server (NTRS)

Baganoff, D.

1992-01-01

Condensed algebraic forms for Maxwell's second- and third-order equations of transfer are developed for the case of molecules described by either elastic hard spheres, inverse-power potentials, or by Bird's variable hard-sphere model. These hardly reduced, yet exact, equations provide a new point of origin, when using the moment method, in seeking approximate solutions in the kinetic theory of gases for molecular models that are physically more realistic than that provided by the Maxwell model. An important by-product of the analysis when using these second- and third-order relations is that a clear mathematical connection develops between Bird's variable hard-sphere model and that for the inverse-power potential.

Application of Degenerately Doped Metal Oxides in the Study of Photoinduced Interfacial Electron Transfer.

PubMed

Farnum, Byron H; Morseth, Zachary A; Brennaman, M Kyle; Papanikolas, John M; Meyer, Thomas J

2015-06-18

Degenerately doped In2O3:Sn semiconductor nanoparticles (nanoITO) have been used to study the photoinduced interfacial electron-transfer reactivity of surface-bound [Ru(II)(bpy)2(4,4'-(PO3H2)2-bpy)](2+) (RuP(2+)) molecules as a function of driving force over a range of 1.8 eV. The metallic properties of the ITO nanoparticles, present within an interconnected mesoporous film, allowed for the driving force to be tuned by controlling their Fermi level with an external bias while their optical transparency allowed for transient absorption spectroscopy to be used to monitor electron-transfer kinetics. Photoinduced electron transfer from excited-state -RuP(2+*) molecules to nanoITO was found to be dependent on applied bias and competitive with nonradiative energy transfer to nanoITO. Back electron transfer from nanoITO to oxidized -RuP(3+) was also dependent on the applied bias but without complication from inter- or intraparticle electron diffusion in the oxide nanoparticles. Analysis of the electron injection kinetics as a function of driving force using Marcus-Gerischer theory resulted in an experimental estimate of the reorganization energy for the excited-state -RuP(3+/2+*) redox couple of λ* = 0.83 eV and an electronic coupling matrix element, arising from electronic wave function overlap between the donor orbital in the molecule and the acceptor orbital(s) in the nanoITO electrode, of Hab = 20-45 cm(-1). Similar analysis of the back electron-transfer kinetics yielded λ = 0.56 eV for the ground-state -RuP(3+/2+) redox couple and Hab = 2-4 cm(-1). The use of these wide band gap, degenerately doped materials provides a unique experimental approach for investigating single-site electron transfer at the surface of oxide nanoparticles.

Electron transfer across a thermal gradient

PubMed Central

Craven, Galen T.

2016-01-01

Charge transfer is a fundamental process that underlies a multitude of phenomena in chemistry and biology. Recent advances in observing and manipulating charge and heat transport at the nanoscale, and recently developed techniques for monitoring temperature at high temporal and spatial resolution, imply the need for considering electron transfer across thermal gradients. Here, a theory is developed for the rate of electron transfer and the associated heat transport between donor–acceptor pairs located at sites of different temperatures. To this end, through application of a generalized multidimensional transition state theory, the traditional Arrhenius picture of activation energy as a single point on a free energy surface is replaced with a bithermal property that is derived from statistical weighting over all configurations where the reactant and product states are equienergetic. The flow of energy associated with the electron transfer process is also examined, leading to relations between the rate of heat exchange among the donor and acceptor sites as functions of the temperature difference and the electronic driving bias. In particular, we find that an open electron transfer channel contributes to enhanced heat transport between sites even when they are in electronic equilibrium. The presented results provide a unified theory for charge transport and the associated heat conduction between sites at different temperatures. PMID:27450086

Describing long-range charge-separation processes with subsystem density-functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solovyeva, Alisa; Neugebauer, Johannes, E-mail: j.neugebauer@uni-muenster.de; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu

2014-04-28

Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants inmore » Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.« less

A Model for Designing Instructional Narratives for Adult Learners: Connecting the Dots

ERIC Educational Resources Information Center

Smith, Debra M.

2013-01-01

The purpose of this study was to develop a research-based model for designing and deploying instructional narratives based on principles derived from narrative theory, development theory, communication theory, learning theory and instructional design theory to enable adult learning and retention and the effective transfer of that retained learning…

Diffuse charge and Faradaic reactions in porous electrodes

NASA Astrophysics Data System (ADS)

Biesheuvel, P. M.; Fu, Yeqing; Bazant, Martin Z.

2011-06-01

Porous electrodes instead of flat electrodes are widely used in electrochemical systems to boost storage capacities for ions and electrons, to improve the transport of mass and charge, and to enhance reaction rates. Existing porous electrode theories make a number of simplifying assumptions: (i) The charge-transfer rate is assumed to depend only on the local electrostatic potential difference between the electrode matrix and the pore solution, without considering the structure of the double layer (DL) formed in between; (ii) the charge-transfer rate is generally equated with the salt-transfer rate not only at the nanoscale of the matrix-pore interface, but also at the macroscopic scale of transport through the electrode pores. In this paper, we extend porous electrode theory by including the generalized Frumkin-Butler-Volmer model of Faradaic reaction kinetics, which postulates charge transfer across the molecular Stern layer located in between the electron-conducting matrix phase and the plane of closest approach for the ions in the diffuse part of the DL. This is an elegant and purely local description of the charge-transfer rate, which self-consistently determines the surface charge and does not require consideration of reference electrodes or comparison with a global equilibrium. For the description of the DLs, we consider the two natural limits: (i) the classical Gouy-Chapman-Stern model for thin DLs compared to the macroscopic pore dimensions, e.g., for high-porosity metallic foams (macropores >50 nm) and (ii) a modified Donnan model for strongly overlapping DLs, e.g., for porous activated carbon particles (micropores <2 nm). Our theory is valid for electrolytes where both ions are mobile, and it accounts for voltage and concentration differences not only on the macroscopic scale of the full electrode, but also on the local scale of the DL. The model is simple enough to allow us to derive analytical approximations for the steady-state and early transients. We also present numerical solutions to validate the analysis and to illustrate the evolution of ion densities, pore potential, surface charge, and reaction rates in response to an applied voltage.

Prospective of employing high porosity open-cell metal foams in passive cryogenic radiators for space applications

NASA Astrophysics Data System (ADS)

Tisha, Dixit; Indranil, Ghosh

2017-02-01

Passive cryogenic radiators work on the principle of dissipating heat to the outer space purely by radiation. High porosity open-cell metal foams are a relatively new class of extended surfaces. These possess the advantages of high surface area density and low weight, characteristics which the space industry looks for. In case of radiative heat transfer, the porous nature of metal foams permits a deeper penetration of the incident radiation. Consequently, the heat transfer area participating in radiative heat exchange increases thereby enhancing the heat transfer rate. However, effective heat conduction in between the foam struts reduces as a result of the void spaces. These two conflicting phenomenon for radiation heat transfer in metal foams have been studied in this work. Similar to the foam conduction-convection heat transfer analysis, a conduction-radiation heat transfer model has been developed for metal foams in analogy with the conventional solid fin theory. Metal foams have been theoretically represented as simple cubic structures. A comparison of the radiative heat transfer through metal foams and solid fins attached to a surface having constant temperature has been presented. Effect of changes in foam characteristic properties such as porosity and pore density have also been studied.

Surface interaction of H2S, SO2, and SO3 on fullerene-like gallium nitride (GaN) nanostructure semiconductor

NASA Astrophysics Data System (ADS)

Salimifard, M.; Rad, A. Shokuhi; Mahanpoor, K.

2017-10-01

Density functional theory (DFT) using MPW1PW91 and B3LYP hybrid functionals was utilized for quantum-based investigations of three major sulfur compounds (H2S, SO2, and SO3) adsorption onto fullerene-like Ga12N12 nanocluster. All chemicals showed high chemisorption with the order of SO3>SO2>>H2S. Results of charge analysis showed that during adsorption, transfer of charge is from H2S to nanocluster while reverse direction of charge transfer is found for SO2 and SO3 molecules. Partial dissociation is found for adsorbates especially for SO2 and SO3 molecules. Results of thermochemistry analysis show negative values for enthalpy and Gibbs free energy of adsorption, confirming exothermic spontaneous process. Analysis of frontier molecular orbital (FMO) showed important role of orbital hybridizing towards formation of new bonds upon adsorption. As a result, we introduce Ga12N12 nanocluster as a strong adsorbent for sulfur compounds.

The Cost of Concreteness: The Effect of Nonessential Information on Analogical Transfer

ERIC Educational Resources Information Center

Kaminski, Jennifer A.; Sloutsky, Vladimir M.; Heckler, Andrew F.

2013-01-01

Most theories of analogical transfer focus on similarities between the learning and transfer domains, where transfer is more likely between domains that share common surface features, similar elements, or common interpretations of structure. We suggest that characteristics of the learning instantiation alone can give rise to different levels of…

Linking Positive Affect and Motivation to Transfer within Training: A Multilevel Study

ERIC Educational Resources Information Center

Paulsen, Hilko Frederik Klaas; Kauffeld, Simone

2017-01-01

Motivation to transfer is a critical element for successful training transfer. Whereas recent research has shown that training-related factors such as training design are related to motivation to transfer, participants' affective experiences have been neglected. Based on the broaden-and-build theory of positive emotions, we conducted a multilevel…

Locally optimal transfer trajectories between libration point orbits using invariant manifolds

NASA Astrophysics Data System (ADS)

Davis, Kathryn E.

2009-12-01

Techniques from dynamical systems theory and primer vector theory have been applied to the construction of locally optimal transfer trajectories between libration point orbits. When two libration point orbits have different energies, it has been found that the unstable manifold of the first orbit can be connected to the stable manifold of the second orbit with a bridging trajectory. A bounding sphere centered on the secondary, with a radius less than the radius of the sphere of influence of the secondary, was used to study the stable and unstable manifold trajectories. It was numerically demonstrated that within the bounding sphere, the two-body parameters of the unstable and stable manifold trajectories could be analyzed to locate low transfer costs. It was shown that as the two-body parameters of an unstable manifold trajectory more closely matched the two-body parameters of a stable manifold trajectory, the total DeltaV necessary to complete the transfer decreased. Primer vector theory was successfully applied to a transfer to determine the optimal maneuvers required to create the bridging trajectory that connected the unstable manifold of the first orbit to the stable manifold of the second orbit. Transfer trajectories were constructed between halo orbits in the Sun-Earth and Earth-Moon three-body systems. Multiple solutions were found between the same initial and final orbits, where certain solutions retraced interior portions of the trajectory. All of the trajectories created satisfied the conditions for optimality. The costs of transfers constructed using invariant manifolds were compared to the costs of transfers constructed without the use of invariant manifolds, when data was available. In all cases, the total cost of the transfers were significantly lower when invariant manifolds were used in the transfer construction. In many cases, the transfers that employed invariant manifolds were three to four times more efficient, in terms of fuel expenditure, than the transfer that did not. The decrease in transfer cost was accompanied by an increase in transfer time of flight. Transfers constructed in the Earth-Moon system were shown to be particularly viable for lunar navigation and communication constellations, as excellent coverage of the lunar surface can be achieved during the transfer.

Students' Learning of a Generalized Theory of Sound Transmission from a Teaching-Learning Sequence about Sound, Hearing and Health

NASA Astrophysics Data System (ADS)

West, Eva; Wallin, Anita

2013-04-01

Learning abstract concepts such as sound often involves an ontological shift because to conceptualize sound transmission as a process of motion demands abandoning sound transmission as a transfer of matter. Thus, for students to be able to grasp and use a generalized model of sound transmission poses great challenges for them. This study involved 199 students aged 10-14. Their views about sound transmission were investigated before and after teaching by comparing their written answers about sound transfer in different media. The teaching was built on a research-based teaching-learning sequence (TLS), which was developed within a framework of design research. The analysis involved interpreting students' underlying theories of sound transmission, including the different conceptual categories that were found in their answers. The results indicated a shift in students' understandings from the use of a theory of matter before the intervention to embracing a theory of process afterwards. The described pattern was found in all groups of students irrespective of age. Thus, teaching about sound and sound transmission is fruitful already at the ages of 10-11. However, the older the students, the more advanced is their understanding of the process of motion. In conclusion, the use of a TLS about sound, hearing and auditory health promotes students' conceptualization of sound transmission as a process in all grades. The results also imply some crucial points in teaching and learning about the scientific content of sound.

A high-power ultrasonic microreactor and its application in gas-liquid mass transfer intensification.

PubMed

Dong, Zhengya; Yao, Chaoqun; Zhang, Xiaoli; Xu, Jie; Chen, Guangwen; Zhao, Yuchao; Yuan, Quan

2015-02-21

The combination of ultrasound and microreactor is an emerging and promising area, but the report of designing high-power ultrasonic microreactor (USMR) is still limited. This work presents a robust, high-power and highly efficient USMR by directly coupling a microreactor plate with a Langevin-type transducer. The USMR is designed as a longitudinal half wavelength resonator, for which the antinode plane of the highest sound intensity is located at the microreactor. According to one dimension design theory, numerical simulation and impedance analysis, a USMR with a maximum power of 100 W and a resonance frequency of 20 kHz was built. The strong and uniform sound field in the USMR was then applied to intensify gas-liquid mass transfer of slug flow in a microfluidic channel. Non-inertial cavitation with multiple surface wave oscillation was excited on the slug bubbles, enhancing the overall mass transfer coefficient by 3.3-5.7 times.

Energy transfer between Eu-Mn and photoluminescence properties of Ba0.75Al11O17.25-BaMgAl10O17:Eu2+,Mn2+ solid solution

NASA Astrophysics Data System (ADS)

Zhou, Jun; Wang, Yuhua; Liu, Bitao; Li, Feng

2010-08-01

In order to evaluate the energy transfer between Eu-Mn in Ba0.75Al11O17.25-BaMgAl10O17 solid solution, Ba0.75Al11O17.25-BaMgAl10O17:Eu2+,Mn2+ phosphors were prepared by flux method. The crystal structure and the morphology of the solid solution were demonstrated by x-ray dirrfactometer and scanning electron microscopy. The photoluminescence mechanisms were explained by the energy transfer of Eu2+ to Mn2+ and the Dexter theory. A redshift of green emission peak and a decrease in decay time with the increase in Mn2+ concentration were observed. These phenomena are attributed to the formation of Mn2+ paired centers after analysis by a method of Pade approximations.

Transferable Force Field for Metal–Organic Frameworks from First-Principles: BTW-FF

PubMed Central

2014-01-01

We present an ab-initio derived force field to describe the structural and mechanical properties of metal–organic frameworks (or coordination polymers). The aim is a transferable interatomic potential that can be applied to MOFs regardless of metal or ligand identity. The initial parametrization set includes MOF-5, IRMOF-10, IRMOF-14, UiO-66, UiO-67, and HKUST-1. The force field describes the periodic crystal and considers effective atomic charges based on topological analysis of the Bloch states of the extended materials. Transferable potentials were developed for the four organic ligands comprising the test set and for the associated Cu, Zn, and Zr metal nodes. The predicted materials properties, including bulk moduli and vibrational frequencies, are in agreement with explicit density functional theory calculations. The modal heat capacity and lattice thermal expansion are also predicted. PMID:25574157

Spectroscopic and theoretical study of the charge transfer interaction effect on the vibrational modes and nonlinear optical properties in L-asparaginium nitrate crystal

NASA Astrophysics Data System (ADS)

Elleuch, Nabil; Abid, Younes; Feki, Habib

2016-09-01

Single crystals of L-asparaginium nitrate (LAsnN) were grown by slow evaporation technique. To confirm the crystalline nature of the obtained compound, samples were the subject of an XRPD. The density functional theory (DFT) computations were carried out at B3LYP/6-31G (d) level to reach the optimized geometry, the vibrational spectra and the NLO properties. The excellent agreement between simulated and observed vibrational spectra led to a reliable vibrational assignment. To demonstrate the various charge transfer interactions that stabilize the compound and led to the high nonlinear optical activity, NBO analysis was performed. Also, owing to the hydrogen bond formation, a lowering in the HOMO-LUMO energy gap is noticed. Moreover, as a result of the charge transfer interactions, the symmetry of the nitrate ions was lost and some forbidden modes were excited.

A novel approach in formulation of special transition elements: Mesh interface elements

NASA Technical Reports Server (NTRS)

Sarigul, Nesrin

1991-01-01

The objective of this research program is in the development of more accurate and efficient methods for solution of singular problems encountered in various branches of mechanics. The research program can be categorized under three levels. The first two levels involve the formulation of a new class of elements called 'mesh interface elements' (MIE) to connect meshes of traditional elements either in three dimensions or in three and two dimensions. The finite element formulations are based on boolean sum and blending operators. MEI are being formulated and tested in this research to account for the steep gradients encountered in aircraft and space structure applications. At present, the heat transfer and structural analysis problems are being formulated from uncoupled theory point of view. The status report: (1) summarizes formulation for heat transfer and structural analysis; (2) explains formulation of MEI; (3) examines computational efficiency; and (4) shows verification examples.

Error of the slanted edge method for measuring the modulation transfer function of imaging systems.

PubMed

Xie, Xufen; Fan, Hongda; Wang, Hongyuan; Wang, Zebin; Zou, Nianyu

2018-03-01

The slanted edge method is a basic approach for measuring the modulation transfer function (MTF) of imaging systems; however, its measurement accuracy is limited in practice. Theoretical analysis of the slanted edge MTF measurement method performed in this paper reveals that inappropriate edge angles and random noise reduce this accuracy. The error caused by edge angles is analyzed using sampling and reconstruction theory. Furthermore, an error model combining noise and edge angles is proposed. We verify the analyses and model with respect to (i) the edge angle, (ii) a statistical analysis of the measurement error, (iii) the full width at half-maximum of a point spread function, and (iv) the error model. The experimental results verify the theoretical findings. This research can be referential for applications of the slanted edge MTF measurement method.

Theory of ITG turbulent saturation in stellarators: identifying mechanisms to reduce turbulent transport

DOE PAGES

Hegna, Chris C.; Terry, Paul W.; Faber, Ben J.

2018-02-01

A three-field fluid model that allows for general three-dimensional equilibrium geometry is developed to describe ion temperature gradient turbulent saturation processes in stellarators. The theory relies on the paradigm of nonlinear transfer of energy from unstable to damped modes at comparable wavelength as the dominant saturation mechanism. The unstable-to-damped mode interaction is enabled by a third mode that for dominant energy transfer channels primarily serves as a regulator of the nonlinear energy transfer rate. The identity of the third wave in the interaction defines different scenarios for turbulent saturation with the dominant scenario depending upon the properties of the 3Dmore » geometry. The nonlinear energy transfer physics is quantified by the product of a turbulent correlation lifetime and a geometric coupling coefficient. The turbulent correlation time is determined by a three-wave frequency mismatch, which at long wavelength can be calculated from the sum of the linear eigenfrequencies of the three modes. Larger turbulent correlation times denote larger levels of nonlinear energy transfer and hence smaller turbulent transport. The theory provides an analytic prediction for how 3D shaping can be tuned to lower turbulent transport through saturation processes.« less

Theory of ITG turbulent saturation in stellarators: identifying mechanisms to reduce turbulent transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hegna, Chris C.; Terry, Paul W.; Faber, Ben J.

A three-field fluid model that allows for general three-dimensional equilibrium geometry is developed to describe ion temperature gradient turbulent saturation processes in stellarators. The theory relies on the paradigm of nonlinear transfer of energy from unstable to damped modes at comparable wavelength as the dominant saturation mechanism. The unstable-to-damped mode interaction is enabled by a third mode that for dominant energy transfer channels primarily serves as a regulator of the nonlinear energy transfer rate. The identity of the third wave in the interaction defines different scenarios for turbulent saturation with the dominant scenario depending upon the properties of the 3Dmore » geometry. The nonlinear energy transfer physics is quantified by the product of a turbulent correlation lifetime and a geometric coupling coefficient. The turbulent correlation time is determined by a three-wave frequency mismatch, which at long wavelength can be calculated from the sum of the linear eigenfrequencies of the three modes. Larger turbulent correlation times denote larger levels of nonlinear energy transfer and hence smaller turbulent transport. The theory provides an analytic prediction for how 3D shaping can be tuned to lower turbulent transport through saturation processes.« less

Prediction and measurement of heat transfer rates for the shock-induced unsteady laminar boundary layer on a flat plate

NASA Technical Reports Server (NTRS)

Cook, W. J.

1972-01-01

The unsteady laminar boundary layer induced by the flow-initiating shock wave passing over a flat plate mounted in a shock tube was theoretically and experimentally studied in terms of heat transfer rates to the plate for shock speeds ranging from 1.695 to 7.34 km/sec. The theory presented by Cook and Chapman for the shock-induced unsteady boundary layer on a plate is reviewed with emphasis on unsteady heat transfer. A method of measuring time-dependent heat-transfer rates using thin-film heat-flux gages and an associated data reduction technique are outlined in detail. Particular consideration is given to heat-flux measurement in short-duration ionized shocktube flows. Experimental unsteady plate heat transfer rates obtained in both air and nitrogen using thin-film heat-flux gages generally agree well with theoretical predictions. The experimental results indicate that the theory continues to predict the unsteady boundary layer behavior after the shock wave leaves the trailing edge of the plate even though the theory is strictly applicable only for the time interval in which the shock remains on the plate.

Coupling of a structural analysis and flow simulation for short-fiber-reinforced polymers: property prediction and transfer of results

NASA Astrophysics Data System (ADS)

Kröner, C.; Altenbach, H.; Naumenko, K.

2009-05-01

The aim of this paper is to discuss the basic theories of interfaces able to transfer the results of an injection molding analyis of fiber-reinforced polymers, performed by using the commercial computer code Moldflow, to the structural analysis program ABAQUS. The elastic constants of the materials, such as Young's modulus, shear modulus, and Poisson's ratio, which depend on both the fiber content and the degree of fiber orientation, were calculated not by the usual method of "orientation averaging," but with the help of linear functions fitted to experimental data. The calculation and transfer of all needed data, such as material properties, geometry, directions of anisotropy, and so on, is performed by an interface developed. The interface is suit able for midplane elements in Moldflow. It calculates and transfers to ABAQUS all data necessary for the use of shell elements. In addition, a method is described how a nonlinear orthotropic behavior can be modeled starting from the generalized Hooke's law. It is also shown how such a model can be implemented in ABAQUS by means of a material subroutine. The results obtained according to this subroutine are compared with those based on an orthotropic, linear, elastic simulation.

Advances in wave turbulence: rapidly rotating flows

NASA Astrophysics Data System (ADS)

Cambon, C.; Rubinstein, R.; Godeferd, F. S.

2004-07-01

At asymptotically high rotation rates, rotating turbulence can be described as a field of interacting dispersive waves by the general theory of weak wave turbulence. However, rotating turbulence has some complicating features, including the anisotropy of the wave dispersion relation and the vanishing of the wave frequency on a non-vanishing set of 'slow' modes. These features prevent straightforward application of existing theories and lead to some interesting properties, including the transfer of energy towards the slow modes. This transfer competes with, and might even replace, the transfer to small scales envisioned in standard turbulence theories. In this paper, anisotropic spectra for rotating turbulence are proposed based on weak turbulence theory; some evidence for their existence is given based on numerical calculations of the wave turbulence equations. Previous arguments based on the properties of resonant wave interactions suggest that the slow modes decouple from the others. Here, an extended wave turbulence theory with non-resonant interactions is proposed in which all modes are coupled; these interactions are possible only because of the anisotropy of the dispersion relation. Finally, the vanishing of the wave frequency on the slow modes implies that these modes cannot be described by weak turbulence theory. A more comprehensive approach to rotating turbulence is proposed to overcome this limitation.

Processes of local alcohol policy-making in England: Does the theory of policy transfer provide useful insights into public health decision-making?

PubMed

Gavens, Lucy; Holmes, John; Buykx, Penny; de Vocht, Frank; Egan, Matt; Grace, Daniel; Lock, Karen; Mooney, John D; Brennan, Alan

2017-06-13

Recent years have seen a rise in new and innovative policies to reduce alcohol consumption and related harm in England, which can be implemented by local, as opposed to national, policy-makers. The aim of this paper is to explore the processes that underpin the adoption of these alcohol policies within local authorities. In particular, it aims to assess whether the concept of policy transfer (i.e. a process through which knowledge about policies in one place is used in the development of policies in another time or place) provides a useful model for understanding local alcohol policy-making. Qualitative data generated through in-depth interviews and focus groups from five case study sites across England were used to explore stakeholder experiences of alcohol policy transfer between local authorities. The purposive sample of policy actors included representatives from the police, trading standards, public health, licensing, and commissioning. Thematic analysis was used inductively to identify key features in the data. Themes from the policy transfer literature identified in the data were: policy copying, emulating, hybridization, and inspiration. Participants described a multitude of ways in which learning was shared between places, ranging from formal academic evaluation to opportunistic conversations in informal settings. Participants also described facilitators and constraints to policy transfer, such as the historical policy context and the local cultural, economic, and bureaucratic context, which influenced whether or not a policy that was perceived to work in one place might be transferred successfully to another context. Theories of policy transfer provide a promising framework for characterising processes of local alcohol policy-making in England, extending beyond debates regarding evidence-informed policy to account for a much wider range of considerations. Applying a policy transfer lens enables us to move beyond simple (but still important) questions of what is supported by 'robust' research evidence by paying greater attention to how policy making is carried out in practice and the multiple methods by which policies diffuse across jurisdictions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Erotized Transference in the Male Patient–Female Therapist Dyad

PubMed Central

Koo, Martha B.

2001-01-01

Little has been published regarding male patients' erotic transferences to female therapists. It has been suggested that male patients do not develop full erotic transferences and rarely experience erotized transferences. The author presents a case report documenting erotization in a male patient–female therapist dyad and reviews current theories on the etiology, therapeutic significance, and treatment strategies indicated for such a transference. PMID:11121005

Patterns of decision making by wives of patients with life-threatening cardiac disease.

PubMed

Hall, Patricia; Sanford, Julie T; Demi, Alice S

2008-08-01

Implementation of the Patient Self-Determination Act (PSDA) in the United States has transferred decision making from the responsibility of health care professionals to the responsibility of family members. Dilemmas occurring as a result of this responsibility may cause stress and conflict among family members. The purpose of this study is to describe the patterns of decision making by family members of patients with life-threatening cardiac disease. Purposive sampling is used to select 10 wives of patients with life-threatening cardiovascular disease. Data are gathered through unstructured interviews and are analyzed using grounded theory and theory triangulation. Analysis of the data reveal three patterns of decision making: advocacy, acquiescence, and abdication.

Ab initio study on the formation of triiodide CT complex from the reaction of iodine with 2,3-diaminopyridine.

PubMed

Al-Hashimi, Nessreen A; Hussein, Yasser H A

2010-01-01

The charge transfer (CT) interaction between iodine and 2,3-diaminopyridine (DAPY) has been thoroughly investigated via theoretical calculations. A Hartree-Fock, 3-21G level of theory was used to optimize and calculate the Mullican charge distribution scheme as well as the vibrational frequencies of DAPY alone and both its CT complexes with one and two iodine molecules. A very good agreement was found between experiment and theory. New illustrations were concluded with a deep analysis and description for the vibrational frequencies of the formed CT complexes. The two-step CT complex formation mechanism published earlier was supported. Copyright 2009 Elsevier B.V. All rights reserved.

Risk transfer modeling among hierarchically associated stakeholders in development of space systems

NASA Astrophysics Data System (ADS)

Henkle, Thomas Grove, III

Research develops an empirically derived cardinal model that prescribes handling and transfer of risks between organizations with hierarchical relationships. Descriptions of mission risk events, risk attitudes, and conditions for risk transfer are determined for client and underwriting entities associated with acquisition, production, and deployment of space systems. The hypothesis anticipates that large client organizations should be able to assume larger dollar-value risks of a program in comparison to smaller organizations even though many current risk transfer arrangements via space insurance violate this hypothesis. A literature survey covers conventional and current risk assessment methods, current techniques used in the satellite industry for complex system development, cardinal risk modeling, and relevant aspects of utility theory. Data gathered from open literature on demonstrated launch vehicle and satellite in-orbit reliability, annual space insurance premiums and losses, and ground fatalities and range damage associated with satellite launch activities are presented. Empirically derived models are developed for risk attitudes of space system clients and third-party underwriters associated with satellite system development and deployment. Two application topics for risk transfer are examined: the client-underwriter relationship on assumption or transfer of risks associated with first-year mission success, and statutory risk transfer agreements between space insurance underwriters and the US government to promote growth in both commercial client and underwriting industries. Results indicate that client entities with wealth of at least an order of magnitude above satellite project costs should retain risks to first-year mission success despite present trends. Furthermore, large client entities such as the US government should never pursue risk transfer via insurance under previously demonstrated probabilities of mission success; potential savings may reasonably exceed multiple tens of $millions per space project. Additional results indicate that current US government statutory arrangements on risk sharing with underwriting entities appears reasonable with respect to stated objectives. This research combines aspects of multiple disciplines to include risk management, decision theory, utility theory, and systems architecting. It also demonstrates development of a more general theory on prescribing risk transfer criteria between distinct, but hierarchically associated entities involved in complex system development with applicability to a variety of technical domains.

Radiative heat transfer in the extreme near field.

PubMed

Kim, Kyeongtae; Song, Bai; Fernández-Hurtado, Víctor; Lee, Woochul; Jeong, Wonho; Cui, Longji; Thompson, Dakotah; Feist, Johannes; Reid, M T Homer; García-Vidal, Francisco J; Cuevas, Juan Carlos; Meyhofer, Edgar; Reddy, Pramod

2015-12-17

Radiative transfer of energy at the nanometre length scale is of great importance to a variety of technologies including heat-assisted magnetic recording, near-field thermophotovoltaics and lithography. Although experimental advances have enabled elucidation of near-field radiative heat transfer in gaps as small as 20-30 nanometres (refs 4-6), quantitative analysis in the extreme near field (less than 10 nanometres) has been greatly limited by experimental challenges. Moreover, the results of pioneering measurements differed from theoretical predictions by orders of magnitude. Here we use custom-fabricated scanning probes with embedded thermocouples, in conjunction with new microdevices capable of periodic temperature modulation, to measure radiative heat transfer down to gaps as small as two nanometres. For our experiments we deposited suitably chosen metal or dielectric layers on the scanning probes and microdevices, enabling direct study of extreme near-field radiation between silica-silica, silicon nitride-silicon nitride and gold-gold surfaces to reveal marked, gap-size-dependent enhancements of radiative heat transfer. Furthermore, our state-of-the-art calculations of radiative heat transfer, performed within the theoretical framework of fluctuational electrodynamics, are in excellent agreement with our experimental results, providing unambiguous evidence that confirms the validity of this theory for modelling radiative heat transfer in gaps as small as a few nanometres. This work lays the foundations required for the rational design of novel technologies that leverage nanoscale radiative heat transfer.

Deep Learning in Intermediate Microeconomics: Using Scaffolding Assignments to Teach Theory and Promote Transfer

ERIC Educational Resources Information Center

Green, Gareth P.; Bean, John C.; Peterson, Dean J.

2013-01-01

Intermediate microeconomics is typically viewed as a theory and tools course that relies on algorithmic problems to help students learn and apply economic theory. However, the authors' assessment research suggests that algorithmic problems by themselves do not encourage students to think about where the theory comes from, why the theory is…

Predicting radiative heat transfer in thermochemical nonequilibrium flow fields. Theory and user's manual for the LORAN code

NASA Technical Reports Server (NTRS)

Chambers, Lin Hartung

1994-01-01

The theory for radiation emission, absorption, and transfer in a thermochemical nonequilibrium flow is presented. The expressions developed reduce correctly to the limit at equilibrium. To implement the theory in a practical computer code, some approximations are used, particularly the smearing of molecular radiation. Details of these approximations are presented and helpful information is included concerning the use of the computer code. This user's manual should benefit both occasional users of the Langley Optimized Radiative Nonequilibrium (LORAN) code and those who wish to use it to experiment with improved models or properties.

Combining Experiments and Simulation of Gas Absorption for Teaching Mass Transfer Fundamentals: Removing CO2 from Air Using Water and NaOH

ERIC Educational Resources Information Center

Clark, William M.; Jackson, Yaminah Z.; Morin, Michael T.; Ferraro, Giacomo P.

2011-01-01

Laboratory experiments and computer models for studying the mass transfer process of removing CO2 from air using water or dilute NaOH solution as absorbent are presented. Models tie experiment to theory and give a visual representation of concentration profiles and also illustrate the two-film theory and the relative importance of various…

Self-Determination and Goal Aspirations: African American and Latino Males' Perceptions of Their Persistence in Community College Basic and Transfer-Level Writing Courses

ERIC Educational Resources Information Center

Villarreal, María de Lourdes; García, Hugo A.

2016-01-01

This Grounded Theory study utilized Self-determination Theory to analyze the interview results of 18 community college African American and Latino males. The goal was to learn what helped participants to succeed and persist in developmental and transfer-level writing courses despite the obstacles that they faced. Three major themes emerged: (a)…

Solvent as electron donor: Donor/acceptor electronic coupling is a dynamical variable

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castner, E.W. Jr.; Kennedy, D.; Cave, R.J.

2000-04-06

The authors combine analysis of measurements by femtosecond optical spectroscopy, computer simulations, and the generalized Mulliken-Hush (GMH) theory in the study of electron-transfer reactions and electron donor-acceptor interactions. The study focus is on ultrafast photoinduced electron-transfer reactions from aromatic amine solvent donors to excited-state acceptors. The experimental results from femtosecond dynamical measurements fall into three categories: six coumarin acceptors reductively quenched by N,N-dimethylaniline (DMA), eight electron-donating amine solvents reductively quenching coumarin 152 (7-(dimethylamino)-4-(trifluoromethyl)-coumarin), and reductive quenching dynamics of two coumarins by DMA as a function of dilution in the nonreactive solvents toluene and chlorobenzene. Applying a combination of molecular dynamicsmore » trajectories, semiempirical quantum mechanical calculations (of the relevant adiabatic electronic states), and GMH theory to the C152/DMA photoreaction, the authors calculate the electron donor/acceptor interaction parameter H{sub DA} at various time frames, H{sub DA} is strongly modulated by both inner-sphere and outer-sphere nuclear dynamics, leading us to conclude that H{sub DA} must be considered as a dynamical variable.« less

Self-exchange reaction of [Ni(mnt)2](1-,2-) in nonaqueous solutions.

PubMed

Kowert, Bruce A; Fehr, Michael J; Sheaff, Pamela J

2008-07-07

The rate constant, k, for the homogeneous electron transfer (self-exchange) reaction between the diamagnetic bis(maleonitriledithiolato)nickel dianion, [Ni(mnt) 2] (2-), and the paramagnetic monoanion, [Ni(mnt) 2] (1-), has been determined in acetone and nitromethane (CH 3NO 2) using (13)C NMR line widths at 22 degrees C (mnt = 1,2-S 2C 2(CN) 2). The values of k (2.91 x 10 (6) M (-1) s (-1) in acetone, 5.78 x 10 (6) M (-1) s (-1) in CH 3NO 2) are faster than those for the electron transfer reactions of other Ni(III,II) couples; the structures of [Ni(mnt) 2] (1-) and [Ni(mnt) 2] (2-) allow for a favorable overlap that lowers the free energy of activation. The values of k are consistent with the predictions of Marcus theory. In addition to k, the spin-lattice relaxation time, T 1e, of [Ni(mnt) 2] (1-) is obtained from the NMR line width analysis; the values are consistent with those predicted by spin relaxation theory.

Kinetic isotope effect in malonaldehyde determined from path integral Monte Carlo simulations.

PubMed

Huang, Jing; Buchowiecki, Marcin; Nagy, Tibor; Vaníček, Jiří; Meuwly, Markus

2014-01-07

The primary H/D kinetic isotope effect on the intramolecular proton transfer in malonaldehyde is determined from quantum instanton path integral Monte Carlo simulations on a fully dimensional and validated potential energy surface for temperatures between 250 and 1500 K. Our calculations, based on thermodynamic integration with respect to the mass of the transferring particle, are significantly accelerated by the direct evaluation of the kinetic isotope effect instead of computing it as a ratio of two rate constants. At room temperature, the KIE from the present simulations is 5.2 ± 0.4. The KIE is found to vary considerably as a function of temperature and the low-T behaviour is dominated by the fact that the free energy derivative in the reactant state increases more rapidly than in the transition state. Detailed analysis of the various contributions to the quantum rate constant together with estimates for rates from conventional transition state theory and from periodic orbit theory suggest that the KIE in malonaldehyde is dominated by zero point energy effects and that tunneling plays a minor role at room temperature.

The nature of the interaction of dimethylselenide with IIIA group element compounds.

PubMed

Madzhidov, Timur I; Chmutova, Galina A

2013-05-16

The first systematic theoretical study of the nature of intermolecular bonding of dimethylselenide as donor and IIIA group element halides as acceptors was made with the help of the approach of Quantum Theory of Atoms in Molecules. Density Functional Theory with "old" Sapporo triple-ζ basis sets was used to calculate geometry, thermodynamics, and wave function of Me2Se···AX3 complexes. The analysis of the electron density distribution and the Laplacian of the electron density allowed us to reveal and explain the tendencies in the influence of the central atom (A = B, Al, Ga, In) and halogen (X = F, Cl, Br, I) on the nature of Se···A bonding. Significant changes in properties of the selenium lone pair upon complexation were described by means of the analysis of the Laplacian of the charge density. Charge transfer characteristics and the contributions to it from electron localization and delocalization were analyzed in terms of localization and delocalization indexes. Common features of the complexation and differences in the nature of bonding were revealed. Performed analysis evidenced that gallium and indium halide complexes can be attributed to charge transfer-driven complexes; aluminum halides complexes seem to be mainly of an electrostatic nature. The nature of bonding in different boron halides essentially varies; these complexes are stabilized mainly by covalent Se···B interaction. In all the complexes under study covalence of the Se···A interaction is rather high.

Experimental and theoretical debate on efficient second harmonic generation in Bis (Cinnamic acid): Hexamine cocrystal

NASA Astrophysics Data System (ADS)

Vijayalakshmi, S.; Kalyanaraman, S.; Ravindran, T. R.

2014-02-01

Second harmonic generation (SHG) in Bis (Cinnamic acid): Hexamine cocrystal was extensively analyzed through charge transfer (CT). The CT interactions through hydrogen bonding were well established with the aid of vibrational analysis and Natural Bond Orbital (NBO) analysis. The retentivity of coplanar nature of the cinnamic acid in the cocrystal was confirmed through UV-Visible spectroscopy and supported by Raman studies. Structural analysis indicated the quinoidal character of the given material presenting a high SHG efficiency. The first order hyperpolarizability value was calculated theoretically by density functional theory (DFT) and Hartree-Fock (HF) methods in support for the large value of SHG.

Mechanisms of Transfer: Modeling Motivational and Self-Regulatory Processes That Promote Transfer of Learning

ERIC Educational Resources Information Center

Gonzalez, John A.

2012-01-01

A critical goal of many school and training interventions is to provide learners with the strategies and foundational knowledge that will allow them to tackle novel problems encountered under circumstances different than the learning situations. This is also quite often referred to as the ability to transfer learning. Theories of transfer posit…

Elaboration d'une structure de collecte des matieres residuelles selon la Theorie Constructale

NASA Astrophysics Data System (ADS)

Al-Maalouf, George

Currently, more than 80% of the waste management costs are attributed to the waste collection phase. In order to reduce these costs, one current solution resides in the implementation of waste transfer stations. In these stations, at least 3 collection vehicles transfer their load into a larger hauling truck. This cost reduction is based on the principle of economy of scale applied to the transportation sector. This solution improves the efficiency of the system; nevertheless, it does not optimize it. Recent studies show that the compactor trucks used in the collection phase generate significant economic losses mainly due to the frequent stops and the transportation to transfer stations often far from the collection area. This study suggests the restructuring of the waste collection process by dividing it into two phases: the collection phase, and the transportation to the transfer station phase. To achieve this, a deterministic theory called: "the Constructal Theory" (CT) is used. The results show that starting a certain density threshold, the application of the CT minimizes energy losses in the system. In fact, the collection is optimal if it is done using a combination of low capacity vehicle to collect door to door and transfer their charge into high-capacity trucks. These trucks will then transport their load to the transfer station. To minimize the costs of labor, this study proposes the use of Cybernetic Transport System (CTS) as an automated collection vehicle to collect small amounts of waste. Finally, the optimization method proposed is part of a decentralized approach to the collection and treatment of waste. This allows the implementation of multi-process waste treatment facilities on a territory scale. Keywords: Waste collection, Constructal Theory, Cybernetic Transportation Systems.

Localized multi-scale energy and vorticity analysis. II. Finite-amplitude instability theory and validation

NASA Astrophysics Data System (ADS)

San Liang, X.; Robinson, Allan R.

2007-12-01

A novel localized finite-amplitude hydrodynamic stability analysis is established in a unified treatment for the study of real oceanic and atmospheric processes, which are in general highly nonlinear, and intermittent in space and time. We first re-state the classical definition using the multi-scale energy and vorticity analysis (MS-EVA) developed in Liang and Robinson [Liang, X.S., Robinson, A.R., 2005. Localized multiscale energy and vorticity analysis. I. Fundamentals. Dyn. Atmos. Oceans 38, 195-230], and then manipulate certain global operators to achieve the temporal and spatial localization. The key of the spatial localization is transfer-transport separation, which is made precise with the concept of perfect transfer, while relaxation of marginalization leads to the localization of time. In doing so the information of transfer lost in the averages is retrieved and an easy-to-use instability metric is obtained. The resulting metric is field-like (Eulerian), conceptually generalizing the classical formalism, a bulk notion over the whole system. In this framework, an instability has a structure, which is of particular use for open flow processes. We check the structure of baroclinic instability with the benchmark Eady model solution, and the Iceland-Faeroe Frontal (IFF) intrusion, a highly localized and nonlinear process occurring frequently in the region between Iceland and Faeroe Islands. A clear isolated baroclinic instability is identified around the intrusion, which is further found to be characterized by the transition from a spatially growing mode to a temporally growing mode. We also check the consistency of the MS-EVA dynamics with the barotropic Kuo model. An observation is that a local perturbation burst does not necessarily imply an instability: the perturbation energy could be transported from other processes occurring elsewhere. We find that our analysis yields a Kuo theorem-consistent mean-eddy interaction, which is not seen in a conventional Reynolds stress framework. Using the techniques of marginalization and localization, this work sets up an example for the generalization of certain geophysical fluid dynamics theories for more generic purposes.

Amplification of large scale magnetic fields in a decaying MHD system

NASA Astrophysics Data System (ADS)

Park, Kiwan

2017-10-01

Dynamo theory explains the amplification of magnetic fields in the conducting fluids (plasmas) driven by the continuous external energy. It is known that the nonhelical continuous kinetic or magnetic energy amplifies the small scale magnetic field; and the helical energy, the instability, or the shear with rotation effect amplifies the large scale magnetic field. However, recently it was reported that the decaying magnetic energy independent of helicity or instability could generate the large scale magnetic field. This phenomenon may look somewhat contradictory to the conventional dynamo theory. But it gives us some clues to the fundamental mechanism of energy transfer in the magnetized conducting fluids. It also implies that an ephemeral astrophysical event emitting the magnetic and kinetic energy can be a direct cause of the large scale magnetic field observed in space. As of now the exact physical mechanism is not yet understood in spite of several numerical results. The plasma motion coupled with a nearly conserved vector potential in the magnetohydrodynamic (MHD) system may transfer magnetic energy to the large scale. Also the intrinsic property of the scaling invariant MHD equation may decide the direction of energy transfer. In this paper we present the simulation results of inversely transferred helical and nonhelical energy in a decaying MHD system. We introduce a field structure model based on the MHD equation to show that the transfer of magnetic energy is essentially bidirectional depending on the plasma motion and initial energy distribution. And then we derive α coefficient algebraically in line with the field structure model to explain how the large scale magnetic field is induced by the helical energy in the system regardless of an external forcing source. And for the algebraic analysis of nonhelical magnetic energy, we use the eddy damped quasinormalized Markovian approximation to show the inverse transfer of magnetic energy.

Judd-Ofelt analysis and energy transfer processes of Er3+ and Nd3+ doped fluoroaluminate glasses with low phosphate content

NASA Astrophysics Data System (ADS)

Huang, Feifei; Zhang, Yu; Hu, Lili; Chen, Danping

2014-12-01

Spectroscopic property and energy transfer processes of singly doped and codoped Er3+ and Nd3+ fluoroaluminate glasses with low phosphate content are systematically analyzed. The absorption spectra of these glasses are tested, and the Judd-Ofelt (J-O) and radiative parameters are discussed based on J-O theory and the parameters changes substantially because of the other codoping ions. As for Nd3+: the main emission bands at 0.9 and 1.05 μm decrease in the codoped sample under the excitation of an 800 nm laser diode from the emission spectra because the Er3+: 4I11/2 level reduces the Nd3+: 4F3/2 level effectively through the energy transfer process Nd3+: 4F3/2 → Er3+: 4I11/2. For Er3+, the emission at 1.5 μm is restrained by codoping with Nd3+ ions from the energy transfer process Er3+: 4I13/2 → Nd3+: 4I15/2. The emission at 2.7 μm is enhanced because the Nd3+ ions deplete the lower level and exert a positive effect on the upper laser level. The microparameters of the energy transfer between the Er3+ and Nd3+ ions are calculated and discussed using Forster-Dexter theory. The energy transfer efficiencies of the Nd3+: 4F3/2 to the Er3+: 4I11/2 and the Er3+: 4I13/2 to the Nd3+: 4I15/2 are 28.8% and 74.5%, respectively. These results indicate that Nd3+ can be an efficient sensitizer for Er3+ to obtain Mid-infrared (Mid-IR) emission and the codoped Er3+/Nd3+ fluoroaluminate glass with low phosphate content is suitable to be used as the fiber optical gain media for 2.7 μm laser generation.

Actor-network theory: a tool to support ethical analysis of commercial genetic testing.

PubMed

Williams-Jones, Bryn; Graham, Janice E

2003-12-01

Social, ethical and policy analysis of the issues arising from gene patenting and commercial genetic testing is enhanced by the application of science and technology studies, and Actor-Network Theory (ANT) in particular. We suggest the potential for transferring ANT's flexible nature to an applied heuristic methodology for gathering empirical information and for analysing the complex networks involved in the development of genetic technologies. Three concepts are explored in this paper--actor-networks, translation, and drift--and applied to the case of Myriad Genetics and their commercial BRACAnalysis genetic susceptibility test for hereditary breast cancer. Treating this test as an active participant in socio-technical networks clarifies the extent to which it interacts with, shapes and is shaped by people, other technologies, and institutions. Such an understanding enables more sophisticated and nuanced technology assessment, academic analysis, as well as public debate about the social, ethical and policy implications of the commercialization of new genetic technologies.

Photoacoustic signal and noise analysis for Si thin plate: signal correction in frequency domain.

PubMed

Markushev, D D; Rabasović, M D; Todorović, D M; Galović, S; Bialkowski, S E

2015-03-01

Methods for photoacoustic signal measurement, rectification, and analysis for 85 μm thin Si samples in the 20-20 000 Hz modulation frequency range are presented. Methods for frequency-dependent amplitude and phase signal rectification in the presence of coherent and incoherent noise as well as distortion due to microphone characteristics are presented. Signal correction is accomplished using inverse system response functions deduced by comparing real to ideal signals for a sample with well-known bulk parameters and dimensions. The system response is a piece-wise construction, each component being due to a particular effect of the measurement system. Heat transfer and elastic effects are modeled using standard Rosencweig-Gersho and elastic-bending theories. Thermal diffusion, thermoelastic, and plasmaelastic signal components are calculated and compared to measurements. The differences between theory and experiment are used to detect and correct signal distortion and to determine detector and sound-card characteristics. Corrected signal analysis is found to faithfully reflect known sample parameters.

A grounded theory of positive youth development through sport based on results from a qualitative meta-study

PubMed Central

Holt, Nicholas L.; Neely, Kacey C.; Slater, Linda G.; Camiré, Martin; Côté, Jean; Fraser-Thomas, Jessica; MacDonald, Dany; Strachan, Leisha; Tamminen, Katherine A.

2017-01-01

ABSTRACT The overall purpose of this study was to create a model of positive youth development (PYD) through sport grounded in the extant qualitative literature. More specifically, the first objective was to review and evaluate qualitative studies of PYD in sport. The second objective was to analyze and synthesize findings from these studies. Following record identification and screening, 63 articles were retained for analysis. Meta-method analysis revealed strengths of studies were the use of multiple data collection and validity techniques, which produced high-quality data. Weaknesses were limited use of ‘named’ methodologies and inadequate reporting of sampling procedures. Philosophical perspectives were rarely reported, and theory was used sparingly. Results of an inductive meta-data analysis produced three categories: PYD climate (adult relationships, peer relationships, and parental involvement), life skills program focus (life skill building activities and transfer activities), and PYD outcomes (in personal, social, and physical domains). A model that distinguishes between implicit and explicit processes to PYD is presented. PMID:27695511

Hydroxide diffuses slower than hydronium in water because its solvated structure inhibits correlated proton transfer

NASA Astrophysics Data System (ADS)

Chen, Mohan; Zheng, Lixin; Santra, Biswajit; Ko, Hsin-Yu; DiStasio, Robert A., Jr.; Klein, Michael L.; Car, Roberto; Wu, Xifan

2018-03-01

Proton transfer via hydronium and hydroxide ions in water is ubiquitous. It underlies acid-base chemistry, certain enzyme reactions, and even infection by the flu. Despite two centuries of investigation, the mechanism underlying why hydroxide diffuses slower than hydronium in water is still not well understood. Herein, we employ state-of-the-art density-functional-theory-based molecular dynamics—with corrections for non-local van der Waals interactions, and self-interaction in the electronic ground state—to model water and hydrated water ions. At this level of theory, we show that structural diffusion of hydronium preserves the previously recognized concerted behaviour. However, by contrast, proton transfer via hydroxide is less temporally correlated, due to a stabilized hypercoordination solvation structure that discourages proton transfer. Specifically, the latter exhibits non-planar geometry, which agrees with neutron-scattering results. Asymmetry in the temporal correlation of proton transfer leads to hydroxide diffusing slower than hydronium.

Understanding the Charge Transfer at the Interface of Electron Donors and Acceptors: TTF–TCNQ as an Example

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Changwon; Atalla, Viktor; Smith, Sean

Charge transfer between an electron donor and an electron acceptor is widely accepted as being independent of their relative configurations if the interaction between them is weak; however, the limit of this concept for an interacting system has not yet been well established. Our study of prototypical electron donor–acceptor molecules, tetrathiafulvalene–tetracyanoquinodimethane, using density functional theory based on an advanced functional, clearly demonstrates that for interacting molecules, their configurational arrangement is as important as their individual electronic properties in the asymptotic limit to determine the charge transfer direction. For the first time, we demonstrate that by changing their relative orientation, onemore » can reverse the charge transfer direction of the pair, causing the molecules to exchange roles as donor and acceptor. In conclusion, our theory has important implications for understanding the interfacial charge-transfer mechanism of hybrid systems and related phenomena.« less

Optimization of Insertion Cost for Transfer Trajectories to Libration Point Orbits

NASA Technical Reports Server (NTRS)

Howell, K. C.; Wilson, R. S.; Lo, M. W.

1999-01-01

The objective of this work is the development of efficient techniques to optimize the cost associated with transfer trajectories to libration point orbits in the Sun-Earth-Moon four body problem, that may include lunar gravity assists. Initially, dynamical systems theory is used to determine invariant manifolds associated with the desired libration point orbit. These manifolds are employed to produce an initial approximation to the transfer trajectory. Specific trajectory requirements such as, transfer injection constraints, inclusion of phasing loops, and targeting of a specified state on the manifold are then incorporated into the design of the transfer trajectory. A two level differential corrections process is used to produce a fully continuous trajectory that satisfies the design constraints, and includes appropriate lunar and solar gravitational models. Based on this methodology, and using the manifold structure from dynamical systems theory, a technique is presented to optimize the cost associated with insertion onto a specified libration point orbit.

The Model of Lake Operation in Water Transfer Projects Based on the Theory of Water- right

NASA Astrophysics Data System (ADS)

Bi-peng, Yan; Chao, Liu; Fang-ping, Tang

the lake operation is a very important content in Water Transfer Projects. The previous studies have not any related to water-right and water- price previous. In this paper, water right is divided into three parts, one is initialization waterright, another is by investment, and the third is government's water- right re-distribution. The water-right distribution model is also build. After analyzing the cost in water transfer project, a model and computation method for the capacity price as well as quantity price is proposed. The model of lake operation in water transfer projects base on the theory of water- right is also build. The simulation regulation for the lake was carried out by using historical data and Genetic Algorithms. Water supply and impoundment control line of the lake was proposed. The result can be used by south to north water transfer projects.

Understanding the Charge Transfer at the Interface of Electron Donors and Acceptors: TTF–TCNQ as an Example

DOE PAGES

Park, Changwon; Atalla, Viktor; Smith, Sean; ...

2017-06-16

Charge transfer between an electron donor and an electron acceptor is widely accepted as being independent of their relative configurations if the interaction between them is weak; however, the limit of this concept for an interacting system has not yet been well established. Our study of prototypical electron donor–acceptor molecules, tetrathiafulvalene–tetracyanoquinodimethane, using density functional theory based on an advanced functional, clearly demonstrates that for interacting molecules, their configurational arrangement is as important as their individual electronic properties in the asymptotic limit to determine the charge transfer direction. For the first time, we demonstrate that by changing their relative orientation, onemore » can reverse the charge transfer direction of the pair, causing the molecules to exchange roles as donor and acceptor. In conclusion, our theory has important implications for understanding the interfacial charge-transfer mechanism of hybrid systems and related phenomena.« less

Time-dependent mean-field determination of the excitation energy in transfer reactions: Application to the reaction 238U on 12C at 6.14 MeV/nucleon

NASA Astrophysics Data System (ADS)

Scamps, G.; Rodríguez-Tajes, C.; Lacroix, D.; Farget, F.

2017-02-01

The internal excitation of nuclei after multinucleon transfer is estimated by using the time-dependent mean-field theory. Transfer probabilities for each channel as well as the energy loss after reseparation are calculated. By combining these two pieces of information, we show that the excitation energy distribution of the transfer fragments can be obtained separately for the different transfer channels. The method is applied to the reaction involving a 238U beam on a 12C target, which has recently been measured at GANIL. It is shown that the excitation energy calculated with the microscopic theory compares well with the experimental observation, provided that the competition with fusion is properly taken into account. The reliability of the excitation energy is further confirmed by the comparison with the phenomenological heavy-ion phase-space model at higher center-of-mass energies.

Serotonergic Psychedelics Temporarily Modify Information Transfer in Humans

PubMed Central

Alonso, Joan Francesc; Romero, Sergio; Mañanas, Miquel Àngel

2015-01-01

Background: Psychedelics induce intense modifications in the sensorium, the sense of “self,” and the experience of reality. Despite advances in our understanding of the molecular and cellular level mechanisms of these drugs, knowledge of their actions on global brain dynamics is still incomplete. Recent imaging studies have found changes in functional coupling between frontal and parietal brain structures, suggesting a modification in information flow between brain regions during acute effects. Methods: Here we assessed the psychedelic-induced changes in directionality of information flow during the acute effects of a psychedelic in humans. We measured modifications in connectivity of brain oscillations using transfer entropy, a nonlinear measure of directed functional connectivity based on information theory. Ten healthy male volunteers with prior experience with psychedelics participated in 2 experimental sessions. They received a placebo or a dose of ayahuasca, a psychedelic preparation containing the serotonergic 5-HT2A agonist N,N-dimethyltryptamine. Results: The analysis showed significant changes in the coupling of brain oscillations between anterior and posterior recording sites. Transfer entropy analysis showed that frontal sources decreased their influence over central, parietal, and occipital sites. Conversely, sources in posterior locations increased their influence over signals measured at anterior locations. Exploratory correlations found that anterior-to-posterior transfer entropy decreases were correlated with the intensity of subjective effects, while the imbalance between anterior-to-posterior and posterior-to-anterior transfer entropy correlated with the degree of incapacitation experienced. Conclusions: These results suggest that psychedelics induce a temporary disruption of neural hierarchies by reducing top-down control and increasing bottom-up information transfer in the human brain. PMID:25820842

Three dimensional rotating flow of Powell-Eyring nanofluid with non-Fourier's heat flux and non-Fick's mass flux theory

NASA Astrophysics Data System (ADS)

Ibrahim, Wubshet

2018-03-01

This article numerically examines three dimensional boundary layer flow of a rotating Powell-Eyring nanofluid. In modeling heat transfer processes, non-Fourier heat flux theory and for mass transfer non-Fick's mass flux theory are employed. This theory is recently re-initiated and it becomes the active research area to resolves some drawback associated with the famous Fourier heat flux and mass flux theory. The mathematical model of the flow problem is a system of non-linear partial differential equations which are obtained using the boundary layer analysis. The non-linear partial differential equations have been transformed into non-linear high order ordinary differential equations using similarity transformation. Employing bvp4c algorithm from matlab software routine, the numerical solution of the transformed ordinary differential equations is obtained. The governing equations are constrained by parameters such as rotation parameter λ , the non-Newtonian parameter N, dimensionless thermal relaxation and concentration relaxation parameters δt and δc . The impacts of these parameters have been discussed thoroughly and illustrated using graphs and tables. The findings show that thermal relaxation time δt reduces the thermal and concentration boundary layer thickness. Further, the results reveal that the rotational parameter λ has the effect of decreasing the velocity boundary layer thickness in both x and y directions. Further examination pinpoints that the skin friction coefficient along x-axis is an increasing and skin friction coefficient along y-axis is a decreasing function of rotation parameter λ . Furthermore, the non-Newtonian fluid parameter N has the characteristic of reducing the amount of local Nusselt numbers -f″ (0) and -g″ (0) both in x and y -directions.

The Conundrum of Functional Brain Networks: Small-World Efficiency or Fractal Modularity

PubMed Central

Gallos, Lazaros K.; Sigman, Mariano; Makse, Hernán A.

2012-01-01

The human brain has been studied at multiple scales, from neurons, circuits, areas with well-defined anatomical and functional boundaries, to large-scale functional networks which mediate coherent cognition. In a recent work, we addressed the problem of the hierarchical organization in the brain through network analysis. Our analysis identified functional brain modules of fractal structure that were inter-connected in a small-world topology. Here, we provide more details on the use of network science tools to elaborate on this behavior. We indicate the importance of using percolation theory to highlight the modular character of the functional brain network. These modules present a fractal, self-similar topology, identified through fractal network methods. When we lower the threshold of correlations to include weaker ties, the network as a whole assumes a small-world character. These weak ties are organized precisely as predicted by theory maximizing information transfer with minimal wiring costs. PMID:22586406

Radiative transfer modelling inside thermal protection system using hybrid homogenization method for a backward Monte Carlo method coupled with Mie theory

NASA Astrophysics Data System (ADS)

Le Foll, S.; André, F.; Delmas, A.; Bouilly, J. M.; Aspa, Y.

2012-06-01

A backward Monte Carlo method for modelling the spectral directional emittance of fibrous media has been developed. It uses Mie theory to calculate the radiative properties of single fibres, modelled as infinite cylinders, and the complex refractive index is computed by a Drude-Lorenz model for the dielectric function. The absorption and scattering coefficient are homogenised over several fibres, but the scattering phase function of a single one is used to determine the scattering direction of energy inside the medium. Sensitivity analysis based on several Monte Carlo results has been performed to estimate coefficients for a Multi-Linear Model (MLM) specifically developed for inverse analysis of experimental data. This model concurs with the Monte Carlo method and is highly computationally efficient. In contrast, the surface emissivity model, which assumes an opaque medium, shows poor agreement with the reference Monte Carlo calculations.

Molecular structure, vibrational spectra and DFT molecular orbital calculations (TD-DFT and NMR) of the antiproliferative drug Methotrexate

NASA Astrophysics Data System (ADS)

Ayyappan, S.; Sundaraganesan, N.; Aroulmoji, V.; Murano, E.; Sebastian, S.

2010-09-01

The FT-IR and FT-Raman spectral studies of the Methotrexate (MTX) were carried out. The equilibrium geometry, various bonding features and harmonic vibrational frequencies of MTX have been investigated with the help of B3LYP density functional theory (DFT) using 6-31G(d) as basis set. Detailed analysis of the vibrational spectra has been made with the aid of theoretically predicted vibrational frequencies. The vibrational analysis confirms the differently acting ring modes, steric repulsion, conjugation and back-donation. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complement with the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occur within the molecule. Good correlations between the experimental 1H and 13C NMR chemical shifts in DMSO solution and calculated GIAO shielding tensors were found.

Relative Evaluation of the Independent Volume Measures of Caverns

DOE Office of Scientific and Technical Information (OSTI.GOV)

MUNSON,DARRELL E.

2000-08-01

Throughout the construction and operation of the caverns of the Strategic Petroleum Reserve (SPR), three types of cavern volume measurements have been maintained. These are: (1) the calculated solution volume determined during initial construction by solution mining and any subsequent solutioning during oil transfers, (2) the calculated sonar volume determined through sonar surveys of the cavern dimensions, and (3) the direct metering of oil to determine the volume of the cavern occupied by the oil. The objective of this study is to compare these measurements to each other and determine, if possible, the uncertainties associated with a given type ofmore » measurement. Over time, each type of measurement has acquired a customary, or an industry accepted, stated uncertainty. This uncertainty is not necessarily the result of a technical analysis. Ultimately there is one definitive quantity, the oil volume measure by the oil custody transfer meters, taken by all parties to the transfer as the correct ledger amount and for which the SPR Project is accountable. However, subsequent transfers within a site may not be with meters of the same accuracy. In this study, a very simple theory of the perfect relationship is used to evaluate the correlation (deviation) of the various measures. This theory permits separation of uncertainty and bias. Each of the four SPR sites are examined, first with comparisons between the calculated solution volumes and the sonar volumes determined during construction, then with comparisons of the oil inventories and the sonar volumes obtained either by surveying through brine prior to oil filling or through the oil directly.« less

Transferências intergeracionais privadas na Amazônia rural brasileira

PubMed Central

Guedes, Gilvan Ramalho; Queiroz, Bernardo Lanza; VanWey, Leah Karin

2010-01-01

What motivates family members to share resources? Past research argues for, on the one hand, love and altruism, and on the other, the expectation of reciprocity. Drawing on this literature, this paper examines intergenerational transfers between small farmers and their non-coresident children in the rural area around the city of Altamira, Pará, Brazil. We apply GoM (Grade of Membership) models to create profiles of private transfers, using data collected in 2005 by a team from Indiana University. The results show three profiles: low intergenerational transfers, high levels of transfers of visits and help, and high levels of transfers of visits and money. There is no clear difference in profile by birth order, but we do find sex differences in profile. Men are more likely to send money while women provide time transfers (work and visits). Upward transfers are most common from children with high levels of education or living in urban areas, suggesting a repayment of prior investments made by parents. Thus, our empirical evidence supports theories arguing that transfers are motivated by intertemporal contracts between parents and children, and that altruistic theories of family transfers should be rethought among rural agricultural populations in contexts characterized by many environmental and institutional challenges. PMID:20927199

Multispectral selective near-perfect light absorption by graphene monolayer using aperiodic multilayer microstructures

NASA Astrophysics Data System (ADS)

Zand, Iman; Dalir, Hamed; Chen, Ray T.; Dowling, Jonathan P.

2018-03-01

We investigate one-dimensional aperiodic multilayer microstructures in order to achieve near-total absorptions at preselected wavelengths in a graphene monolayer. The proposed structures are designed using a genetic optimization algorithm coupled to a transfer matrix code. Coupled-mode-theory analysis, consistent with transfer matrix method results, indicates the existence of a critical coupling in the graphene monolayer for perfect absorptions. Our findings show that the near-total-absorption peaks are highly tunable and can be controlled simultaneously or independently in a wide range of wavelengths in the near-infrared and visible ranges. The proposed approach is metal-free, does not require surface texturing or patterning, and can be also applied for other two-dimensional materials.

Transfers between libration-point orbits in the elliptic restricted problem

NASA Astrophysics Data System (ADS)

Hiday-Johnston, L. A.; Howell, K. C.

1994-04-01

A strategy is formulated to design optimal time-fixed impulsive transfers between three-dimensional libration-point orbits in the vicinity of the interior L1 libration point of the Sun-Earth/Moon barycenter system. The adjoint equation in terms of rotating coordinates in the elliptic restricted three-body problem is shown to be of a distinctly different form from that obtained in the analysis of trajectories in the two-body problem. Also, the necessary conditions for a time-fixed two-impulse transfer to be optimal are stated in terms of the primer vector. Primer vector theory is then extended to nonoptimal impulsive trajectories in order to establish a criterion whereby the addition of an interior impulse reduces total fuel expenditure. The necessary conditions for the local optimality of a transfer containing additional impulses are satisfied by requiring continuity of the Hamiltonian and the derivative of the primer vector at all interior impulses. Determination of location, orientation, and magnitude of each additional impulse is accomplished by the unconstrained minimization of the cost function using a multivariable search method. Results indicate that substantial savings in fuel can be achieved by the addition of interior impulsive maneuvers on transfers between libration-point orbits.

Resonant electronic excitation energy transfer by exchange mechanism in the quantum dot system

NASA Astrophysics Data System (ADS)

Chikalova-Luzina, O. P.; Samosvat, D. M.; Vyatkin, V. M.; Zegrya, G. G.

2017-11-01

A microscopic theory of nonradiative resonance energy transfer between spherical A3B5 semiconductor quantum dots by the exchange mechanism is suggested. The interdot Coulomb interaction is taken into consideration. It is assumed that the quantum dot-donor and the quantum dot-acceptor are made from the same A3B5 compound and are embedded in the matrix of another material that produces potential barriers for electrons and holes. The dependences of the energy transfer rate on the quantum-dot system parameters are found in the frame of the Kane model that provides the most adequate description of the real spectra of A3B5 semiconductors. The analytical treatment is carried out with using the density matrix method, which enabled us to perform an energy transfer analysis both in the weak-interaction approximation and in the strong-interaction approximation. The numerical calculations showed the saturation of the energy transfer rate at the distances between the donor and the acceptor approaching the contact one. The contributions of the exchange and direct Coulomb intractions can be of the same order at the small distances and can have the same value in the saturation range.

Theoretical analysis of co-solvent effect on the proton transfer reaction of glycine in a water-acetonitrile mixture

NASA Astrophysics Data System (ADS)

Kasai, Yukako; Yoshida, Norio; Nakano, Haruyuki

2015-05-01

The co-solvent effect on the proton transfer reaction of glycine in a water-acetonitrile mixture was examined using the reference interaction-site model self-consistent field theory. The free energy profiles of the proton transfer reaction of glycine between the carboxyl oxygen and amino nitrogen were computed in a water-acetonitrile mixture solvent at various molar fractions. Two types of reactions, the intramolecular proton transfer and water-mediated proton transfer, were considered. In both types of the reactions, a similar tendency was observed. In the pure water solvent, the zwitterionic form, where the carboxyl oxygen is deprotonated while the amino nitrogen is protonated, is more stable than the neutral form. The reaction free energy is -10.6 kcal mol-1. On the other hand, in the pure acetonitrile solvent, glycine takes only the neutral form. The reaction free energy from the neutral to zwitterionic form gradually increases with increasing acetonitrile concentration, and in an equally mixed solvent, the zwitterionic and neutral forms are almost isoenergetic, with a difference of only 0.3 kcal mol-1. The free energy component analysis based on the thermodynamic cycle of the reaction also revealed that the free energy change of the neutral form is insensitive to the change of solvent environment but the zwitterionic form shows drastic changes. In particular, the excess chemical potential, one of the components of the solvation free energy, is dominant and contributes to the stabilization of the zwitterionic form.

The charger transfer electronic coupling in diabatic perspective: A multi-state density functional theory study

NASA Astrophysics Data System (ADS)

Guo, Xinwei; Qu, Zexing; Gao, Jiali

2018-01-01

The multi-state density functional theory (MSDFT) provides a convenient way to estimate electronic coupling of charge transfer processes based on a diabatic representation. Its performance has been benchmarked against the HAB11 database with a mean unsigned error (MUE) of 17 meV between MSDFT and ab initio methods. The small difference may be attributed to different representations, diabatic from MSDFT and adiabatic from ab initio calculations. In this discussion, we conclude that MSDFT provides a general and efficient way to estimate the electronic coupling for charge-transfer rate calculations based on the Marcus-Hush model.

Collaborative Investigations of Shallow Water Optics Problems

DTIC Science & Technology

2004-12-01

Appendix E. Reprint of Radiative transfer equation inversion: Theory and shape factor models for retrieval of oceanic inherent optical properties, by F ...4829-4834. 5 Hoge, F . E., P. E. Lyon, C. D. Mobley, and L. K. Sundman, 2003. Radiative transfer equation inversion: Theory and shape factor models for...multilinear regression algorithms for the inversion of synthetic ocean colour spectra,, Int. J. Remote Sensing, 25(21), 4829-4834. Hoge, F . E., P. E. Lyon

Communication: CDFT-CI couplings can be unreliable when there is fractional charge transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mavros, Michael G.; Van Voorhis, Troy, E-mail: tvan@mit.edu

2015-12-21

Constrained density functional theory with configuration interaction (CDFT-CI) is a useful, low-cost tool for the computational prediction of electronic couplings between pseudo-diabatic constrained electronic states. Such couplings are of paramount importance in electron transfer theory and transition state theory, among other areas of chemistry. Unfortunately, CDFT-CI occasionally fails significantly, predicting a coupling that does not decay exponentially with distance and/or overestimating the expected coupling by an order of magnitude or more. In this communication, we show that the eigenvalues of the difference density matrix between the two constrained states can be used as an a priori metric to determine whenmore » CDFT-CI are likely to be reliable: when the eigenvalues are near 0 or ±1, transfer of a whole electron is occurring, and CDFT-CI can be trusted. We demonstrate the utility of this metric with several illustrative examples.« less

Communication: CDFT-CI couplings can be unreliable when there is fractional charge transfer

NASA Astrophysics Data System (ADS)

Mavros, Michael G.; Van Voorhis, Troy

2015-12-01

Constrained density functional theory with configuration interaction (CDFT-CI) is a useful, low-cost tool for the computational prediction of electronic couplings between pseudo-diabatic constrained electronic states. Such couplings are of paramount importance in electron transfer theory and transition state theory, among other areas of chemistry. Unfortunately, CDFT-CI occasionally fails significantly, predicting a coupling that does not decay exponentially with distance and/or overestimating the expected coupling by an order of magnitude or more. In this communication, we show that the eigenvalues of the difference density matrix between the two constrained states can be used as an a priori metric to determine when CDFT-CI are likely to be reliable: when the eigenvalues are near 0 or ±1, transfer of a whole electron is occurring, and CDFT-CI can be trusted. We demonstrate the utility of this metric with several illustrative examples.

Qualitative content analysis in nursing research: concepts, procedures and measures to achieve trustworthiness.

PubMed

Graneheim, U H; Lundman, B

2004-02-01

Qualitative content analysis as described in published literature shows conflicting opinions and unsolved issues regarding meaning and use of concepts, procedures and interpretation. This paper provides an overview of important concepts (manifest and latent content, unit of analysis, meaning unit, condensation, abstraction, content area, code, category and theme) related to qualitative content analysis; illustrates the use of concepts related to the research procedure; and proposes measures to achieve trustworthiness (credibility, dependability and transferability) throughout the steps of the research procedure. Interpretation in qualitative content analysis is discussed in light of Watzlawick et al.'s [Pragmatics of Human Communication. A Study of Interactional Patterns, Pathologies and Paradoxes. W.W. Norton & Company, New York, London] theory of communication.

The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission.

PubMed

Kiani, Mehdi; Ghovanloo, Maysam

2012-09-01

Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor ( Q ) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory.

The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission

PubMed Central

Kiani, Mehdi; Ghovanloo, Maysam

2014-01-01

Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory. PMID:24683368

The functional transfer of genes from the mitochondria to the nucleus: the effects of selection, mutation, population size and rate of self-fertilization.

PubMed

Brandvain, Yaniv; Wade, Michael J

2009-08-01

The transfer of mitochondrial genes to the nucleus is a recurrent and consistent feature of eukaryotic genome evolution. Although many theories have been proposed to explain such transfers, little relevant data exist. The observation that clonal and self-fertilizing plants transfer more mitochondrial genes to their nuclei than do outcrossing plants contradicts predictions of major theories based on nuclear recombination and leaves a gap in our conceptual understanding how the observed pattern of gene transfer could arise. Here, with a series of deterministic and stochastic simulations, we show how epistatic selection and relative mutation rates of mitochondrial and nuclear genes influence mitochondrial-to-nuclear gene transfer. Specifically, we show that when there is a benefit to having a mitochondrial gene present in the nucleus, but absent in the mitochondria, self-fertilization dramatically increases both the rate and the probability of gene transfer. However, absent such a benefit, when mitochondrial mutation rates exceed those of the nucleus, self-fertilization decreases the rate and probability of transfer. This latter effect, however, is much weaker than the former. Our results are relevant to understanding the probabilities of fixation when loci in different genomes interact.

Heat transfer in freeboard region of fluidized beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biyikli, S.; Tuzla, K.; Chen, J.C.

1983-10-01

This research involved the study of heat transfer and fluid mechanic characteristics around a horizontal tube in the freeboard region of fluidized beds. Heat transfer coefficients were experimetnally measured for different bed temperatures, particle sizes, gas flow rates, and tube elevations in the freeboard region of air fluidized beds at atmospheric pressure. Local heat transfer coefficients were found to vary significantly with angular position around the tube. Average heat transfer coefficients were found to decrease with increasing freeboard tube elevation and approach the values for gas convection plus radiation for any given gas velocity. For a fixed tube elevation, heatmore » transfer coefficients generally increased with increasing gas velocity and with high particle entrainment they can approach the magnitudes found for immersed tubes. Heat transfer coefficients were also found to increase with increasing bed temperature. It was concluded that this increase is partly due to increase of radiative heat transfer and partly due to change of thermal properties of the fluidizing gas and particles. To investigate the fluid mechanic behavior of gas and particles around a freeboard tube, transient particle tube contacts were measured with a special capacitance probe in room temperature experiments. The results indicated that the tube surface experiences alternating dense and lean phase contacts. Quantitative information for local characteristics was obtained from the capacitance signals and used to develop a phenomenological model for prediction of the heat transfer coefficients around freeboard tubes. The packet renewal theory was modified to account for the dense phase heat transfer and a new model was suggested for the lean phase heat transfer. Finally, an empirical freeboard heat transfer correlation was developed from functional analysis of the freeboard heat transfer data using nondimensional groups representing gas velocity and tube elevation.« less

An Automated Method to Identify Mesoscale Convective Complexes (MCCs) Implementing Graph Theory

NASA Astrophysics Data System (ADS)

Whitehall, K. D.; Mattmann, C. A.; Jenkins, G. S.; Waliser, D. E.; Rwebangira, R.; Demoz, B.; Kim, J.; Goodale, C. E.; Hart, A. F.; Ramirez, P.; Joyce, M. J.; Loikith, P.; Lee, H.; Khudikyan, S.; Boustani, M.; Goodman, A.; Zimdars, P. A.; Whittell, J.

2013-12-01

Mesoscale convective complexes (MCCs) are convectively-driven weather systems with a duration of ~10 - 12 hours and contributions of large amounts to the rainfall daily and monthly totals. More than 400 MCCs occur annually over various locations on the globe. In West Africa, ~170 MCCs occur annually during the 180 days representing the summer months (June - November), and contribute ~75% of the annual wet season rainfall. The main objective of this study is to improve automatic identification of MCC over West Africa. The spatial expanse of MCCs and the spatio-temporal variability in their convective characteristics make them difficult to characterize even in dense networks of radars and/or surface gauges. As such there exist criteria for identifying MCCs with satellite images - mostly using infrared (IR) data. Automated MCC identification methods are based on forward and/or backward in time spatial-temporal analysis of the IR satellite data and characteristically incorporate a manual component as these algorithms routinely falter with merging and splitting cloud systems between satellite images. However, these algorithms are not readily transferable to voluminous data or other satellite-derived datasets (e.g. TRMM), thus hindering comprehensive studies of these features both at weather and climate timescales. Recognizing the existing limitations of automated methods, this study explores the applicability of graph theory to creating a fully automated method for deriving a West African MCC dataset from hourly infrared satellite images between 2001- 2012. Graph theory, though not heavily implemented in the atmospheric sciences, has been used for the predicting (nowcasting) of thunderstorms from radar and satellite data by considering the relationship between atmospheric variables at a given time, or for the spatial-temporal analysis of cloud volumes. From these few studies, graph theory appears to be innately applicable to the complexity, non-linearity and inherent chaos of the atmospheric system. Our preliminary results show that the use of graph theory improves data management thus allowing for longer periods to be studied, and creates a transferable method that allows for other data to be utilized.

Vibrational spectral investigation, NBO, first hyperpolarizability and UV-Vis spectral analysis of 3,5-dichlorobenzonitrile and m-bromobenzonitrile by ab initio and density functional theory methods.

PubMed

Senthil kumar, J; Jeyavijayan, S; Arivazhagan, M

2015-02-05

The FT-IR and FT-Raman spectra of 3,5-dichlorobenzonitrile and m-bromobenzonitrile have been recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1), respectively. The optimized geometry, wave numbers and intensity of vibrational bonds of title molecules are obtained by ab initio and DFT level of theory with complete relaxation in the potential energy surface using 6-311++G(d, p) basis set. A complete vibrational assignments aided by the theoretical harmonic frequency, analysis have been proposed. The harmonic vibrational frequencies calculated have been compared with experimental FT-IR and FT-Raman spectra. The observed and calculated frequencies are found to be in good agreement. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The UV-Vis spectral analysis of the molecules has also been done which confirms the charge transfer of the molecules. Furthermore, the first hyperpolarizability and total dipole moment of the molecules have been calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

Measurements of Heat Transfer and Boundary-Layer Transition on an 8-Inch-Diameter Hemisphere-Cylinder in Free Flight for a Mach Number Range of 2.00 to 3.88

NASA Technical Reports Server (NTRS)

Garland, Benjamine J.; Chauvin, Leo T.

1957-01-01

Measurements of aerodynamic heat transfer have been made along the hemisphere and cylinder of a hemisphere-cylinder rocket-propelled model in free flight up to a Mach number of 3.88. The test Reynolds number based on free-stream condition and diameter of model covered a range from 2.69 x l0(exp 6) to 11.70 x 10(exp 6). Laminar, transitional, and turbulent heat-transfer coefficients were obtained. The laminar data along the body agreed with laminar theory for blunt bodies whereas the turbulent data along the cylinder were consistently lower than that predicted by the turbulent theory for a flat plate. Measurements of heat transfer at the stagnation point were, in general, lower than the theory for stagnation-point heat transfer. When the Reynolds number to the junction of the hemisphere-cylinder was greater than 6 x l0(exp 6), the transitional Reynolds number varied from 0.8 x l0(exp 6) to 3.0 x 10(exp 6); however, than 6 x l(exp 6) when the Reynolds number to the junction was less, than the transitional Reynolds number varied from 7.0 x l0(exp 6) to 24.7 x 10(exp 6).

Structure and Electronic Spectra of Purine-Methyl Viologen Charge Transfer Complexes

PubMed Central

Jalilov, Almaz S.; Patwardhan, Sameer; Singh, Arunoday; Simeon, Tomekia; Sarjeant, Amy A.; Schatz, George C.; Lewis, Frederick D.

2014-01-01

The structure and properties of the electron donor-acceptor complexes formed between methyl viologen (MV) and purine nucleosides and nucleotides in water and the solid state have been investigated using a combination of experimental and theoretical methods. Solution studies were performed using UV-vis and 1H NMR spectroscopy. Theoretical calculations were performed within the framework of density functional theory (DFT). Energy decomposition analysis indicates that dispersion and induction (charge-transfer) interactions dominate the total binding energy, whereas electrostatic interactions are largely repulsive. The appearance of charge transfer bands in the absorption spectra of the complexes are well described by time-dependent (TD) DFT and are further explained in terms of the redox properties of purine monomers and solvation effects. Crystal structures are reported for complexes of methyl viologen with the purines 2′-deoxyguanosine 3′-monophosphate GMP (DAD′DAD′ type) and 7-deazaguanosine zG (DAD′ADAD′ type). Comparison of the structures determined in the solid state and by theoretical methods in solution provides valuable insights into the nature of charge-transfer interactions involving purine bases as electron donors. PMID:24294996

Dynamics of charge-transfer excitons in type-II semiconductor heterostructures

NASA Astrophysics Data System (ADS)

Stein, M.; Lammers, C.; Richter, P.-H.; Fuchs, C.; Stolz, W.; Koch, M.; Vänskä, O.; Weseloh, M. J.; Kira, M.; Koch, S. W.

2018-03-01

The formation, decay, and coherence properties of charge-transfer excitons in semiconductor heterostructures are investigated by applying four-wave-mixing and terahertz spectroscopy in combination with a predictive microscopic theory. A charge-transfer process is identified where the optically induced coherences decay directly into a charge-transfer electron-hole plasma and exciton states. It is shown that charge-transfer excitons are more sensitive to the fermionic electron-hole substructure than regular excitons.

NiO: correlated band structure of a charge-transfer insulator.

PubMed

Kunes, J; Anisimov, V I; Skornyakov, S L; Lukoyanov, A V; Vollhardt, D

2007-10-12

The band structure of the prototypical charge-transfer insulator NiO is computed by using a combination of an ab initio band structure method and the dynamical mean-field theory with a quantum Monte-Carlo impurity solver. Employing a Hamiltonian which includes both Ni d and O p orbitals we find excellent agreement with the energy bands determined from angle-resolved photoemission spectroscopy. This brings an important progress in a long-standing problem of solid-state theory. Most notably we obtain the low-energy Zhang-Rice bands with strongly k-dependent orbital character discussed previously in the context of low-energy model theories.

A density functional theory (DFT) and time-dependent density functional theory (TDDFT) study on optical transitions in oligo(p-phenylenevinylene)-fullerene dyads and the applicability to resonant energy transfer.

PubMed

Toivonen, Teemu L J; Hukka, Terttu I

2007-06-07

The optical transitions of three different size oligo(p-phenylenevinylene)-fullerene dyads (OPV(n)-MPC(60); n = 2-4) and of the corresponding separate molecules are studied using density functional theory (DFT) and time-dependent density functional theory. The DFT is used to determine the geometries and the electronic structures of the ground states. Transition energies and excited-state structures are obtained from the TDDFT calculations. Resonant energy transfer from OPV(n) to MPC(60) is also studied and the Fermi golden rule is used, along with two simple models to describe the electronic coupling to calculate the energy transfer rates. The hybrid-type PBE0 functional is used with a split-valence basis set augmented with a polarization function (SV(P)) in calculations and the calculated results are compared to the corresponding experimental results. The calculated PBE0 spectra of the OPV(n)-MPC(60) dyads correspond to the experimental spectra very well and are approximately sums of the absorption spectra of the separate OPV(n) and MPC(60) molecules. Also, the absorption energies of OPV(n) and MPC(60) and the emission energies of OPV(n) are predicted well with the PBE0 functional. The PBE0 calculated resonant energy transfer rates are in a good agreement with the experimental rates and show the existence of many possible pathways for energy transfer from the first excited singlet states of the OPV(n) molecules to the MPC(60) molecule.

Entrepreneurship for Physicists; A practical guide to move inventions from university to market

NASA Astrophysics Data System (ADS)

Iannuzzi, Davide

2017-10-01

This book offers a concise analysis of the key ingredients that enable physicists to successfully move their idea from university to market, bringing added value to their customers. It dives into a set of theories, models, and tools that play fundamental roles in technology transfer including topics often neglected by other books including trust, communication, and persuasion. It also explains how most of the topics discussed are applicable to careers in a broader sense.

Rocket propulsion elements - An introduction to the engineering of rockets (6th revised and enlarged edition)

NASA Astrophysics Data System (ADS)

Sutton, George P.

The subject of rocket propulsion is treated with emphasis on the basic technology, performance, and design rationale. Attention is given to definitions and fundamentals, nozzle theory and thermodynamic relations, heat transfer, flight performance, chemical rocket propellant performance analysis, and liquid propellant rocket engine fundamentals. The discussion also covers solid propellant rocket fundamentals, hybrid propellant rockets, thrust vector control, selection of rocket propulsion systems, electric propulsion, and rocket testing.

How education for sustainable development is implemented in Germany: Looking through the lens of educational governance theory

NASA Astrophysics Data System (ADS)

Bormann, Inka; Nikel, Jutta

2017-12-01

The United Nations (UN) Decade of Education for Sustainable Development (ESD) aimed to integrate the principles, values and practices of sustainable development into all aspects of education and learning around the world. The authors of this article address the implementation process of ESD in Germany during the UN Decade (2005-2014). By undertaking a meta-analysis of the findings of four related sub-studies they carried out during a three-year project funded by the German Federal Ministry of Education and Research, the authors contribute to the understanding of the process of transferring the concept of ESD within a multi-level education system. They investigated this process at two levels - the federal state (a sub-national entity in Germany) and the communal level. Drawing on educational governance theory, the authors unveil principles, norms, rules and procedures in the coordination of action within constellations of heterogeneous actors contributing to the implementation of ESD in their social entities. The outcome of the meta-analysis describes an emerging governance regime in ESD, taking into consideration the following features impacting the coordination of action being carried out by the actors involved: (1) the understanding of the normative concept of ESD as content of negotiation; (2) the perceived opportunity for actors to gain and increase appreciation within the field of ESD as an incentive for and driver of engagement; and (3) the dynamic quality of the set-up, rules and principles of the coordination of action, which renders these subject to situative changes. In the final part of the paper, the findings are discussed from the perspectives of the theory of transfer and the current empirical basis of ESD policy and governance.

Game theory based models to analyze water conflicts in the Middle Route of the South-to-North Water Transfer Project in China.

PubMed

Wei, Shouke; Yang, Hong; Abbaspour, Karim; Mousavi, Jamshid; Gnauck, Albrecht

2010-04-01

This study applied game theory based models to analyze and solve water conflicts concerning water allocation and nitrogen reduction in the Middle Route of the South-to-North Water Transfer Project in China. The game simulation comprised two levels, including one main game with five players and four sub-games with each containing three sub-players. We used statistical and econometric regression methods to formulate payoff functions of the players, economic valuation methods (EVMs) to transform non-monetary value into economic one, cost-benefit Analysis (CBA) to compare the game outcomes, and scenario analysis to investigate the future uncertainties. The validity of game simulation was evaluated by comparing predictions with observations. The main results proved that cooperation would make the players collectively better off, though some player would face losses. However, players were not willing to cooperate, which would result in a prisoners' dilemma. Scenarios simulation results displayed that players in water scare area could not solve its severe water deficit problem without cooperation with other players even under an optimistic scenario, while the uncertainty of cooperation would come from the main polluters. The results suggest a need to design a mechanism to reduce the risk of losses of those players by a side payment, which provides them with economic incentives to cooperate. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Density functional theory calculations on transition metal atoms adsorbed on graphene monolayers

NASA Astrophysics Data System (ADS)

Dimakis, Nicholas; Flor, Fernando Antonio; Salgado, Andres; Adjibi, Kolade; Vargas, Sarah; Saenz, Justin

2017-11-01

Transition metal atom adsorption on graphene monolayers has been elucidated using periodic density functional theory under hybrid and generalized gradient approximation functionals. More specifically, we examined the adsorption of Cu, Fe, Zn, Ru, and Os on graphene monolayers by calculating, among others, the electronic density-of-states spectra of the adatom-graphene system and the overlap populations of the adatom with the nearest adsorbing graphene carbon atoms. These calculations reveal that Cu form primarily covalent bonds with graphene atoms via strong hybridization between the adatom orbitals and the sp band of the graphene substrate, whereas the interaction of the Ru and Os with graphene also contain ionic parts. Although the interaction of Fe with graphene atoms is mostly covalent, some charge transfer to graphene is also observed. The interaction of Zn with graphene is weak. Mulliken population analysis and charge contour maps are used to elucidate charge transfers between the adatom and the substrate. The adsorption strength is correlated with the metal adsorption energy and the height of the metal adatom from the graphene plane for the geometrically optimized adatom-graphene system. Our analysis shows that show that metal adsorption strength follows the adatom trend Ru ≈ Os > Fe > Cu > Zn, as verified by corresponding changes in the adsorption energies. The increased metal-carbon orbital overlap for the Ru relative to Os adatom is attributed to hybridization defects.

All-Atom Multiscale Molecular Dynamics Theory and Simulation of Self-Assembly, Energy Transfer and Structural Transition in Nanosystems

NASA Astrophysics Data System (ADS)

Espinosa Duran, John Michael

The study of nanosystems and their emergent properties requires the development of multiscale computational models, theories and methods that preserve atomic and femtosecond resolution, to reveal details that cannot be resolved experimentally today. Considering this, three long time scale phenomena were studied using molecular dynamics and multiscale methods: self-assembly of organic molecules on graphite, energy transfer in nanosystems, and structural transition in vault nanoparticles. Molecular dynamics simulations of the self-assembly of alkoxybenzonitriles with different tail lengths on graphite were performed to learn about intermolecular interactions and phases exhibited by self-organized materials. This is important for the design of ordered self-assembled organic photovoltaic materials with greater efficiency than the disordered blends. Simulations revealed surface dynamical behaviors that cannot be resolved experimentally today due to the lack of spatiotemporal resolution. Atom-resolved structures predicted by simulations agreed with scanning tunneling microscopy images and unit cell measurements. Then, a multiscale theory based on the energy density as a field variable is developed to study energy transfer in nanoscale systems. For applications like photothermal microscopy or cancer phototherapy is required to understand how the energy is transferred to/from nanosystems. This multiscale theory could be applied in this context and here is tested for cubic nanoparticles immersed in water for energy being transferred to/from the nanoparticle. The theory predicts the energy transfer dynamics and reveals phenomena that cannot be described by current phenomenological theories. Finally, temperature-triggered structural transitions were revealed for vault nanoparticles using molecular dynamics and multiscale simulations. Vault is a football-shaped supramolecular assembly very distinct from the commonly observed icosahedral viruses. It has very promising applications in drug delivery and has been extensively studied experimentally. Sub-microsecond multiscale simulations at 310 K on the vault revealed the opening and closing of fractures near the shoulder while preserving the overall structure. This fracture mechanism could explain the uptake and release of small drugs while maintaining the overall structure. Higher temperature simulations show the generation of large fractures near the waist, which enables interaction of the external medium with the inner vault residues. Simulation results agreed with microscopy and spectroscopy measurements, and revealed new structures and mechanisms.

Heat Transfer to Surfaces of Finite Catalytic Activity in Frozen Dissociated Hypersonic Flow

NASA Technical Reports Server (NTRS)

Chung, Paul M.; Anderson, Aemer D.

1961-01-01

The heat transfer due to catalytic recombination of a partially dissociated diatomic gas along the surfaces of two-dimensional and axisymmetric bodies with finite catalytic efficiencies is studied analytically. An integral method is employed resulting in simple yet relatively complete solutions for the particular configurations considered. A closed form solution is derived which enables one to calculate atom mass-fraction distribution, therefore catalytic heat transfer distribution, along the surface of a flat plate in frozen compressible flow with and without transpiration. Numerical calculations are made to determine the atom mass-fraction distribution along an axisymmetric conical body with spherical nose in frozen hypersonic compressible flow. A simple solution based on a local similarity concept is found to be in good agreement with these numerical calculations. The conditions are given for which the local similarity solution is expected to be satisfactory. The limitations on the practical application of the analysis to the flight of the blunt bodies in the atmosphere are discussed. The use of boundary-layer theory and the assumption of frozen flow restrict application of the analysis to altitudes between about 150,000 and 250,000 feet.

Pressure transfer function of a JT15D nozzle due to acoustic and convected entropy fluctuations

NASA Astrophysics Data System (ADS)

Miles, J. H.

An acoustic transmission matrix analysis of sound propagation in a variable area duct with and without flow is extended to include convected entropy fluctuations. The boundary conditions used in the analysis are a transfer function relating entropy and pressure at the nozzle inlet and the nozzle exit impedance. The nozzle pressure transfer function calculated is compared with JT15D turbofan engine nozzle data. The one dimensional theory for sound propagation in a variable area nozzle with flow but without convected entropy is good at the low engine speeds where the nozzle exit Mach number is low (M=0.2) and the duct exit impedance model is good. The effect of convected entropy appears to be so negligible that it is obscured by the inaccuracy of the nozzle exit impedance model, the lack of information on the magnitude of the convected entropy and its phase relationship with the pressure, and the scatter in the data. An improved duct exit impedance model is required at the higher engine speeds where the nozzle exit Mach number is high (M=0.56) and at low frequencies (below 120 Hz).

Structural investigation, spectroscopic and energy level studies of Schiff base: 2-[(3‧-N-salicylidenephenyl)benzimidazole] using experimental and DFT methods

NASA Astrophysics Data System (ADS)

Suman, G. R.; Bubbly, S. G.; Gudennavar, S. B.; Muthu, S.; Roopashree, B.; Gayatri, V.; Nanje Gowda, N. M.

2017-07-01

The Schiff base 2-[(3‧-N-salicylidenephenyl)benzimidazole] (Spbzl) was characterized by FT-Raman, 1H NMR, 13C NMR and single crystal X-ray diffraction technique. Crystallographic studies reveal the presence of two water molecules in the asymmetry unit which aid the intermolecular hydrogen bonding with imidazole ring, and the trans-conformation of the azomethine bond. Theoretical computations conducted using density functional theory (DFT) analysis support the experimental facts. Energy levels estimated by DFT studies are in good agreement with the values obtained from cyclic voltammetry technique. Frontier molecular orbital analysis shows that charge transfer has taken place from donor to acceptor moiety, which is also supported by the high hyperpolarizability values in both gaseous and solution phases, indicating high charge transfer capability of the molecule. A comparative theoretical study of Spbzl with derivative 4-((3-(1H-benzimidazol-2-yl)phenylimino)methyl)-3-hydroxybenzoic acid (Pbzlb) having an added anchor group COOH substituted at para position in the acceptor ring has been made. The result shows the feasibility of charge transfer to the semiconductor surface in dye sensitized solar cell (DSSC) applications for Pbzlb.

Cosmic ray sources, acceleration and propagation

NASA Technical Reports Server (NTRS)

Ptuskin, V. S.

1986-01-01

A review is given of selected papers on the theory of cosmic ray (CR) propagation and acceleration. The high isotropy and a comparatively large age of galactic CR are explained by the effective interaction of relativistic particles with random and regular electromagnetic fields in interstellar medium. The kinetic theory of CR propagation in the Galaxy is formulated similarly to the elaborate theory of CR propagation in heliosphere. The substantial difference between these theories is explained by the necessity to take into account in some cases the collective effects due to a rather high density of relativisitc particles. In particular, the kinetic CR stream instability and the hydrodynamic Parker instability is studied. The interaction of relativistic particles with an ensemble of given weak random magnetic fields is calculated by perturbation theory. The theory of CR transfer is considered to be basically completed for this case. The main problem consists in poor information about the structure of the regular and the random galactic magnetic fields. An account is given of CR transfer in a turbulent medium.

Groups in the radiative transfer theory

NASA Astrophysics Data System (ADS)

Nikoghossian, Arthur

2016-11-01

The paper presents a group-theoretical description of radiation transfer in inhomogeneous and multi-component atmospheres with the plane-parallel geometry. It summarizes and generalizes the results obtained recently by the author for some standard transfer problems of astrophysical interest with allowance of the angle and frequency distributions of the radiation field. We introduce the concept of composition groups for media with different optical and physical properties. Group representations are derived for two possible cases of illumination of a composite finite atmosphere. An algorithm for determining the reflectance and transmittance of inhomogeneous and multi-component atmospheres is described. The group theory is applied also to determining the field of radiation inside an inhomogeneous atmosphere. The concept of a group of optical depth translations is introduced. The developed theory is illustrated with the problem of radiation diffusion with partial frequency distribution assuming that the inhomogeneity is due to depth-variation of the scattering coefficient. It is shown that once reflectance and transmittance of a medium are determined, the internal field of radiation in the source-free atmosphere is found without solving any new equations. The transfer problems for a semi-infinite atmosphere and an atmosphere with internal sources of energy are discussed. The developed theory allows to derive summation laws for the mean number of scattering events underwent by the photons in the course of diffusion in the atmosphere.

Toward a Theory of Adaptive Transfer: Expanding Disciplinary Discussions of "Transfer" in Second-Language Writing and Composition Studies

ERIC Educational Resources Information Center

DePalma, Michael-John; Ringer, Jeffrey M.

2011-01-01

In this paper, we argue that discussions of transfer in L2 writing and composition studies have focused primarily on the reuse of past learning and thus have not adequately accounted for the adaptation of learned writing knowledge in unfamiliar situations. In an effort to expand disciplinary discussions of transfer in L2 writing and composition…

Child versus adult psychoanalysis: two processes or one?

PubMed

Sugarman, Alan

2009-12-01

Child analysis continues to be seen as a different technique from adult analysis because children are still involved in a developmental process and because the primary objects continue to play active roles in their lives. This paper argues that this is a false dichotomy. An extended vignette of the analysis of a latency-aged girl is used to demonstrate that the psychoanalytic process that develops in child analysis is structurally the same as that in adult analysis. Both revolve around the analysis of resistance and transference and use both to promote knowledge of the patient's mind at work. And both techniques formulate interventions based on the analyst's appraisal of the patient's mental organization. It is hoped that stressing the essential commonality of both techniques will promote the development of an overarching theory of psychoanalytic technique.

A review of health behaviour theories: how useful are these for developing interventions to promote long-term medication adherence for TB and HIV/AIDS?

PubMed Central

Munro, Salla; Lewin, Simon; Swart, Tanya; Volmink, Jimmy

2007-01-01

Background Suboptimal treatment adherence remains a barrier to the control of many infectious diseases, including tuberculosis and HIV/AIDS, which contribute significantly to the global disease burden. However, few of the many interventions developed to address this issue explicitly draw on theories of health behaviour. Such theories could contribute to the design of more effective interventions to promote treatment adherence and to improving assessments of the transferability of these interventions across different health issues and settings. Methods This paper reviews behaviour change theories applicable to long-term treatment adherence; assesses the evidence for their effectiveness in predicting behaviour change; and examines the implications of these findings for developing strategies to improve TB and HIV/AIDS medication adherence. We searched a number of electronic databases for theories of behaviour change. Eleven theories were examined. Results Little empirical evidence was located on the effectiveness of these theories in promoting adherence. However, several models have the potential to both improve understanding of adherence behaviours and contribute to the design of more effective interventions to promote adherence to TB and HIV/AIDS medication. Conclusion Further research and analysis is needed urgently to determine which models might best improve adherence to long-term treatment regimens. PMID:17561997

A study of vibrational spectra and investigations of charge transfer and chemical bonding features of 2-chloro benzimidazole based on DFT computations

NASA Astrophysics Data System (ADS)

Muthunatesan, S.; Ragavendran, V.

2015-01-01

Benzimidazoles are bicyclic heteroatomic molecules. Polycyclic heteroatomic molecules have extensive coupling of different modes leading to strong coupling of force constants associated with the various chemical bonds of the molecules. To carry out a detailed vibrational spectroscopic analysis of such a bicyclic heteroatomic molecule, FT-IR and FT-Raman spectra of 2-chloro benzimidazole (CBZ) have been recorded in the condensed phase. Density Functional Theory calculations in the B3LYP/6-31G* level have been carried out to determine the optimized geometry and vibrational frequencies. In order to obtain a close agreement between theoretical and observed frequencies and hence to perform a reliable assignment, the theoretical DFT force field was transformed from Cartesian to local symmetry co-ordinates and then scaled empirically using SQM methodology. The SQM treatment resulted in a RMS deviation of 9.4 cm-1. For visual comparison, the observed and calculated spectra are presented on a common wavenumber scale. From the NBO analysis, the electron density (ED) charge transfers in the σ* and π* antibonding orbitals and second order delocalization energies E(2) confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The calculated Homo and Lumo energies show that charge transfer occurs within the molecule. The results obtained from the vibrational, NBO and HOMO-LUMO analyses have been properly tabulated.

Satellite scheduling considering maximum observation coverage time and minimum orbital transfer fuel cost

NASA Astrophysics Data System (ADS)

Zhu, Kai-Jian; Li, Jun-Feng; Baoyin, He-Xi

2010-01-01

In case of an emergency like the Wenchuan earthquake, it is impossible to observe a given target on earth by immediately launching new satellites. There is an urgent need for efficient satellite scheduling within a limited time period, so we must find a way to reasonably utilize the existing satellites to rapidly image the affected area during a short time period. Generally, the main consideration in orbit design is satellite coverage with the subsatellite nadir point as a standard of reference. Two factors must be taken into consideration simultaneously in orbit design, i.e., the maximum observation coverage time and the minimum orbital transfer fuel cost. The local time of visiting the given observation sites must satisfy the solar radiation requirement. When calculating the operational orbit elements as optimal parameters to be evaluated, we obtain the minimum objective function by comparing the results derived from the primer vector theory with those derived from the Hohmann transfer because the operational orbit for observing the disaster area with impulse maneuvers is considered in this paper. The primer vector theory is utilized to optimize the transfer trajectory with three impulses and the Hohmann transfer is utilized for coplanar and small inclination of non-coplanar cases. Finally, we applied this method in a simulation of the rescue mission at Wenchuan city. The results of optimizing orbit design with a hybrid PSO and DE algorithm show that the primer vector and Hohmann transfer theory proved to be effective methods for multi-object orbit optimization.

The cost of concreteness: the effect of nonessential information on analogical transfer.

PubMed

Kaminski, Jennifer A; Sloutsky, Vladimir M; Heckler, Andrew F

2013-03-01

Most theories of analogical transfer focus on similarities between the learning and transfer domains, where transfer is more likely between domains that share common surface features, similar elements, or common interpretations of structure. We suggest that characteristics of the learning instantiation alone can give rise to different levels of transfer. We propose that concreteness of the learning instantiation can hinder analogical transfer of well-defined structured concepts, such as mathematical concepts. We operationalize the term concreteness as the amount of information communicated through a specific instantiation of a concept. The 5 reported experiments with undergraduate students tested the hypothesis by presenting participants with the concept of a commutative mathematical group of order 3. The experiments varied the level of concreteness of the training instantiation and measured transfer of learning to a new instantiation. The results support the hypothesis, demonstrating better transfer from more generic instantiations (i.e., ones that communicate minimal extraneous information) than from more concrete instantiations. Specifically, concreteness was found to create an obstacle to successful structural alignment across domains, whereas generic instantiations led to spontaneous structural alignment. These findings have important implications for the theory of learning and transfer and practical implications for the design of educational material. Although some concreteness may activate prior knowledge and perhaps offer a leg up in the learning process, this benefit may come at the cost of transfer.

Organic solar cells: understanding the role of Förster resonance energy transfer.

PubMed

Feron, Krishna; Belcher, Warwick J; Fell, Christopher J; Dastoor, Paul C

2012-12-12

Organic solar cells have the potential to become a low-cost sustainable energy source. Understanding the photoconversion mechanism is key to the design of efficient organic solar cells. In this review, we discuss the processes involved in the photo-electron conversion mechanism, which may be subdivided into exciton harvesting, exciton transport, exciton dissociation, charge transport and extraction stages. In particular, we focus on the role of energy transfer as described by F¨orster resonance energy transfer (FRET) theory in the photoconversion mechanism. FRET plays a major role in exciton transport, harvesting and dissociation. The spectral absorption range of organic solar cells may be extended using sensitizers that efficiently transfer absorbed energy to the photoactive materials. The limitations of F¨orster theory to accurately calculate energy transfer rates are discussed. Energy transfer is the first step of an efficient two-step exciton dissociation process and may also be used to preferentially transport excitons to the heterointerface, where efficient exciton dissociation may occur. However, FRET also competes with charge transfer at the heterointerface turning it in a potential loss mechanism. An energy cascade comprising both energy transfer and charge transfer may aid in separating charges and is briefly discussed. Considering the extent to which the photo-electron conversion efficiency is governed by energy transfer, optimisation of this process offers the prospect of improved organic photovoltaic performance and thus aids in realising the potential of organic solar cells.

Knowledge Theories Can Inform Evaluation Practice: What Can a Complexity Lens Add?

ERIC Educational Resources Information Center

Hawe, Penelope; Bond, Lyndal; Butler, Helen

2009-01-01

Programs and policies invariably contain new knowledge. Theories about knowledge utilization, diffusion, implementation, transfer, and knowledge translation theories illuminate some mechanisms of change processes. But more often than not, when it comes to understanding patterns about change processes, "the foreground" is privileged more…

DFT investigation on the electronic structure of Faujasite

NASA Astrophysics Data System (ADS)

Popeneciu, Horea; Calborean, Adrian; Tudoran, Cristian; Buimaga-Iarinca, Luiza

2013-11-01

We report here first-principle pseudopotential DFT calculations to investigate relevant aspects of the electronic structure of zeolites based FAU. Fundamental molecular issues of the band-gap and electronic population analysis were reviewed under GGA/RPBE level of theory, corroborated with a DZP basis set and Troullier-Martins norm conserving pseudo-potentials. The atom-projected density of states and the analysis of HOMO-LUMO frontier orbitals at Gamma point were performed. Their electronic transfers are discussed through the alignment and relative positions of orbitals in order to determine the way that the molecule interacts with adsorbed molecules and other practical applications. Mulliken population analysis was employed for describing atomic charge distribution in the chosen systems.

Maintaining the Transfer of In-Service Teachers' Training in the Workplace

ERIC Educational Resources Information Center

Cheng, Eddie W. L.

2016-01-01

Professional training and development is a major component of updating teachers' pedagogical knowledge and skills. However, transferring such knowledge and skill may not always be successful. Based on the theory of planned behaviour (TPB), the present study has developed a model specifying the factors affecting transfer maintenance intention and…

A Model of the Antecedents of Training Transfer

ERIC Educational Resources Information Center

Mohammed Turab, Ghaneemah; Casimir, Gian

2015-01-01

Many organizations have invested heavily in training. However, only a small percentage of what is learnt from training is applied or transferred to the workplace. This study examines factors that influence training transfer. A conceptual model based on the Theory of Reasoned Action is hypothesized and tested. The sample consisted of 123 full-time…

Pathways to Engineering: The Validation Experiences of Transfer Students

ERIC Educational Resources Information Center

Zhang, Yi; Ozuna, Taryn

2015-01-01

Community college engineering transfer students are a critical student population of engineering degree recipients and technical workforce in the United States. Focusing on this group of students, we adopted Rendón's (1994) validation theory to explore the students' experiences in community colleges prior to transferring to a four-year…

A multi-layer discrete-ordinate method for vector radiative transfer in a vertically-inhomogeneous, emitting and scattering atmosphere. I - Theory. II - Application

NASA Technical Reports Server (NTRS)

Weng, Fuzhong

1992-01-01

A theory is developed for discretizing the vector integro-differential radiative transfer equation including both solar and thermal radiation. A complete solution and boundary equations are obtained using the discrete-ordinate method. An efficient numerical procedure is presented for calculating the phase matrix and achieving computational stability. With natural light used as a beam source, the Stokes parameters from the model proposed here are compared with the analytical solutions of Chandrasekhar (1960) for a Rayleigh scattering atmosphere. The model is then applied to microwave frequencies with a thermal source, and the brightness temperatures are compared with those from Stamnes'(1988) radiative transfer model.

Effective field theory models for nonviolent information transfer from black holes

NASA Astrophysics Data System (ADS)

Giddings, Steven B.; Shi, Yinbo

2014-06-01

Transfer of quantum information from the interior of a black hole to its atmosphere is described, in models based on effective field theory. This description illustrates that such transfer need not be violent to the semiclassical geometry or to infalling observers, and in particular can avoid producing a singular horizon or "firewall". One can specifically quantify the rate of information transfer and show that a rate necessary to unitarize black hole evaporation produces a relatively mild modification to the stress tensor near the horizon. In an exterior description of the transfer, the new interactions responsible for it are approximated by "effective sources" acting on fields in the black hole atmosphere. If the necessary interactions couple to general modes in the black hole atmosphere, one also finds a straightforward mechanism for information transfer rates to increase when a black hole is mined, avoiding paradoxical behavior. Correspondence limits are discussed, in the presence of such new interactions, for both small black holes and large ones; the near-horizon description of the latter is approximately that of Rindler space.

Inclusive fitness and differential productivity across the life course determine intergenerational transfers in a small-scale human society.

PubMed

Hooper, Paul L; Gurven, Michael; Winking, Jeffrey; Kaplan, Hillard S

2015-03-22

Transfers of resources between generations are an essential element in current models of human life-history evolution accounting for prolonged development, extended lifespan and menopause. Integrating these models with Hamilton's theory of inclusive fitness, we predict that the interaction of biological kinship with the age-schedule of resource production should be a key driver of intergenerational transfers. In the empirical case of Tsimane' forager-horticulturalists in Bolivian Amazonia, we provide a detailed characterization of net transfers of food according to age, sex, kinship and the net need of donors and recipients. We show that parents, grandparents and siblings provide significant net downward transfers of food across generations. We demonstrate that the extent of provisioning responds facultatively to variation in the productivity and demographic composition of families, as predicted by the theory. We hypothesize that the motivation to provide these critical transfers is a fundamental force that binds together human nuclear and extended families. The ubiquity of three-generational families in human societies may thus be a direct reflection of fundamental evolutionary constraints on an organism's life-history and social organization.

Correlation of AH-1G airframe flight vibration data with a coupled rotor-fuselage analysis

NASA Technical Reports Server (NTRS)

Sangha, K.; Shamie, J.

1990-01-01

The formulation and features of the Rotor-Airframe Comprehensive Analysis Program (RACAP) is described. The analysis employs a frequency domain, transfer matrix approach for the blade structural model, a time domain wake or momentum theory aerodynamic model, and impedance matching for rotor-fuselage coupling. The analysis is applied to the AH-1G helicopter, and a correlation study is conducted on fuselage vibration predictions. The purpose of the study is to evaluate the state-of-the-art in helicopter fuselage vibration prediction technology. The fuselage vibration predicted using RACAP are fairly good in the vertical direction and somewhat deficient in the lateral/longitudinal directions. Some of these deficiencies are traced to the fuselage finite element model.

Serotonergic psychedelics temporarily modify information transfer in humans.

PubMed

Alonso, Joan Francesc; Romero, Sergio; Mañanas, Miquel Àngel; Riba, Jordi

2015-03-28

Psychedelics induce intense modifications in the sensorium, the sense of "self," and the experience of reality. Despite advances in our understanding of the molecular and cellular level mechanisms of these drugs, knowledge of their actions on global brain dynamics is still incomplete. Recent imaging studies have found changes in functional coupling between frontal and parietal brain structures, suggesting a modification in information flow between brain regions during acute effects. Here we assessed the psychedelic-induced changes in directionality of information flow during the acute effects of a psychedelic in humans. We measured modifications in connectivity of brain oscillations using transfer entropy, a nonlinear measure of directed functional connectivity based on information theory. Ten healthy male volunteers with prior experience with psychedelics participated in 2 experimental sessions. They received a placebo or a dose of ayahuasca, a psychedelic preparation containing the serotonergic 5-HT2A agonist N,N-dimethyltryptamine. The analysis showed significant changes in the coupling of brain oscillations between anterior and posterior recording sites. Transfer entropy analysis showed that frontal sources decreased their influence over central, parietal, and occipital sites. Conversely, sources in posterior locations increased their influence over signals measured at anterior locations. Exploratory correlations found that anterior-to-posterior transfer entropy decreases were correlated with the intensity of subjective effects, while the imbalance between anterior-to-posterior and posterior-to-anterior transfer entropy correlated with the degree of incapacitation experienced. These results suggest that psychedelics induce a temporary disruption of neural hierarchies by reducing top-down control and increasing bottom-up information transfer in the human brain. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Exciton-exciton annihilation in a disordered molecular system by direct and multistep Förster transfer

NASA Astrophysics Data System (ADS)

Fennel, Franziska; Lochbrunner, Stefan

2015-10-01

Exciton annihilation dynamics in a disordered organic model system is investigated by ultrafast absorption spectroscopy. We show that the temporal evolution of the exciton density can be quantitatively understood by applying Förster energy transfer theory to describe the diffusion of the excitons as well as the annihilation step itself. To this end, previous formulations of Förster theory are extended to account for the inhomogeneous distribution of the S0-S1 transition energies resulting in an effective exciton diffusion constant. Two annihilation pathways are considered, the direct transfer of an exciton between two excited molecules and diffusive motion by multiple transfer steps towards a second exciton preceding the annihilation event. One pathway can be emphasized with respect to the other by tuning the exciton diffusion constant via the chromophore concentration. The investigated system allows one to extract all relevant parameters for the description and provides in this way a proof that the annihilation dynamics can be entirely understood and modeled by Förster energy transfer.

Diabatization for Time-Dependent Density Functional Theory: Exciton Transfers and Related Conical Intersections.

PubMed

Tamura, Hiroyuki

2016-11-23

Intermolecular exciton transfers and related conical intersections are analyzed by diabatization for time-dependent density functional theory. The diabatic states are expressed as a linear combination of the adiabatic states so as to emulate the well-defined reference states. The singlet exciton coupling calculated by the diabatization scheme includes contributions from the Coulomb (Förster) and electron exchange (Dexter) couplings. For triplet exciton transfers, the Dexter coupling, charge transfer integral, and diabatic potentials of stacked molecules are calculated for analyzing direct and superexchange pathways. We discuss some topologies of molecular aggregates that induce conical intersections on the vanishing points of the exciton coupling, namely boundary of H- and J-aggregates and T-shape aggregates, as well as canceled exciton coupling to the bright state of H-aggregate, i.e., selective exciton transfer to the dark state. The diabatization scheme automatically accounts for the Berry phase by fixing the signs of reference states while scanning the coordinates.

Radiative heat transfer and nonequilibrium Casimir-Lifshitz force in many-body systems with planar geometry

NASA Astrophysics Data System (ADS)

Latella, Ivan; Ben-Abdallah, Philippe; Biehs, Svend-Age; Antezza, Mauro; Messina, Riccardo

2017-05-01

A general theory of photon-mediated energy and momentum transfer in N -body planar systems out of thermal equilibrium is introduced. It is based on the combination of the scattering theory and the fluctuational-electrodynamics approach in many-body systems. By making a Landauer-like formulation of the heat transfer problem, explicit formulas for the energy transmission coefficients between two distinct slabs as well as the self-coupling coefficients are derived and expressed in terms of the reflection and transmission coefficients of the single bodies. We also show how to calculate local equilibrium temperatures in such systems. An analogous formulation is introduced to quantify momentum transfer coefficients describing Casimir-Lifshitz forces out of thermal equilibrium. Forces at thermal equilibrium are readily obtained as a particular case. As an illustration of this general theoretical framework, we show on three-body systems how the presence of a fourth slab can impact equilibrium temperatures in heat-transfer problems and equilibrium positions resulting from the forces acting on the system.

Physico-chemical studies of the experimental and theoretical properties of organic nonlinear optical material 4-chloro-4'methoxy benzylideneaniline

NASA Astrophysics Data System (ADS)

George, Merin; John, Nimmy L.; Saravana Kumar, M.; Subashini, A.; Sajan, D.

2017-01-01

The FT-IR, FT-Raman and UV-visible spectral analysis of 4-chloro 4'-methoxy benzylidene aniline were done experimentally and interpreted with the aid of normal coordinate analysis based on density functional theory (DFT) at the B3LYP/6-311++G (d, p) level of theory. Natural Bond orbital analysis was performed to understand the charge transfer interactions and reactive sites within the system. HOMO-LUMO analysis and first static and dynamic hyperpolarizability calculations were carried out in order to confirm the NLO activity of CMOBA. Photophysical characterization was done to understand the fluorescence emission and lifetime of CMOBA leading to application in blue OLEDs. The Molecular Electrostatic Potential Map was simulated to identify the active sites for electrophilic and nucleophilic attack or the active sites of the molecule which can bind to proteins. Molecular docking analysis revealed its potential as an inhibitor for different proteins which are responsible for cancer and many inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, Crohn's disease and psoriasis. Experimental studies of invitro antiproliferative effect by MTT assay verified the anticancer properties of CMOBA.

Analytical Electrochemistry: Theory and Instrumentation of Dynamic Techniques.

ERIC Educational Resources Information Center

Johnson, Dennis C.

1980-01-01

Emphasizes trends in the development of six topics concerning analytical electrochemistry, including books and reviews (34 references cited), mass transfer (59), charge transfer (25), surface effects (33), homogeneous reactions (21), and instrumentation (31). (CS)

Mathematic Model of Digital Control System with PID Regulator and Regular Step of Quantization with Information Transfer via the Channel of Plural Access

NASA Astrophysics Data System (ADS)

Abramov, G. V.; Emeljanov, A. E.; Ivashin, A. L.

Theoretical bases for modeling a digital control system with information transfer via the channel of plural access and a regular quantization cycle are submitted. The theory of dynamic systems with random changes of the structure including elements of the Markov random processes theory is used for a mathematical description of a network control system. The characteristics of similar control systems are received. Experimental research of the given control systems is carried out.

Transfer function modeling of damping mechanisms in viscoelastic plates

NASA Technical Reports Server (NTRS)

Slater, J. C.; Inman, D. J.

1991-01-01

This work formulates a method for the modeling of material damping characteristics in plates. The Sophie German equation of classical plate theory is modified to incorporate hysteresis effects represented by complex stiffness using the transfer function approach proposed by Golla and Hughes, (1985). However, this procedure is not limited to this representation. The governing characteristic equation is decoupled through separation of variables, yielding a solution similar to that of undamped classical plate theory, allowing solution of the steady state as well as the transient response problem.

Investigation of the Laminar Aerodynamic Heat-transfer Characteristics of a Hemisphere-cylinder in the Langley 11-inch Hypersonic Tunnel at a Mach Number of 6.8

NASA Technical Reports Server (NTRS)

Crawford, Davis H; Mccauley, William D

1957-01-01

A program to investigate the aerodynamic heat transfer of a nonisothermal hemisphere-cylinder has been conducted in the Langley 11-inch hypersonic tunnel at a Mach number of 6.8 and a Reynolds number from approximately 0.14 x 10(6) to 1.06 x 10(6) based on diameter and free-stream conditions. The experimental heat-transfer coefficients were slightly less over the whole body than those predicted by the theory of Stine and Wanlass (NACA technical note 3344) for an isothermal surface. For stations within 45 degrees of the stagnation point the heat-transfer coefficients could be correlated by a single relation between local Stanton number and local Reynolds number. Pitot pressure profiles taken at a Mach number of 6.8 on a hemisphere-cylinder have verified that the local Mach number or velocity outside the boundary layer required in the theories may be computed from the surface pressures by using isentropic flow relations and conditions immediately behind a normal shock. The experimental pressure distribution at Mach number of 6.8 is closely predicted by the modified Newtonian theory.

The Theory of a Free Jet of a Compressible Gas

NASA Technical Reports Server (NTRS)

Abramovich, G. N.

1944-01-01

In the present report the theory of free turbulence propagation and the boundary layer theory are developed for a plane-parallel free stream of a compressible fluid. In constructing the theory use was made of the turbulence hypothesis by Taylor (transport of vorticity) which gives best agreement with test results for problems involving heat transfer in free jets.

Neutron transport analysis for nuclear reactor design

DOEpatents

Vujic, Jasmina L.

1993-01-01

Replacing regular mesh-dependent ray tracing modules in a collision/transfer probability (CTP) code with a ray tracing module based upon combinatorial geometry of a modified geometrical module (GMC) provides a general geometry transfer theory code in two dimensions (2D) for analyzing nuclear reactor design and control. The primary modification of the GMC module involves generation of a fixed inner frame and a rotating outer frame, where the inner frame contains all reactor regions of interest, e.g., part of a reactor assembly, an assembly, or several assemblies, and the outer frame, with a set of parallel equidistant rays (lines) attached to it, rotates around the inner frame. The modified GMC module allows for determining for each parallel ray (line), the intersections with zone boundaries, the path length between the intersections, the total number of zones on a track, the zone and medium numbers, and the intersections with the outer surface, which parameters may be used in the CTP code to calculate collision/transfer probability and cross-section values.

Neutron transport analysis for nuclear reactor design

DOEpatents

Vujic, J.L.

1993-11-30

Replacing regular mesh-dependent ray tracing modules in a collision/transfer probability (CTP) code with a ray tracing module based upon combinatorial geometry of a modified geometrical module (GMC) provides a general geometry transfer theory code in two dimensions (2D) for analyzing nuclear reactor design and control. The primary modification of the GMC module involves generation of a fixed inner frame and a rotating outer frame, where the inner frame contains all reactor regions of interest, e.g., part of a reactor assembly, an assembly, or several assemblies, and the outer frame, with a set of parallel equidistant rays (lines) attached to it, rotates around the inner frame. The modified GMC module allows for determining for each parallel ray (line), the intersections with zone boundaries, the path length between the intersections, the total number of zones on a track, the zone and medium numbers, and the intersections with the outer surface, which parameters may be used in the CTP code to calculate collision/transfer probability and cross-section values. 28 figures.

Analysis of vibrational-translational energy transfer using the direct simulation Monte Carlo method

NASA Technical Reports Server (NTRS)

Boyd, Iain D.

1991-01-01

A new model is proposed for energy transfer between the vibrational and translational modes for use in the direct simulation Monte Carlo method (DSMC). The model modifies the Landau-Teller theory for a harmonic oscillator and the rate transition is related to an experimental correlation for the vibrational relaxation time. Assessment of the model is made with respect to three different computations: relaxation in a heat bath, a one-dimensional shock wave, and hypersonic flow over a two-dimensional wedge. These studies verify that the model achieves detailed balance, and excellent agreement with experimental data is obtained in the shock wave calculation. The wedge flow computation reveals that the usual phenomenological method for simulating vibrational nonequilibrium in the DSMC technique predicts much higher vibrational temperatures in the wake region.

A mathematical analysis of drug dissolution in the USP flow through apparatus

NASA Astrophysics Data System (ADS)

McDonnell, David; D'Arcy, D. M.; Crane, L. J.; Redmond, Brendan

2018-03-01

This paper applies boundary layer theory to the process of drug dissolution in the USP (United States Pharmacopeia) Flow Through Apparatus. The mass transfer rate from the vertical planar surface of a compact within the device is examined. The theoretical results obtained are then compared with those of experiment. The paper also examines the effect on the dissolution process caused by the interaction between natural and forced convection within the apparatus and the introduction of additional boundaries.

Channel analysis for single photon underwater free space quantum key distribution.

PubMed

Shi, Peng; Zhao, Shi-Cheng; Gu, Yong-Jian; Li, Wen-Dong

2015-03-01

We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater free space QKD is feasible in the clearest ocean water.

The Impact of Changing International Relations on the Scientific and Technical Community (Incidence sur la Communaute Scientifique et Technique des Transformations en cours dans les Relations Internationales.

DTIC Science & Technology

1993-04-01

Processing of special formats (diagrams, tables) - Determination of words to be Pre-analysis Programs added to system dictionary Dictionary ...language Lexicon combinations, via a standardized interface (MIR) which maps METAL operates -n both monolingual lexicons and one the results of analyses...in uniform ways. transfer lexicon for each language pair. The monolingual lexi- Unfortunately, there is at present no linguistic theory which cons

Initial Parameter Estimation for Inverse Thermal Analysis of Ti-6Al-4V Deep Penetration Welds

DTIC Science & Technology

2014-05-16

theory, for the case of deep-penetration welding, is simulation of the coupling of keyhole formation, melting, fluid flow in the weld melt pool and...isothermal boundaires, e.g., TTB and TM. A specific procedure for interpolation, however, has not been considered. For the present study, the close ...Clarendon Press, Oxford, 2nd ed, 374, 1959. 19. R. Rai, J.W. Elmer, T.A. Palmer, T. DebRoy, Heat Transfer and Fluid Flow During Keyhole Mode Laser Welding

Long-Range Reduced Predictive Information Transfers of Autistic Youths in EEG Sensor-Space During Face Processing.

PubMed

Khadem, Ali; Hossein-Zadeh, Gholam-Ali; Khorrami, Anahita

2016-03-01

The majority of previous functional/effective connectivity studies conducted on the autistic patients converged to the underconnectivity theory of ASD: "long-range underconnectivity and sometimes short-rang overconnectivity". However, to the best of our knowledge the total (linear and nonlinear) predictive information transfers (PITs) of autistic patients have not been investigated yet. Also, EEG data have rarely been used for exploring the information processing deficits in autistic subjects. This study is aimed at comparing the total (linear and nonlinear) PITs of autistic and typically developing healthy youths during human face processing by using EEG data. The ERPs of 12 autistic youths and 19 age-matched healthy control (HC) subjects were recorded while they were watching upright and inverted human face images. The PITs among EEG channels were quantified using two measures separately: transfer entropy with self-prediction optimality (TESPO), and modified transfer entropy with self-prediction optimality (MTESPO). Afterwards, the directed differential connectivity graphs (dDCGs) were constructed to characterize the significant changes in the estimated PITs of autistic subjects compared with HC ones. By using both TESPO and MTESPO, long-range reduction of PITs of ASD group during face processing was revealed (particularly from frontal channels to right temporal channels). Also, it seemed the orientation of face images (upright or upside down) did not modulate the binary pattern of PIT-based dDCGs, significantly. Moreover, compared with TESPO, the results of MTESPO were more compatible with the underconnectivity theory of ASD in the sense that MTESPO showed no long-range increase in PIT. It is also noteworthy that to the best of our knowledge it is the first time that a version of MTE is applied for patients (here ASD) and it is also its first use for EEG data analysis.

Access to enhanced differences in Marcus-Hush and Butler-Volmer electron transfer theories by systematic analysis of higher order AC harmonics.

PubMed

Stevenson, Gareth P; Baker, Ruth E; Kennedy, Gareth F; Bond, Alan M; Gavaghan, David J; Gillow, Kathryn

2013-02-14

The potential-dependences of the rate constants associated with heterogeneous electron transfer predicted by the empirically based Butler-Volmer and fundamentally based Marcus-Hush formalisms are well documented for dc cyclic voltammetry. However, differences are often subtle, so, presumably on the basis of simplicity, the Butler-Volmer method is generally employed in theoretical-experimental comparisons. In this study, the ability of Large Amplitude Fourier Transform AC Cyclic Voltammetry to distinguish the difference in behaviour predicted by the two formalisms has been investigated. The focus of this investigation is on the difference in the profiles of the first to sixth harmonics, which are readily accessible when a large amplitude of the applied ac potential is employed. In particular, it is demonstrated that systematic analysis of the higher order harmonic responses in suitable kinetic regimes provides predicted deviations of Marcus-Hush from Butler-Volmer behaviour to be established from a single experiment under conditions where the background charging current is minimal.

Coherent transport and energy flow patterns in photosynthesis under incoherent excitation.

PubMed

Pelzer, Kenley M; Can, Tankut; Gray, Stephen K; Morr, Dirk K; Engel, Gregory S

2014-03-13

Long-lived coherences have been observed in photosynthetic complexes after laser excitation, inspiring new theories regarding the extreme quantum efficiency of photosynthetic energy transfer. Whether coherent (ballistic) transport occurs in nature and whether it improves photosynthetic efficiency remain topics of debate. Here, we use a nonequilibrium Green's function analysis to model exciton transport after excitation from an incoherent source (as opposed to coherent laser excitation). We find that even with an incoherent source, the rate of environmental dephasing strongly affects exciton transport efficiency, suggesting that the relationship between dephasing and efficiency is not an artifact of coherent excitation. The Green's function analysis provides a clear view of both the pattern of excitonic fluxes among chromophores and the multidirectionality of energy transfer that is a feature of coherent transport. We see that even in the presence of an incoherent source, transport occurs by qualitatively different mechanisms as dephasing increases. Our approach can be generalized to complex synthetic systems and may provide a new tool for optimizing synthetic light harvesting materials.

Vibrational spectral investigation and natural bond orbital analysis of pharmaceutical compound 7-Amino-2,4-dimethylquinolinium formate - DFT approach

NASA Astrophysics Data System (ADS)

Suresh, D. M.; Amalanathan, M.; Sebastian, S.; Sajan, D.; Hubert Joe, I.; Bena Jothy, V.; Nemec, Ivan

2013-11-01

The molecular geometry, the normal mode frequencies and corresponding vibrational assignments, natural bond orbital analysis and the HOMO-LUMO analysis of 7-Amino-2,4-dimethylquinolinium formate in the ground state were performed by B3LYP levels of theory using the 6-31G(d) basis set. The optimised bond lengths and bond angles are in good agreement with the X-ray data. The vibrational spectra of the title compound which is calculated by DFT method, reproduces vibrational wave numbers and intensities with an accuracy which allows reliable vibrational assignments. The possibility of N-H⋯O hydrogen bonding was identified using NBO analysis. Natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction.

The influence of dielectric relaxation on intramolecular electron transfer

NASA Astrophysics Data System (ADS)

Heitele, H.; Michel-Beyerle, M. E.; Finckh, P.

1987-07-01

An unusually strong temperature dependence on the intramolecular electron-transfer rate has been observed for bridged donor-acceptor compounds in propylene glycol solution. In the frame of recent electron-transfer theories this effect reflects the influence of dielectric relaxation dynamics on electron transfer. With increasing dielectric relaxation time a smooth transition from non-adiabatic to solvent-controlled adiabatic behaviour is observed. The electron transfer rate in the solvent-controlled adiabatic limit is dominated by an inhomogeneous distribution of relaxation times.

A molecularly based theory for electron transfer reorganization energy.

PubMed

Zhuang, Bilin; Wang, Zhen-Gang

2015-12-14

Using field-theoretic techniques, we develop a molecularly based dipolar self-consistent-field theory (DSCFT) for charge solvation in pure solvents under equilibrium and nonequilibrium conditions and apply it to the reorganization energy of electron transfer reactions. The DSCFT uses a set of molecular parameters, such as the solvent molecule's permanent dipole moment and polarizability, thus avoiding approximations that are inherent in treating the solvent as a linear dielectric medium. A simple, analytical expression for the free energy is obtained in terms of the equilibrium and nonequilibrium electrostatic potential profiles and electric susceptibilities, which are obtained by solving a set of self-consistent equations. With no adjustable parameters, the DSCFT predicts activation energies and reorganization energies in good agreement with previous experiments and calculations for the electron transfer between metallic ions. Because the DSCFT is able to describe the properties of the solvent in the immediate vicinity of the charges, it is unnecessary to distinguish between the inner-sphere and outer-sphere solvent molecules in the calculation of the reorganization energy as in previous work. Furthermore, examining the nonequilibrium free energy surfaces of electron transfer, we find that the nonequilibrium free energy is well approximated by a double parabola for self-exchange reactions, but the curvature of the nonequilibrium free energy surface depends on the charges of the electron-transferring species, contrary to the prediction by the linear dielectric theory.

A linear stability analysis for nonlinear, grey, thermal radiative transfer problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wollaber, Allan B., E-mail: wollaber@lanl.go; Larsen, Edward W., E-mail: edlarsen@umich.ed

2011-02-20

We present a new linear stability analysis of three time discretizations and Monte Carlo interpretations of the nonlinear, grey thermal radiative transfer (TRT) equations: the widely used 'Implicit Monte Carlo' (IMC) equations, the Carter Forest (CF) equations, and the Ahrens-Larsen or 'Semi-Analog Monte Carlo' (SMC) equations. Using a spatial Fourier analysis of the 1-D Implicit Monte Carlo (IMC) equations that are linearized about an equilibrium solution, we show that the IMC equations are unconditionally stable (undamped perturbations do not exist) if {alpha}, the IMC time-discretization parameter, satisfies 0.5 < {alpha} {<=} 1. This is consistent with conventional wisdom. However, wemore » also show that for sufficiently large time steps, unphysical damped oscillations can exist that correspond to the lowest-frequency Fourier modes. After numerically confirming this result, we develop a method to assess the stability of any time discretization of the 0-D, nonlinear, grey, thermal radiative transfer problem. Subsequent analyses of the CF and SMC methods then demonstrate that the CF method is unconditionally stable and monotonic, but the SMC method is conditionally stable and permits unphysical oscillatory solutions that can prevent it from reaching equilibrium. This stability theory provides new conditions on the time step to guarantee monotonicity of the IMC solution, although they are likely too conservative to be used in practice. Theoretical predictions are tested and confirmed with numerical experiments.« less

A linear stability analysis for nonlinear, grey, thermal radiative transfer problems

NASA Astrophysics Data System (ADS)

Wollaber, Allan B.; Larsen, Edward W.

2011-02-01

We present a new linear stability analysis of three time discretizations and Monte Carlo interpretations of the nonlinear, grey thermal radiative transfer (TRT) equations: the widely used “Implicit Monte Carlo” (IMC) equations, the Carter Forest (CF) equations, and the Ahrens-Larsen or “Semi-Analog Monte Carlo” (SMC) equations. Using a spatial Fourier analysis of the 1-D Implicit Monte Carlo (IMC) equations that are linearized about an equilibrium solution, we show that the IMC equations are unconditionally stable (undamped perturbations do not exist) if α, the IMC time-discretization parameter, satisfies 0.5 < α ⩽ 1. This is consistent with conventional wisdom. However, we also show that for sufficiently large time steps, unphysical damped oscillations can exist that correspond to the lowest-frequency Fourier modes. After numerically confirming this result, we develop a method to assess the stability of any time discretization of the 0-D, nonlinear, grey, thermal radiative transfer problem. Subsequent analyses of the CF and SMC methods then demonstrate that the CF method is unconditionally stable and monotonic, but the SMC method is conditionally stable and permits unphysical oscillatory solutions that can prevent it from reaching equilibrium. This stability theory provides new conditions on the time step to guarantee monotonicity of the IMC solution, although they are likely too conservative to be used in practice. Theoretical predictions are tested and confirmed with numerical experiments.

Spectroscopic analysis and charge transfer interaction studies of 4-benzyloxy-2-nitroaniline insecticide: A density functional theoretical approach

NASA Astrophysics Data System (ADS)

Arul Dhas, D.; Hubert Joe, I.; Roy, S. D. D.; Balachandran, S.

2015-01-01

A widespread exploration on the intra-molecular charge transfer interaction through an efficient π-conjugated path from a strong electron-donor group (amino) to a strong electron-acceptor group (nitro) has been carried out using FTIR, FT-Raman, UV-Vis, fluorescence and NMR spectra on insecticide compound 4-benzyloxy-2-nitroaniline. Density functional theory method is used to determine optimized molecular geometry, harmonic vibrational wavenumbers and intensities using 6-311G(d,p) basis set by means of Gaussian 09W program suit. A comprehensive investigation on the sp2 to sp3 hybridization and non-planarity property has been performed. Natural bond orbital analysis is used to study the existence of C-H⋯O, N-H⋯O and C-H⋯π proper and improper hydrogen bonds. The HOMO and LUMO analysis reveals the possibility of charge transfer within the molecule. A complete assignment of the experimental absorption peaks in the ultraviolet region has also been performed. Isotropic chemical shifts of 13C, 1H, 15N and 18O NMR and nuclear spin-spin coupling constants have been computed using the gauge-invariant atomic orbital method. The biological activity of substituent amino and nitro groups are evident from the hydrogen bonds through which the target amino acids are linked to the drug as evidenced from molecular docking.

Interaction of Kelvin waves and nonlocality of energy transfer in superfluids

NASA Astrophysics Data System (ADS)

Laurie, Jason; L'Vov, Victor S.; Nazarenko, Sergey; Rudenko, Oleksii

2010-03-01

We argue that the physics of interacting Kelvin Waves (KWs) is highly nontrivial and cannot be understood on the basis of pure dimensional reasoning. A consistent theory of KW turbulence in superfluids should be based upon explicit knowledge of their interactions. To achieve this, we present a detailed calculation and comprehensive analysis of the interaction coefficients for KW turbuelence, thereby, resolving previous mistakes stemming from unaccounted contributions. As a first application of this analysis, we derive a local nonlinear (partial differential) equation. This equation is much simpler for analysis and numerical simulations of KWs than the Biot-Savart equation, and in contrast to the completely integrable local induction approximation (in which the energy exchange between KWs is absent), describes the nonlinear dynamics of KWs. Second, we show that the previously suggested Kozik-Svistunov energy spectrum for KWs, which has often been used in the analysis of experimental and numerical data in superfluid turbulence, is irrelevant, because it is based upon an erroneous assumption of the locality of the energy transfer through scales. Moreover, we demonstrate the weak nonlocality of the inverse cascade spectrum with a constant particle-number flux and find resulting logarithmic corrections to this spectrum.

Deformed quantum double realization of the toric code and beyond

NASA Astrophysics Data System (ADS)

Padmanabhan, Pramod; Ibieta-Jimenez, Juan Pablo; Bernabe Ferreira, Miguel Jorge; Teotonio-Sobrinho, Paulo

2016-09-01

Quantum double models, such as the toric code, can be constructed from transfer matrices of lattice gauge theories with discrete gauge groups and parametrized by the center of the gauge group algebra and its dual. For general choices of these parameters the transfer matrix contains operators acting on links which can also be thought of as perturbations to the quantum double model driving it out of its topological phase and destroying the exact solvability of the quantum double model. We modify these transfer matrices with perturbations and extract exactly solvable models which remain in a quantum phase, thus nullifying the effect of the perturbation. The algebra of the modified vertex and plaquette operators now obey a deformed version of the quantum double algebra. The Abelian cases are shown to be in the quantum double phase whereas the non-Abelian phases are shown to be in a modified phase of the corresponding quantum double phase. These are illustrated with the groups Zn and S3. The quantum phases are determined by studying the excitations of these systems namely their fusion rules and the statistics. We then go further to construct a transfer matrix which contains the other Z2 phase namely the double semion phase. More generally for other discrete groups these transfer matrices contain the twisted quantum double models. These transfer matrices can be thought of as being obtained by introducing extra parameters into the transfer matrix of lattice gauge theories. These parameters are central elements belonging to the tensor products of the algebra and its dual and are associated to vertices and volumes of the three dimensional lattice. As in the case of the lattice gauge theories we construct the operators creating the excitations in this case and study their braiding and fusion properties.

Entropy generation and momentum transfer in the superconductor-normal and normal-superconductor phase transformations and the consistency of the conventional theory of superconductivity

NASA Astrophysics Data System (ADS)

Hirsch, J. E.

2018-05-01

Since the discovery of the Meissner effect, the superconductor to normal (S-N) phase transition in the presence of a magnetic field is understood to be a first-order phase transformation that is reversible under ideal conditions and obeys the laws of thermodynamics. The reverse (N-S) transition is the Meissner effect. This implies in particular that the kinetic energy of the supercurrent is not dissipated as Joule heat in the process where the superconductor becomes normal and the supercurrent stops. In this paper, we analyze the entropy generation and the momentum transfer between the supercurrent and the body in the S-N transition and the N-S transition as described by the conventional theory of superconductivity. We find that it is not possible to explain the transition in a way that is consistent with the laws of thermodynamics unless the momentum transfer between the supercurrent and the body occurs with zero entropy generation, for which the conventional theory of superconductivity provides no mechanism. Instead, we point out that the alternative theory of hole superconductivity does not encounter such difficulties.

Theoretical analysis of co-solvent effect on the proton transfer reaction of glycine in a water–acetonitrile mixture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasai, Yukako; Yoshida, Norio, E-mail: noriwo@chem.kyushu-univ.jp; Nakano, Haruyuki

2015-05-28

The co-solvent effect on the proton transfer reaction of glycine in a water–acetonitrile mixture was examined using the reference interaction-site model self-consistent field theory. The free energy profiles of the proton transfer reaction of glycine between the carboxyl oxygen and amino nitrogen were computed in a water–acetonitrile mixture solvent at various molar fractions. Two types of reactions, the intramolecular proton transfer and water-mediated proton transfer, were considered. In both types of the reactions, a similar tendency was observed. In the pure water solvent, the zwitterionic form, where the carboxyl oxygen is deprotonated while the amino nitrogen is protonated, is moremore » stable than the neutral form. The reaction free energy is −10.6 kcal mol{sup −1}. On the other hand, in the pure acetonitrile solvent, glycine takes only the neutral form. The reaction free energy from the neutral to zwitterionic form gradually increases with increasing acetonitrile concentration, and in an equally mixed solvent, the zwitterionic and neutral forms are almost isoenergetic, with a difference of only 0.3 kcal mol{sup −1}. The free energy component analysis based on the thermodynamic cycle of the reaction also revealed that the free energy change of the neutral form is insensitive to the change of solvent environment but the zwitterionic form shows drastic changes. In particular, the excess chemical potential, one of the components of the solvation free energy, is dominant and contributes to the stabilization of the zwitterionic form.« less

Density functional theory study of direct and indirect photodegradation mechanisms of sulfameter.

PubMed

Shah, Shaheen; Hao, Ce

2016-10-01

Sulfonamide antibiotics (SAs) have been observed to undergo direct and indirect photodegradation in natural water environments. In this study, the density functional theory (DFT) method was employed for the study of direct and indirect photodegradation mechanisms of sulfameter (SME) with excited triplet states of dissolved organic matter ((3)DOM(*)) and metal ions. SME was adopted as a representative of SAs, and SO2 extrusion product was obtained with different energy paths in the triplet-sensitized photodegradation of the neutral (SME(0)) and the anionic (SME(-)) form of SME. The selected divalent metal ions (Ca(2+), Mg(2+), and Zn(2+)) promoted the triplet-sensitized photodegradation of SME(0) but showed an inhibitory effect in triplet-sensitized photodegradation of SME(-). The triplet-sensitized indirect photodegradation mechanism of SME was investigated with the three DOM analogues, i.e., 2-acetonaphthone (2-AN), fluorenone (FN), and thioxanthone (TN). Results indicated that the selected DOM analogues are highly responsible for the photodegradation via attacking on amine moiety of SME. According to the natural bond orbital (NBO) analysis, the triplet-sensitized photodegradation mechanism of SME(0) with 2-AN, FN, and TN was H-transfer, and the SME(-) was proton plus electron transfer with these DOM analogues.

Triboelectric effect: A new perspective on electron transfer process

NASA Astrophysics Data System (ADS)

Pan, Shuaihang; Zhang, Zhinan

2017-10-01

As interest in the triboelectric effect increases in line with the development of tribo-electrification related devices, the mechanisms involved in this phenomenon require more systematic review from the dual perspectives of developed classical insights and emerging quantum understanding. In this paper, the clear energy changing and transferring process of electrons have been proposed from the quantum point of view as the trigger for the charging initiation process in the triboelectric effect, and the phonon modes on the friction surfaces are believed to hold great importance as one of the main driving forces. Compatible with Maxwell Displacement Current theory, the complete consideration for charging steady state, i.e., the competition mechanisms between the breakdown process and the continuously charging process, and the balance mechanisms of phonon-electron interaction, built voltage, and induced polarization, are illustrated. In brief, the proposed theory emphasizes the fundamental role of electron transferring in tribo-electrical fields. By comparing certain experimental results from the previous studies, the theory is justified.

A Simple Geometric Model for the Marcus Theory of Proton Transfer

ERIC Educational Resources Information Center

McLennan, Duncan J.

1976-01-01

Uses the intersecting parabola model to derive an equation that relates the observed free energy of activation for a slow proton transfer to the overall thermodynamic free energy change in the reaction. (MLH)

On the theory of nonadiabatic bridge-mediated electron transfer. Influence of structural and energetic disorder

NASA Astrophysics Data System (ADS)

Bade, L.; Petrov, E. G.; May, V.

2003-10-01

Effects of structural and energetic disorder on nonadiabatic electron transfer (ET) reactions are discussed theoretically. To account for the sequential as well as the superexchange mechanism of ET our recent approach is used presented in J. Phys. Chem. A 105, 10176 (2001). The overall charge motion is characterized by the numerical solution of rate equations for the electronic state populations and an averaging with respect to the disorder configurations. Introducing a single effective transfer rate which can be deduced from the experiment the dependence of this rate is discussed on the geometry of the ET system as well as on the disorder model. The theory is applied to donor acceptor complexes connected by oligomers of the amino acid proline. In particular, a pronounced dependence is found of the effective transfer rate on disorder with respect to the reorganization energy.

Transfer Entropy and Transient Limits of Computation

PubMed Central

Prokopenko, Mikhail; Lizier, Joseph T.

2014-01-01

Transfer entropy is a recently introduced information-theoretic measure quantifying directed statistical coherence between spatiotemporal processes, and is widely used in diverse fields ranging from finance to neuroscience. However, its relationships to fundamental limits of computation, such as Landauer's limit, remain unknown. Here we show that in order to increase transfer entropy (predictability) by one bit, heat flow must match or exceed Landauer's limit. Importantly, we generalise Landauer's limit to bi-directional information dynamics for non-equilibrium processes, revealing that the limit applies to prediction, in addition to retrodiction (information erasure). Furthermore, the results are related to negentropy, and to Bremermann's limit and the Bekenstein bound, producing, perhaps surprisingly, lower bounds on the computational deceleration and information loss incurred during an increase in predictability about the process. The identified relationships set new computational limits in terms of fundamental physical quantities, and establish transfer entropy as a central measure connecting information theory, thermodynamics and theory of computation. PMID:24953547

Transfer of Recalibration from Audition to Touch: Modality Independence as a Special Case of Anatomical Independence

ERIC Educational Resources Information Center

Wagman, Jeffrey B.; Abney, Drew H.

2012-01-01

An important step in developing a theory of calibration is establishing what it is that participants become calibrated to as a result of feedback. Three experiments used a transfer of calibration paradigm to investigate this issue. In particular, these experiments investigated whether recalibration of perception of length transferred from audition…

Knowledge Transfer and Capacity for Dissemination: A Review and Proposals for Further Research on Academic Knowledge Transfer

ERIC Educational Resources Information Center

Kuiken, Janna; van der Sijde, Peter

2011-01-01

The process of knowledge transfer has been extensively studied in the context of a variety of theoretical considerations. In this paper the authors adopt a communication theory perspective and focus on capacity for dissemination. Many studies assume that universities are able to disseminate and commercialize their knowledge (and technology).…

Effects of Transference Work in the Context of Therapeutic Alliance and Quality of Object Relations

ERIC Educational Resources Information Center

Hoglend, Per; Hersoug, Anne Grete; Bogwald, Kjell-Petter; Amlo, Svein; Marble, Alice; Sorbye, Oystein; Rossberg, Jan Ivar; Ulberg, Randi; Gabbard, Glen O.; Crits-Christoph, Paul

2011-01-01

Objective: Transference interpretation is considered as a core active ingredient in dynamic psychotherapy. In common clinical theory, it is maintained that more mature relationships, as well as a strong therapeutic alliance, may be prerequisites for successful transference work. In this study, the interaction between quality of object relations,…

Transfer over Time: Stories about Transfer Years after Training

ERIC Educational Resources Information Center

Yelon, Stephen L.; Ford, J. Kevin; Golden, Simon

2013-01-01

The purpose of this qualitative study is to form a grounded theory of the process of long-term transfer. Eight physicians were interviewed to discover if, years later, they had used what they were taught in a faculty development training program. We found that these autonomous professionals continued to apply the teaching ideas they learned. Each,…

Nonlocal Quantum Information Transfer Without Superluminal Signalling and Communication

NASA Astrophysics Data System (ADS)

Walleczek, Jan; Grössing, Gerhard

2016-09-01

It is a frequent assumption that—via superluminal information transfers—superluminal signals capable of enabling communication are necessarily exchanged in any quantum theory that posits hidden superluminal influences. However, does the presence of hidden superluminal influences automatically imply superluminal signalling and communication? The non-signalling theorem mediates the apparent conflict between quantum mechanics and the theory of special relativity. However, as a `no-go' theorem there exist two opposing interpretations of the non-signalling constraint: foundational and operational. Concerning Bell's theorem, we argue that Bell employed both interpretations, and that he finally adopted the operational position which is associated often with ontological quantum theory, e.g., de Broglie-Bohm theory. This position we refer to as "effective non-signalling". By contrast, associated with orthodox quantum mechanics is the foundational position referred to here as "axiomatic non-signalling". In search of a decisive communication-theoretic criterion for differentiating between "axiomatic" and "effective" non-signalling, we employ the operational framework offered by Shannon's mathematical theory of communication, whereby we distinguish between Shannon signals and non-Shannon signals. We find that an effective non-signalling theorem represents two sub-theorems: (1) Non-transfer-control (NTC) theorem, and (2) Non-signification-control (NSC) theorem. Employing NTC and NSC theorems, we report that effective, instead of axiomatic, non-signalling is entirely sufficient for prohibiting nonlocal communication. Effective non-signalling prevents the instantaneous, i.e., superluminal, transfer of message-encoded information through the controlled use—by a sender-receiver pair —of informationally-correlated detection events, e.g., in EPR-type experiments. An effective non-signalling theorem allows for nonlocal quantum information transfer yet—at the same time—effectively denies superluminal signalling and communication.

Childhood obesity in transition zones: an analysis using structuration theory.

PubMed

Chan, Christine; Deave, Toity; Greenhalgh, Trisha

2010-07-01

Childhood obesity is particularly prevalent in areas that have seen rapid economic growth, urbanisation, cultural transition, and commodification of food systems. Structuration theory may illuminate the interaction between population and individual-level causes of obesity. We conducted in-depth ethnographies of six overweight/obese and four non-overweight preschool children in Hong Kong, each followed for 12-18 months. Analysis was informed by Stones' strong structuration theory. Risk factors played out differently for different children as social structures were enacted at the level of family and preschool. The network of caregiving roles and relationships around the overweight/obese child was typically weak and disjointed, and the primary caregiver appeared confused by mixed messages about what is normal, expected and legitimate behaviour. In particular, external social structures created pressure to shift childcare routines from the logic of nurturing to the logic of consumption. Our findings suggest that threats to what Giddens called ontological security in the primary caregiver may underpin the poor parenting, family stress and weak mealtime routines that mediate the relationship between an obesogenic environment and the development of obesity in a particular child. This preliminary study offers a potentially transferable approach for studying emerging epidemics of diseases of modernity in transition societies.

Investigating synoptic-scale monsoonal disturbances in an idealized moist model

NASA Astrophysics Data System (ADS)

Clark, S.; Ming, Y.

2017-12-01

Recent studies have highlighted the potential utility of a theory for a "moisture-dynamical" instability in explaining the time and spatial scales of intra-seasonal variability associated with the Indian summer monsoon. These studies suggest that a localized region in the subtropics with mean low-level westerly winds and mean temperature increasing poleward will allow the formation of westward propagating precipitation anomalies associated with moist Rossby-like waves. Here we test this theory in an idealized moist model with realistic radiative transfer by inducing a local poleward-increasing temperature gradient by placing a continent with simplified hydrology in the subtropics. We experiment with different treatments of land-surface hydrology, ranging from the extreme (treating land as having the same heat capacity as the slab ocean used in the model, and turning off evaporation completely over land) to the more realistic (bucket hydrology, with a decreased heat capacity over land), and different continental shapes, ranging from a zonally-symmetric continent, to Earth-like continental geometry. Precipitation rates produced by the simulations are analyzed using space-time spectral analysis, and connected to variability in the winds through regression analysis. The observed behavior is discussed with respect to predictions from the theory.

On the relationships of gas transfer velocity with turbulent kinetic energy dissipation rate and wind waves

NASA Astrophysics Data System (ADS)

Zhao, D.

2012-12-01

The exchange of carbon dioxide across the air-sea interface is an important component of the atmospheric CO2 budget. Understanding how future changes in climate will affect oceanic uptake and releaser CO2 requires accurate estimation of air-sea CO2 flux. This flux is typically expressed as the product of gas transfer velocity, CO2 partial pressure difference in seawater and air, and the CO2 solubility. As the key parameter, gas transfer velocity has long been known to be controlled by the near-surface turbulence in water, which is affected by many factors, such as wind forcing, ocean waves, water-side convection and rainfall. Although the wind forcing is believed as the major factor dominating the near-surface turbulence, many studies have shown that the wind waves and their breaking would greatly enhance turbulence compared with the classical solid wall theory. Gas transfer velocity has been parameterized in terms of wind speed, turbulent kinetic energy dissipation rate, and wave parameters on the basis of observational data or theoretical analysis. However, great discrepancies, as large as one order, exist among these formulas. In this study, we will systematically analyze the differences of gas transfer velocity proposed so far, and try to find the reason that leads to their uncertainties. Finally, a new formula for gas transfer velocity will be given in terms of wind speed and wind wave parameter.

Convective Heat Transfer in the Reusable Solid Rocket Motor of the Space Transportation System

NASA Technical Reports Server (NTRS)

Ahmad, Rashid A.; Cash, Stephen F. (Technical Monitor)

2002-01-01

This simulation involved a two-dimensional axisymmetric model of a full motor initial grain of the Reusable Solid Rocket Motor (RSRM) of the Space Transportation System (STS). It was conducted with CFD (computational fluid dynamics) commercial code FLUENT. This analysis was performed to: a) maintain continuity with most related previous analyses, b) serve as a non-vectored baseline for any three-dimensional vectored nozzles, c) provide a relatively simple application and checkout for various CFD solution schemes, grid sensitivity studies, turbulence modeling and heat transfer, and d) calculate nozzle convective heat transfer coefficients. The accuracy of the present results and the selection of the numerical schemes and turbulence models were based on matching the rocket ballistic predictions of mass flow rate, head end pressure, vacuum thrust and specific impulse, and measured chamber pressure drop. Matching these ballistic predictions was found to be good. This study was limited to convective heat transfer and the results compared favorably with existing theory. On the other hand, qualitative comparison with backed-out data of the ratio of the convective heat transfer coefficient to the specific heat at constant pressure was made in a relative manner. This backed-out data was devised to match nozzle erosion that was a result of heat transfer (convective, radiative and conductive), chemical (transpirating), and mechanical (shear and particle impingement forces) effects combined.

Modeling lidar waveforms with time-dependent stochastic radiative transfer theory for remote estimations of forest structure

NASA Astrophysics Data System (ADS)

Kotchenova, Svetlana Y.; Shabanov, Nikolay V.; Knyazikhin, Yuri; Davis, Anthony B.; Dubayah, Ralph; Myneni, Ranga B.

2003-08-01

Large footprint waveform-recording laser altimeters (lidars) have demonstrated a potential for accurate remote sensing of forest biomass and structure, important for regional and global climate studies. Currently, radiative transfer analyses of lidar data are based on the simplifying assumption that only single scattering contributes to the return signal, which may lead to errors in the modeling of the lower portions of recorded waveforms in the near-infrared spectrum. In this study we apply time-dependent stochastic radiative transfer (RT) theory to model the propagation of lidar pulses through forest canopies. A time-dependent stochastic RT equation is formulated and solved numerically. Such an approach describes multiple scattering events, allows for realistic representation of forest structure including foliage clumping and gaps, simulates off-nadir and multiangular observations, and has the potential to provide better approximations of return waveforms. The model was tested with field data from two conifer forest stands (southern old jack pine and southern old black spruce) in central Canada and two closed canopy deciduous forest stands (with overstory dominated by tulip poplar) in eastern Maryland. Model-simulated signals were compared with waveforms recorded by the Scanning Lidar Imager of Canopies by Echo Recovery (SLICER) over these regions. Model simulations show good agreement with SLICER signals having a slow decay of the waveform. The analysis of the effects of multiple scattering shows that multiply scattered photons magnify the amplitude of the reflected signal, especially that originating from the lower portions of the canopy.

Electronic origin of the dependence of hydrogen bond strengths on nearest-neighbor and next-nearest-neighbor hydrogen bonds in polyhedral water clusters (H 2 O) n , n = 8, 20 and 24

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iwata, Suehiro; Akase, Dai; Aida, Misako

2016-01-01

The relative stability and the characteristics of the hydrogen bond networks in the cubic cages of (H2O)8, dodecahedral cages of (H2O)20,and tetrakaidodecahedral cages of (H2O)24 are studied. The charge-transfer and dispersion interaction terms of every pair of the hydrogen bonds are evaluated by using the perturbation theory based on the locally-projected molecular orbital (LPMO PT). Every water molecule and every hydrogen-bonded pair in polyhedral clusters are classified by the types of the adjacent molecules and hydrogen bonds. The relative binding energies among the polyhedral clusters are grouped by these classifications. The necessary condition for the stable conformers and the rulesmore » of the ordering of the relative stability among the isomers are derived from the analysis. The O–O distances and the pair-wise charge-transfer terms are dependent not only on the types of the hydrogen donor and acceptor waters but also on the types of the adjacent waters. This dependence is analyzed with Mulliken’s charge-transfer theory. The work is partially supported by the Grant-in-Aid for Science Research of JSPS (SI, DA, MA). SSX was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Battelle operates the Pacific Northwest National Laboratory for the US Department of Energy.« less

Global stabilization analysis of inertial memristive recurrent neural networks with discrete and distributed delays.

PubMed

Wang, Leimin; Zeng, Zhigang; Ge, Ming-Feng; Hu, Junhao

2018-05-02

This paper deals with the stabilization problem of memristive recurrent neural networks with inertial items, discrete delays, bounded and unbounded distributed delays. First, for inertial memristive recurrent neural networks (IMRNNs) with second-order derivatives of states, an appropriate variable substitution method is invoked to transfer IMRNNs into a first-order differential form. Then, based on nonsmooth analysis theory, several algebraic criteria are established for the global stabilizability of IMRNNs under proposed feedback control, where the cases with both bounded and unbounded distributed delays are successfully addressed. Finally, the theoretical results are illustrated via the numerical simulations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using information theory to assess the communicative capacity of circulating microRNA.

PubMed

Finn, Nnenna A; Searles, Charles D

2013-10-11

The discovery of extracellular microRNAs (miRNAs) and their transport modalities (i.e., microparticles, exosomes, proteins and lipoproteins) has sparked theories regarding their role in intercellular communication. Here, we assessed the information transfer capacity of different miRNA transport modalities in human serum by utilizing basic principles of information theory. Zipf Statistics were calculated for each of the miRNA transport modalities identified in human serum. Our analyses revealed that miRNA-mediated information transfer is redundant, as evidenced by negative Zipf's Statistics with magnitudes greater than one. In healthy subjects, the potential communicative capacity of miRNA in complex with circulating proteins was significantly lower than that of miRNA encapsulated in circulating microparticles and exosomes. Moreover, the presence of coronary heart disease significantly lowered the communicative capacity of all circulating miRNA transport modalities. To assess the internal organization of circulating miRNA signals, Shannon's zero- and first-order entropies were calculated. Microparticles (MPs) exhibited the lowest Shannon entropic slope, indicating a relatively high capacity for information transfer. Furthermore, compared to the other miRNA transport modalities, MPs appeared to be the most efficient at transferring miRNA to cultured endothelial cells. Taken together, these findings suggest that although all transport modalities have the capacity for miRNA-based information transfer, MPs may be the simplest and most robust way to achieve miRNA-based signal transduction in sera. This study presents a novel method for analyzing the quantitative capacity of miRNA-mediated information transfer while providing insight into the communicative characteristics of distinct circulating miRNA transport modalities. Published by Elsevier Inc.

Predicting Accurate Electronic Excitation Transfer Rates via Marcus Theory with Boys or Edmiston-Ruedenberg Localized Diabatization †

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subotnik, Joseph E.; Vura-Weis, Josh; Sodt, Alex J.

We model the triplet-triplet energy-transfer experiments from the Closs group [Closs, G. L.; et al. J. Am. Chem. Soc. 1988, 110, 2652.] using a combination of Marcus theory and either Boys or Edmiston-Ruedenberg localized diabatization, and we show that relative and absolute rates of electronic excitation transfer may be computed successfully. For the case where both the donor and acceptor occupy equatorial positions on a rigid cyclohexane bridge, we find βcalc = 2.8 per C-C bond, compared with the experimental value βexp = 2.6. This work highlights the power of using localized diabatization methods as a tool for modeling nonequilibriummore » processes.« less

Predicting Accurate Electronic Excitation Transfer Rates via Marcus Theory with Boys or Edmiston-Ruedenberg Localized Diabatization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subotnik, Joseph E.; Vura-Weis, Josh; Sodt, Alex J.

We model the triplet-triplet energy-transfer experiments from the Closs group [Closs, G. L.; et al. J. Am. Chem. Soc. 1988, 110, 2652.] using a combination of Marcus theory and either Boys or Edmiston-Ruedenberg localized diabatization, and we show that relative and absolute rates of electronic excitation transfer may be computed successfully. For the case where both the donor and acceptor occupy equatorial positions on a rigid cyclohexane bridge, we find β calc = 2.8 per C-C bond, compared with the experimental value β exp = 2.6. This work highlights the power of using localized diabatization methods as a tool formore » modeling nonequilibrium processes.« less

Theory of atomistic simulation of spin-transfer torque in nanomagnets

NASA Astrophysics Data System (ADS)

Tay, Tiamhock; Sham, L. J.

2013-05-01

In spin-transfer torque (STT) for technological applications, the miniaturization of the magnet may reach the stage of requiring a fully quantum-mechanical treatment. We present an STT theory which uses the quantum macrospin ground and excited (magnon) states of the nanomagnet. This allows for energy and angular momentum exchanges between the current electron and the nano-magnet. We develop a method of magnetization dynamics simulation which captures the heating effect on the magnet by the spin-polarized current and the temperature dependence in STT. We also discuss the magnetostatics effect on magnon scattering for ferromagnetic relaxation in a thin film. Our work demonstrates a realistic step towards simulation of quantum spin-transfer torque physics in nanoscale magnets.

Organic Solar Cells: Understanding the Role of Förster Resonance Energy Transfer

PubMed Central

Feron, Krishna; Belcher, Warwick J.; Fell, Christopher J.; Dastoor, Paul C.

2012-01-01

Organic solar cells have the potential to become a low-cost sustainable energy source. Understanding the photoconversion mechanism is key to the design of efficient organic solar cells. In this review, we discuss the processes involved in the photo-electron conversion mechanism, which may be subdivided into exciton harvesting, exciton transport, exciton dissociation, charge transport and extraction stages. In particular, we focus on the role of energy transfer as described by Förster resonance energy transfer (FRET) theory in the photoconversion mechanism. FRET plays a major role in exciton transport, harvesting and dissociation. The spectral absorption range of organic solar cells may be extended using sensitizers that efficiently transfer absorbed energy to the photoactive materials. The limitations of Förster theory to accurately calculate energy transfer rates are discussed. Energy transfer is the first step of an efficient two-step exciton dissociation process and may also be used to preferentially transport excitons to the heterointerface, where efficient exciton dissociation may occur. However, FRET also competes with charge transfer at the heterointerface turning it in a potential loss mechanism. An energy cascade comprising both energy transfer and charge transfer may aid in separating charges and is briefly discussed. Considering the extent to which the photo-electron conversion efficiency is governed by energy transfer, optimisation of this process offers the prospect of improved organic photovoltaic performance and thus aids in realising the potential of organic solar cells. PMID:23235328

Towards a theory of stochastic vorticity-augmentation. [tornado model

NASA Technical Reports Server (NTRS)

Liu, V. C.

1977-01-01

A new hypothesis to account for the formation of tornadoes is presented. An elementary one-dimensional theory is formulated for vorticity transfer between an ambient sheared wind and a transverse penetrating jet. The theory points out the relevant quantities to be determined in describing the present stochastic mode of vorticity augmentation.

Urban Adolescents' Exercise Intentions and Behaviors: An Exploratory Study of a Trans-Contextual Model

ERIC Educational Resources Information Center

Shen, Bo; McCaughtry, Nate; Martin, Jeffrey

2008-01-01

Using a multi-theory approach, the current study was designed to identify gender differences in the psychological mechanisms by which urban adolescents' motivation in physical education transfers into their leisure-time activities. The theoretical frameworks of Self-Determination Theory and the Theory of Planned Behavior were integrated to…

Transfer and capture into distant retrograde orbits

NASA Astrophysics Data System (ADS)

Scott, Christopher J.

This dissertation utilizes theory and techniques derived from the fields of dynamical systems theory, astrodyanamics, celestial mechanics, and fluid mechanics to analyze the phenomenon of satellite capture and interrelated spacecraft transfers in restricted three-body systems. The results extend current knowledge and understanding of capture dynamics in the context of astrodynamics and celestial mechanics. Manifold theory, fast Lyapunov indicator maps, and the classification of space structure facilitate an analysis of the transport of objects from the chaotic reaches of the solar system to the distant retrograde region in the sun-Jupiter system. Apart from past studies this dissertation considers the role of the complex lobe structure encompassing stable regions in the circular restricted three-body problem. These structures are shown to be responsible for the phenomenon of sticky orbits and the transport of objects among stable regions. Since permanent capture can only be achieved through a change in energy, fast Lyapunov indicator maps and other methods which reveal the structure of the conservative system are used to discern capture regions and identify the underpinnings of the dynamics. Fast Lyapunov indicator maps provide an accurate classification of orbits of permanent capture and escape, yet monopolize computational resources. In anticipation of a fully three-dimensional analysis in the dissipative system a new mapping parameter is introduced based on energy degradation and averaged velocity. Although the study specifically addresses the sun-Jupiter system, the qualitative results and devised techniques can be applied throughout the solar system and to capture about extrasolar planets. Extending the analysis beyond the exterior of the stable distant retrograde region fosters the construction of transfer orbits from low-Earth orbit to a stable periodic orbit at the center of the stable distant retrograde region. Key to this analysis is the predictability of collision orbits within the highly chaotic region commonly recognized as a saddle point on the energy manifold. The pragmatic techniques derived from this analysis solve a number of complications apparent in the literature. Notably a reliable methodology for the construction of an arbitrary number of transfer orbits circumvents the requirement of computing specialized periodic orbits or extensive numerical sampling of the phase space. The procedure provides a complete description of the design space accessing a wide range of distant retrograde orbits sizes, insertion points, and parking orbit altitudes in an automated manner. The transfers are studied in a similar fashion to periodic orbits unveiling the intimate relationship among design parameters and phase space structure. An arbitrary number of Earth return periodic orbits can be generated as a by-product. These orbits may be useful for spacecraft that must make a number of passes near the second primary without a reduction in energy. Further analysis of the lobe dynamics and a modification of the transfers to the center of the stable region yields sets of single impulse transfers to sticky distant retrograde orbits. It is shown that the evolution of the phase space structures with energy corresponds to the variation of capture time and target size. Capture phenomenon is related to the stability characteristics of the unstable periodic orbit and the geometry of the corresponding homoclinic tangle at various energies. Future spacecraft with little or no propulsive means may take advantage of these natural trajectories for operations in the region. Temporary capture along a sticky orbit may come before incremental stabilization of the spacecraft by way of a series of small impulsive or a low continuous thrust maneuvers. The requirements of small stabilization maneuver are calculated and compared to a direct transfer to the center of stable region. This mission design may be desirable as any failure in the classic set of maneuvers to the center of the stable region could result in the loss of the spacecraft. A simple low-thrust stabilization method is analyzed in a similar manner to nebular drag. It is shown that stabilization maneuvers initiated within the sticky region can be achieved via a simple control law. Moreover, the sticky region can be used as a staging point for both spiral-in and spiral-out maneuvers. For the spiral in maneuver this negates a large, initial maneuver required to reach the center of the stable region. It is shown that large lengths of orbits exist within the sticky regions which reliably lead to permanent capture. In the case of spiral-out the spacecraft is transported to a highly energetic yet stable orbit about the second primary. From here a small maneuver could allow the spacecraft to access other regions of the solar system.

Mechanical characterization and structural analysis of recycled fiber-reinforced-polymer resin-transfer-molded beams

NASA Astrophysics Data System (ADS)

Tan, Eugene Wie Loon

1999-09-01

The present investigation was focussed on the mechanical characterization and structural analysis of resin-transfer-molded beams containing recycled fiber-reinforced polymers. The beams were structurally reinforced with continuous unidirectional glass fibers. The reinforcing filler materials consisted entirely of recycled fiber-reinforced polymer wastes (trim and overspray). The principal resin was a 100-percent dicyclo-pentadiene unsaturated polyester specially formulated with very low viscosity for resin transfer molding. Variations of the resin transfer molding technique were employed to produce specimens for material characterization. The basic materials that constituted the structural beams, continuous-glass-fiber-reinforced, recycled-trim-filled and recycled-overspray-filled unsaturated polyesters, were fully characterized in axial and transverse compression and tension, and inplane and interlaminar shear, to ascertain their strengths, ultimate strains, elastic moduli and Poisson's ratios. Experimentally determined mechanical properties of the recycled-trim-filled and recycled-overspray-filled materials from the present investigation were superior to those of unsaturated polyester polymer concretes and Portland cement concretes. Mechanical testing and finite element analyses of flexure (1 x 1 x 20 in) and beam (2 x 4 x 40 in) specimens were conducted. These structurally-reinforced specimens were tested and analyzed in four-point, third-point flexure to determine their ultimate loads, maximum fiber stresses and mid-span deflections. The experimentally determined load capacities of these specimens were compared to those of equivalent steel-reinforced Portland cement concrete beams computed using reinforced concrete theory. Mechanics of materials beam theory was utilized to predict the ultimate loads and mid-span deflections of the flexure and beam specimens. However, these predictions proved to be severely inadequate. Finite element (fracture propagation) analyses of the flexure and beam specimens were also performed. These progressive failure analyses more closely approximated flexural behavior under actual testing conditions by reducing the elastic moduli of elements that were considered to have partially or totally failed. Individual element failures were predicted using the maximum stress, Tsai-Hill and Tsai-Wu failure criteria. Excellent predictions of flexural behavior were attributed to the progressive failure analyses combined with an appropriate failure criterion, and the reliable input material properties that were generated.

Guide to dowel load transfer systems for jointed concrete roadway pavements.

DOT National Transportation Integrated Search

2011-09-01

This guide provides a summary of the factors and design theories that should be considered when designing : dowel load transfer systems for concrete pavement systems (including dowel basket design and fabrication) and : presents recommendations for w...

An estimator-predictor approach to PLL loop filter design

NASA Technical Reports Server (NTRS)

Statman, J. I.; Hurd, W. J.

1986-01-01

An approach to the design of digital phase locked loops (DPLLs), using estimation theory concepts in the selection of a loop filter, is presented. The key concept is that the DPLL closed-loop transfer function is decomposed into an estimator and a predictor. The estimator provides recursive estimates of phase, frequency, and higher order derivatives, while the predictor compensates for the transport lag inherent in the loop. This decomposition results in a straightforward loop filter design procedure, enabling use of techniques from optimal and sub-optimal estimation theory. A design example for a particular choice of estimator is presented, followed by analysis of the associated bandwidth, gain margin, and steady state errors caused by unmodeled dynamics. This approach is under consideration for the design of the Deep Space Network (DSN) Advanced Receiver Carrier DPLL.

The cognitive therapy of depression rests on substantial theoretical, empirical and clinical foundations: a reply to Dr Gipps

PubMed Central

Moorey, Stirling

2017-01-01

Dr Gipps claims that the cognitive therapy for depression rests on a mistake. But his anachronistic analysis of Beck's early research from the perspective of current psychoanalytic theory misses the point. The value of the research was not that it disproved psychoanalytic theory, but that it generated a model of depression that has revolutionised psychotherapy research. Psychoanalysts are belatedly adopting research methods that Beck pioneered half a century ago. The cognitive model of depression has explanatory power for both maintenance and vulnerability and has substantial research underpinning it. Cognitive therapy for depression has a larger body of evidence for its efficacy and relapse prevention effect than any other psychotherapy. Transference-focused approaches to depression have yet to establish themselves in the same way. PMID:29018552

Toward an integrative theory of training motivation: a meta-analytic path analysis of 20 years of research.

PubMed

Colquitt, J A; LePine, J A; Noe, R A

2000-10-01

This article meta-analytically summarizes the literature on training motivation, its antecedents, and its relationships with training outcomes such as declarative knowledge, skill acquisition, and transfer. Significant predictors of training motivation and outcomes included individual characteristics (e.g., locus of control, conscientiousness, anxiety, age, cognitive ability, self-efficacy, valence, job involvement) and situational characteristics (e.g., climate). Moreover, training motivation explained incremental variance in training outcomes beyond the effects of cognitive ability. Meta-analytic path analyses further showed that the effects of personality, climate, and age on training outcomes were only partially mediated by self-efficacy, valence, and job involvement. These findings are discussed in terms of their practical significance and their implications for an integrative theory of training motivation.

Some Consequences of an Analysis of the Kelvin-Clausius Entropy Formulation Based on Traditional Axiomatics

NASA Astrophysics Data System (ADS)

Jesudason, Christopher G.

2003-09-01

Recently, there have appeared interesting correctives or challenges [Entropy 1999, 1, 111-147] to the Second law formulations, especially in the interpretation of the Clausius equivalent transformations, closely related in area to extensions of the Clausius principle to irreversible processes [Chem. Phys. Lett. 1988, 143(1), 65-70]. Since the traditional formulations are central to science, a brief analysis of some of these newer theories along traditional lines is attempted, based on well-attested axioms which have formed the basis of equilibrium thermodynamics. It is deduced that the Clausius analysis leading to the law of increasing entropy does not follow from the given axioms but it can be proved that for irreversible transitions, the total entropy change of the system and thermal reservoirs (the "Universe") is not negative, even for the case when the reservoirs are not at the same temperature as the system during heat transfer. On the basis of two new simple theorems and three corollaries derived for the correlation between irreversible and reversible pathways and the traditional axiomatics, it is shown that a sequence of reversible states can never be used to describe a corresponding sequence of irreversible states for at least closed systems, thereby restricting the principle of local equilibrium. It is further shown that some of the newer irreversible entropy forms given exhibit some paradoxical properties relative to the standard axiomatics. It is deduced that any reconciliation between the traditional approach and novel theories lie in creating a well defined set of axioms to which all theoretical developments should attempt to be based on unless proven not be useful, in which case there should be consensus in removing such axioms from theory. Clausius' theory of equivalent transformations do not contradict the traditional understanding of heat- work efficiency. It is concluded that the intuitively derived assumptions over the last two centuries seem to be reasonably well grounded, requiring perhaps some minor elaboration to the concepts of (i) system, (ii) the mechanism of heat transfer, and (iii) the environment, which would be expected to evolve with time in any case. If new generalizations at variance with Clausius' concepts are presented, then these ideas could be expected to require a different axiomatic basis than the one for equilibrium theory, and this difference must be stated at the outset of any new development. So far such empirically self-consistent axiomatic developments are not very much in evidence.

Alternative definitions of the frozen energy in energy decomposition analysis of density functional theory calculations.

PubMed

Horn, Paul R; Head-Gordon, Martin

2016-02-28

In energy decomposition analysis (EDA) of intermolecular interactions calculated via density functional theory, the initial supersystem wavefunction defines the so-called "frozen energy" including contributions such as permanent electrostatics, steric repulsions, and dispersion. This work explores the consequences of the choices that must be made to define the frozen energy. The critical choice is whether the energy should be minimized subject to the constraint of fixed density. Numerical results for Ne2, (H2O)2, BH3-NH3, and ethane dissociation show that there can be a large energy lowering associated with constant density orbital relaxation. By far the most important contribution is constant density inter-fragment relaxation, corresponding to charge transfer (CT). This is unwanted in an EDA that attempts to separate CT effects, but it may be useful in other contexts such as force field development. An algorithm is presented for minimizing single determinant energies at constant density both with and without CT by employing a penalty function that approximately enforces the density constraint.

Numerical verification of composite rods theory on multi-story buildings analysis

NASA Astrophysics Data System (ADS)

El-Din Mansour, Alaa; Filatov, Vladimir; Gandzhuntsev, Michael; Ryasny, Nikita

2018-03-01

In the article, a verification proposal of the composite rods theory on the structural analysis of skeletons for high-rise buildings. A testing design model been formed on which horizontal elements been represented by a multilayer cantilever beam operates on transverse bending on which slabs are connected with a moment-non-transferring connections and a multilayer columns represents the vertical elements. Those connections are sufficiently enough to form a shearing action can be approximated by a certain shear forces function, the thing which significantly reduces the overall static indeterminacy degree of the structural model. A system of differential equations describe the operation mechanism of the multilayer rods that solved using the numerical approach of successive approximations method. The proposed methodology to be used while preliminary calculations for the sake of determining the rigidity characteristics of the structure; are needed. In addition, for a qualitative assessment of the results obtained by other methods when performing calculations with the verification aims.

An analysis of laminar free-convection flow and heat transfer about a flat plate paralled to the direction of the generating body force

NASA Technical Reports Server (NTRS)

Ostrach, Simon

1953-01-01

The free-convection flow and heat transfer (generated by a body force) about a flat plate parallel to the direction of the body force are formally analyzed and the type of flow is found to be dependent on the Grashof number alone. For large Grashof numbers (which are of interest in aeronautics), the flow is of the boundary-layer type and the problem is reduced in a formal manner, which is analogous to Prandtl's forced-flow boundary-layer theory, to the simultaneous solution of two ordinary differential equations subject to the proper boundary conditions. Velocity and temperature distributions for Prandtl numbers of 0.01, 0.72, 0.733, 1, 1, 10, 100, and 1000 are computed, and it is shown that velocities and Nusselt numbers of the order of magnitude of those encountered in forced-convection flows may be obtained in free-convection flows. The theoretical and experimental velocity and temperature distributions are in good agreement. A flow and a heat-transfer parameter, from which the important physical quantities such as shear stress and heat-transfer rate can be computed, are derived as functions of Prandtl number alone.

Incorporation of charge transfer into the explicit polarization fragment method by grand canonical density functional theory.

PubMed

Isegawa, Miho; Gao, Jiali; Truhlar, Donald G

2011-08-28

Molecular fragmentation algorithms provide a powerful approach to extending electronic structure methods to very large systems. Here we present a method for including charge transfer between molecular fragments in the explicit polarization (X-Pol) fragment method for calculating potential energy surfaces. In the conventional X-Pol method, the total charge of each fragment is preserved, and charge transfer between fragments is not allowed. The description of charge transfer is made possible by treating each fragment as an open system with respect to the number of electrons. To achieve this, we applied Mermin's finite temperature method to the X-Pol wave function. In the application of this method to X-Pol, the fragments are open systems that partially equilibrate their number of electrons through a quasithermodynamics electron reservoir. The number of electrons in a given fragment can take a fractional value, and the electrons of each fragment obey the Fermi-Dirac distribution. The equilibrium state for the electrons is determined by electronegativity equalization with conservation of the total number of electrons. The amount of charge transfer is controlled by re-interpreting the temperature parameter in the Fermi-Dirac distribution function as a coupling strength parameter. We determined this coupling parameter so as to reproduce the charge transfer energy obtained by block localized energy decomposition analysis. We apply the new method to ten systems, and we show that it can yield reasonable approximations to potential energy profiles, to charge transfer stabilization energies, and to the direction and amount of charge transferred. © 2011 American Institute of Physics

Incorporation of charge transfer into the explicit polarization fragment method by grand canonical density functional theory

PubMed Central

Isegawa, Miho; Gao, Jiali; Truhlar, Donald G.

2011-01-01

Molecular fragmentation algorithms provide a powerful approach to extending electronic structure methods to very large systems. Here we present a method for including charge transfer between molecular fragments in the explicit polarization (X-Pol) fragment method for calculating potential energy surfaces. In the conventional X-Pol method, the total charge of each fragment is preserved, and charge transfer between fragments is not allowed. The description of charge transfer is made possible by treating each fragment as an open system with respect to the number of electrons. To achieve this, we applied Mermin's finite temperature method to the X-Pol wave function. In the application of this method to X-Pol, the fragments are open systems that partially equilibrate their number of electrons through a quasithermodynamics electron reservoir. The number of electrons in a given fragment can take a fractional value, and the electrons of each fragment obey the Fermi–Dirac distribution. The equilibrium state for the electrons is determined by electronegativity equalization with conservation of the total number of electrons. The amount of charge transfer is controlled by re-interpreting the temperature parameter in the Fermi–Dirac distribution function as a coupling strength parameter. We determined this coupling parameter so as to reproduce the charge transfer energy obtained by block localized energy decomposition analysis. We apply the new method to ten systems, and we show that it can yield reasonable approximations to potential energy profiles, to charge transfer stabilization energies, and to the direction and amount of charge transferred. PMID:21895159

Application of adult attachment theory to group member transference and the group therapy process.

PubMed

Markin, Rayna D; Marmarosh, Cheri

2010-03-01

Although clinical researchers have applied attachment theory to client conceptualization and treatment in individual therapy, few researchers have applied this theory to group therapy. The purpose of this article is to begin to apply theory and research on adult dyadic and group attachment styles to our understanding of group dynamics and processes in adult therapy groups. In particular, we set forth theoretical propositions on how group members' attachment styles affect relationships within the group. Specifically, this article offers some predictions on how identifying group member dyadic and group attachment styles could help leaders predict member transference within the therapy group. Implications of group member attachment for the selection and composition of a group and the different group stages are discussed. Recommendations for group clinicians and researchers are offered. PsycINFO Database Record (c) 2010 APA, all rights reserved

Localization of electrons and excitations

NASA Astrophysics Data System (ADS)

Larsson, Sven

2006-07-01

Electrons, electron holes, or excitations in finite or infinite 'multimer systems' may be localized or delocalized. In the theory of Hush, localization depends on the ratio Δ/ λ ( Δ/2 = coupling; λ = reorganization energy). The latter theory has been extended to the infinite system [S. Larsson, A. Klimkāns, Mol. Cryst. Liq. Cryst. 355 (2000) 217]. The metal/insulator transition often takes place abruptly as a function of Δ/ λ. It is argued that localization in a system with un-filled bands cannot be determined on the basis of Mott-Hubbard U alone, but depends on the number of accessible valence states, reorganization energy λ and coupling Δ (=2t). In fact U = 0 does not necessarily imply delocalization. The analysis here shows that there are many different situations for an insulator to metal transition. Charge transfer in doped NiO is characterized by Ni 2+ - Ni 3+ exchange while charge transfer in pure NiO is characterized by a disproportionation 2Ni 2+ → Ni + + Ni 3+. In spite of the great differences between these two cases, U has been applied without discrimination to both. The relevant localization parameters appear to be Δ and λ in the first case, with only two oxidation states, and U, Δ and λ in the second case with three oxidation states. The analysis is extended to insulator-metal transitions, giant magnetic resistance (GMR) and high Tc superconductivity (SC). λ and Δ can be determined quite accurately in quantum mechanical calculations involving only one and two monomers, respectively.

Intuitive Density Functional Theory-Based Energy Decomposition Analysis for Protein-Ligand Interactions.

PubMed

Phipps, M J S; Fox, T; Tautermann, C S; Skylaris, C-K

2017-04-11

First-principles quantum mechanical calculations with methods such as density functional theory (DFT) allow the accurate calculation of interaction energies between molecules. These interaction energies can be dissected into chemically relevant components such as electrostatics, polarization, and charge transfer using energy decomposition analysis (EDA) approaches. Typically EDA has been used to study interactions between small molecules; however, it has great potential to be applied to large biomolecular assemblies such as protein-protein and protein-ligand interactions. We present an application of EDA calculations to the study of ligands that bind to the thrombin protein, using the ONETEP program for linear-scaling DFT calculations. Our approach goes beyond simply providing the components of the interaction energy; we are also able to provide visual representations of the changes in density that happen as a result of polarization and charge transfer, thus pinpointing the functional groups between the ligand and protein that participate in each kind of interaction. We also demonstrate with this approach that we can focus on studying parts (fragments) of ligands. The method is relatively insensitive to the protocol that is used to prepare the structures, and the results obtained are therefore robust. This is an application to a real protein drug target of a whole new capability where accurate DFT calculations can produce both energetic and visual descriptors of interactions. These descriptors can be used to provide insights for tailoring interactions, as needed for example in drug design.

Molecular conformational analysis, vibrational spectra, NBO analysis and first hyperpolarizability of (2E)-3-phenylprop-2-enoic anhydride based on density functional theory calculations.

PubMed

Sheena Mary, Y; Raju, K; Panicker, C Yohannan; Al-Saadi, Abdulaziz A; Thiemann, Thies; Van Alsenoy, Christian

2014-07-15

The conformational behavior and structural stability of (2E)-3-phenylprop-2-enoic anhydride were investigated by using density functional theory. Seventeen possible stable conformations of the title compound were determined and verified with their calculated vibrational frequencies being all positive. The optimized molecular structure, vibrational wavenumbers, corresponding vibrational assignments of (2E)-3-phenylprop-2-enoic anhydride have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of normal modes vibrations was done using GAR2PED program. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The calculated first hyperpolarizability of the title compound is 12×10(-30) esu and is 92.31 times that of the standard NLO material urea and the title compound is an attractive object for future studies of nonlinear optical properties. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. Copyright © 2014 Elsevier B.V. All rights reserved.

Transfer of Learning between 2D and 3D Sources during Infancy: Informing Theory and Practice

ERIC Educational Resources Information Center

Barr, Rachel

2010-01-01

The ability to transfer learning across contexts is an adaptive skill that develops rapidly during early childhood. Learning from television is a specific instance of transfer of learning between a two-dimensional (2D) representation and a three-dimensional (3D) object. Understanding the conditions under which young children might accomplish this…

Sulfur K-edge X-ray absorption spectroscopy and density functional theory calculations on monooxo Mo(IV) and bisoxo Mo(VI) bis-dithiolenes: insights into the mechanism of oxo transfer in sulfite oxidase and its relation to the mechanism of DMSO reductase.

PubMed

Ha, Yang; Tenderholt, Adam L; Holm, Richard H; Hedman, Britt; Hodgson, Keith O; Solomon, Edward I

2014-06-25

Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations have been used to determine the electronic structures of two complexes [Mo(IV)O(bdt)2](2-) and [Mo(VI)O2(bdt)2](2-) (bdt = benzene-1,2-dithiolate(2-)) that relate to the reduced and oxidized forms of sulfite oxidase (SO). These are compared with those of previously studied dimethyl sulfoxide reductase (DMSOr) models. DFT calculations supported by the data are extended to evaluate the reaction coordinate for oxo transfer to a phosphite ester substrate. Three possible transition states are found with the one at lowest energy, stabilized by a P-S interaction, in good agreement with experimental kinetics data. Comparison of both oxo transfer reactions shows that in DMSOr, where the oxo is transferred from the substrate to the metal ion, the oxo transfer induces electron transfer, while in SO, where the oxo transfer is from the metal site to the substrate, the electron transfer initiates oxo transfer. This difference in reactivity is related to the difference in frontier molecular orbitals (FMO) of the metal-oxo and substrate-oxo bonds. Finally, these experimentally related calculations are extended to oxo transfer by sulfite oxidase. The presence of only one dithiolene at the enzyme active site selectively activates the equatorial oxo for transfer, and allows facile structural reorganization during turnover.

Beyond the standard two-film theory: Computational fluid dynamics simulations for carbon dioxide capture in a wetted wall column

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chao; Xu, Zhijie; Lai, Canhai

The standard two-film theory (STFT) is a diffusion-based mechanism that can be used to describe gas mass transfer across liquid film. Fundamental assumptions of the STFT impose serious limitations on its ability to predict mass transfer coefficients. To better understand gas absorption across liquid film in practical situations, a multiphase computational fluid dynamics (CFD) model fully equipped with mass transport and chemistry capabilities has been developed for solvent-based carbon dioxide (CO 2) capture to predict the CO 2 mass transfer coefficient in a wetted wall column. The hydrodynamics is modeled using a volume of fluid method, and the diffusive andmore » reactive mass transfer between the two phases is modeled by adopting a one-fluid formulation. We demonstrate that the proposed CFD model can naturally account for the influence of many important factors on the overall mass transfer that cannot be quantitatively explained by the STFT, such as the local variation in fluid velocities and properties, flow instabilities, and complex geometries. The CFD model also can predict the local mass transfer coefficient variation along the column height, which the STFT typically does not consider.« less

Beyond the standard two-film theory: Computational fluid dynamics simulations for carbon dioxide capture in a wetted wall column

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chao; Xu, Zhijie; Lai, Canhai

The standard two-film theory (STFT) is a diffusion-based mechanism that can be used to describe gas mass transfer across liquid film. Fundamental assumptions of the STFT impose serious limitations on its ability to predict mass transfer coefficients. To better understand gas absorption across liquid film in practical situations, a multiphase computational fluid dynamics (CFD) model fully equipped with mass transport and chemistry capabilities has been developed for solvent-based carbon dioxide (CO2) capture to predict the CO2 mass transfer coefficient in a wetted wall column. The hydrodynamics is modeled using a volume of fluid method, and the diffusive and reactive massmore » transfer between the two phases is modeled by adopting a one-fluid formulation. We demonstrate that the proposed CFD model can naturally account for the influence of many important factors on the overall mass transfer that cannot be quantitatively explained by the STFT, such as the local variation in fluid velocities and properties, flow instabilities, and complex geometries. The CFD model also can predict the local mass transfer coefficient variation along the column height, which the STFT typically does not consider.« less

Beyond the standard two-film theory: Computational fluid dynamics simulations for carbon dioxide capture in a wetted wall column

DOE PAGES

Wang, Chao; Xu, Zhijie; Lai, Canhai; ...

2018-03-27

The standard two-film theory (STFT) is a diffusion-based mechanism that can be used to describe gas mass transfer across liquid film. Fundamental assumptions of the STFT impose serious limitations on its ability to predict mass transfer coefficients. To better understand gas absorption across liquid film in practical situations, a multiphase computational fluid dynamics (CFD) model fully equipped with mass transport and chemistry capabilities has been developed for solvent-based carbon dioxide (CO 2) capture to predict the CO 2 mass transfer coefficient in a wetted wall column. The hydrodynamics is modeled using a volume of fluid method, and the diffusive andmore » reactive mass transfer between the two phases is modeled by adopting a one-fluid formulation. We demonstrate that the proposed CFD model can naturally account for the influence of many important factors on the overall mass transfer that cannot be quantitatively explained by the STFT, such as the local variation in fluid velocities and properties, flow instabilities, and complex geometries. The CFD model also can predict the local mass transfer coefficient variation along the column height, which the STFT typically does not consider.« less

Detailed Modeling and Irreversible Transfer Process Analysis of a Multi-Element Thermoelectric Generator System

NASA Astrophysics Data System (ADS)

Xiao, Heng; Gou, Xiaolong; Yang, Suwen

2011-05-01

Thermoelectric (TE) power generation technology, due to its several advantages, is becoming a noteworthy research direction. Many researchers conduct their performance analysis and optimization of TE devices and related applications based on the generalized thermoelectric energy balance equations. These generalized TE equations involve the internal irreversibility of Joule heating inside the thermoelectric device and heat leakage through the thermoelectric couple leg. However, it is assumed that the thermoelectric generator (TEG) is thermally isolated from the surroundings except for the heat flows at the cold and hot junctions. Since the thermoelectric generator is a multi-element device in practice, being composed of many fundamental TE couple legs, the effect of heat transfer between the TE couple leg and the ambient environment is not negligible. In this paper, based on basic theories of thermoelectric power generation and thermal science, detailed modeling of a thermoelectric generator taking account of the phenomenon of energy loss from the TE couple leg is reported. The revised generalized thermoelectric energy balance equations considering the effect of heat transfer between the TE couple leg and the ambient environment have been derived. Furthermore, characteristics of a multi-element thermoelectric generator with irreversibility have been investigated on the basis of the new derived TE equations. In the present investigation, second-law-based thermodynamic analysis (exergy analysis) has been applied to the irreversible heat transfer process in particular. It is found that the existence of the irreversible heat convection process causes a large loss of heat exergy in the TEG system, and using thermoelectric generators for low-grade waste heat recovery has promising potential. The results of irreversibility analysis, especially irreversible effects on generator system performance, based on the system model established in detail have guiding significance for the development and application of thermoelectric generators, particularly for the design and optimization of TE modules.

Design and analysis of composite structures with stress concentrations

NASA Technical Reports Server (NTRS)

Garbo, S. P.

1983-01-01

An overview of an analytic procedure which can be used to provide comprehensive stress and strength analysis of composite structures with stress concentrations is given. The methodology provides designer/analysts with a user-oriented procedure which, within acceptable engineering accuracy, accounts for the effects of a wide range of application design variables. The procedure permits the strength of arbitrary laminate constructions under general bearing/bypass load conditions to be predicted with only unnotched unidirectional strength and stiffness input data required. Included is a brief discussion of the relevancy of this analysis to the design of primary aircraft structure; an overview of the analytic procedure with theory/test correlations; and an example of the use and interaction of this strength analysis relative to the design of high-load transfer bolted composite joints.

Unified theory of the exciplex formation/dissipation.

PubMed

Khokhlova, Svetlana S; Burshtein, Anatoly I

2010-11-04

The natural extension and reformulation of the unified theory (UT) proposed here makes it integro-differential and capable of describing the distant quenching of excitation by electron transfer, accompanied with contact but reversible exciplex formation. The numerical solution of the new UT equations allows specifying the kinetics of the fluorescence quenching and exciplex association/dissociation as well as those reactions' quantum yields. It was demonstrated that the distant electron transfer in either the normal or inverted Marcus regions screens the contact reaction of exciplex formation, especially at slow diffusion.

Quantum approach of mesoscopic magnet dynamics with spin transfer torque

NASA Astrophysics Data System (ADS)

Wang, Yong; Sham, L. J.

2013-05-01

We present a theory of magnetization dynamics driven by spin-polarized current in terms of the quantum master equation. In the spin coherent state representation, the master equation becomes a Fokker-Planck equation, which naturally includes the spin transfer and quantum fluctuation. The current electron scattering state is correlated to the magnet quantum states, giving rise to quantum correction to the electron transport properties in the usual semiclassical theory. In the large-spin limit, the magnetization dynamics is shown to obey the Hamilton-Jacobi equation or the Hamiltonian canonical equations.

Modeling multi-layer effects in passive microwave remote sensing of dry snow using Dense Media Radiative Transfer Theory (DMRT) based on quasicrystalline approximation

USGS Publications Warehouse

Liang, D.; Xu, X.; Tsang, L.; Andreadis, K.M.; Josberger, E.G.

2008-01-01

The Dense Media Radiative Transfer theory (DMRT) of Quasicrystalline Approximation of Mie scattering by sticky particles is used to study the multiple scattering effects in layered snow in microwave remote sensing. Results are illustrated for various snow profile characteristics. Polarization differences and frequency dependences of multilayer snow model are significantly different from that of the single-layer snow model. Comparisons are also made with CLPX data using snow parameters as given by the VIC model. ?? 2007 IEEE.

DFT investigation on the electronic structure of Faujasite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popeneciu, Horea; Calborean, Adrian; Tudoran, Cristian

2013-11-13

We report here first-principle pseudopotential DFT calculations to investigate relevant aspects of the electronic structure of zeolites based FAU. Fundamental molecular issues of the band-gap and electronic population analysis were reviewed under GGA/RPBE level of theory, corroborated with a DZP basis set and Troullier-Martins norm conserving pseudo-potentials. The atom-projected density of states and the analysis of HOMO-LUMO frontier orbitals at Gamma point were performed. Their electronic transfers are discussed through the alignment and relative positions of orbitals in order to determine the way that the molecule interacts with adsorbed molecules and other practical applications. Mulliken population analysis was employed formore » describing atomic charge distribution in the chosen systems.« less

Multiscale strain analysis of tissue equivalents using a custom-designed biaxial testing device.

PubMed

Bell, B J; Nauman, E; Voytik-Harbin, S L

2012-03-21

Mechanical signals transferred between a cell and its extracellular matrix play an important role in regulating fundamental cell behavior. To further define the complex mechanical interactions between cells and matrix from a multiscale perspective, a biaxial testing device was designed and built. Finite element analysis was used to optimize the cruciform specimen geometry so that stresses within the central region were concentrated and homogenous while minimizing shear and grip effects. This system was used to apply an equibiaxial loading and unloading regimen to fibroblast-seeded tissue equivalents. Digital image correlation and spot tracking were used to calculate three-dimensional strains and associated strain transfer ratios at macro (construct), meso, matrix (collagen fibril), cell (mitochondria), and nuclear levels. At meso and matrix levels, strains in the 1- and 2-direction were statistically similar throughout the loading-unloading cycle. Interestingly, a significant amplification of cellular and nuclear strains was observed in the direction perpendicular to the cell axis. Findings indicate that strain transfer is dependent upon local anisotropies generated by the cell-matrix force balance. Such multiscale approaches to tissue mechanics will assist in advancement of modern biomechanical theories as well as development and optimization of preconditioning regimens for functional engineered tissue constructs. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Mean-Eddy-Turbulence Interaction through Canonical Transfer Analysis: Theory and Application to the Kuroshio Extension Energetics Study

NASA Astrophysics Data System (ADS)

Liang, X. S.

2016-02-01

Central at the processes of mean-eddy-turbulence interaction, e.g., mesoscale eddy shedding, relaminarization, etc., is the transfer of energy among different scales. The existing classical transfers, however, do not take into account the issue of energy conservation and, therefore, are not faithful representations of the real interaction processes, which are fundamentally a redistribution of energy among scales. Based on a new analysis machinery, namely, multiscale window transform (Liang and Anderson, 2007), we were able to obtain a formula for this important processes, with the property of energy conservation a naturally embedded property. This formula has a form reminiscent of the Poisson bracket in Hamiltonian dynamics. It has been validated with many benchmark processes, and, particularly, has been applied with success to control the eddy shedding behind a bluff body. Presented here will be an application study of the instabilities and mean-eddy interactions in the Kuroshio Extension (KE) region. Generally, it is found that the unstable KE jet fuels the mesoscale eddies, but in the offshore eddy decaying region, the cause-effect relation reverses: it is the latter that drive the former. On the whole the eddies act to decelerate the jet in the upstream, whereas accelerating it downstream.

Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: energy decomposition analysis and energy budget.

PubMed

Yokoyama, Naoto; Takaoka, Masanori

2014-12-01

A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode a(k) and its companion mode a(-k) is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.

Effect of the ratio of radial gap to radius of the coils on the transmission efficiency of wireless power transfer via coupled magnetic resonances

NASA Astrophysics Data System (ADS)

Gao, Pengfei; Tian, Zijian; Wang, Xuqi; Wu, Jun; Gui, Weifeng

2018-03-01

Wireless power transfer (WPT) via coupled magnetic resonance is a promising technology to be applied in many fields. In general, there will be a radial gap in practical application, and some special application environments need to limit the radius of the coils. Therefore, in this paper, considering the comprehensive analysis of the radial gap and the radius of the coils, the concept of the ratio of radial gap to the radius of the coils was proposed. Based on the circuit theory, the formula between the ratio and transmission efficiency of WPT was deduced, and the effects of the ratio on the transmission efficiency were studied respectively at different axial distances. Simulation experiments were carried out and the results not only demonstrate the influence law of the ratio on transmission efficiency, but also validate the value of the ratio which the axial distance has the greatest effect on the transmission efficiency. Besides, the results shows the relationship between the effect of the ratio on the efficiency and the effect of the axial distance on the efficiency. The experimental results show that the theoretical analysis is correct, thus providing an useful theoretical reference for the design and further research on the wireless power transfer system in complicated environment.

Relativistic theory for picosecond time transfer in the vicinity of Earth

NASA Technical Reports Server (NTRS)

Petit, G.; Wolf, P.

1994-01-01

The problem of light propagation is treated in a geocentric reference system with the goal of ensuring picosecond accuracy for time transfer techniques using electromagnetic signals in the vicinity of the Earth. We give an explicit formula for a one way time transfer, to be applied when the spatial coordinates of the time transfer stations are known in a geocentric reference system rotating with the Earth. This expression is extended, at the same accuracy level of one picosecond, to the special cases of two way and LASSO time transfers via geostationary satellites.

Investigation of Heat Transfer to a Flat Plate in a Shock Tube.

DTIC Science & Technology

1987-12-01

2 Objectives and Scope . . . . . .. .. .. .... 5 11. Theory ............... ....... 7 Shock Tube Principles........... 7 Boundary Layer Theory ...in *excess of theory , but the rounded edge flat plate exhibited data which matched or was less than what theory predicted for each Mach number tested...normal shock advancing along an infinite flat plate. For x< Ugt there is a region of interaction between the downstream influence of the leading edge

Quantum Calculations of Electron Tunneling in Respiratory Complex III.

PubMed

Hagras, Muhammad A; Hayashi, Tomoyuki; Stuchebrukhov, Alexei A

2015-11-19

The most detailed and comprehensive to date study of electron transfer reactions in the respiratory complex III of aerobic cells, also known as bc1 complex, is reported. In the framework of the tunneling current theory, electron tunneling rates and atomistic tunneling pathways between different redox centers were investigated for all electron transfer reactions comprising different stages of the proton-motive Q-cycle. The calculations reveal that complex III is a smart nanomachine, which under certain conditions undergoes conformational changes gating electron transfer, or channeling electrons to specific pathways. One-electron tunneling approximation was adopted in the tunneling calculations, which were performed using hybrid Broken-Symmetry (BS) unrestricted DFT/ZINDO levels of theory. The tunneling orbitals were determined using an exact biorthogonalization scheme that uniquely separates pairs of tunneling orbitals with small overlaps out of the remaining Franck-Condon orbitals with significant overlap. Electron transfer rates in different redox pairs show exponential distance dependence, in agreement with the reported experimental data; some reactions involve coupled proton transfer. Proper treatment of a concerted two-electron bifurcated tunneling reaction at the Q(o) site is given.

Heat-Transfer and Pressure Measurements on a Flat-Face Cylinder at a Mach Number Range of 2.49 to 4.44

NASA Technical Reports Server (NTRS)

Burbank, Paige B.; Stallings, Robert L., Jr.

1959-01-01

Heat-transfer coefficients and pressure distributions were obtained on a 4-inch-diameter flat-face cylinder in the Langley Unitary Plan wind tunnel. The measured stagnation heat-transfer coefficient agrees well with 55 percent of the theoretical value predicted by the modified Sibulkin method for a hemisphere. Pressure measurements indicated the dimensionless velocity gradient parameter r du\\ a(sub t) dx, where x=0 at the stagnation point was approximately 0.3 and invariant throughout the Mach number range from 2.49 to 4.44 and the Reynolds number range from 0.77 x 10(exp 6) to 1.46 x 10(exp 6). The heat-transfer coefficients on the cylindrical afterbody could be predicted with reasonable accuracy by flat-plate theory at an angle of attack of 0 deg. At angles of attack the cylindrical afterbody stagnation-line heat transfer could be computed from swept-cylinder theory for large distances back of the nose when the Reynolds number is based on the distance from the flow reattachment points.

The role of individual differences in cognitive training and transfer.

PubMed

Jaeggi, Susanne M; Buschkuehl, Martin; Shah, Priti; Jonides, John

2014-04-01

Working memory (WM) training has recently become a topic of intense interest and controversy. Although several recent studies have reported near- and far-transfer effects as a result of training WM-related skills, others have failed to show far transfer, suggesting that generalization effects are elusive. Also, many of the earlier intervention attempts have been criticized on methodological grounds. The present study resolves some of the methodological limitations of previous studies and also considers individual differences as potential explanations for the differing transfer effects across studies. We recruited intrinsically motivated participants and assessed their need for cognition (NFC; Cacioppo & Petty Journal of Personality and Social Psychology 42:116-131, 1982) and their implicit theories of intelligence (Dweck, 1999) prior to training. We assessed the efficacy of two WM interventions by comparing participants' improvements on a battery of fluid intelligence tests against those of an active control group. We observed that transfer to a composite measure of fluid reasoning resulted from both WM interventions. In addition, we uncovered factors that contributed to training success, including motivation, need for cognition, preexisting ability, and implicit theories about intelligence.

Validation of Heat Transfer and Film Cooling Capabilities of the 3-D RANS Code TURBO

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Ameri, Ali; Chen, Jen-Ping

2010-01-01

The capabilities of the 3-D unsteady RANS code TURBO have been extended to include heat transfer and film cooling applications. The results of simulations performed with the modified code are compared to experiment and to theory, where applicable. Wilcox s k-turbulence model has been implemented to close the RANS equations. Two simulations are conducted: (1) flow over a flat plate and (2) flow over an adiabatic flat plate cooled by one hole inclined at 35 to the free stream. For (1) agreement with theory is found to be excellent for heat transfer, represented by local Nusselt number, and quite good for momentum, as represented by the local skin friction coefficient. This report compares the local skin friction coefficients and Nusselt numbers on a flat plate obtained using Wilcox's k-model with the theory of Blasius. The study looks at laminar and turbulent flows over an adiabatic flat plate and over an isothermal flat plate for two different wall temperatures. It is shown that TURBO is able to accurately predict heat transfer on a flat plate. For (2) TURBO shows good qualitative agreement with film cooling experiments performed on a flat plate with one cooling hole. Quantitatively, film effectiveness is under predicted downstream of the hole.

A hybrid approach to simulation of electron transfer in complex molecular systems

PubMed Central

Kubař, Tomáš; Elstner, Marcus

2013-01-01

Electron transfer (ET) reactions in biomolecular systems represent an important class of processes at the interface of physics, chemistry and biology. The theoretical description of these reactions constitutes a huge challenge because extensive systems require a quantum-mechanical treatment and a broad range of time scales are involved. Thus, only small model systems may be investigated with the modern density functional theory techniques combined with non-adiabatic dynamics algorithms. On the other hand, model calculations based on Marcus's seminal theory describe the ET involving several assumptions that may not always be met. We review a multi-scale method that combines a non-adiabatic propagation scheme and a linear scaling quantum-chemical method with a molecular mechanics force field in such a way that an unbiased description of the dynamics of excess electron is achieved and the number of degrees of freedom is reduced effectively at the same time. ET reactions taking nanoseconds in systems with hundreds of quantum atoms can be simulated, bridging the gap between non-adiabatic ab initio simulations and model approaches such as the Marcus theory. A major recent application is hole transfer in DNA, which represents an archetypal ET reaction in a polarizable medium. Ongoing work focuses on hole transfer in proteins, peptides and organic semi-conductors. PMID:23883952

Electronic transfer studies of fullerene/polymer hybrids

NASA Astrophysics Data System (ADS)

Farrell, Garrett F.; Chambers, Gordon; Dalton, Alan B.; Byrne, Hugh J.

2003-03-01

In this study we examine the interaction of both cis and trans poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene (PmPV-co-DOctOPV) with C60 in solution From the presented data it is clear that there is an interaction between the HE PmPV and C60. Just what this interaction is however is not as clear. A possible explanation that fits the available data involves the HE PmPV wrapping around the C60 molecules, similar to the effect observed by Dalton et al with Carbon Nanotubes. In theory the close proximately of the coils to the C60 molecules may allow for charge transfer or energy transfer between to the two molecules. If this theory is correct it would explain the why the absorption spectra of HE-PmPV at the different loaded fraction displays a negative deviation for the expected values. It may be speculated that due to the coiling the C60 molecules are prevented from absorbing photons of light, consequently resulting in a reduction in it's contribution to the overall intensity. This theory would also explain the increased quenching effect observed in the luminescence spectra at the same percentage weights, since the close proximity of the coils to the C60 molecules allows for charge or energy transfer between the two.

Exploring Knowledge Exchange between Senior and Future Leaders: A Grounded-Theory Study

ERIC Educational Resources Information Center

Gonzaga, Stephanie Young

2009-01-01

A grounded theory study examined senior leaders methods of knowledge sharing with junior leaders in a small commercial mortgage company. The study was designed to develop an emergent theory to explain the cultural elements that influenced the methods leaders used to transfer knowledge to junior people. The study identified a systemic value of…

Schema Theories as a Base for the Structural Representation of the Knowledge State.

ERIC Educational Resources Information Center

Dochy, F. J. R. C.; Bouwens, M. R. J.

From the view of schema-transfer theory, the use of schemata with their several functions gives an explanation for the facilitative effect of prior knowledge on learning processes. This report gives a theoretical exploration of the concept of schemata, underlying schema theories, and functions of schemata to indicate the importance of schema…

Dynamic surface tension measurements of ionic surfactants using maximum bubble pressure tensiometry

NASA Astrophysics Data System (ADS)

Ortiz, Camilla U.; Moreno, Norman; Sharma, Vivek

Dynamic surface tension refers to the time dependent variation in surface tension, and is intimately linked with the rate of mass transfer of a surfactant from liquid sub-phase to the interface. The diffusion- or adsorption-limited kinetics of mass transfer to interfaces is said to impact the so-called foamability and the Gibbs-Marangoni elasticity of surfaces. Dynamic surface tension measurements carried out with conventional methods like pendant drop analysis, Wilhelmy plate, etc. are limited in their temporal resolution (>50 ms). In this study, we describe design and application of maximum bubble pressure tensiometry for the measurement of dynamic surface tension effects at extremely short (1-50 ms) timescales. Using experiments and theory, we discuss the overall adsorption kinetics of charged surfactants, paying special attention to the influence of added salt on dynamic surface tension.

Spin Transfer in Polymer Degradation of Abnormal Linkage

NASA Astrophysics Data System (ADS)

Yu, Tianrong; Tian, Chuanjin; Liu, Xizhe; Wang, Jia; Gao, Yang; Wang, Zhigang

2017-07-01

The degradation of polymer materials plays an important role in production and life. In this work, the degradation mechanism of poly-α-methylstyrene (PAMS) tetramers with abnormal linkage was investigated by using density functional theory (DFT). Calculated results indicate that the head-to-head and the tail-to-tail reactions needed to overcome the energy barriers are about 0.15 eV and about 1.26 eV, respectively. The broken C-C bond at the unsaturated end of the chain leads to the dissociation of alpha-methylstyrene (AMS) monomers one by one. Furthermore, the analyses of bond characteristics are in good agreement with the results of energy barriers. In addition, the spin population analysis presents an interesting net spin transfer process in depolymerization reactions. We hope that the current theoretical results provide useful help to understand the degradation mechanism of polymers.

Blinking suppression of CdTe quantum dots on epitaxial graphene and the analysis with Marcus electron transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirose, Takuya; Tamai, Naoto, E-mail: tamai@kwansei.ac.jp; Kutsuma, Yasunori

We have prepared epitaxial graphene by a Si sublimation method from 4H-SiC. Single-particle spectroscopy of CdTe quantum dots (QDs) on epitaxial graphene covered with polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) showed the suppression of luminescence blinking and ∼10 times decreased luminescence intensity as compared with those on a glass. The electronic coupling constant, H{sub 01}, between CdTe QDs and graphene was calculated to be (3.3 ± 0.4) × 10{sup 2 }cm{sup −1} in PVP and (3.7 ± 0.8) × 10{sup 2 }cm{sup −1} in PEG based on Marcus theory of electron transfer and Tang-Marcus model of blinking with statistical distribution.

Intensive care survivors' experiences of ward-based care: Meleis' theory of nursing transitions and role development among critical care outreach services.

PubMed

Ramsay, Pam; Huby, Guro; Thompson, Andrew; Walsh, Tim

2014-03-01

To explore the psychosocial needs of patients discharged from intensive care, the extent to which they are captured using existing theory on transitions in care and the potential role development of critical care outreach, follow-up and liaison services. Intensive care patients are at an increased risk of adverse events, deterioration or death following ward transfer. Nurse-led critical care outreach, follow-up or liaison services have been adopted internationally to prevent these potentially avoidable sequelae. The need to provide patients with psychosocial support during the transition to ward-based care has also been identified, but the evidence base for role development is currently limited. Twenty participants were invited to discuss their experiences of ward-based care as part of a broader study on recovery following prolonged critical illness. Psychosocial distress was a prominent feature of their accounts, prompting secondary data analysis using Meleis et al.'s mid-range theory on experiencing transitions. Participants described a sense of disconnection in relation to profound debilitation and dependency and were often distressed by a perceived lack of understanding, indifference or insensitivity among ward staff to their basic care needs. Negotiating the transition between dependence and independence was identified as a significant source of distress following ward transfer. Participants varied in the extent to which they were able to express their needs and negotiate recovery within professionally mediated boundaries. These data provide new insights into the putative origins of the psychosocial distress that patients experience following ward transfer. Meleis et al.'s work has resonance in terms of explicating intensive care patients' experiences of psychosocial distress throughout the transition to general ward-based care, such that the future role development of critical care outreach, follow-up and liaison services may be more theoretically informed. © 2013 John Wiley & Sons Ltd.

Nature of the Galactic centre NIR-excess sources. I. What can we learn from the continuum observations of the DSO/G2 source?

NASA Astrophysics Data System (ADS)

Zajaček, Michal; Britzen, Silke; Eckart, Andreas; Shahzamanian, Banafsheh; Busch, Gerold; Karas, Vladimír; Parsa, Marzieh; Peissker, Florian; Dovčiak, Michal; Subroweit, Matthias; Dinnbier, František; Zensus, J. Anton

2017-06-01

Context. The Dusty S-cluster Object (DSO/G2) orbiting the supermassive black hole (Sgr A*) in the Galactic centre has been monitored in both near-infrared continuum and line emission. There has been a dispute about the character and the compactness of the object: it being interpreted as either a gas cloud or a dust-enshrouded star. A recent analysis of polarimetry data in Ks-band (2.2 μm) allows us to put further constraints on the geometry of the DSO. Aims: The purpose of this paper is to constrain the nature and the geometry of the DSO. Methods: We compared 3D radiative transfer models of the DSO with the near-infrared (NIR) continuum data including polarimetry. In the analysis, we used basic dust continuum radiative transfer theory implemented in the 3D Monte Carlo code Hyperion. Moreover, we implemented analytical results of the two-body problem mechanics and the theory of non-thermal processes. Results: We present a composite model of the DSO - a dust-enshrouded star that consists of a stellar source, dusty, optically thick envelope, bipolar cavities, and a bow shock. This scheme can match the NIR total as well as polarized properties of the observed spectral energy distribution (SED). The SED may be also explained in theory by a young pulsar wind nebula that typically exhibits a large linear polarization degree due to magnetospheric synchrotron emission. Conclusions: The analysis of NIR polarimetry data combined with the radiative transfer modelling shows that the DSO is a peculiar source of compact nature in the S cluster (r ≲ 0.04 pc). It is most probably a young stellar object embedded in a non-spherical dusty envelope, whose components include optically thick dusty envelope, bipolar cavities, and a bow shock. Alternatively, the continuum emission could be of a non-thermal origin due to the presence of a young neutron star and its wind nebula. Although there has been so far no detection of X-ray and radio counterparts of the DSO, the analysis of the neutron star model shows that young, energetic neutron stars similar to the Crab pulsar could in principle be detected in the S cluster with current NIR facilities and they appear as apparent reddened, near-infrared-excess sources. The searches for pulsars in the NIR bands can thus complement standard radio searches, which can put further constraints on the unexplored pulsar population in the Galactic centre. Both thermal and non-thermal models are in accordance with the observed compactness, total as well polarized continuum emission of the DSO.

Heat-transfer distributions on a 0.013-scale shuttle solid rocket booster at Mach 3.70 and angles of attack from 0 deg to 180 deg

NASA Technical Reports Server (NTRS)

Lamb, M.; Stallings, R. L., Jr.

1976-01-01

An experimental investigation was conducted in the Langley Unitary Plan wind tunnel to estimate the peak aerodynamic heating on the space shuttle solid rocket booster during the descent phase of its flight. Heat transfer measurements were obtained using 0.013 scale models instrumented with thermocouples at a Mach number of 3.70, Reynolds number per meter of 11.48 million, and angles of attack from 0 to 180 deg. At angles of attack of 0 and 180 deg, heat transfer measurements on the cylindrical section of the model between the conical nose and ring interaction region were in good agreement with flat plate strip theory for laminar and turbulent flow. At angles of attack up to 30 deg, measurements on this section of the model were in good agreement with laminar swept-cylinder theory, whereas at angles of attack from 120 to 180 deg, the measurements were in good agreement with turbulent swept-cylinder theory. The good agreement with turbulent theory indicated that large flow disturbances created by the nozzle and afterbody flare at these large angles of attack influenced the downstream heating primarily by promoting boundary layer transition. Measurements obtained at 90 deg angle of attack were indicative of laminar flow.

Energy Transfer and Dual Cascade in Kinetic Magnetized Plasma Turbulence

NASA Astrophysics Data System (ADS)

Plunk, G. G.; Tatsuno, T.

2011-04-01

The question of how nonlinear interactions redistribute the energy of fluctuations across available degrees of freedom is of fundamental importance in the study of turbulence and transport in magnetized weakly collisional plasmas, ranging from space settings to fusion devices. In this Letter, we present a theory for the dual cascade found in such plasmas, which predicts a range of new behavior that distinguishes this cascade from that of neutral fluid turbulence. These phenomena are explained in terms of the constrained nature of spectral transfer in nonlinear gyrokinetics. Accompanying this theory are the first observations of these phenomena, obtained via direct numerical simulations using the gyrokinetic code AstroGK. The basic mechanisms that are found provide a framework for understanding the turbulent energy transfer that couples scales both locally and nonlocally.

Electroexcitation of the Δ +(1232) at low momentum transfer

DOE PAGES

Blomberg, A.; Anez, D.; Sparveris, N.; ...

2016-07-05

We report on new pmore » $$(e,e^\\prime p)\\pi^\\circ$$ measurements at the $$\\Delta^{+}(1232)$$ resonance at the low momentum transfer region. The mesonic cloud dynamics is predicted to be dominant and rapidly changing in this kinematic region offering a test bed for chiral effective field theory calculations. The new data explore the low $Q^2$ dependence of the resonant quadrupole amplitudes while extending the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements suggest that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements.« less

Research review: dopamine transfer deficit: a neurobiological theory of altered reinforcement mechanisms in ADHD.

PubMed

Tripp, Gail; Wickens, Jeff R

2008-07-01

This review considers the hypothesis that changes in dopamine signalling might account for altered sensitivity to positive reinforcement in children with ADHD. The existing evidence regarding dopamine cell activity in relation to positive reinforcement is reviewed. We focus on the anticipatory firing of dopamine cells brought about by a transfer of dopamine cell responses to cues that precede reinforcers. It is proposed that in children with ADHD there is diminished anticipatory dopamine cell firing, which we call the dopamine transfer deficit (DTD). The DTD theory leads to specific and testable predictions for human and animal research. The extent to which DTD explains symptoms of ADHD and effects of pharmacological interventions is discussed. We conclude by considering the neural changes underlying the etiology of DTD.

Laminar Heat-Transfer and Pressure-Distribution Studies on a Series of Reentry Nose Shapes at a Mach Number of 19.4 in Helium

NASA Technical Reports Server (NTRS)

Wagner, Richard D., Jr.; Pine, W. Clint; Henderson, Arthur, Jr.

1961-01-01

An experimental investigation has been conducted in the 2-inch helium tunnel at the Langley Research Center at a Mach number of 19.4 to determine the pressure distributions and heat-transfer characteristics of a family of reentry nose shapes. The pressure and heat-transfer-rate distributions on the nose shapes are compared with theoretical predictions to ascertain the limitations and validity of the theories at hypersonic speeds. The experimental results were found to be adequately predicted by existing theories. Two of the nose shapes were tested with variable-length flow-separation spikes. The results obtained by previous investigators of spike-nose bodies were found to prevail at the higher Mach number of the present investigation.

Miniature Heat Transport System for Spacecraft Thermal Control

NASA Technical Reports Server (NTRS)

Ochterbeck, Jay M.; Ku, Jentung (Technical Monitor)

2002-01-01

Loop heat pipes (LHP) are efficient devices for heat transfer and use the basic principle of a closed evaporation-condensation cycle. The advantage of using a loop heat pipe over other conventional methods is that large quantities of heat can be transported through a small cross-sectional area over a considerable distance with no additional power input to the system. By using LHPs, it seems possible to meet the growing demand for high-power cooling devices. Although they are somewhat similar to conventional heat pipes, LHPs have a whole set of unique properties, such as low pressure drops and flexible lines between condenser and evaporator, that make them rather promising. LHPs are capable of providing a means of transporting heat over long distances with no input power other than the heat being transported because of the specially designed evaporator and the separation of liquid and vapor lines. For LHP design and fabrication, preliminary analysis on the basis of dimensionless criteria is necessary because of certain complicated phenomena that take place in the heat pipe. Modeling the performance of the LHP and miniaturizing its size are tasks and objectives of current research. In the course of h s work, the LHP and its components, including the evaporator (the most critical and complex part of the LHP), were modeled with the corresponding dimensionless groups also being investigated. Next, analysis of heat and mass transfer processes in the LHP, selection of the most weighted criteria from known dimensionless groups (thermal-fluid sciences), heat transfer rate limits, (heat pipe theory), and experimental ratios which are unique to a given heat pipe class are discussed. In the third part of the report, two-phase flow heat and mass transfer performances inside the LHP condenser are analyzed and calculated for Earth-normal gravity and microgravity conditions. On the basis of recent models and experimental databanks, an analysis for condensing two-phase flow regimes, pressure gradients, and local heat transfer coefficients using ammonia, propylene, and R134, are carried out.

State Theory, Grassroots Agency, and Global Policy Transfer: The Life and Death of Colombia's "Escuela Nueva in Brazil" (1997-2012)

ERIC Educational Resources Information Center

Tarlau, Rebecca

2017-01-01

This article analyzes the transfer and 15-year policy trajectory of Colombia's "global best practice" "Escuela Nueva in Brazil." This program, initially transferred to Brazil in 1997 with the help of the World Bank, was largely unknown for the first decade of its life span. Then, between 2008 and 2011, "after" the…

The Effect of Training on Productivity: The Transfer of On-the-Job Training from the Perspective of Economics

ERIC Educational Resources Information Center

De Grip, Andries; Sauermann, Jan

2013-01-01

Although the transfer of on-the-job training to the workplace belongs to the realm of educational research, it is also highly related to labour economics. In the economic literature, the transfer of training is based on the theoretical framework of human capital theory and has been extensively analysed empirically in econometric studies that take…

Transfer function analysis of thermospheric perturbations

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Harris, I.; Varosi, F.; Herrero, F. A.; Spencer, N. W.

1986-01-01

Applying perturbation theory, a spectral model in terms of vectors spherical harmonics (Legendre polynomials) is used to describe the short term thermospheric perturbations originating in the auroral regions. The source may be Joule heating, particle precipitation or ExB ion drift-momentum coupling. A multiconstituent atmosphere is considered, allowing for the collisional momentum exchange between species including Ar, O2, N2, O, He and H. The coupled equations of energy, mass and momentum conservation are solved simultaneously for the major species N2 and O. Applying homogeneous boundary conditions, the integration is carred out from the Earth's surface up to 700 km. In the analysis, the spherical harmonics are treated as eigenfunctions, assuming that the Earth's rotation (and prevailing circulation) do not significantly affect perturbations with periods which are typically much less than one day. Under these simplifying assumptions, and given a particular source distribution in the vertical, a two dimensional transfer function is constructed to describe the three dimensional response of the atmosphere. In the order of increasing horizontal wave numbers (order of polynomials), this transfer function reveals five components. To compile the transfer function, the numerical computations are very time consuming (about 100 hours on a VAX for one particular vertical source distribution). However, given the transfer function, the atmospheric response in space and time (using Fourier integral representation) can be constructed with a few seconds of a central processing unit. This model is applied in a case study of wind and temperature measurements on the Dynamics Explorer B, which show features characteristic of a ringlike excitation source in the auroral oval. The data can be interpreted as gravity waves which are focused (and amplified) in the polar region and then are reflected to propagate toward lower latitudes.

Transfer function analysis of thermospheric perturbations

NASA Astrophysics Data System (ADS)

Mayr, H. G.; Harris, I.; Varosi, F.; Herrero, F. A.; Spencer, N. W.

1986-06-01

Applying perturbation theory, a spectral model in terms of vectors spherical harmonics (Legendre polynomials) is used to describe the short term thermospheric perturbations originating in the auroral regions. The source may be Joule heating, particle precipitation or ExB ion drift-momentum coupling. A multiconstituent atmosphere is considered, allowing for the collisional momentum exchange between species including Ar, O2, N2, O, He and H. The coupled equations of energy, mass and momentum conservation are solved simultaneously for the major species N2 and O. Applying homogeneous boundary conditions, the integration is carred out from the Earth's surface up to 700 km. In the analysis, the spherical harmonics are treated as eigenfunctions, assuming that the Earth's rotation (and prevailing circulation) do not significantly affect perturbations with periods which are typically much less than one day. Under these simplifying assumptions, and given a particular source distribution in the vertical, a two dimensional transfer function is constructed to describe the three dimensional response of the atmosphere. In the order of increasing horizontal wave numbers (order of polynomials), this transfer function reveals five components. To compile the transfer function, the numerical computations are very time consuming (about 100 hours on a VAX for one particular vertical source distribution). However, given the transfer function, the atmospheric response in space and time (using Fourier integral representation) can be constructed with a few seconds of a central processing unit. This model is applied in a case study of wind and temperature measurements on the Dynamics Explorer B, which show features characteristic of a ringlike excitation source in the auroral oval. The data can be interpreted as gravity waves which are focused (and amplified) in the polar region and then are reflected to propagate toward lower latitudes.

Experimental and Theoretical Studies of Condensation on a Horizontal Tube Row with Vapour Shear

NASA Astrophysics Data System (ADS)

Aoune, Azzeddine

Available from UMI in association with The British Library. This thesis presents an experimental and theoretical investigation into the effect of vapour shear on the condensation of steam flowing vertically downwards over a single horizontal tube and a horizontal tube in a row. Honda and Fujii's conjugate heat transfer analysis has been adapted and modified to take account of property variation with temperature and release of sensible heat to the condensing film. In industrial condensers, even in the first row, the vapour velocity profile around a tube is affected by the presence of its neighbours. This work extends Honda and Fujii's analysis to investigate the effect of tube spacing on the heat transfer. The finite element method was used to obtain the velocity field around the tube in a row and subsequently the boundary layer equations for the condensate and vapour film along with the heat flow in the tube wall were solved simultaneously. Data have been obtained at absolute pressures of 0.8 and 0.9 bar and for steam superheat up to 40 degC. Approach steam velocities up to 25 m/s were covered. Cooling water velocities and temperatures were in the range 0.68-1.16 m/s and 18-43^circ C, respectively. Honda et al (67), Roshko's flow, theory was found to fit the data for the steam flowing over the isolated tube. The theoretical data for the latter agreed well with the Shekriladze and Gomelauri (2) and Rose (40) correlations and Honda et al (67), potential flow, theory. On | Nu| Re^{-1/2} versus F basis, an average enhancement of 50% in condensate film heat transfer was observed in the case of steam flowing over the tube in a row compared to the isolated tube. This compared with the predicted value of 23% enhancement.

Endosymbiotic gene transfer from prokaryotic pangenomes: Inherited chimerism in eukaryotes.

PubMed

Ku, Chuan; Nelson-Sathi, Shijulal; Roettger, Mayo; Garg, Sriram; Hazkani-Covo, Einat; Martin, William F

2015-08-18

Endosymbiotic theory in eukaryotic-cell evolution rests upon a foundation of three cornerstone partners--the plastid (a cyanobacterium), the mitochondrion (a proteobacterium), and its host (an archaeon)--and carries a corollary that, over time, the majority of genes once present in the organelle genomes were relinquished to the chromosomes of the host (endosymbiotic gene transfer). However, notwithstanding eukaryote-specific gene inventions, single-gene phylogenies have never traced eukaryotic genes to three single prokaryotic sources, an issue that hinges crucially upon factors influencing phylogenetic inference. In the age of genomes, single-gene trees, once used to test the predictions of endosymbiotic theory, now spawn new theories that stand to eventually replace endosymbiotic theory with descriptive, gene tree-based variants featuring supernumerary symbionts: prokaryotic partners distinct from the cornerstone trio and whose existence is inferred solely from single-gene trees. We reason that the endosymbiotic ancestors of mitochondria and chloroplasts brought into the eukaryotic--and plant and algal--lineage a genome-sized sample of genes from the proteobacterial and cyanobacterial pangenomes of their respective day and that, even if molecular phylogeny were artifact-free, sampling prokaryotic pangenomes through endosymbiotic gene transfer would lead to inherited chimerism. Recombination in prokaryotes (transduction, conjugation, transformation) differs from recombination in eukaryotes (sex). Prokaryotic recombination leads to pangenomes, and eukaryotic recombination leads to vertical inheritance. Viewed from the perspective of endosymbiotic theory, the critical transition at the eukaryote origin that allowed escape from Muller's ratchet--the origin of eukaryotic recombination, or sex--might have required surprisingly little evolutionary innovation.

Bilingualism and Phonological Awareness: Re-examining Theories of Cross-Language Transfer and Structural Sensitivity

PubMed Central

Kuo, Li-Jen; Uchikoshi, Yuuko; Kim, Tae-Jin; Yang, Xinyuan

2016-01-01

The purpose of this study was to examine the relationship between bilingualism and phonological awareness by re-evaluating structural sensitivity theory and expanding cross-language transfer theory. The study was conducted with three groups of 1st and 2nd graders matched in age, SES and non-verbal IQ: a) monolingual English-speaking children from a general education program, b) native Japanese-speaking children from a Japanese-English two-way immersion bilingual program and c) native English-speaking children from the same bilingual program. An odd-man-out task that took into account the phonological and orthographical contrasts between English and Japanese was developed to assess onset awareness. The results showed that the bilingual children outperformed their monolingual peers in processing onsets that are shared between the two languages, which provided empirical support for the first hypothesis derived from structural sensitivity theory and highlighted the importance of contextual variability in bilingual metalinguistic processing. The second hypothesis derived from structural sensitivity theory, which predicated that bilingual advantage would be more evident in processing novel stimuli, was not confirmed in the present study. The absence of the predicted group difference may be attributed to the disparity in the extent of novelty of the stimuli and the difference in the comparability of participants’ degrees of bilingualism between the present study and previous research. Finally, expanding existing research, results from this study showed that cross-language transfer can occur at a phonetic featural level. Future research and theoretical implications were discussed. PMID:28025589

Concerted One-Electron Two-Proton Transfer Processes in Models Inspired by the Tyr-His Couple of Photosystem II

DOE PAGES

Huynh, Mioy T.; Mora, S. Jimena; Villalba, Matias; ...

2017-05-09

Nature employs a TyrZ-His pair as a redox relay that couples proton transfer to the redox process between P680 and the water oxidizing catalyst in photosystem II. Artificial redox relays composed of different benzimidazole–phenol dyads (benzimidazole models His and phenol models Tyr) with substituents designed to simulate the hydrogen bond network surrounding the TyrZ-His pair have been prepared. Furthermore, when the benzimidazole substituents are strong proton acceptors such as primary or tertiary amines, theory predicts that a concerted two proton transfer process associated with the electrochemical oxidation of the phenol will take place. Furthermore, theory predicts a decrease in themore » redox potential of the phenol by ~300 mV and a small kinetic isotope effect (KIE). Indeed, electrochemical, spectroelectrochemical, and KIE experimental data are consistent with these predictions. Our results were obtained by using theory to guide the rational design of artificial systems and have implications for managing proton activity to optimize efficiency at energy conversion sites involving water oxidation and reduction.« less

Multi-fluid CFD analysis in Process Engineering

NASA Astrophysics Data System (ADS)

Hjertager, B. H.

2017-12-01

An overview of modelling and simulation of flow processes in gas/particle and gas/liquid systems are presented. Particular emphasis is given to computational fluid dynamics (CFD) models that use the multi-dimensional multi-fluid techniques. Turbulence modelling strategies for gas/particle flows based on the kinetic theory for granular flows are given. Sub models for the interfacial transfer processes and chemical kinetics modelling are presented. Examples are shown for some gas/particle systems including flow and chemical reaction in risers as well as gas/liquid systems including bubble columns and stirred tanks.

Synthesis, crystal structure and redox properties of dihydropyrazole-bridged ferrocene-based derivatives

NASA Astrophysics Data System (ADS)

Li, Heng-Dong; Ma, Zai-He; Yang, Kun; Xie, Li-Li; Yuan, Yao-Feng

2012-09-01

Dihydropyrazole-bridged ferrocene-based derivatives were prepared by corresponding chalcones with hydrazine hydrate, then acylation with 3-(ethoxycarbonyl)propionyl chloride directly in high yields and purity. All of these compounds were characterized by MS, IR, 1H NMR, 13C NMR and elemental analysis. The relationship between the structure and redox properties was investigated based on the results of single crystal X-ray structure determinations and cyclic voltammetry. The mechanism of the electron transfer for representative compound 4b was verified by density functional theory (DFT) calculations.

Analysis of the instability underlying electrostatic suppression of the Leidenfrost state

NASA Astrophysics Data System (ADS)

Shahriari, Arjang; Das, Soumik; Bahadur, Vaibhav; Bonnecaze, Roger T.

2017-03-01

A liquid droplet on a hot solid can generate enough vapor to prevent its contact on the surface and reduce the rate of heat transfer, the so-called Leidenfrost effect. We show theoretically and experimentally that for a sufficiently high electrostatic potential on the droplet, the formation of the vapor layer is suppressed. The interplay of the destabilizing electrostatic force and stabilizing capillary force and evaporation determines the minimum or threshold voltage to suppress the Leidenfrost effect. Linear stability theory accurately predicts threshold voltages for different size droplets and varying temperatures.

Twisted intramolecular charge transfer investigation of semi organic L-Glutamic acid hydrochloride single crystal for organic light-emitting and optical limiting applications

NASA Astrophysics Data System (ADS)

Joy, Lija K.; George, Merin; Alex, Javeesh; Aravind, Arun; Sajan, D.; Vinitha, G.

2018-03-01

Single crystals of L-Glutamic acid hydrochloride (LGHCl) were grown by slow evaporation solution technique and good crystalline perfection was confirmed by Powder X-ray diffraction studies. The complete vibrational studies of the compound were analyzed by FT-IR, FT-Raman and UV-visible spectra combined with Normal Coordinate Analysis (NCA) following the scaled quantum mechanical force field methodology and density functional theory (DFT). Twisted Intramolecular Charge Transfer (ICT) occurs due to the presence of strong ionic intra-molecular Nsbnd H⋯O hydrogen bonding was confirmed by Hirshfeld Surface analysis. The existence of intermolecular Nsbnd H⋯Cl hydrogen bonds due to the interaction between the lone pair of oxygen with the antibonding orbital was established by NBO analysis. The Z-scan result indicated that the title molecule exhibits saturable absorption behavior. The attractive third-order nonlinear properties suggest that LGHCl can be a promising candidate for the design and development devices for optical limiting applications. LGHCL exhibits distinct emission in the blue region of the fluorescence lifetime which proves to be a potential candidate for blue- Organic light-emitting diodes (OLEDs) fabrication.

Heat Transfer and Thermodynamics: a Compilation

NASA Technical Reports Server (NTRS)

1974-01-01

A compilation is presented for the dissemination of information on technological developments which have potential utility outside the aerospace and nuclear communities. Studies include theories and mechanical considerations in the transfer of heat and the thermodynamic properties of matter and the causes and effects of certain interactions.

Rain, Snow, and Spring Runoff Revisited.

ERIC Educational Resources Information Center

Bohren, Craig F.

1995-01-01

Explores the theory behind the correlation between warm rain, rapid snowmelt, and the subsequent runoff using the concepts of enthalpy, thermal transfer, and energy transfer. Concludes that rapid runoff is not a consequence of rain per se but of the high humidities associated with the rain. (JRH)

Rationalizing Neglect: An Institutional Response to Transfer Students

ERIC Educational Resources Information Center

Tobolowsky, Barbara F.; Cox, Bradley E.

2012-01-01

This qualitative study focuses on institutional efforts affecting the transfer student experience at a single research institution. Findings based on interviews with institutional representatives, both faculty and staff, using the rational, natural, and open system perspectives of organizational theory, provide insights into the institutional…

Electronic-structure and quantum dynamical study of the photochromism of the aromatic Schiff base salicylideneaniline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz-Sanchez, Juan Manuel; Gelabert, Ricard; Moreno, Miquel

2008-12-07

The ultrafast proton transfer dynamics of salicylideneaniline has been theoretically analyzed in the ground and first singlet excited electronic states using density functional theory (DFT) and time-dependent DFT calculations, which predict a ({pi},{pi}*) barrierless excited state intramolecular proton transfer (ESIPT). In addition to this, the photochemistry of salicylideneaniline is experimentally known to present fast depopulation processes of the photoexcited species before and after the proton transfer reaction. Such processes are explained by means of conical intersections between the ground and first singlet ({pi},{pi}*) excited electronic states. The electronic energies obtained by the time-dependent density functional theory formalism have been fittedmore » to a monodimensional potential energy surface in order to perform quantum dynamics study of the processes. Our results show that the proton transfer and deactivation of the photoexcited species before the ESIPT processes are completed within 49.6 and 37.7 fs, respectively, which is in remarkable good agreement with experiments.« less

Marcus Bell-Shaped Electron Transfer Kinetics Observed in an Arrhenius Plot.

PubMed

Waskasi, Morteza M; Kodis, Gerdenis; Moore, Ana L; Moore, Thomas A; Gust, Devens; Matyushov, Dmitry V

2016-07-27

The Marcus theory of electron transfer predicts a bell-shaped dependence of the reaction rate on the reaction free energy. The top of the "inverted parabola" corresponds to zero activation barrier when the electron-transfer reorganization energy and the reaction free energy add up to zero. Although this point has traditionally been reached by altering the chemical structures of donors and acceptors, the theory suggests that it can also be reached by varying other parameters of the system including temperature. We find here dramatic evidence of this phenomenon from experiments on a fullerene-porphyrin dyad. Following photoinduced electron transfer, the rate of charge recombination shows a bell-shaped dependence on the inverse temperature, first increasing with cooling and then decreasing at still lower temperatures. This non-Arrhenius rate law is a result of a strong, approximately hyperbolic temperature variation of the reorganization energy and the reaction free energy. Our results provide potentially the cleanest confirmation of the Marcus energy gap law so far since no modification of the chemical structure is involved.

Thermal inertia effect in an axisymmetric thermoelastic problem based on generalized thermoelasticity

NASA Astrophysics Data System (ADS)

Xie, Yushu; Li, Fatao

2010-06-01

The objective of this paper is to study thermal inertia effect due to the fact of the properties of the hyperbolic equations based on LS theory in generalized thermoelasticity. Simulations in a 2D hollow cylinder for uncoupled dynamic thermal stresses and thermal displacements were predicted by use of finite element method with Newmark algorithm. The thermal inertia effect on LS theory in rapid transient heat transfer process is also investigated in comparison with in steady heat transfer process. When different specific heat capacity is chosen, dynamic thermal stresses appear different types of vibration, in which less heat capacity causes more violent dynamic thermal stresses because of the thermal inertia effect. Both dynamic thermal stresses and thermal displacements in rapid transient heat transfer process have the larger amplitude and higher frequency than in steady heat transfer process due to thermal inertia from the results of simulation, which is consistent with the nature of the generalized thermoelasticity.

Heat-Transfer and Pressure Measurements from a Flight Test of the Third 1/18-Scale Model of the Titan Intercontinental Ballistic Missile up to a Mach Number of 3.86 and Reynolds Number per Foot of 23.5 x 10(exp 6) and a Comparison with Heat Transfer

NASA Technical Reports Server (NTRS)

Graham, John B., Jr.

1958-01-01

Heat-transfer and pressure measurements were obtained from a flight test of a 1/18-scale model of the Titan intercontinental ballistic missile up to a Mach number of 3.86 and Reynolds number per foot of 23.5 x 10(exp 6) and are compared with the data of two previously tested 1/18-scale models. Boundary-layer transition was observed on the nose of the model. Van Driest's theory predicted heat-transfer coefficients reasonably well for the fully laminar flow but predictions made by Van Driest's theory for turbulent flow were considerably higher than the measurements when the skin was being heated. Comparison with the flight test of two similar models shows fair repeatability of the measurements for fully laminar or turbulent flow.

Few-femtosecond-resolution characterization and suppression of excess timing jitter and drift in indoor atmospheric frequency comb transfer.

PubMed

Kang, Jinho; Shin, Junho; Kim, Chur; Jung, Kwangyun; Park, Suhyeon; Kim, Jungwon

2014-10-20

We characterize the timing jitter spectral density of the time-of-flight (TOF) in the indoor atmospheric transfer of optical pulse train over 10 decades of Fourier frequency range (10 μHz - 100 kHz) with sub-100-as resolution using a balanced optical cross-correlator (BOC). Based on the well-known theory for atmospheric transfer of a laser beam, we could fit the measured timing jitter power spectral density to the theory and analyze it with a fairly good agreement from 20 mHz to 10 Hz Fourier frequency range. Moreover, we demonstrate that the BOC-based timing stabilization method can suppress the excess fluctuations in timing from >200 fs (rms) to 2.6 fs (rms) maintained over 130 hours when an optical pulse train is transferred over a 76.2-m long free-space beam path in laboratory environment. The demonstrated stabilization result corresponds to 4 × 10(-20) overlapping Allan deviation at 117,000 s averaging time.

Viviparous placentotrophy in reptiles and the parent-offspring conflict.

PubMed

Blackburn, Daniel G

2015-09-01

In placentotrophic viviparous reptiles, pregnant females deliver nutrients to their developing fetuses by diverse morphological specializations that reflect independent evolutionary origins. A survey of these specializations reveals a major emphasis on histotrophy (uterine secretion and fetal absorption) rather than hemotrophy (transfer between maternal and fetal blood streams). Of available hypotheses for the prevalence of histotrophic transfer, the most promising derives insights from the theoretical parent-offspring conflict over nutrient investment. I suggest that histotrophy gives pregnant females greater control over nutrient synthesis, storage, and delivery than hemotrophic transfer, reflecting maternal preeminence in any potential parent-offspring competition over nutrient investment. One lizard species shows invasive ovo-implantation and direct contact between fetal tissues and maternal blood vessels, potentially conferring control over nutrient transfer to the embryo. Future research on squamates will benefit from application of parent-offspring conflict theory to the transition from incipient to substantial matrotrophy, as well as by testing theory-derived predictions on both facultatively and highly placentotrophic forms. © 2015 Wiley Periodicals, Inc.

CFD Based Computations of Flexible Helicopter Blades for Stability Analysis

NASA Technical Reports Server (NTRS)

Guruswamy, Guru P.

2011-01-01

As a collaborative effort among government aerospace research laboratories an advanced version of a widely used computational fluid dynamics code, OVERFLOW, was recently released. This latest version includes additions to model flexible rotating multiple blades. In this paper, the OVERFLOW code is applied to improve the accuracy of airload computations from the linear lifting line theory that uses displacements from beam model. Data transfers required at every revolution are managed through a Unix based script that runs jobs on large super-cluster computers. Results are demonstrated for the 4-bladed UH-60A helicopter. Deviations of computed data from flight data are evaluated. Fourier analysis post-processing that is suitable for aeroelastic stability computations are performed.

Numerical and experimental analysis of fusion offset in splicing photonic crystal fiber with CO2 laser

NASA Astrophysics Data System (ADS)

Jin, Wa; Bi, Weihong; Fu, Guangwei

2014-09-01

Single mode fibers (SMFs) need more fusion energy than PCFs during a splicing process, and it is necessary to make some offsets of the center of heat source toward to the SMFs. Based on the study of characteristics of heat transfer of PCFs and SMFs during splicing process with CO2 laser as the heat source, this paper reports the first systematic analysis of the optimal splicing offset of splicing SMFs and PCFs in theory and experiments. The results show that fusion splicing offsets can be applied to control the air-hole collapse and realize the practical splicing process between PCFs and SMFs with low loss.

Monte Carlo study on pulse response of underwater optical channel

NASA Astrophysics Data System (ADS)

Li, Jing; Ma, Yong; Zhou, Qunqun; Zhou, Bo; Wang, Hongyuan

2012-06-01

Pulse response of the underwater wireless optical channel is significant for the analysis of channel capacity and error probability. Traditional vector radiative transfer theory (VRT) is not able to deal with the effect of receiving aperture. On the other hand, general water tank experiments cannot acquire an accurate pulse response due to the limited time resolution of the photo-electronic detector. We present a Monte Carlo simulation model to extract the time-domain pulse response undersea. In comparison with the VRT model, a more accurate pulse response for practical ocean communications could be achieved through statistical analysis of the received photons. The proposed model is more reasonable for the study of the underwater optical channel.

Enhancing Student Recruitment: A Theory for Understanding and Changing Student Decisions. AIR 1991 Annual Forum Paper.

ERIC Educational Resources Information Center

Pryor, Brandt W.

This paper presents a theoretical discussion of how students make educational behavior decisions including attending a given institution, transferring, or dropping out. The theory is seen to apply to students of all ages and both sexes with implications for all areas of postsecondary education. The theory holds that educational decisions are based…

Midwives׳ decision making about transfers for 'slow' labour in rural New Zealand.

PubMed

Patterson, Jean; Skinner, Joan; Foureur, Maralyn

2015-06-01

Midwives who provided Lead Maternity Care (LMC) to women in rural areas were invited to share their experiences of decision making around transfer in labour. Ethics approval was obtained from the NZ National Ethics Committee. to explore midwives׳ decision making processes when making transfer decisions for slow labour progress from rural areas to specialist care. individual and group interviews were conducted with a purposive sample of rural midwives. The recalled decision processes of the midwives were subjected to a content and thematic analysis to expose experiences in common and to highlight aspects of probabilistic (normative), heuristic (behavioural), and group decision making theory within the rural context. New Zealand. 15 midwives who provided LMC services to women in their rural areas. 'making the mind shift', 'sitting on the boundary', 'timing the transfer' and 'the community interest' emerged as key themes. The decision processes were also influenced by the woman׳s preferences and the distance and time involved in the transfer. the findings contribute insights into the challenge of making transfer decisions in rural units; particularly for otherwise well women who were experiencing slow labour progress. Knowledge of the fallibility of our heuristic decision making strategies may encourage the practitioner to step back and take a more deliberative, probabilistic view of the situation. In addition to the clinical picture, this process should include the relational and aspirational aspects for the woman, and any logistical challenges of the particular rural context. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dynamics of sperm transfer in the ant Leptothorax gredleri

NASA Astrophysics Data System (ADS)

Oppelt, Angelika; Heinze, Jürgen

2007-09-01

Mating tactics differ remarkably between and within species of social Hymenoptera (bees, wasps, ants) concerning, e.g., mating frequencies, sperm competition, and the degree of male sperm limitation. Although social Hymenoptera might, therefore, potentially be ideal model systems for testing sexual selection theory, the dynamics of mating and sperm transfer have rarely been studied in species other than social bees, and basic information needed to draw conclusions about possible sperm competition and female choice is lacking. We investigated sperm transfer in the ant Leptothorax gredleri, a species in which female sexuals attract males by “female calling.” The analysis of 38 female sexuals fixed immediately or up to 7 days after copulation with a single male each revealed that the sperm is transferred into the female bursa copulatrix embedded in a gelatinous mass, presumably a spermatophore. Sperm cells rapidly start to migrate from the tip of the spermatophore towards the spermatheca, but transfer is drastically slowed down by an extreme constriction of the spermathecal duct, through which sperm cells have to pass virtually one by one. This results in the spermatheca being filled only between one and several hours after mating. During this time, the posterior part of the spermatophore seals the junction between bursa copulatrix and spermathecal duct and prevents sperm loss. The prolonged duration of sperm transfer might allow female sexuals to chose between ejaculates and explain previously reported patterns of single paternity of the offspring of multiply mated queens.

The transfer of Crel contextual control (same, opposite, less than, more than) through equivalence relations.

PubMed

Perez, William F; Kovac, Roberta; Nico, Yara C; Caro, Daniel M; Fidalgo, Adriana P; Linares, Ila; de Almeida, João Henrique; de Rose, Júlio C

2017-11-01

According to Relational Frame Theory (RFT) C rel denotes a contextual stimulus that controls a particular type of relational response (sameness, opposition, comparative, temporal, hierarchical etc.) in a given situation. Previous studies suggest that contextual functions may be indirectly acquired via transfer of function. The present study investigated the transfer of C rel contextual control through equivalence relations. Experiment 1 evaluated the transfer of C rel contextual functions for relational responses based on sameness and opposition. Experiment 2 extended these findings by evaluating transfer of function using comparative C rel stimuli. Both experiments followed a similar sequence of phases. First, abstract forms were established as C rel stimuli via multiple exemplar training (Phase 1). The contextual cues were then applied to establish arbitrary relations among nonsense words and to test derived relations (Phase 2). After that, equivalence relations involving the original C rel stimuli and other abstract forms were trained and tested (Phase 3). Transfer of function was evaluated by replacing the directly established C rel stimuli with their equivalent stimuli in the former experimental tasks (Phases 1 and 2). Results from both experiments suggest that C rel contextual control may be extended via equivalence relations, allowing other arbitrarily related stimuli to indirectly acquire C rel functions and regulate behavior by evoking appropriate relational responses in the presence of both previously known and novel stimuli. © 2017 Society for the Experimental Analysis of Behavior.

Electronic energy transfer through non-adiabatic vibrational-electronic resonance. I. Theory for a dimer

NASA Astrophysics Data System (ADS)

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

2017-10-01

Non-adiabatic vibrational-electronic resonance in the excited electronic states of natural photosynthetic antennas drastically alters the adiabatic framework, in which electronic energy transfer has been conventionally studied, and suggests the possibility of exploiting non-adiabatic dynamics for directed energy transfer. Here, a generalized dimer model incorporates asymmetries between pigments, coupling to the environment, and the doubly excited state relevant for nonlinear spectroscopy. For this generalized dimer model, the vibrational tuning vector that drives energy transfer is derived and connected to decoherence between singly excited states. A correlation vector is connected to decoherence between the ground state and the doubly excited state. Optical decoherence between the ground and singly excited states involves linear combinations of the correlation and tuning vectors. Excitonic coupling modifies the tuning vector. The correlation and tuning vectors are not always orthogonal, and both can be asymmetric under pigment exchange, which affects energy transfer. For equal pigment vibrational frequencies, the nonadiabatic tuning vector becomes an anti-correlated delocalized linear combination of intramolecular vibrations of the two pigments, and the nonadiabatic energy transfer dynamics become separable. With exchange symmetry, the correlation and tuning vectors become delocalized intramolecular vibrations that are symmetric and antisymmetric under pigment exchange. Diabatic criteria for vibrational-excitonic resonance demonstrate that anti-correlated vibrations increase the range and speed of vibronically resonant energy transfer (the Golden Rule rate is a factor of 2 faster). A partial trace analysis shows that vibronic decoherence for a vibrational-excitonic resonance between two excitons is slower than their purely excitonic decoherence.

Using dual-process theory and analogical transfer to explain facilitation on a hypothetico-deductive reasoning task.

PubMed

Koenig, Cynthia S; Platt, Richard D; Griggs, Richard A

2007-07-01

Using the analogical transfer paradigm, the present study investigated the competing explanations of Girotto and Legrenzi (Psychological Research 51: 129-135, 1993) and Griggs, Platt, Newstead, and Jackson (Thinking and Reasoning 4: 1-14, 1998) for facilitation on the SARS version of the THOG problem, a hypothetico-deductive reasoning task. Girotto and Legrenzi argue that facilitation is based on logical analysis of the task [System 2 reasoning in Evans's (Trends in Cognitive Sciences 7: 454-459, 2003) dual-process account of reasoning] while Griggs et al. maintain that facilitation is due to an attentional heuristic produced by the wording of the problem (System 1 reasoning). If Girotto and Legrenzi are correct, then System 2 reasoning, which is volitional and responsible for deductive reasoning, should be elicited, and participants should comprehend the solution principle of the THOG task and exhibit analogical transfer. However, if Griggs et al. are correct, then System 1 reasoning, which is responsible for heuristic problem solving strategies such as an attentional heuristic, should occur, and participants should not abstract the solution principle and transfer should not occur. Significant facilitation (68 and 82% correct) was only observed for the two SARS source problems, but significant analogical transfer did not occur. This lack of transfer suggests that System 1 reasoning was responsible for the facilitation observed in the SARS problem, supporting Griggs et al.'s attentional heuristic explanation. The present results also underscore the explanatory value of using analogical transfer rather than facilitation as the criterion for problem understanding.

Electronic energy transfer through non-adiabatic vibrational-electronic resonance. I. Theory for a dimer.

PubMed

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

2017-10-21

Non-adiabatic vibrational-electronic resonance in the excited electronic states of natural photosynthetic antennas drastically alters the adiabatic framework, in which electronic energy transfer has been conventionally studied, and suggests the possibility of exploiting non-adiabatic dynamics for directed energy transfer. Here, a generalized dimer model incorporates asymmetries between pigments, coupling to the environment, and the doubly excited state relevant for nonlinear spectroscopy. For this generalized dimer model, the vibrational tuning vector that drives energy transfer is derived and connected to decoherence between singly excited states. A correlation vector is connected to decoherence between the ground state and the doubly excited state. Optical decoherence between the ground and singly excited states involves linear combinations of the correlation and tuning vectors. Excitonic coupling modifies the tuning vector. The correlation and tuning vectors are not always orthogonal, and both can be asymmetric under pigment exchange, which affects energy transfer. For equal pigment vibrational frequencies, the nonadiabatic tuning vector becomes an anti-correlated delocalized linear combination of intramolecular vibrations of the two pigments, and the nonadiabatic energy transfer dynamics become separable. With exchange symmetry, the correlation and tuning vectors become delocalized intramolecular vibrations that are symmetric and antisymmetric under pigment exchange. Diabatic criteria for vibrational-excitonic resonance demonstrate that anti-correlated vibrations increase the range and speed of vibronically resonant energy transfer (the Golden Rule rate is a factor of 2 faster). A partial trace analysis shows that vibronic decoherence for a vibrational-excitonic resonance between two excitons is slower than their purely excitonic decoherence.

Open-Circuit Voltage Losses in Selenium-Substituted Organic Photovoltaic Devices from Increased Density of Charge-Transfer States

DOE PAGES

Sulas, Dana B.; Yao, Kai; Intemann, Jeremy J.; ...

2015-09-12

Using an analysis based on Marcus theory, we characterize losses in open-circuit voltage (V OC) due to changes in charge-transfer state energy, electronic coupling, and spatial density of charge-transfer states in a series of polymer/fullerene solar cells. Here, we use a series of indacenodithiophene polymers and their selenium-substituted analogs as electron donor materials and fullerenes as the acceptors. By combining device measurements and spectroscopic studies (including subgap photocurrent, electroluminescence, and, importantly, time-resolved photoluminescence of the charge-transfer state) we are able to isolate the values for electronic coupling and the density of charge-transfer states (NCT), rather than the more commonly measuredmore » product of these values. We find values for NCT that are surprisingly large (~4.5 × 10 21–6.2 × 10 22 cm -3), and we find that a significant increase in N CT upon selenium substitution in donor polymers correlates with lower VOC for bulk heterojunction photovoltaic devices. The increase in N CT upon selenium substitution is also consistent with nanoscale morphological characterization. Using transmission electron microscopy, selected area electron diffraction, and grazing incidence wide-angle X-ray scattering, we find evidence of more intermixed polymer and fullerene domains in the selenophene blends, which have higher densities of polymer/fullerene interfacial charge-transfer states. Our results provide an important step toward understanding the spatial nature of charge-transfer states and their effect on the open-circuit voltage of polymer/fullerene solar cells« less

Tunneling induced electron transfer between separated protons

NASA Astrophysics Data System (ADS)

Vindel-Zandbergen, Patricia; Meier, Christoph; Sola, Ignacio R.

2018-04-01

We study electron transfer between two separated protons using local control theory. In this symmetric system one can favour a slow transfer by biasing the algorithm, achieving high efficiencies for fixed nuclei. The solution can be parametrized using a sequence of a pump followed by a dump pulse that lead to tunneling-induced electron transfer. Finally, we study the effect of the nuclear kinetic energy on the efficiency. Even in the absence of relative motion between the protons, the spreading of the nuclear wave function is enough to reduce the yield of electronic transfer to less than one half.

Stagnation-point Heat Transfer to Blunt Shapes in Hypersonic Flight, Including Effects of Yaw

NASA Technical Reports Server (NTRS)

Eggers, A J , Jr; Hansen, C Frederick; Cunningham, Bernard E

1958-01-01

An approximate theory is developed for predicting the rate of heat transfer to the stagnation region of blunt bodies in hypersonic flight. Attention is focused on the case where wall temperature is small compared to stagnation temperature. The theoretical heat-transfer rate at the stagnation point of a hemispherical body is found to agree with available experimental data. The effect of yaw on heat transfer to a cylindrical stagnation region is treated at some length, and it is predicted that large yaw should cause sizable reductions in heat-transfer rate.